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Sample records for duplicated gene family

  1. Predictions of Gene Family Distributions in Microbial Genomes: Evolution by Gene Duplication and Modification

    NASA Astrophysics Data System (ADS)

    Yanai, Itai; Camacho, Carlos J.; Delisi, Charles

    2000-09-01

    A universal property of microbial genomes is the considerable fraction of genes that are homologous to other genes within the same genome. The process by which these homologues are generated is not well understood, but sequence analysis of 20 microbial genomes unveils a recurrent distribution of gene family sizes. We show that a simple evolutionary model based on random gene duplication and point mutations fully accounts for these distributions and permits predictions for the number of gene families in genomes not yet complete. Our findings are consistent with the notion that a genome evolves from a set of precursor genes to a mature size by gene duplications and increasing modifications.

  2. Genome-Wide Analysis of Homeobox Gene Family in Legumes: Identification, Gene Duplication and Expression Profiling

    PubMed Central

    Garg, Rohini; Jain, Mukesh

    2015-01-01

    Homeobox genes encode transcription factors that are known to play a major role in different aspects of plant growth and development. In the present study, we identified homeobox genes belonging to 14 different classes in five legume species, including chickpea, soybean, Medicago, Lotus and pigeonpea. The characteristic differences within homeodomain sequences among various classes of homeobox gene family were quite evident. Genome-wide expression analysis using publicly available datasets (RNA-seq and microarray) indicated that homeobox genes are differentially expressed in various tissues/developmental stages and under stress conditions in different legumes. We validated the differential expression of selected chickpea homeobox genes via quantitative reverse transcription polymerase chain reaction. Genome duplication analysis in soybean indicated that segmental duplication has significantly contributed in the expansion of homeobox gene family. The Ka/Ks ratio of duplicated homeobox genes in soybean showed that several members of this family have undergone purifying selection. Moreover, expression profiling indicated that duplicated genes might have been retained due to sub-functionalization. The genome-wide identification and comprehensive gene expression profiling of homeobox gene family members in legumes will provide opportunities for functional analysis to unravel their exact role in plant growth and development. PMID:25745864

  3. Genome-wide analysis of homeobox gene family in legumes: identification, gene duplication and expression profiling.

    PubMed

    Bhattacharjee, Annapurna; Ghangal, Rajesh; Garg, Rohini; Jain, Mukesh

    2015-01-01

    Homeobox genes encode transcription factors that are known to play a major role in different aspects of plant growth and development. In the present study, we identified homeobox genes belonging to 14 different classes in five legume species, including chickpea, soybean, Medicago, Lotus and pigeonpea. The characteristic differences within homeodomain sequences among various classes of homeobox gene family were quite evident. Genome-wide expression analysis using publicly available datasets (RNA-seq and microarray) indicated that homeobox genes are differentially expressed in various tissues/developmental stages and under stress conditions in different legumes. We validated the differential expression of selected chickpea homeobox genes via quantitative reverse transcription polymerase chain reaction. Genome duplication analysis in soybean indicated that segmental duplication has significantly contributed in the expansion of homeobox gene family. The Ka/Ks ratio of duplicated homeobox genes in soybean showed that several members of this family have undergone purifying selection. Moreover, expression profiling indicated that duplicated genes might have been retained due to sub-functionalization. The genome-wide identification and comprehensive gene expression profiling of homeobox gene family members in legumes will provide opportunities for functional analysis to unravel their exact role in plant growth and development.

  4. Predictions of Gene Family Distributions in Microbial Genomes: Evolution by Gene Duplication and Modification

    SciTech Connect

    Yanai, Itai; Camacho, Carlos J.; DeLisi, Charles

    2000-09-18

    A universal property of microbial genomes is the considerable fraction of genes that are homologous to other genes within the same genome. The process by which these homologues are generated is not well understood, but sequence analysis of 20 microbial genomes unveils a recurrent distribution of gene family sizes. We show that a simple evolutionary model based on random gene duplication and point mutations fully accounts for these distributions and permits predictions for the number of gene families in genomes not yet complete. Our findings are consistent with the notion that a genome evolves from a set of precursor genes to a mature size by gene duplications and increasing modifications. (c) 2000 The American Physical Society.

  5. Duplication of OsHAP family genes and their association with heading date in rice.

    PubMed

    Li, Qiuping; Yan, Wenhao; Chen, Huaxia; Tan, Cong; Han, Zhongmin; Yao, Wen; Li, Guangwei; Yuan, Mengqi; Xing, Yongzhong

    2016-03-01

    Heterotrimeric Heme Activator Protein (HAP) family genes are involved in the regulation of flowering in plants. It is not clear how many HAP genes regulate heading date in rice. In this study, we identified 35 HAP genes, including seven newly identified genes, and performed gene duplication and candidate gene-based association analyses. Analyses showed that segmental duplication and tandem duplication are the main mechanisms of HAP gene duplication. Expression profiling and functional identification indicated that duplication probably diversifies the functions of HAP genes. A nucleotide diversity analysis revealed that 13 HAP genes underwent selection. A candidate gene-based association analysis detected four HAP genes related to heading date. An investigation of transgenic plants or mutants of 23 HAP genes confirmed that overexpression of at least four genes delayed heading date under long-day conditions, including the previously cloned Ghd8/OsHAP3H. Our results indicate that the large number of HAP genes in rice was mainly produced by gene duplication, and a few HAP genes function to regulate heading date. Selection of HAP genes is probably caused by their diverse functions rather than regulation of heading.

  6. Extensive and continuous duplication facilitates rapid evolution and diversification of gene families.

    PubMed

    Chang, Dan; Duda, Thomas F

    2012-08-01

    The origin of novel gene functions through gene duplication, mutation, and natural selection represents one of the mechanisms by which organisms diversify and one of the possible paths leading to adaptation. Nonetheless, the extent, role, and consequences of duplications in the origins of ecological adaptations, especially in the context of species interactions, remain unclear. To explore the evolution of a gene family that is likely linked to species associations, we investigated the evolutionary history of the A-superfamily of conotoxin genes of predatory marine cone snails (Conus species). Members of this gene family are expressed in the venoms of Conus species and are presumably involved in predator-prey associations because of their utility in prey capture. We recovered sequences of this gene family from genomic DNA of four closely related species of Conus and reconstructed the evolutionary history of these genes. Our study is the first to directly recover conotoxin genes from Conus genomes to investigate the evolution of conotoxin gene families. Our results revealed a phenomenon of rapid and continuous gene turnover that is coupled with heightened rates of evolution. This continuous duplication pattern has not been observed previously, and the rate of gene turnover is at least two times higher than estimates from other multigene families. Conotoxin genes are among the most rapidly evolving protein-coding genes in metazoans, a phenomenon that may be facilitated by extensive gene duplications and have driven changes in conotoxin functions through neofunctionalization. Together these mechanisms led to dramatically divergent arrangements of A-superfamily conotoxin genes among closely related species of Conus. Our findings suggest that extensive and continuous gene duplication facilitates rapid evolution and drastic divergence in venom compositions among species, processes that may be associated with evolutionary responses to predator-prey interactions.

  7. Gene duplications and losses within the cyclooxygenase family of teleosts and other chordates.

    PubMed

    Havird, Justin C; Miyamoto, Michael M; Choe, Keith P; Evans, David H

    2008-11-01

    Cyclooxygenase (COX) produces prostaglandins in animals via the oxidation and reduction of arachidonic acid. Different types and numbers of COX genes have been found in corals, sea squirts, fishes, and tetrapods, but no study has used a comparative phylogenetic approach to investigate the evolutionary history of this complex gene family. Therefore, to examine COX evolution in the teleosts and chordates, 9 novel COX sequences (possessing residues and domains critical to COX function) were acquired from the euryhaline killifish, longhorn sculpin, sea lamprey, Atlantic hagfish, and amphioxus using standard polymerase chain reaction (PCR) and cloning methods. Phylogenetic analyses of these and other COX sequences show a complicated history of COX duplications and losses. There are three main lineages of COX in the chordates corresponding to the three subphyla in the phylum Chordata, with each lineage representing an independent COX duplication. Hagfish and lamprey most likely have traditional COX-1/2 genes, suggesting that these genes originated with the first round of genome duplication in the vertebrates according to the 2R hypothesis and are not exclusively present in the gnathostomes. All teleosts examined have three COX genes due to a teleost-specific genome duplication followed by variable loss of a COX-1 (in the zebrafish and rainbow trout) or COX-2 gene (in the derived teleosts). Future studies should examine the functional ramifications of these differential gene losses.

  8. Duplications and losses in gene families of rust pathogens highlight putative effectors

    PubMed Central

    Pendleton, Amanda L.; Smith, Katherine E.; Feau, Nicolas; Martin, Francis M.; Grigoriev, Igor V.; Hamelin, Richard; Nelson, C. Dana; Burleigh, J. Gordon; Davis, John M.

    2014-01-01

    Rust fungi are a group of fungal pathogens that cause some of the world's most destructive diseases of trees and crops. A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen genomes. The establishment of disease by biotrophic pathogens is reliant upon effector proteins that are encoded in the fungal genome and secreted from the pathogen into the host's cell apoplast or within the cells. This study uses a comparative genomic approach to elucidate putative effectors and determine their evolutionary histories. We used OrthoMCL to identify nearly 20,000 gene families in proteomes of 16 diverse fungal species, which include 15 basidiomycetes and one ascomycete. We inferred patterns of duplication and loss for each gene family and identified families with distinctive patterns of expansion/contraction associated with the evolution of rust fungal genomes. To recognize potential contributors for the unique features of rust pathogens, we identified families harboring secreted proteins that: (i) arose or expanded in rust pathogens relative to other fungi, or (ii) contracted or were lost in rust fungal genomes. While the origin of rust fungi appears to be associated with considerable gene loss, there are many gene duplications associated with each sampled rust fungal genome. We also highlight two putative effector gene families that have expanded in Cqf that we hypothesize have roles in pathogenicity. PMID:25018762

  9. Convergent gene loss following gene and genome duplications creates single-copy families in flowering plants.

    PubMed

    De Smet, Riet; Adams, Keith L; Vandepoele, Klaas; Van Montagu, Marc C E; Maere, Steven; Van de Peer, Yves

    2013-02-19

    The importance of gene gain through duplication has long been appreciated. In contrast, the importance of gene loss has only recently attracted attention. Indeed, studies in organisms ranging from plants to worms and humans suggest that duplication of some genes might be better tolerated than that of others. Here we have undertaken a large-scale study to investigate the existence of duplication-resistant genes in the sequenced genomes of 20 flowering plants. We demonstrate that there is a large set of genes that is convergently restored to single-copy status following multiple genome-wide and smaller scale duplication events. We rule out the possibility that such a pattern could be explained by random gene loss only and therefore propose that there is selection pressure to preserve such genes as singletons. This is further substantiated by the observation that angiosperm single-copy genes do not comprise a random fraction of the genome, but instead are often involved in essential housekeeping functions that are highly conserved across all eukaryotes. Furthermore, single-copy genes are generally expressed more highly and in more tissues than non-single-copy genes, and they exhibit higher sequence conservation. Finally, we propose different hypotheses to explain their resistance against duplication.

  10. Age distribution of human gene families shows significant roles of both large- and small-scale duplications in vertebrate evolution.

    PubMed

    Gu, Xun; Wang, Yufeng; Gu, Jianying

    2002-06-01

    The classical (two-round) hypothesis of vertebrate genome duplication proposes two successive whole-genome duplication(s) (polyploidizations) predating the origin of fishes, a view now being seriously challenged. As the debate largely concerns the relative merits of the 'big-bang mode' theory (large-scale duplication) and the 'continuous mode' theory (constant creation by small-scale duplications), we tested whether a significant proportion of paralogous genes in the contemporary human genome was indeed generated in the early stage of vertebrate evolution. After an extensive search of major databases, we dated 1,739 gene duplication events from the phylogenetic analysis of 749 vertebrate gene families. We found a pattern characterized by two waves (I, II) and an ancient component. Wave I represents a recent gene family expansion by tandem or segmental duplications, whereas wave II, a rapid paralogous gene increase in the early stage of vertebrate evolution, supports the idea of genome duplication(s) (the big-bang mode). Further analysis indicated that large- and small-scale gene duplications both make a significant contribution during the early stage of vertebrate evolution to build the current hierarchy of the human proteome.

  11. Importance of gene duplication in the evolution of genomic imprinting revealed by molecular evolutionary analysis of the type I MADS-box gene family in Arabidopsis species.

    PubMed

    Yoshida, Takanori; Kawabe, Akira

    2013-01-01

    The pattern of molecular evolution of imprinted genes is controversial and the entire picture is still to be unveiled. Recently, a relationship between the formation of imprinted genes and gene duplication was reported in genome-wide survey of imprinted genes in Arabidopsis thaliana. Because gene duplications influence the molecular evolution of the duplicated gene family, it is necessary to investigate both the pattern of molecular evolution and the possible relationship between gene duplication and genomic imprinting for a better understanding of evolutionary aspects of imprinted genes. In this study, we investigated the evolutionary changes of type I MADS-box genes that include imprinted genes by using relative species of Arabidopsis thaliana (two subspecies of A. lyrata and three subspecies of A. halleri). A duplicated gene family enables us to compare DNA sequences between imprinted genes and its homologs. We found an increased number of gene duplications within species in clades containing the imprinted genes, further supporting the hypothesis that local gene duplication is one of the driving forces for the formation of imprinted genes. Moreover, data obtained by phylogenetic analysis suggested "rapid evolution" of not only imprinted genes but also its closely related orthologous genes, which implies the effect of gene duplication on molecular evolution of imprinted genes.

  12. bMERB domains are bivalent Rab8 family effectors evolved by gene duplication.

    PubMed

    Rai, Amrita; Oprisko, Anastasia; Campos, Jeremy; Fu, Yangxue; Friese, Timon; Itzen, Aymelt; Goody, Roger S; Gazdag, Emerich Mihai; Müller, Matthias P

    2016-08-23

    In their active GTP-bound form, Rab proteins interact with proteins termed effector molecules. In this study, we have thoroughly characterized a Rab effector domain that is present in proteins of the Mical and EHBP families, both known to act in endosomal trafficking. Within our study, we show that these effectors display a preference for Rab8 family proteins (Rab8, 10, 13 and 15) and that some of the effector domains can bind two Rab proteins via separate binding sites. Structural analysis allowed us to explain the specificity towards Rab8 family members and the presence of two similar Rab binding sites that must have evolved via gene duplication. This study is the first to thoroughly characterize a Rab effector protein that contains two separate Rab binding sites within a single domain, allowing Micals and EHBPs to bind two Rabs simultaneously, thus suggesting previously unknown functions of these effector molecules in endosomal trafficking.

  13. Evolution of the KCS gene family in plants: the history of gene duplication, sub/neofunctionalization and redundancy.

    PubMed

    Guo, Hai-Song; Zhang, Yan-Mei; Sun, Xiao-Qin; Li, Mi-Mi; Hang, Yue-Yu; Xue, Jia-Yu

    2016-04-01

    Very long-chain fatty acids (VLCFAs) play an important role in the survival and development of plants, and VLCFA synthesis is regulated by β-ketoacyl-CoA synthases (KCSs), which catalyze the condensation of an acyl-CoA with malonyl-CoA. Here, we present a genome-wide survey of the genes encoding these enzymes, KCS genes, in 28 species (26 genomes and two transcriptomes), which represents a large phylogenetic scale, and also reconstruct the evolutionary history of this gene family. KCS genes were initially single-copy genes in the green plant lineage; duplication resulted in five ancestral copies in land plants, forming five fundamental monophyletic groups in the phylogenetic tree. Subsequently, KCS genes duplicated to generate 11 genes of angiosperm origin, expanding up to 20-30 members in further-diverged angiosperm species. During this process, tandem duplications had only a small contribution, whereas polyploidy events and large-scale segmental duplications appear to be the main driving force. Accompanying this expansion were variations that led to the sub- and neofunctionalization of different members, resulting in specificity that is likely determined by the 3-D protein structure. Novel functions involved in other physiological processes emerged as well, though redundancy is also observed, largely among recent duplications. Conserved sites and variable sites of KCS proteins are also identified by statistical analysis. The variable sites are likely to be involved in the emergence of product specificity and catalytic power, and conserved sites are possibly responsible for the preservation of fundamental function.

  14. Structure of Mycobacterium tuberculosis Rv2714, a representative of a duplicated gene family in Actinobacteria

    PubMed Central

    Graña, Martin; Bellinzoni, Marco; Miras, Isabelle; Fiez-Vandal, Cedric; Haouz, Ahmed; Shepard, William; Buschiazzo, Alejandro; Alzari, Pedro M.

    2009-01-01

    The gene Rv2714 from Mycobacterium tuberculosis, which codes for a hypothetical protein of unknown function, is a representative member of a gene family that is largely confined to the order Actinomycetales of Actinobacteria. Sequence analysis indicates the presence of two paralogous genes in most mycobacterial genomes and suggests that gene duplication was an ancient event in bacterial evolution. The crystal structure of Rv2714 has been determined at 2.6 Å resolution, revealing a trimer in which the topology of the protomer core is similar to that observed in a functionally diverse set of enzymes, including purine nucleoside phosphorylases, some carboxypeptidases, bacterial peptidyl-tRNA hydrolases and even the plastidic form of an intron splicing factor. However, some structural elements, such as a β-hairpin insertion involved in protein oligomerization and a C-terminal α-helical domain that serves as a lid to the putative substrate-binding (or ligand-binding) site, are only found in Rv2714 bacterial homologues and represent specific signatures of this protein family. PMID:19851001

  15. bMERB domains are bivalent Rab8 family effectors evolved by gene duplication

    PubMed Central

    Rai, Amrita; Oprisko, Anastasia; Campos, Jeremy; Fu, Yangxue; Friese, Timon; Itzen, Aymelt; Goody, Roger S; Gazdag, Emerich Mihai; Müller, Matthias P

    2016-01-01

    In their active GTP-bound form, Rab proteins interact with proteins termed effector molecules. In this study, we have thoroughly characterized a Rab effector domain that is present in proteins of the Mical and EHBP families, both known to act in endosomal trafficking. Within our study, we show that these effectors display a preference for Rab8 family proteins (Rab8, 10, 13 and 15) and that some of the effector domains can bind two Rab proteins via separate binding sites. Structural analysis allowed us to explain the specificity towards Rab8 family members and the presence of two similar Rab binding sites that must have evolved via gene duplication. This study is the first to thoroughly characterize a Rab effector protein that contains two separate Rab binding sites within a single domain, allowing Micals and EHBPs to bind two Rabs simultaneously, thus suggesting previously unknown functions of these effector molecules in endosomal trafficking. DOI: http://dx.doi.org/10.7554/eLife.18675.001 PMID:27552051

  16. Genome-wide analysis of the Dof transcription factor gene family reveals soybean-specific duplicable and functional characteristics.

    PubMed

    Guo, Yong; Qiu, Li-Juan

    2013-01-01

    The Dof domain protein family is a classic plant-specific zinc-finger transcription factor family involved in a variety of biological processes. There is great diversity in the number of Dof genes in different plants. However, there are only very limited reports on the characterization of Dof transcription factors in soybean (Glycine max). In the present study, 78 putative Dof genes were identified from the whole-genome sequence of soybean. The predicted GmDof genes were non-randomly distributed within and across 19 out of 20 chromosomes and 97.4% (38 pairs) were preferentially retained duplicate paralogous genes located in duplicated regions of the genome. Soybean-specific segmental duplications contributed significantly to the expansion of the soybean Dof gene family. These Dof proteins were phylogenetically clustered into nine distinct subgroups among which the gene structure and motif compositions were considerably conserved. Comparative phylogenetic analysis of these Dof proteins revealed four major groups, similar to those reported for Arabidopsis and rice. Most of the GmDofs showed specific expression patterns based on RNA-seq data analyses. The expression patterns of some duplicate genes were partially redundant while others showed functional diversity, suggesting the occurrence of sub-functionalization during subsequent evolution. Comprehensive expression profile analysis also provided insights into the soybean-specific functional divergence among members of the Dof gene family. Cis-regulatory element analysis of these GmDof genes suggested diverse functions associated with different processes. Taken together, our results provide useful information for the functional characterization of soybean Dof genes by combining phylogenetic analysis with global gene-expression profiling.

  17. Divergence of the Dof gene families in poplar, Arabidopsis, and rice suggests multiple modes of gene evolution after duplication.

    PubMed

    Yang, Xiaohan; Tuskan, Gerald A; Cheng, Max Zong-Ming

    2006-11-01

    It is widely accepted that gene duplication is a primary source of genetic novelty. However, the evolutionary fate of duplicated genes remains largely unresolved. The classical Ohno's Duplication-Retention-Non/Neofunctionalization theory, and the recently proposed alternatives such as subfunctionalization or duplication-degeneration-complementation, and subneofunctionalization, each can explain one or more aspects of gene fate after duplication. Duplicated genes are also affected by epigenetic changes. We constructed a phylogenetic tree using Dof (DNA binding with one finger) protein sequences from poplar (Populus trichocarpa) Torr. & Gray ex Brayshaw, Arabidopsis (Arabidopsis thaliana), and rice (Oryza sativa). From the phylogenetic tree, we identified 27 pairs of paralogous Dof genes in the terminal nodes. Analysis of protein motif structure of the Dof paralogs and their ancestors revealed six different gene fates after gene duplication. Differential protein methylation was revealed between a pair of duplicated poplar Dof genes, which have identical motif structure and similar expression pattern, indicating that epigenetics is involved in evolution. Analysis of reverse transcription-PCR, massively parallel signature sequencing, and microarray data revealed that the paralogs differ in expression pattern. Furthermore, analysis of nonsynonymous and synonymous substitution rates indicated that divergence of the duplicated genes was driven by positive selection. About one-half of the motifs in Dof proteins were shared by non-Dof proteins in the three plants species, indicating that motif co-option may be one of the forces driving gene diversification. We provided evidence that the Ohno's Duplication-Retention-Non/Neofunctionalization, subfunctionalization/duplication-degeneration-complementation, and subneofunctionalization hypotheses are complementary with, not alternative to, each other.

  18. Tubulin evolution in insects: gene duplication and subfunctionalization provide specialized isoforms in a functionally constrained gene family

    PubMed Central

    2010-01-01

    Background The completion of 19 insect genome sequencing projects spanning six insect orders provides the opportunity to investigate the evolution of important gene families, here tubulins. Tubulins are a family of eukaryotic structural genes that form microtubules, fundamental components of the cytoskeleton that mediate cell division, shape, motility, and intracellular trafficking. Previous in vivo studies in Drosophila find a stringent relationship between tubulin structure and function; small, biochemically similar changes in the major alpha 1 or testis-specific beta 2 tubulin protein render each unable to generate a motile spermtail axoneme. This has evolutionary implications, not a single non-synonymous substitution is found in beta 2 among 17 species of Drosophila and Hirtodrosophila flies spanning 60 Myr of evolution. This raises an important question, How do tubulins evolve while maintaining their function? To answer, we use molecular evolutionary analyses to characterize the evolution of insect tubulins. Results Sixty-six alpha tubulins and eighty-six beta tubulin gene copies were retrieved and subjected to molecular evolutionary analyses. Four ancient clades of alpha and beta tubulins are found in insects, a major isoform clade (alpha 1, beta 1) and three minor, tissue-specific clades (alpha 2-4, beta 2-4). Based on a Homarus americanus (lobster) outgroup, these were generated through gene duplication events on major beta and alpha tubulin ancestors, followed by subfunctionalization in expression domain. Strong purifying selection acts on all tubulins, yet maximum pairwise amino acid distances between tubulin paralogs are large (0.464 substitutions/site beta tubulins, 0.707 alpha tubulins). Conversely orthologs, with the exception of reproductive tissue isoforms, show little sequence variation except in the last 15 carboxy terminus tail (CTT) residues, which serve as sites for post-translational modifications (PTMs) and interactions with microtubule

  19. Diversification of the light-harvesting complex gene family via intra- and intergenic duplications in the coral symbiotic alga Symbiodinium.

    PubMed

    Maruyama, Shinichiro; Shoguchi, Eiichi; Satoh, Nori; Minagawa, Jun

    2015-01-01

    The light-harvesting complex (LHC) is an essential component in light energy capture and transduction to facilitate downstream photosynthetic reactions in plant and algal chloroplasts. The unicellular dinoflagellate alga Symbiodinium is an endosymbiont of cnidarian animals, including corals and sea anemones, and provides carbohydrates generated through photosynthesis to host animals. Although Symbiodinium possesses a unique LHC gene family, called chlorophyll a-chlorophyll c2-peridinin protein complex (acpPC), its genome-level diversity and evolutionary trajectories have not been investigated. Here, we describe a phylogenetic analysis revealing that many of the LHCs are encoded by highly duplicated genes with multi-subunit polyprotein structures in the nuclear genome of Symbiodinium minutum. This analysis provides an extended list of the LHC gene family in a single organism, including 80 loci encoding polyproteins composed of 145 LHC subunits recovered in the phylogenetic tree. In S. minutum, 5 phylogenetic groups of the Lhcf-type gene family, which is exclusively conserved in algae harboring secondary plastids of red algal origin, were identified. Moreover, 5 groups of the Lhcr-type gene family, of which members are known to be associated with PSI in red algal plastids and secondary plastids of red algal origin, were identified. Notably, members classified within a phylogenetic group of the Lhcf-type (group F1) are highly duplicated, which may explain the presence of an unusually large number of LHC genes in this species. Some gene units were homologous to other units within single loci of the polyprotein genes, whereas intergenic homologies between separate loci were conspicuous in other cases, implying that gene unit 'shuffling' by gene conversion and/or genome rearrangement might have been a driving force for diversification. These results suggest that vigorous intra- and intergenic gene duplication events have resulted in the genomic framework of

  20. Tandem Duplication Events in the Expansion of the Small Heat Shock Protein Gene Family in Solanum lycopersicum (cv. Heinz 1706).

    PubMed

    Krsticevic, Flavia J; Arce, Débora P; Ezpeleta, Joaquín; Tapia, Elizabeth

    2016-10-13

    In plants, fruit maturation and oxidative stress can induce small heat shock protein (sHSP) synthesis to maintain cellular homeostasis. Although the tomato reference genome was published in 2012, the actual number and functionality of sHSP genes remain unknown. Using a transcriptomic (RNA-seq) and evolutionary genomic approach, putative sHSP genes in the Solanum lycopersicum (cv. Heinz 1706) genome were investigated. A sHSP gene family of 33 members was established. Remarkably, roughly half of the members of this family can be explained by nine independent tandem duplication events that determined, evolutionarily, their functional fates. Within a mitochondrial class subfamily, only one duplicated member, Solyc08g078700, retained its ancestral chaperone function, while the others, Solyc08g078710 and Solyc08g078720, likely degenerated under neutrality and lack ancestral chaperone function. Functional conservation occurred within a cytosolic class I subfamily, whose four members, Solyc06g076570, Solyc06g076560, Solyc06g076540, and Solyc06g076520, support ∼57% of the total sHSP RNAm in the red ripe fruit. Subfunctionalization occurred within a new subfamily, whose two members, Solyc04g082720 and Solyc04g082740, show heterogeneous differential expression profiles during fruit ripening. These findings, involving the birth/death of some genes or the preferential/plastic expression of some others during fruit ripening, highlight the importance of tandem duplication events in the expansion of the sHSP gene family in the tomato genome. Despite its evolutionary diversity, the sHSP gene family in the tomato genome seems to be endowed with a core set of four homeostasis genes: Solyc05g014280, Solyc03g082420, Solyc11g020330, and Solyc06g076560, which appear to provide a baseline protection during both fruit ripening and heat shock stress in different tomato tissues.

  1. Tandem Duplication Events in the Expansion of the Small Heat Shock Protein Gene Family in Solanum lycopersicum (cv. Heinz 1706)

    PubMed Central

    Krsticevic, Flavia J.; Arce, Débora P.; Ezpeleta, Joaquín; Tapia, Elizabeth

    2016-01-01

    In plants, fruit maturation and oxidative stress can induce small heat shock protein (sHSP) synthesis to maintain cellular homeostasis. Although the tomato reference genome was published in 2012, the actual number and functionality of sHSP genes remain unknown. Using a transcriptomic (RNA-seq) and evolutionary genomic approach, putative sHSP genes in the Solanum lycopersicum (cv. Heinz 1706) genome were investigated. A sHSP gene family of 33 members was established. Remarkably, roughly half of the members of this family can be explained by nine independent tandem duplication events that determined, evolutionarily, their functional fates. Within a mitochondrial class subfamily, only one duplicated member, Solyc08g078700, retained its ancestral chaperone function, while the others, Solyc08g078710 and Solyc08g078720, likely degenerated under neutrality and lack ancestral chaperone function. Functional conservation occurred within a cytosolic class I subfamily, whose four members, Solyc06g076570, Solyc06g076560, Solyc06g076540, and Solyc06g076520, support ∼57% of the total sHSP RNAm in the red ripe fruit. Subfunctionalization occurred within a new subfamily, whose two members, Solyc04g082720 and Solyc04g082740, show heterogeneous differential expression profiles during fruit ripening. These findings, involving the birth/death of some genes or the preferential/plastic expression of some others during fruit ripening, highlight the importance of tandem duplication events in the expansion of the sHSP gene family in the tomato genome. Despite its evolutionary diversity, the sHSP gene family in the tomato genome seems to be endowed with a core set of four homeostasis genes: Solyc05g014280, Solyc03g082420, Solyc11g020330, and Solyc06g076560, which appear to provide a baseline protection during both fruit ripening and heat shock stress in different tomato tissues. PMID:27565886

  2. The fate of tandemly duplicated genes assessed by the expression analysis of a group of Arabidopsis thaliana RING-H2 ubiquitin ligase genes of the ATL family.

    PubMed

    Aguilar-Hernández, Victor; Guzmán, Plinio

    2014-03-01

    Gene duplication events exert key functions on gene innovations during the evolution of the eukaryotic genomes. A large portion of the total gene content in plants arose from tandem duplications events, which often result in paralog genes with high sequence identity. Ubiquitin ligases or E3 enzymes are components of the ubiquitin proteasome system that function during the transfer of the ubiquitin molecule to the substrate. In plants, several E3s have expanded in their genomes as multigene families. To gain insight into the consequences of gene duplications on the expansion and diversification of E3s, we examined the evolutionary basis of a cluster of six genes, duplC-ATLs, which arose from segmental and tandem duplication events in Brassicaceae. The assessment of the expression suggested two patterns that are supported by lineage. While retention of expression domains was observed, an apparent absence or reduction of expression was also inferred. We found that two duplC-ATL genes underwent pseudogenization and that, in one case, gene expression is probably regained. Our findings provide insights into the evolution of gene families in plants, defining key events on the expansion of the Arabidopsis Tóxicos en Levadura family of E3 ligases.

  3. Duplications and positive selection drive the evolution of parasitism associated gene families in the nematode Strongyloides papillosus.

    PubMed

    Baskaran, Praveen; Jaleta, Tegegn G; Streit, Adrian; Rödelsperger, Christian

    2017-03-02

    Gene duplication is one major mechanism playing a role in the evolution of phenotypic complexity and in the generation of novel traits. By comparing parasitic and nonparasitic nematodes, a recent study found that the evolution of parasitism in Strongyloididae is associated with a large expansion in the Astacin and CAP gene families.To gain novel insights into the developmental processes in the sheep parasite Strongyloides papillosus, we sequenced transcriptomes of different developmental stages and sexes. Overall, we found that the majority of genes are developmentally regulated and have one-to-one orthologs in the diverged S. ratti genome. Together with the finding of similar expression profiles between S. papillosus and S. ratti, these results indicate a strong evolutionary constraint acting against change at sequence and expression levels. However, the comparison between parasitic and free-living females demonstrates a quite divergent pattern that is mostly due to the previously mentioned expansion in the Astacin and CAP gene families. More detailed phylogenetic analysis of both gene families shows that most members date back to single expansion events early in the Strongyloides lineage and have undergone subfunctionalization resulting in clusters that are highly expressed either in infective larvae or in parasitic females. Finally, we found increased evidence for positive selection in both gene families relative to the genome-wide expectation.In summary, our study reveals first insights into the developmental transcriptomes of S. papillosus and provides a detailed analysis of sequence and expression evolution in parasitism associated gene families.

  4. Duplications and Positive Selection Drive the Evolution of Parasitism-Associated Gene Families in the Nematode Strongyloides papillosus

    PubMed Central

    Baskaran, Praveen; Jaleta, Tegegn G.; Streit, Adrian

    2017-01-01

    Gene duplication is a major mechanism playing a role in the evolution of phenotypic complexity and in the generation of novel traits. By comparing parasitic and nonparasitic nematodes, a recent study found that the evolution of parasitism in Strongyloididae is associated with a large expansion in the Astacin and CAP gene families. To gain novel insights into the developmental processes in the sheep parasite Strongyloides papillosus, we sequenced transcriptomes of different developmental stages and sexes. Overall, we found that the majority of genes are developmentally regulated and have one-to-one orthologs in the diverged S. ratti genome. Together with the finding of similar expression profiles between S. papillosus and S. ratti, these results indicate a strong evolutionary constraint acting against change at sequence and expression levels. However, the comparison between parasitic and free-living females demonstrates a quite divergent pattern that is mostly due to the previously mentioned expansion in the Astacin and CAP gene families. More detailed phylogenetic analysis of both gene families shows that most members date back to single expansion events early in the Strongyloides lineage and have undergone subfunctionalization resulting in clusters that are highly expressed either in infective larvae or in parasitic females. Finally, we found increased evidence for positive selection in both gene families relative to the genome-wide expectation. In summary, our study reveals first insights into the developmental transcriptomes of S. papillosus and provides a detailed analysis of sequence and expression evolution in parasitism-associated gene families. PMID:28338804

  5. Gene duplication event in family 12 glycosyl hydrolase from Phytophthora spp.

    PubMed

    Costanzo, Stefano; Ospina-Giraldo, M D; Deahl, K L; Baker, C J; Jones, Richard W

    2006-10-01

    A total of 18 paralogs of xyloglucan-specific endoglucanases (EGLs) from the glycosyl hydrolase family 12 were identified and characterized in Phytophthora sojae and Phytophthora ramorum. These genes encode predicted extracellular enzymes, with sizes ranging from 189 to 435 amino acid residues, that would be capable of hydrolyzing the xyloglucan component of the host cell wall. In two cases, four and six functional copies of these genes were found in tight succession within a region of 5 and 18 kb, respectively. The overall gene copy number and relative organization appeared well conserved between P. sojae and P. ramorum, with apparent synteny in this region of their respective genomes. Phylogenetic analyses of Phytophthora endoglucanases of family 12 and other known members of EGL 12, revealed a close relatedness with a fairly conserved gene sub-family containing, among others, sequences from the fungi Emericella desertorum and Aspergillus aculeatus. This is the first report of family 12 EGLs present in plant pathogenic eukaryotes.

  6. Phylogenetic relationships among Perissodactyla: secretoglobin 1A1 gene duplication and triplication in the Equidae family.

    PubMed

    Côté, Olivier; Viel, Laurent; Bienzle, Dorothee

    2013-12-01

    Secretoglobin family 1A member 1 (SCGB 1A1) is a small anti-inflammatory and immunomodulatory protein that is abundantly secreted in airway surface fluids. We recently reported the existence of three distinct SCGB1A1 genes in the domestic horse genome as opposed to the single gene copy consensus present in other mammals. The origin of SCGB1A1 gene triplication and the evolutionary relationship of the three genes amongst Equidae family members are unknown. For this study, SCGB1A1 genomic data were collected from various Equus individuals including E. caballus, E. przewalskii, E. asinus, E. grevyi, and E. quagga. Three SCGB1A1 genes in E. przewalskii, two SCGB1A1 genes in E. asinus, and a single SCGB1A1 gene in E. grevyi and E. quagga were identified. Sequence analysis revealed that the non-synonymous nucleotide substitutions between the different equid genes coded for 17 amino acid changes. Most of these changes localized to the SCGB 1A1 central cavity that binds hydrophobic ligands, suggesting that this area of SCGB 1A1 evolved to accommodate diverse molecular interactions. Three-dimensional modeling of the proteins revealed that the size of the SCGB 1A1 central cavity is larger than that of SCGB 1A1A. Altogether, these findings suggest that evolution of the SCGB1A1 gene may parallel the separation of caballine and non-caballine species amongst Equidae, and may indicate an expansion of function for SCGB1A1 gene products.

  7. Discrimination of Deletion and Duplication Subtypes of the Deleted in Azoospermia Gene Family in the Context of Frequent Interloci Gene Conversion

    PubMed Central

    Vaszkó, Tibor; Papp, János; Krausz, Csilla; Casamonti, Elena; Géczi, Lajos; Olah, Edith

    2016-01-01

    Due to its palindromic setup, AZFc (Azoospermia Factor c) region of chromosome Y is one of the most unstable regions of the human genome. It contains eight gene families expressed mainly in the testes. Several types of rearrangement resulting in changes in the cumulative copy number of the gene families were reported to be associated with diseases such as male infertility and testicular germ cell tumors. The best studied AZFc rearrangement is gr/gr deletion. Its carriers show widespread phenotypic variation from azoospermia to normospermia. This phenomenon was initially attributed to different gr/gr subtypes that would eliminate distinct members of the affected gene families. However, studies conducted to confirm this hypothesis have brought controversial results, perhaps, in part, due to the shortcomings of the utilized subtyping methodology. This proof-of-concept paper is meant to introduce here a novel method aimed at subtyping AZFc rearrangements. It is able to differentiate the partial deletion and partial duplication subtypes of the Deleted in Azoospermia (DAZ) gene family. The keystone of the method is the determination of the copy number of the gene family member-specific variant(s) in a series of sequence family variant (SFV) positions. Most importantly, we present a novel approach for the correct interpretation of the variant copy number data to determine the copy number of the individual DAZ family members in the context of frequent interloci gene conversion.Besides DAZ1/DAZ2 and DAZ3/DAZ4 deletions, not yet described rearrangements such as DAZ2/DAZ4 deletion and three duplication subtypes were also found by the utilization of the novel approach. A striking feature is the extremely high concordance among the individual data pointing to a certain type of rearrangement. In addition to being able to identify DAZ deletion subtypes more reliably than the methods used previously, this approach is the first that can discriminate DAZ duplication subtypes as well

  8. The vertebrate makorin ubiquitin ligase gene family has been shaped by large-scale duplication and retroposition from an ancestral gonad-specific, maternal-effect gene

    PubMed Central

    2010-01-01

    Background Members of the makorin (mkrn) gene family encode RING/C3H zinc finger proteins with U3 ubiquitin ligase activity. Although these proteins have been described in a variety of eukaryotes such as plants, fungi, invertebrates and vertebrates including human, almost nothing is known about their structural and functional evolution. Results Via partial sequencing of a testis cDNA library from the poeciliid fish Xiphophorus maculatus, we have identified a new member of the makorin gene family, that we called mkrn4. In addition to the already described mkrn1 and mkrn2, mkrn4 is the third example of a makorin gene present in both tetrapods and ray-finned fish. However, this gene was not detected in mouse and rat, suggesting its loss in the lineage leading to rodent murids. Mkrn2 and mkrn4 are located in large ancient duplicated regions in tetrapod and fish genomes, suggesting the possible involvement of ancestral vertebrate-specific genome duplication in the formation of these genes. Intriguingly, many mkrn1 and mkrn2 intronless retrocopies have been detected in mammals but not in other vertebrates, most of them corresponding to pseudogenes. The nature and number of zinc fingers were found to be conserved in Mkrn1 and Mkrn2 but much more variable in Mkrn4, with lineage-specific differences. RT-qPCR analysis demonstrated a highly gonad-biased expression pattern for makorin genes in medaka and zebrafish (ray-finned fishes) and amphibians, but a strong relaxation of this specificity in birds and mammals. All three mkrn genes were maternally expressed before zygotic genome activation in both medaka and zebrafish early embryos. Conclusion Our analysis demonstrates that the makorin gene family has evolved through large-scale duplication and subsequent lineage-specific retroposition-mediated duplications in vertebrates. From the three major vertebrate mkrn genes, mkrn4 shows the highest evolutionary dynamics, with lineage-specific loss of zinc fingers and even complete

  9. Evolution of Gene Duplication in Plants.

    PubMed

    Panchy, Nicholas; Lehti-Shiu, Melissa; Shiu, Shin-Han

    2016-08-01

    Ancient duplication events and a high rate of retention of extant pairs of duplicate genes have contributed to an abundance of duplicate genes in plant genomes. These duplicates have contributed to the evolution of novel functions, such as the production of floral structures, induction of disease resistance, and adaptation to stress. Additionally, recent whole-genome duplications that have occurred in the lineages of several domesticated crop species, including wheat (Triticum aestivum), cotton (Gossypium hirsutum), and soybean (Glycine max), have contributed to important agronomic traits, such as grain quality, fruit shape, and flowering time. Therefore, understanding the mechanisms and impacts of gene duplication will be important to future studies of plants in general and of agronomically important crops in particular. In this review, we survey the current knowledge about gene duplication, including gene duplication mechanisms, the potential fates of duplicate genes, models explaining duplicate gene retention, the properties that distinguish duplicate from singleton genes, and the evolutionary impact of gene duplication.

  10. A Complex Interplay of Tandem- and Whole-Genome Duplication Drives Expansion of the L-Type Lectin Receptor Kinase Gene Family in the Brassicaceae

    PubMed Central

    Govers, Francine; Bouwmeester, Klaas; Schranz, M. Eric

    2015-01-01

    The comparative analysis of plant gene families in a phylogenetic framework has greatly accelerated due to advances in next generation sequencing. In this study, we provide an evolutionary analysis of the L-type lectin receptor kinase and L-type lectin domain proteins (L-type LecRKs and LLPs) that are considered as components in plant immunity, in the plant family Brassicaceae and related outgroups. We combine several lines of evidence provided by sequence homology, HMM-driven protein domain annotation, phylogenetic analysis, and gene synteny for large-scale identification of L-type LecRK and LLP genes within nine core-eudicot genomes. We show that both polyploidy and local duplication events (tandem duplication and gene transposition duplication) have played a major role in L-type LecRK and LLP gene family expansion in the Brassicaceae. We also find significant differences in rates of molecular evolution based on the mode of duplication. Additionally, we show that LLPs share a common evolutionary origin with L-type LecRKs and provide a consistent gene family nomenclature. Finally, we demonstrate that the largest and most diverse L-type LecRK clades are lineage-specific. Our evolutionary analyses of these plant immune components provide a framework to support future plant resistance breeding. PMID:25635042

  11. A complex interplay of tandem- and whole-genome duplication drives expansion of the L-type lectin receptor kinase gene family in the brassicaceae.

    PubMed

    Hofberger, Johannes A; Nsibo, David L; Govers, Francine; Bouwmeester, Klaas; Schranz, M Eric

    2015-01-28

    The comparative analysis of plant gene families in a phylogenetic framework has greatly accelerated due to advances in next generation sequencing. In this study, we provide an evolutionary analysis of the L-type lectin receptor kinase and L-type lectin domain proteins (L-type LecRKs and LLPs) that are considered as components in plant immunity, in the plant family Brassicaceae and related outgroups. We combine several lines of evidence provided by sequence homology, HMM-driven protein domain annotation, phylogenetic analysis, and gene synteny for large-scale identification of L-type LecRK and LLP genes within nine core-eudicot genomes. We show that both polyploidy and local duplication events (tandem duplication and gene transposition duplication) have played a major role in L-type LecRK and LLP gene family expansion in the Brassicaceae. We also find significant differences in rates of molecular evolution based on the mode of duplication. Additionally, we show that LLPs share a common evolutionary origin with L-type LecRKs and provide a consistent gene family nomenclature. Finally, we demonstrate that the largest and most diverse L-type LecRK clades are lineage-specific. Our evolutionary analyses of these plant immune components provide a framework to support future plant resistance breeding.

  12. Evolution by leaps: gene duplication in bacteria

    PubMed Central

    2009-01-01

    Background Sequence related families of genes and proteins are common in bacterial genomes. In Escherichia coli they constitute over half of the genome. The presence of families and superfamilies of proteins suggest a history of gene duplication and divergence during evolution. Genome encoded protein families, their size and functional composition, reflect metabolic potentials of the organisms they are found in. Comparing protein families of different organisms give insight into functional differences and similarities. Results Equivalent enzyme families with metabolic functions were selected from the genomes of four experimentally characterized bacteria belonging to separate genera. Both similarities and differences were detected in the protein family memberships, with more similarities being detected among the more closely related organisms. Protein family memberships reflected known metabolic characteristics of the organisms. Differences in divergence of functionally characterized enzyme family members accounted for characteristics of taxa known to differ in those biochemical properties and capabilities. While some members of the gene families will have been acquired by lateral exchange and other former family members will have been lost over time, duplication and divergence of genes and functions appear to have been a significant contributor to the functional diversity of today’s microbes. Conclusions Protein families seem likely to have arisen during evolution by gene duplication and divergence where the gene copies that have been retained are the variants that have led to distinct bacterial physiologies and taxa. Thus divergence of the duplicate enzymes has been a major process in the generation of different kinds of bacteria. Reviewers This article was reviewed by Drs. Iyer Aravind, Ardcady Mushegian, and Pierre Pontarotti. PMID:19930658

  13. Evolution and expansion of the Mycobacterium tuberculosis PE and PPE multigene families and their association with the duplication of the ESAT-6 (esx) gene cluster regions

    PubMed Central

    Gey van Pittius, Nicolaas C; Sampson, Samantha L; Lee, Hyeyoung; Kim, Yeun; van Helden, Paul D; Warren, Robin M

    2006-01-01

    Background The PE and PPE multigene families of Mycobacterium tuberculosis comprise about 10% of the coding potential of the genome. The function of the proteins encoded by these large gene families remains unknown, although they have been proposed to be involved in antigenic variation and disease pathogenesis. Interestingly, some members of the PE and PPE families are associated with the ESAT-6 (esx) gene cluster regions, which are regions of immunopathogenic importance, and encode a system dedicated to the secretion of members of the potent T-cell antigen ESAT-6 family. This study investigates the duplication characteristics of the PE and PPE gene families and their association with the ESAT-6 gene clusters, using a combination of phylogenetic analyses, DNA hybridization, and comparative genomics, in order to gain insight into their evolutionary history and distribution in the genus Mycobacterium. Results The results showed that the expansion of the PE and PPE gene families is linked to the duplications of the ESAT-6 gene clusters, and that members situated in and associated with the clusters represent the most ancestral copies of the two gene families. Furthermore, the emergence of the repeat protein PGRS and MPTR subfamilies is a recent evolutionary event, occurring at defined branching points in the evolution of the genus Mycobacterium. These gene subfamilies are thus present in multiple copies only in the members of the M. tuberculosis complex and close relatives. The study provides a complete analysis of all the PE and PPE genes found in the sequenced genomes of members of the genus Mycobacterium such as M. smegmatis, M. avium paratuberculosis, M. leprae, M. ulcerans, and M. tuberculosis. Conclusion This work provides insight into the evolutionary history for the PE and PPE gene families of the mycobacteria, linking the expansion of these families to the duplications of the ESAT-6 (esx) gene cluster regions, and showing that they are composed of subgroups

  14. Evolution, organization, and expression of alpha-tubulin genes in the antarctic fish Notothenia coriiceps. Adaptive expansion of a gene family by recent gene duplication, inversion, and divergence.

    PubMed

    Parker, S K; Detrich, H W

    1998-12-18

    To assess the organization and expression of tubulin genes in ectothermic vertebrates, we have chosen the Antarctic yellowbelly rockcod, Notothenia coriiceps, as a model system. The genome of N. coriiceps contains approximately 15 distinct DNA fragments complementary to alpha-tubulin cDNA probes, which suggests that the alpha-tubulins of this cold-adapted fish are encoded by a substantial multigene family. From an N. coriiceps testicular DNA library, we isolated a 13.8-kilobase pair genomic clone that contains a tightly linked cluster of three alpha-tubulin genes, designated NcGTbalphaa, NcGTbalphab, and NcGTbalphac. Two of these genes, NcGTbalphaa and NcGTbalphab, are linked in head-to-head (5' to 5') orientation with approximately 500 bp separating their start codons, whereas NcGTbalphaa and NcGTbalphac are linked tail-to-tail (3' to 3') with approximately 2.5 kilobase pairs between their stop codons. The exons, introns, and untranslated regions of the three alpha-tubulin genes are strikingly similar in sequence, and the intergenic region between the alphaa and alphab genes is significantly palindromic. Thus, this cluster probably evolved by duplication, inversion, and divergence of a common ancestral alpha-tubulin gene. Expression of the NcGTbalphac gene is cosmopolitan, with its mRNA most abundant in hematopoietic, neural, and testicular tissues, whereas NcGTbalphaa and NcGTbalphab transcripts accumulate primarily in brain. The differential expression of the three genes is consistent with distinct suites of putative promoter and enhancer elements. We propose that cold adaptation of the microtubule system of Antarctic fishes is based in part on expansion of the alpha- and beta-tubulin gene families to ensure efficient synthesis of tubulin polypeptides.

  15. Characterization of duplicated Dunaliella viridis SPT1 genes provides insights into early gene divergence after duplication.

    PubMed

    Guan, Zhenwei; Meng, Xiangzong; Sun, Zhenhua; Xu, Zhengkai; Song, Rentao

    2008-10-15

    The sodium-dependent phosphate transporter gene from unicellular green algae Dunaliella viridis, DvSPT1, shares similarity with members of Pi transporter family. Sequencing analysis of D. viridis BAC clone containing the DvSPT1 gene revealed two inverted duplicated copies of this gene (DvSPT1 and DvSPT1-2 respectively). The duplication covered most of both genes except for their 3' downstream region. The duplicated genomic sequences exhibited 97.9% identity with a synonymous divergence of Ks=0.0126 in the coding region. This data indicated very recent gene duplication in D. viridis genome, providing an excellent opportunity to investigate sequence and expression divergence of duplicated genes at an early stage. Scattered point mutations and length polymorphism of simple sequence repeats (SSRs) were predominant among the sequence divergence soon after gene duplication. Due to sequence divergence in the 5' regulatory regions and a swap of the entire 3' downstream regions (3'-UTR), DvSPT1 and DvSPT1-2 showed expression divergence in response to extra-cellular NaCl concentration changes. According to their expression patterns, the two diverged gene copies would provide better adaptation to a broader range of extra-cellular NaCl concentration. Furthermore, Southern blot analysis indicated that there might be a large phosphate transporter gene family in D. viridis.

  16. Functional requirements driving the gene duplication in 12 Drosophila species

    PubMed Central

    2013-01-01

    Background Gene duplication supplies the raw materials for novel gene functions and many gene families arisen from duplication experience adaptive evolution. Most studies of young duplicates have focused on mammals, especially humans, whereas reports describing their genome-wide evolutionary patterns across the closely related Drosophila species are rare. The sequenced 12 Drosophila genomes provide the opportunity to address this issue. Results In our study, 3,647 young duplicate gene families were identified across the 12 Drosophila species and three types of expansions, species-specific, lineage-specific and complex expansions, were detected in these gene families. Our data showed that the species-specific young duplicate genes predominated (86.6%) over the other two types. Interestingly, many independent species-specific expansions in the same gene family have been observed in many species, even including 11 or 12 Drosophila species. Our data also showed that the functional bias observed in these young duplicate genes was mainly related to responses to environmental stimuli and biotic stresses. Conclusions This study reveals the evolutionary patterns of young duplicates across 12 Drosophila species on a genomic scale. Our results suggest that convergent evolution acts on young duplicate genes after the species differentiation and adaptive evolution may play an important role in duplicate genes for adaption to ecological factors and environmental changes in Drosophila. PMID:23945147

  17. Evolutionary analysis of multidrug resistance genes in fungi - impact of gene duplication and family conservation.

    PubMed

    Gossani, Cristiani; Bellieny-Rabelo, Daniel; Venancio, Thiago M

    2014-11-01

    Although the emergence of bacterial drug resistance is of great concern to the scientific community, few studies have evaluated this phenomenon systematically in fungi by using genome-wide datasets. In the present study, we assembled a large compendium of Saccharomyces cerevisiae chemical genetic data to study the evolution of multidrug resistance genes (MDRs) in the fungal lineage. We found that MDRs typically emerge in widely conserved families, most of which containing homologs from pathogenic fungi, such as Candida albicans and Coccidioides immitis, which could favor the evolution of drug resistance in those species. By integrating data from chemical genetics with protein family conservation, genetic and protein interactions, we found that gene families rarely have more than one MDR, indicating that paralogs evolve asymmetrically with regard to multidrug resistance roles. Furthermore, MDRs have more genetic and protein interaction partners than non-MDRs, supporting their participation in complex biochemical systems underlying the tolerance to multiple bioactive molecules. MDRs share more chemical genetic interactions with other MDRs than with non-MDRs, regardless of their evolutionary affinity. These results suggest the existence of an intricate system involved in the global drug tolerance phenotypes. Finally, MDRs are more likely to be hit repeatedly by mutations in laboratory evolution experiments, indicating that they have great adaptive potential. The results presented here not only reveal the main genomic features underlying the evolution of MDRs, but also shed light on the gene families from which drug resistance is more likely to emerge in fungi.

  18. The roles of gene duplication, gene conversion and positive selection in rodent Esp and Mup pheromone gene families with comparison to the Abp family.

    PubMed

    Karn, Robert C; Laukaitis, Christina M

    2012-01-01

    Three proteinaceous pheromone families, the androgen-binding proteins (ABPs), the exocrine-gland secreting peptides (ESPs) and the major urinary proteins (MUPs) are encoded by large gene families in the genomes of Mus musculus and Rattus norvegicus. We studied the evolutionary histories of the Mup and Esp genes and compared them with what is known about the Abp genes. Apparently gene conversion has played little if any role in the expansion of the mouse Class A and Class B Mup genes and pseudogenes, and the rat Mups. By contrast, we found evidence of extensive gene conversion in many Esp genes although not in all of them. Our studies of selection identified at least two amino acid sites in β-sheets as having evolved under positive selection in the mouse Class A and Class B MUPs and in rat MUPs. We show that selection may have acted on the ESPs by determining K(a)/K(s) for Exon 3 sequences with and without the converted sequence segment. While it appears that purifying selection acted on the ESP signal peptides, the secreted portions of the ESPs probably have undergone much more rapid evolution. When the inner gene converted fragment sequences were removed, eleven Esp paralogs were present in two or more pairs with K(a)/K(s) >1.0 and thus we propose that positive selection is detectable by this means in at least some mouse Esp paralogs. We compare and contrast the evolutionary histories of all three mouse pheromone gene families in light of their proposed functions in mouse communication.

  19. The reduced expression of endogenous duplications (REED) in the maize R gene family is mediated by DNA methylation.

    PubMed Central

    Ronchi, A; Petroni, K; Tonelli, C

    1995-01-01

    The duplicated R and Sn genes regulate the maize anthocyanin biosynthetic pathway and encode tissue-specific products that are homologous to helix-loop-helix transcriptional activators. As a consequence of their coupling in the genome, Sn is partially silenced. Genomic restriction analysis failed to reveal gross structural DNA alterations between the strong original phenotype and the weak derivatives. However, the differences in pigmentation were inversely correlated with differences in the methylation of the Sn promoter. Accordingly, treatment with 5-azacytidine (AZA), a demethylating agent, restored a strong pigmentation pattern that was transmitted to the progeny and that was correlated with differential expression of the Sn transcript. Genomic sequencing confirmed that methylation of the Sn promoter was more apparent in the less pigmented seedlings and was greatly reduced in the AZA revertants. In addition, some methylcytosines were located in non-symmetrical C sequences. These findings provide an insight into Sn and R interaction, a process that we have termed Reduced Expression of Endogenous Duplications (REED). We propose that increasing the copy number of regulatory genes by endogenous duplication leads to such epigenetic mechanisms of silencing. Further understanding of the REED process may have broader implications for gene regulation and may identify new levels of regulation within eukaryotic genomes. Images PMID:7489721

  20. Genomic evidence for adaptation by gene duplication.

    PubMed

    Qian, Wenfeng; Zhang, Jianzhi

    2014-08-01

    Gene duplication is widely believed to facilitate adaptation, but unambiguous evidence for this hypothesis has been found in only a small number of cases. Although gene duplication may increase the fitness of the involved organisms by doubling gene dosage or neofunctionalization, it may also result in a simple division of ancestral functions into daughter genes, which need not promote adaptation. Hence, the general validity of the adaptation by gene duplication hypothesis remains uncertain. Indeed, a genome-scale experiment found similar fitness effects of deleting pairs of duplicate genes and deleting individual singleton genes from the yeast genome, leading to the conclusion that duplication rarely results in adaptation. Here we contend that the above comparison is unfair because of a known duplication bias among genes with different fitness contributions. To rectify this problem, we compare homologous genes from the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. We discover that simultaneously deleting a duplicate gene pair in S. cerevisiae reduces fitness significantly more than deleting their singleton counterpart in S. pombe, revealing post-duplication adaptation. The duplicates-singleton difference in fitness effect is not attributable to a potential increase in gene dose after duplication, suggesting that the adaptation is owing to neofunctionalization, which we find to be explicable by acquisitions of binary protein-protein interactions rather than gene expression changes. These results provide genomic evidence for the role of gene duplication in organismal adaptation and are important for understanding the genetic mechanisms of evolutionary innovation.

  1. Expansion of banana (Musa acuminata) gene families involved in ethylene biosynthesis and signalling after lineage-specific whole-genome duplications.

    PubMed

    Jourda, Cyril; Cardi, Céline; Mbéguié-A-Mbéguié, Didier; Bocs, Stéphanie; Garsmeur, Olivier; D'Hont, Angélique; Yahiaoui, Nabila

    2014-05-01

    Whole-genome duplications (WGDs) are widespread in plants, and three lineage-specific WGDs occurred in the banana (Musa acuminata) genome. Here, we analysed the impact of WGDs on the evolution of banana gene families involved in ethylene biosynthesis and signalling, a key pathway for banana fruit ripening. Banana ethylene pathway genes were identified using comparative genomics approaches and their duplication modes and expression profiles were analysed. Seven out of 10 banana ethylene gene families evolved through WGD and four of them (1-aminocyclopropane-1-carboxylate synthase (ACS), ethylene-insensitive 3-like (EIL), ethylene-insensitive 3-binding F-box (EBF) and ethylene response factor (ERF)) were preferentially retained. Banana orthologues of AtEIN3 and AtEIL1, two major genes for ethylene signalling in Arabidopsis, were particularly expanded. This expansion was paralleled by that of EBF genes which are responsible for control of EIL protein levels. Gene expression profiles in banana fruits suggested functional redundancy for several MaEBF and MaEIL genes derived from WGD and subfunctionalization for some of them. We propose that EIL and EBF genes were co-retained after WGD in banana to maintain balanced control of EIL protein levels and thus avoid detrimental effects of constitutive ethylene signalling. In the course of evolution, subfunctionalization was favoured to promote finer control of ethylene signalling.

  2. Gene Duplicability of Core Genes Is Highly Consistent across All Angiosperms.

    PubMed

    Li, Zhen; Defoort, Jonas; Tasdighian, Setareh; Maere, Steven; Van de Peer, Yves; De Smet, Riet

    2016-02-01

    Gene duplication is an important mechanism for adding to genomic novelty. Hence, which genes undergo duplication and are preserved following duplication is an important question. It has been observed that gene duplicability, or the ability of genes to be retained following duplication, is a nonrandom process, with certain genes being more amenable to survive duplication events than others. Primarily, gene essentiality and the type of duplication (small-scale versus large-scale) have been shown in different species to influence the (long-term) survival of novel genes. However, an overarching view of "gene duplicability" is lacking, mainly due to the fact that previous studies usually focused on individual species and did not account for the influence of genomic context and the time of duplication. Here, we present a large-scale study in which we investigated duplicate retention for 9178 gene families shared between 37 flowering plant species, referred to as angiosperm core gene families. For most gene families, we observe a strikingly consistent pattern of gene duplicability across species, with gene families being either primarily single-copy or multicopy in all species. An intermediate class contains gene families that are often retained in duplicate for periods extending to tens of millions of years after whole-genome duplication, but ultimately appear to be largely restored to singleton status, suggesting that these genes may be dosage balance sensitive. The distinction between single-copy and multicopy gene families is reflected in their functional annotation, with single-copy genes being mainly involved in the maintenance of genome stability and organelle function and multicopy genes in signaling, transport, and metabolism. The intermediate class was overrepresented in regulatory genes, further suggesting that these represent putative dosage-balance-sensitive genes.

  3. Identification of a novel duplication mutation in the VHL gene in a large Chinese family with Von Hippel-Lindau (VHL) syndrome.

    PubMed

    Cao, L H; Kuang, B H; Chen, C; Hu, C; Sun, Z; Chen, H; Wang, S S; Luo, Y

    2014-12-04

    Von Hippel-Lindau (VHL) syndrome is characterized by hemangioblastomas of the brain, spinal cord, and retina, renal cysts, clear cell renal cell carcinoma, and pheochromocytoma. VHL is caused by mutations in the VHL tumor suppressor gene. We attempted to detect mutation in the VHL gene in a 5-generation Chinese family with VHL. We identified a novel small duplication that altered the reading frame downstream and created a premature TGA stop signal, resulting in severely truncated pVHL30 (p.Gly114Serfs*50) and pVHL19 (p.Gly61Serfs*50). This change was predicted to be an elongin-binding domain deletion.

  4. Gene Duplicability of Core Genes Is Highly Consistent across All Angiosperms[OPEN

    PubMed Central

    Li, Zhen; Van de Peer, Yves; De Smet, Riet

    2016-01-01

    Gene duplication is an important mechanism for adding to genomic novelty. Hence, which genes undergo duplication and are preserved following duplication is an important question. It has been observed that gene duplicability, or the ability of genes to be retained following duplication, is a nonrandom process, with certain genes being more amenable to survive duplication events than others. Primarily, gene essentiality and the type of duplication (small-scale versus large-scale) have been shown in different species to influence the (long-term) survival of novel genes. However, an overarching view of “gene duplicability” is lacking, mainly due to the fact that previous studies usually focused on individual species and did not account for the influence of genomic context and the time of duplication. Here, we present a large-scale study in which we investigated duplicate retention for 9178 gene families shared between 37 flowering plant species, referred to as angiosperm core gene families. For most gene families, we observe a strikingly consistent pattern of gene duplicability across species, with gene families being either primarily single-copy or multicopy in all species. An intermediate class contains gene families that are often retained in duplicate for periods extending to tens of millions of years after whole-genome duplication, but ultimately appear to be largely restored to singleton status, suggesting that these genes may be dosage balance sensitive. The distinction between single-copy and multicopy gene families is reflected in their functional annotation, with single-copy genes being mainly involved in the maintenance of genome stability and organelle function and multicopy genes in signaling, transport, and metabolism. The intermediate class was overrepresented in regulatory genes, further suggesting that these represent putative dosage-balance-sensitive genes. PMID:26744215

  5. Tandem duplication within a Neurofibromatosis type I (NFI) gene exon in a family with features of Watson syndrome and Noonan syndrome

    SciTech Connect

    Tassabehji, M.; Strachan, T.; Colley, A.; Donnai, D.; Harris, R.; Thakker, N. ); Sharland, M )

    1993-07-01

    Type 1 neurofibromatosis (NF1), Watson syndrome (WS), and Noonan syndrome (NS) show some overlap in clinical manifestations. In addition, WS has been shown to be linked to markers flanking the NF1 locus and a deletion at the NF1 locus demonstrated in a WS patient. This suggests either that WS and NF1 are allelic or the phenotypes arise from mutations in very closely linked genes. Here the authors provide evidence for the former by demonstrating a mutation in the NF1 gene in a family with features of both WS and NS. The mutation is an almost perfect in-frame tandem duplication of 42 bases in exon 28 of the NF1 gene. Unlike the mutations previously described in classical NF1, which show a preponderance of null alleles, the mutation in this family would be expected to result in a mutant neurofibromin product. 31 refs., 2 figs.

  6. Tandem duplication within a neurofibromatosis type 1 (NF1) gene exon in a family with features of Watson syndrome and Noonan syndrome.

    PubMed Central

    Tassabehji, M; Strachan, T; Sharland, M; Colley, A; Donnai, D; Harris, R; Thakker, N

    1993-01-01

    Type 1 neurofibromatosis (NF1), Watson syndrome (WS), and Noonan syndrome (NS) show some overlap in clinical manifestations. In addition, WS has been shown to be linked to markers flanking the NF1 locus and a deletion at the NF1 locus demonstrated in a WS patient. This suggests either that WS and NF1 are allelic or that phenotypes arise from mutations in very closely linked genes. Here we provide evidence for the former by demonstrating a mutation in the NF1 gene in a family with features of both WS and NS. The mutation is an almost perfect in-frame tandem duplication of 42 bases in exon 28 of the NF1 gene. Unlike the mutations previously described in classical NF1, which show a preponderance of null alleles, the mutation in this family would be expected to result in a mutant neurofibromin product. Images Figure 1 Figure 2 PMID:8317503

  7. Gene duplication in the evolution of sexual dimorphism.

    PubMed

    Wyman, Minyoung J; Cutter, Asher D; Rowe, Locke

    2012-05-01

    Males and females share most of the same genes, so selection in one sex will typically produce a correlated response in the other sex. Yet, the sexes have evolved to differ in a multitude of behavioral, morphological, and physiological traits. How did this sexual dimorphism evolve despite the presence of a common underlying genome? We investigated the potential role of gene duplication in the evolution of sexual dimorphism. Because duplication events provide extra genetic material, the sexes each might use this redundancy to facilitate sex-specific gene expression, permitting the evolution of dimorphism. We investigated this hypothesis at the genome-wide level in Drosophila melanogaster, using the presence of sex-biased expression as a proxy for the sex-specific specialization of gene function. We expected that if sexually antagonistic selection is a potent force acting upon individual genes, duplication will result in paralog families whose members differ in sex-biased expression. Gene members of the same duplicate family can have different expression patterns in males versus females. In particular, duplicate pairs containing a male-biased gene are found more frequently than expected, in agreement with previous studies. Furthermore, when the singleton ortholog is unbiased, duplication appears to allow one of the paralog copies to acquire male-biased expression. Conversely, female-biased expression is not common among duplicates; fewer duplicate genes are expressed in the female-soma and ovaries than in the male-soma and testes. Expression divergence exists more in older than in younger duplicates pairs, but expression divergence does not correlate with protein sequence divergence. Finally, genomic proximity may have an effect on whether paralogs differ in sex-biased expression. We conclude that the data are consistent with a role of gene duplication in fostering male-biased, but not female-biased, gene expression, thereby aiding the evolution of sexual dimorphism.

  8. Altered patterns of gene duplication and differential gene gain and loss in fungal pathogens

    PubMed Central

    Powell, Amy J; Conant, Gavin C; Brown, Douglas E; Carbone, Ignazio; Dean, Ralph A

    2008-01-01

    Background Duplication, followed by fixation or random loss of novel genes, contributes to genome evolution. Particular outcomes of duplication events are possibly associated with pathogenic life histories in fungi. To date, differential gene gain and loss have not been studied at genomic scales in fungal pathogens, despite this phenomenon's known importance in virulence in bacteria and viruses. Results To determine if patterns of gene duplication differed between pathogens and non-pathogens, we identified gene families across nine euascomycete and two basidiomycete species. Gene family size distributions were fit to power laws to compare gene duplication trends in pathogens versus non-pathogens. Fungal phytopathogens showed globally altered patterns of gene duplication, as indicated by differences in gene family size distribution. We also identified sixteen examples of gene family expansion and five instances of gene family contraction in pathogenic lineages. Expanded gene families included those predicted to be important in melanin biosynthesis, host cell wall degradation and transport functions. Contracted families included those encoding genes involved in toxin production, genes with oxidoreductase activity, as well as subunits of the vacuolar ATPase complex. Surveys of the functional distribution of gene duplicates indicated that pathogens show enrichment for gene duplicates associated with receptor and hydrolase activities, while euascomycete pathogens appeared to have not only these differences, but also significantly more duplicates associated with regulatory and carbohydrate binding functions. Conclusion Differences in the overall levels of gene duplication in phytopathogenic species versus non-pathogenic relatives implicate gene inventory flux as an important virulence-associated process in fungi. We hypothesize that the observed patterns of gene duplicate enrichment, gene family expansion and contraction reflect adaptation within pathogenic life

  9. Selection for Higher Gene Copy Number after Different Types of Plant Gene Duplications

    PubMed Central

    Hudson, Corey M.; Puckett, Emily E.; Bekaert, Michaël; Pires, J. Chris; Conant, Gavin C.

    2011-01-01

    The evolutionary origins of the multitude of duplicate genes in the plant genomes are still incompletely understood. To gain an appreciation of the potential selective forces acting on these duplicates, we phylogenetically inferred the set of metabolic gene families from 10 flowering plant (angiosperm) genomes. We then compared the metabolic fluxes for these families, predicted using the Arabidopsis thaliana and Sorghum bicolor metabolic networks, with the families' duplication propensities. For duplications produced by both small scale (small-scale duplications) and genome duplication (whole-genome duplications), there is a significant association between the flux and the tendency to duplicate. Following this global analysis, we made a more fine-scale study of the selective constraints observed on plant sodium and phosphate transporters. We find that the different duplication mechanisms give rise to differing selective constraints. However, the exact nature of this pattern varies between the gene families, and we argue that the duplication mechanism alone does not define a duplicated gene's subsequent evolutionary trajectory. Collectively, our results argue for the interplay of history, function, and selection in shaping the duplicate gene evolution in plants. PMID:22056313

  10. Clinical characterization and identification of duplication breakpoints in a Japanese family with Xq28 duplication syndrome including MECP2.

    PubMed

    Fukushi, Daisuke; Yamada, Kenichiro; Nomura, Noriko; Naiki, Misako; Kimura, Reiko; Yamada, Yasukazu; Kumagai, Toshiyuki; Yamaguchi, Kumiko; Miyake, Yoshishige; Wakamatsu, Nobuaki

    2014-04-01

    Xq28 duplication syndrome including MECP2 is a neurodevelopmental disorder characterized by axial hypotonia at infancy, severe intellectual disability, developmental delay, mild characteristic facial appearance, epilepsy, regression, and recurrent infections in males. We identified a Japanese family of Xq28 duplications, in which the patients presented with cerebellar ataxia, severe constipation, and small feet, in addition to the common clinical features. The 488-kb duplication spanned from L1CAM to EMD and contained 17 genes, two pseudo genes, and three microRNA-coding genes. FISH and nucleotide sequence analyses demonstrated that the duplication was tandem and in a forward orientation, and the duplication breakpoints were located in AluSc at the EMD side, with a 32-bp deletion, and LTR50 at the L1CAM side, with "tc" and "gc" microhomologies at the duplication breakpoints, respectively. The duplicated segment was completely segregated from the grandmother to the patients. These results suggest that the duplication was generated by fork-stalling and template-switching at the AluSc and LTR50 sites. This is the first report to determine the size and nucleotide sequences of the duplicated segments at Xq28 of three generations of a family and provides the genotype-phenotype correlation of the patients harboring the specific duplicated segment.

  11. Sequencing of Pax6 Loci from the Elephant Shark Reveals a Family of Pax6 Genes in Vertebrate Genomes, Forged by Ancient Duplications and Divergences

    PubMed Central

    Gautier, Philippe; Loosli, Felix; Tay, Boon-Hui; Tay, Alice; Murdoch, Emma; Coutinho, Pedro; van Heyningen, Veronica; Brenner, Sydney; Venkatesh, Byrappa; Kleinjan, Dirk A.

    2013-01-01

    family of Pax6 genes, forged by ancient duplication events and by independent, lineage-specific gene losses. PMID:23359656

  12. Duplicated gelsolin family genes in zebrafish: a novel scinderin-like gene (scinla) encodes the major corneal crystallin.

    PubMed

    Jia, Sujuan; Omelchenko, Marina; Garland, Donita; Vasiliou, Vasilis; Kanungo, Jyotshnabala; Spencer, Michael; Wolf, Yuri; Koonin, Eugene; Piatigorsky, Joram

    2007-10-01

    We have previously identified a gelsolin-like protein (C/L-gelsolin) as a corneal crystallin in zebrafish. Here we show by phylogenetic analysis that there are at least six genes encoding gelsolin-like proteins based on their gelsolin domains in zebrafish: gsna and gsnb group with the vertebrate gelsolin gene, scina and scinb group with the scinderin (adseverin) gene, and scinla (C/L-gelsolin) and scinlb are novel scinderin-like genes. RT-PCR showed that scinla, scinlb, and gsnb are preferentially expressed in the adult cornea whereas gsna is expressed to a similar extent in cornea, lens, brain, and heart; scina and scinb expression were detectable only in whole zebrafish and not in these adult tissues. Quantitative RT-PCR and 2-dimensional polyacrylamide gel electrophoresis followed by MALDI/TOF mass spectroscopy confirmed high expression of beta-actin and scinla, moderate expression of scinlb, and very low expression of gsna and gsnb in the cornea. Finally, transgenic zebrafish carrying a green fluorescent protein reporter transgene driven by a 4 kb scinla promoter fragment showed expression in the cornea, snout, dorsal fin, and tail fin of 3-day-old zebrafish larvae. Our data suggest that scinla and scinlb are diverged paralogs of the vertebrate scinderin gene and show that scinla encodes the zebrafish corneal crystallin previously called C/L-gelsolin.

  13. Duplication of the EFNB1 Gene in Familial Hypertelorism: Imbalance in Ephrin-B1 Expression and Abnormal Phenotypes in Humans and Mice

    PubMed Central

    Babbs, Christian; Stewart, Helen S; Williams, Louise J; Connell, Lyndsey; Goriely, Anne; Twigg, Stephen RF; Smith, Kim; Lester, Tracy; Wilkie, Andrew OM

    2011-01-01

    Familial hypertelorism, characterized by widely spaced eyes, classically shows autosomal dominant inheritance (Teebi type), but some pedigrees are compatible with X-linkage. No mechanism has been described previously, but clinical similarity has been noted to craniofrontonasal syndrome (CFNS), which is caused by mutations in the X-linked EFNB1 gene. Here we report a family in which females in three generations presented with hypertelorism, but lacked either craniosynostosis or a grooved nasal tip, excluding CFNS. DNA sequencing of EFNB1 was normal, but further analysis revealed a duplication of 937 kb including EFNB1 and two flanking genes: PJA1 and STARD8. We found that the X chromosome bearing the duplication produces ∼1.6-fold more EFNB1 transcript than the normal X chromosome and propose that, in the context of X-inactivation, this difference in expression level of EFNB1 results in abnormal cell sorting leading to hypertelorism. To support this hypothesis, we provide evidence from a mouse model carrying a targeted human EFNB1 cDNA, that abnormal cell sorting occurs in the cranial region. Hence, we propose that X-linked cases resembling Teebi hypertelorism may have a similar mechanism to CFNS, and that cellular mosaicism for different levels of ephrin-B1 (as well as simple presence/absence) leads to craniofacial abnormalities. Hum Mutat 32:1–9, 2011. © 2011 Wiley-Liss, Inc. PMID:21542058

  14. Mechanisms of Gene Duplication and Amplification

    PubMed Central

    Reams, Andrew B.; Roth, John R.

    2015-01-01

    Changes in gene copy number are among the most frequent mutational events in all genomes and were among the mutations for which a physical basis was first known. Yet mechanisms of gene duplication remain uncertain because formation rates are difficult to measure and mechanisms may vary with position in a genome. Duplications are compared here to deletions, which seem formally similar but can arise at very different rates by distinct mechanisms. Methods of assessing duplication rates and dependencies are described with several proposed formation mechanisms. Emphasis is placed on duplications formed in extensively studied experimental situations. Duplications studied in microbes are compared with those observed in metazoan cells, specifically those in genomes of cancer cells. Duplications, and especially their derived amplifications, are suggested to form by multistep processes often under positive selection for increased copy number. PMID:25646380

  15. Genome-wide identification and comparative expression analysis reveal a rapid expansion and functional divergence of duplicated genes in the WRKY gene family of cabbage, Brassica oleracea var. capitata.

    PubMed

    Yao, Qiu-Yang; Xia, En-Hua; Liu, Fei-Hu; Gao, Li-Zhi

    2015-02-15

    WRKY transcription factors (TFs), one of the ten largest TF families in higher plants, play important roles in regulating plant development and resistance. To date, little is known about the WRKY TF family in Brassica oleracea. Recently, the completed genome sequence of cabbage (B. oleracea var. capitata) allows us to systematically analyze WRKY genes in this species. A total of 148 WRKY genes were characterized and classified into seven subgroups that belong to three major groups. Phylogenetic and synteny analyses revealed that the repertoire of cabbage WRKY genes was derived from a common ancestor shared with Arabidopsis thaliana. The B. oleracea WRKY genes were found to be preferentially retained after the whole-genome triplication (WGT) event in its recent ancestor, suggesting that the WGT event had largely contributed to a rapid expansion of the WRKY gene family in B. oleracea. The analysis of RNA-Seq data from various tissues (i.e., roots, stems, leaves, buds, flowers and siliques) revealed that most of the identified WRKY genes were positively expressed in cabbage, and a large portion of them exhibited patterns of differential and tissue-specific expression, demonstrating that these gene members might play essential roles in plant developmental processes. Comparative analysis of the expression level among duplicated genes showed that gene expression divergence was evidently presented among cabbage WRKY paralogs, indicating functional divergence of these duplicated WRKY genes.

  16. Evolution of Gene Duplication in Plants1[OPEN

    PubMed Central

    2016-01-01

    Ancient duplication events and a high rate of retention of extant pairs of duplicate genes have contributed to an abundance of duplicate genes in plant genomes. These duplicates have contributed to the evolution of novel functions, such as the production of floral structures, induction of disease resistance, and adaptation to stress. Additionally, recent whole-genome duplications that have occurred in the lineages of several domesticated crop species, including wheat (Triticum aestivum), cotton (Gossypium hirsutum), and soybean (Glycine max), have contributed to important agronomic traits, such as grain quality, fruit shape, and flowering time. Therefore, understanding the mechanisms and impacts of gene duplication will be important to future studies of plants in general and of agronomically important crops in particular. In this review, we survey the current knowledge about gene duplication, including gene duplication mechanisms, the potential fates of duplicate genes, models explaining duplicate gene retention, the properties that distinguish duplicate from singleton genes, and the evolutionary impact of gene duplication. PMID:27288366

  17. Opsin gene duplication and divergence in ray-finned fish.

    PubMed

    Rennison, Diana J; Owens, Gregory L; Taylor, John S

    2012-03-01

    Opsin gene sequences were first reported in the 1980s. The goal of that research was to test the hypothesis that human opsins were members of a single gene family and that variation in human color vision was mediated by mutations in these genes. While the new data supported both hypotheses, the greatest contribution of this work was, arguably, that it provided the data necessary for PCR-based surveys in a diversity of other species. Such studies, and recent whole genome sequencing projects, have uncovered exceptionally large opsin gene repertoires in ray-finned fishes (taxon, Actinopterygii). Guppies and zebrafish, for example, have 10 visual opsin genes each. Here we review the duplication and divergence events that have generated these gene collections. Phylogenetic analyses revealed that large opsin gene repertories in fish have been generated by gene duplication and divergence events that span the age of the ray-finned fishes. Data from whole genome sequencing projects and from large-insert clones show that tandem duplication is the primary mode of opsin gene family expansion in fishes. In some instances gene conversion between tandem duplicates has obscured evolutionary relationships among genes and generated unique key-site haplotypes. We mapped amino acid substitutions at so-called key-sites onto phylogenies and this exposed many examples of convergence. We found that dN/dS values were higher on the branches of our trees that followed gene duplication than on branches that followed speciation events, suggesting that duplication relaxes constraints on opsin sequence evolution. Though the focus of the review is opsin sequence evolution, we also note that there are few clear connections between opsin gene repertoires and variation in spectral environment, morphological traits, or life history traits.

  18. Duplication and maintenance of the Myb genes of vertebrate animals.

    PubMed

    Davidson, Colin J; Guthrie, Erin E; Lipsick, Joseph S

    2013-02-15

    Gene duplication is an important means of generating new genes. The major mechanisms by which duplicated genes are preserved in the face of purifying selection are thought to be neofunctionalization, subfunctionalization, and increased gene dosage. However, very few duplicated gene families in vertebrate species have been analyzed by functional tests in vivo. We have therefore examined the three vertebrate Myb genes (c-Myb, A-Myb, and B-Myb) by cytogenetic map analysis, by sequence analysis, and by ectopic expression in Drosophila. We provide evidence that the vertebrate Myb genes arose by two rounds of regional genomic duplication. We found that ubiquitous expression of c-Myb and A-Myb, but not of B-Myb or Drosophila Myb, was lethal in Drosophila. Expression of any of these genes during early larval eye development was well tolerated. However, expression of c-Myb and A-Myb, but not of B-Myb or Drosophila Myb, during late larval eye development caused drastic alterations in adult eye morphology. Mosaic analysis implied that this eye phenotype was cell-autonomous. Interestingly, some of the eye phenotypes caused by the retroviral v-Myb oncogene and the normal c-Myb proto-oncogene from which v-Myb arose were quite distinct. Finally, we found that post-translational modifications of c-Myb by the GSK-3 protein kinase and by the Ubc9 SUMO-conjugating enzyme that normally occur in vertebrate cells can modify the eye phenotype caused by c-Myb in Drosophila. These results support a model in which the three Myb genes of vertebrates arose by two sequential duplications. The first duplication was followed by a subfunctionalization of gene expression, then neofunctionalization of protein function to yield a c/A-Myb progenitor. The duplication of this progenitor was followed by subfunctionalization of gene expression to give rise to tissue-specific c-Myb and A-Myb genes.

  19. A Family Harboring CMT1A Duplication and HNPP Deletion.

    PubMed

    Lee, Jung Hwa; Kang, Hee Jin; Song, Hyunseok; Hwang, Su Jin; Cho, Sun-Young; Kim, Sang-Beom; Kim, Joonki; Chung, Ki Wha; Choi, Byung-Ok

    2007-06-01

    Charcot-Marie-Tooth disease type 1A (CMT1A) is associated with duplication of chromosome 17p11.2-p12, whereas hereditary neuropathy with liability to pressure palsies (HNPP), which is an autosomal dominant neuropathy showing characteristics of recurrent pressure palsies, is associated with 17p11.2-p12 deletion. An altered gene dosage of PMP22 is believed to the main cause underlying the CMT1A and HNPP phenotypes. Although CMT1A and HNPP are associated with the same locus, there has been no report of these two mutations within a single family. We report a rare family harboring CMT1A duplication and HNPP deletion.

  20. Genome duplication and gene loss affect the evolution of heat shock transcription factor genes in legumes.

    PubMed

    Lin, Yongxiang; Cheng, Ying; Jin, Jing; Jin, Xiaolei; Jiang, Haiyang; Yan, Hanwei; Cheng, Beijiu

    2014-01-01

    Whole-genome duplication events (polyploidy events) and gene loss events have played important roles in the evolution of legumes. Here we show that the vast majority of Hsf gene duplications resulted from whole genome duplication events rather than tandem duplication, and significant differences in gene retention exist between species. By searching for intraspecies gene colinearity (microsynteny) and dating the age distributions of duplicated genes, we found that genome duplications accounted for 42 of 46 Hsf-containing segments in Glycine max, while paired segments were rarely identified in Lotus japonicas, Medicago truncatula and Cajanus cajan. However, by comparing interspecies microsynteny, we determined that the great majority of Hsf-containing segments in Lotus japonicas, Medicago truncatula and Cajanus cajan show extensive conservation with the duplicated regions of Glycine max. These segments formed 17 groups of orthologous segments. These results suggest that these regions shared ancient genome duplication with Hsf genes in Glycine max, but more than half of the copies of these genes were lost. On the other hand, the Glycine max Hsf gene family retained approximately 75% and 84% of duplicated genes produced from the ancient genome duplication and recent Glycine-specific genome duplication, respectively. Continuous purifying selection has played a key role in the maintenance of Hsf genes in Glycine max. Expression analysis of the Hsf genes in Lotus japonicus revealed their putative involvement in multiple tissue-/developmental stages and responses to various abiotic stimuli. This study traces the evolution of Hsf genes in legume species and demonstrates that the rates of gene gain and loss are far from equilibrium in different species.

  1. Drosophila melanogaster metallothionein genes: Selection for duplications

    SciTech Connect

    Lange, B.W.

    1989-01-01

    The metallothionein genes of Drosophila melanogaster, Mtn and Mto, may play an important role in heavy-metal detoxification. In order to investigate the possibility of increased selection for duplications of these genes in natural populations exposed to high levels of heavy metals, I compared the frequencies of such duplications among flies collected from metal-contaminated and non-contaminated orchards in Pennsylvania, Tennessee, and Georgia. Contaminated of collection sites and of local flies was confirmed by atomic absorption spectrosphotometry. Six-nucleotide-recognizing restriction enzyme analysis was used to screen 1666 wild third chromosomes for Mtn duplications. A subset (327) of these lines was screened for Mto duplications: none were found. Cadmium tolerance test performed on F{sub 2} progeny of wild females failed to detect a difference in tolerance levels between flies from contaminated orchards and flies from control orchards. Estimates of sequence diversity among a subsample (92) of the chromosomes used in the duplication survey, including all 27 Mtn duplication chromosomes, were obtained using four-nucleotide-recognizing restriction enzyme analysis.

  2. Tempo and Mode of Gene Duplication in Mammalian Ribosomal Protein Evolution

    PubMed Central

    Gajdosik, Matthew D.; Simon, Amanda; Nelson, Craig E.

    2014-01-01

    Gene duplication has been widely recognized as a major driver of evolutionary change and organismal complexity through the generation of multi-gene families. Therefore, understanding the forces that govern the evolution of gene families through the retention or loss of duplicated genes is fundamentally important in our efforts to study genome evolution. Previous work from our lab has shown that ribosomal protein (RP) genes constitute one of the largest classes of conserved duplicated genes in mammals. This result was surprising due to the fact that ribosomal protein genes evolve slowly and transcript levels are very tightly regulated. In our present study, we identified and characterized all RP duplicates in eight mammalian genomes in order to investigate the tempo and mode of ribosomal protein family evolution. We show that a sizable number of duplicates are transcriptionally active and are very highly conserved. Furthermore, we conclude that existing gene duplication models do not readily account for the preservation of a very large number of intact retroduplicated ribosomal protein (RT-RP) genes observed in mammalian genomes. We suggest that selection against dominant-negative mutations may underlie the unexpected retention and conservation of duplicated RP genes, and may shape the fate of newly duplicated genes, regardless of duplication mechanism. PMID:25369106

  3. Tempo and mode of gene duplication in mammalian ribosomal protein evolution.

    PubMed

    Dharia, Asav P; Obla, Ajay; Gajdosik, Matthew D; Simon, Amanda; Nelson, Craig E

    2014-01-01

    Gene duplication has been widely recognized as a major driver of evolutionary change and organismal complexity through the generation of multi-gene families. Therefore, understanding the forces that govern the evolution of gene families through the retention or loss of duplicated genes is fundamentally important in our efforts to study genome evolution. Previous work from our lab has shown that ribosomal protein (RP) genes constitute one of the largest classes of conserved duplicated genes in mammals. This result was surprising due to the fact that ribosomal protein genes evolve slowly and transcript levels are very tightly regulated. In our present study, we identified and characterized all RP duplicates in eight mammalian genomes in order to investigate the tempo and mode of ribosomal protein family evolution. We show that a sizable number of duplicates are transcriptionally active and are very highly conserved. Furthermore, we conclude that existing gene duplication models do not readily account for the preservation of a very large number of intact retroduplicated ribosomal protein (RT-RP) genes observed in mammalian genomes. We suggest that selection against dominant-negative mutations may underlie the unexpected retention and conservation of duplicated RP genes, and may shape the fate of newly duplicated genes, regardless of duplication mechanism.

  4. Phylogenetics of lophotrochozoan bHLH genes and the evolution of lineage-specific gene duplicates.

    PubMed

    Bao, Yongbo; Xu, Fei; Shimeld, Sebastian M

    2017-03-11

    The gain and loss of genes encoding transcription factors is of importance to understanding the evolution of gene regulatory complexity. The basic helix-loop-helix (bHLH) genes encode a large superfamily of transcription factors. We systematically classify the bHLH genes from five mollusc, two annelid and one brachiopod genomes, tracing the pattern of bHLH gene evolution across these poorly-studied Phyla. 56 to 88 bHLH genes were identified in each genome, with most identifiable as members of previously described bilaterian families, or of new families we define. Of such families only one, Mesp, appears lost by all these species. Additional duplications have also played a role in the evolution of the bHLH gene repertoire, with many new lophotrochozoan-, mollusc-, bivalve- or gastropod-specific genes defined. Using a combination of transcriptome mining, RT-PCR and in situ hybridization we compared the expression of several of these novel genes in tissues and embryos of the molluscs Crassostrea gigas and Patella vulgata, finding both conserved expression and evidence for neofunctionalisation. We also map the positions of the genes across these genomes, identifying numerous gene linkages. Some reflect recent paralogue divergence by tandem duplication, others are remnants of ancient tandem duplications dating to the lophotrochozoan or bilaterian common ancestors. These data are built into a model of the evolution of bHLH genes in molluscs, showing formidable evolutionary stasis at the family level but considerable within-family diversification by tandem gene duplication.

  5. Evolutionary history of the alpha2,8-sialyltransferase (ST8Sia) gene family: Tandem duplications in early deuterostomes explain most of the diversity found in the vertebrate ST8Sia genes

    PubMed Central

    2008-01-01

    Background The animal sialyltransferases, which catalyze the transfer of sialic acid to the glycan moiety of glycoconjugates, are subdivided into four families: ST3Gal, ST6Gal, ST6GalNAc and ST8Sia, based on acceptor sugar specificity and glycosidic linkage formed. Despite low overall sequence identity between each sialyltransferase family, all sialyltransferases share four conserved peptide motifs (L, S, III and VS) that serve as hallmarks for the identification of the sialyltransferases. Currently, twenty subfamilies have been described in mammals and birds. Examples of the four sialyltransferase families have also been found in invertebrates. Focusing on the ST8Sia family, we investigated the origin of the three groups of α2,8-sialyltransferases demonstrated in vertebrates to carry out poly-, oligo- and mono-α2,8-sialylation. Results We identified in the genome of invertebrate deuterostomes, orthologs to the common ancestor for each of the three vertebrate ST8Sia groups and a set of novel genes named ST8Sia EX, not found in vertebrates. All these ST8Sia sequences share a new conserved family-motif, named "C-term" that is involved in protein folding, via an intramolecular disulfide bridge. Interestingly, sequences from Branchiostoma floridae orthologous to the common ancestor of polysialyltransferases possess a polysialyltransferase domain (PSTD) and those orthologous to the common ancestor of oligosialyltransferases possess a new ST8Sia III-specific motif similar to the PSTD. In osteichthyans, we have identified two new subfamilies. In addition, we describe the expression profile of ST8Sia genes in Danio rerio. Conclusion Polysialylation appeared early in the deuterostome lineage. The recent release of several deuterostome genome databases and paralogons combined with synteny analysis allowed us to obtain insight into events at the gene level that led to the diversification of the ST8Sia genes, with their corresponding enzymatic activities, in both

  6. Comparative study of human mitochondrial proteome reveals extensive protein subcellular relocalization after gene duplications

    PubMed Central

    2009-01-01

    Background Gene and genome duplication is the principle creative force in evolution. Recently, protein subcellular relocalization, or neolocalization was proposed as one of the mechanisms responsible for the retention of duplicated genes. This hypothesis received support from the analysis of yeast genomes, but has not been tested thoroughly on animal genomes. In order to evaluate the importance of subcellular relocalizations for retention of duplicated genes in animal genomes, we systematically analyzed nuclear encoded mitochondrial proteins in the human genome by reconstructing phylogenies of mitochondrial multigene families. Results The 456 human mitochondrial proteins selected for this study were clustered into 305 gene families including 92 multigene families. Among the multigene families, 59 (64%) consisted of both mitochondrial and cytosolic (non-mitochondrial) proteins (mt-cy families) while the remaining 33 (36%) were composed of mitochondrial proteins (mt-mt families). Phylogenetic analyses of mt-cy families revealed three different scenarios of their neolocalization following gene duplication: 1) relocalization from mitochondria to cytosol, 2) from cytosol to mitochondria and 3) multiple subcellular relocalizations. The neolocalizations were most commonly enabled by the gain or loss of N-terminal mitochondrial targeting signals. The majority of detected subcellular relocalization events occurred early in animal evolution, preceding the evolution of tetrapods. Mt-mt protein families showed a somewhat different pattern, where gene duplication occurred more evenly in time. However, for both types of protein families, most duplication events appear to roughly coincide with two rounds of genome duplications early in vertebrate evolution. Finally, we evaluated the effects of inaccurate and incomplete annotation of mitochondrial proteins and found that our conclusion of the importance of subcellular relocalization after gene duplication on the genomic scale was

  7. Gene duplication followed by exon structure divergence substitutes for alternative splicing in zebrafish.

    PubMed

    Lambert, Matthew J; Olsen, Kyle G; Cooper, Cynthia D

    2014-08-10

    In this study we report novel findings regarding the evolutionary relationship between gene duplication and alternative splicing, two processes that increase proteomic diversity. By studying teleost fish, we find that gene duplication followed by exon structure divergence between paralogs, but not gene duplication alone, leads to a significant reduction in alternative splicing, as measured by both the proportion of genes that undergo alternative splicing as well as mean number of transcripts per gene. Additionally, we show that this effect is independent of gene family size and gene function. Furthermore, we provide evidence that the reduction in alternative splicing may be due to the partitioning of ancestral splice forms among the duplicate genes - a form of subfunctionalization. Taken together these results indicate that exon structure evolution subsequent to gene duplication may be a common substitute for alternative splicing.

  8. The birth of new genes by RNA- and DNA-mediated duplication during mammalian evolution.

    PubMed

    Jun, Jin; Ryvkin, Paul; Hemphill, Edward; Mandoiu, Ion; Nelson, Craig

    2009-10-01

    Gene duplication has long been recognized as a major force in genome evolution and has recently been recognized as an important source of individual variation. For many years, the origin of functional gene duplicates was assumed to be whole or partial genome duplication events, but recently retrotransposition has also been shown to contribute new functional protein coding genes and siRNA's. In this study, we utilize pseudogenes to recreate more complete gene family histories, and compare the rates of RNA and DNA-mediated duplication and new functional gene formation in five mammalian genomes. We find that RNA-mediated duplication occurs at a much higher and more variable rate than DNA-mediated duplication, and gives rise to many more duplicated sequences over time. We show that, while the chance of RNA-mediated duplicates becoming functional is much lower than that of their DNA-mediated counterparts, the higher rate of retrotransposition leads to nearly equal contributions of new genes by each mechanism. We also find that functional RNA-mediated duplicates are closer to neighboring genes than non-functional RNA-mediated copies, consistent with co-option of regulatory elements at the site of insertion. Overall, new genes derived from DNA and RNA-mediated duplication mechanisms are under similar levels of purifying selective pressure, but have broadly different functions. RNA-mediated duplication gives rise to a diversity of genes but is dominated by the highly expressed genes of RNA metabolic pathways. DNA-mediated duplication can copy regulatory material along with the protein coding region of the gene and often gives rise to classes of genes whose function are dependent on complex regulatory information. This mechanistic difference may in part explain why we find that mammalian protein families tend to evolve by either one mechanism or the other, but rarely by both. Supplementary Material has been provided (see online Supplementary Material at www.liebertonline.com ).

  9. Gene duplication within the Green Lineage: the case of TEL genes.

    PubMed

    Charon, Céline; Bruggeman, Quentin; Thareau, Vincent; Henry, Yves

    2012-09-01

    Recent years have witnessed a breathtaking increase in the availability of genome sequence data, providing evidence of the highly duplicate nature of eukaryotic genomes. Plants are exceptional among eukaryotic organisms in that duplicate loci compose a large fraction of their genomes, partly because of the frequent occurrence of polyploidy (or whole-genome duplication) events. Tandem gene duplication and transposition have also contributed to the large number of duplicated genes in plant genomes. Evolutionary analyses allowed the dynamics of duplicate gene evolution to be studied and several models were proposed. It seems that, over time, many duplicated genes were lost and some of those that were retained gained new functions and/or expression patterns (neofunctionalization) or subdivided their functions and/or expression patterns between them (subfunctionalization). Recent studies have provided examples of genes that originated by duplication with successive diversification within plants. In this review, we focused on the TEL (TERMINAL EAR1-like) genes to illustrate such mechanisms. Emerged from the mei2 gene family, these TEL genes are likely to be land plant-specific. Phylogenetic analyses revealed one or two TEL copies per diploid genome. TEL gene degeneration and loss in several Angiosperm species such as in poplar and maize seem to have occurred. In Arabidopsis thaliana, whose genome experienced at least three polyploidy events followed by massive gene loss and genomic reorganization, two TEL genes were retained and two new shorter TEL-like (MCT) genes emerged. Molecular and expression analyses suggest for these genes sub- and neofunctionalization events, but confirmation will come from their functional characterization.

  10. Genome changes after gene duplication: haploidy vs. diploidy.

    PubMed

    Xue, Cheng; Huang, Ren; Maxwell, Taylor J; Fu, Yun-Xin

    2010-09-01

    Since genome size and the number of duplicate genes observed in genomes increase from haploid to diploid organisms, diploidy might provide more evolutionary probabilities through gene duplication. It is still unclear how diploidy promotes genomic evolution in detail. In this study, we explored the evolution of segmental gene duplication in haploid and diploid populations by analytical and simulation approaches. Results show that (1) under the double null recessive (DNR) selective model, given the same recombination rate, the evolutionary trajectories and consequences are very similar between the same-size gene-pool haploid vs. diploid populations; (2) recombination enlarges the probability of preservation of duplicate genes in either haploid or diploid large populations, and haplo-insufficiency reinforces this effect; and (3) the loss of duplicate genes at the ancestor locus is limited under recombination while under complete linkage the loss of duplicate genes is always random at the ancestor and newly duplicated loci. Therefore, we propose a model to explain the advantage of diploidy: diploidy might facilitate the increase of recombination rate, especially under sexual reproduction; more duplicate genes are preserved under more recombination by originalization (by which duplicate genes are preserved intact at a special quasi-mutation-selection balance under the DNR or haplo-insufficient selective model), so genome sizes and the number of duplicate genes in diploid organisms become larger. Additionally, it is suggested that small genomic rearrangements due to the random loss of duplicate genes might be limited under recombination.

  11. Gene duplication and transfer events in plant mitochondria genome

    SciTech Connect

    Xiong Aisheng Peng Rihe; Zhuang Jing; Gao Feng; Zhu Bo; Fu Xiaoyan; Xue Yong; Jin Xiaofen; Tian Yongsheng; Zhao Wei; Yao Quanhong

    2008-11-07

    Gene or genome duplication events increase the amount of genetic material available to increase the genomic, and thereby phenotypic, complexity of organisms during evolution. Gene duplication and transfer events have been important to molecular evolution in all three domains of life, and may be the first step in the emergence of new gene functions. Gene transfer events have been proposed as another accelerator of evolution. The duplicated gene or genome, mainly nuclear, has been the subject of several recent reviews. In addition to the nuclear genome, organisms have organelle genomes, including mitochondrial genome. In this review, we briefly summarize gene duplication and transfer events in the plant mitochondrial genome.

  12. Gene duplication as a major force in evolution.

    PubMed

    Magadum, Santoshkumar; Banerjee, Urbi; Murugan, Priyadharshini; Gangapur, Doddabhimappa; Ravikesavan, Rajasekar

    2013-04-01

    Gene duplication is an important mechanism for acquiring new genes and creating genetic novelty in organisms. Many new gene functions have evolved through gene duplication and it has contributed tremendously to the evolution of developmental programmes in various organisms. Gene duplication can result from unequal crossing over, retroposition or chromosomal (or genome) duplication. Understanding the mechanisms that generate duplicate gene copies and the subsequent dynamics among gene duplicates is vital because these investigations shed light on localized and genomewide aspects of evolutionary forces shaping intra-specific and inter-specific genome contents, evolutionary relationships, and interactions. Based on whole-genome analysis of Arabidopsis thaliana, there is compelling evidence that angiosperms underwent two whole-genome duplication events early during their evolutionary history. Recent studies have shown that these events were crucial for creation of many important developmental and regulatory genes found in extant angiosperm genomes. Recent studies also provide strong indications that even yeast (Saccharomyces cerevisiae), with its compact genome, is in fact an ancient tetraploid. Gene duplication can provide new genetic material for mutation, drift and selection to act upon, the result of which is specialized or new gene functions. Without gene duplication the plasticity of a genome or species in adapting to changing environments would be severely limited. Whether a duplicate is retained depends upon its function, its mode of duplication, (i.e. whether it was duplicated during a whole-genome duplication event), the species in which it occurs, and its expression rate. The exaptation of preexisting secondary functions is an important feature in gene evolution, just as it is in morphological evolution.

  13. Preservation of duplicate genes by complementary, degenerative mutations.

    PubMed Central

    Force, A; Lynch, M; Pickett, F B; Amores, A; Yan, Y L; Postlethwait, J

    1999-01-01

    The origin of organismal complexity is generally thought to be tightly coupled to the evolution of new gene functions arising subsequent to gene duplication. Under the classical model for the evolution of duplicate genes, one member of the duplicated pair usually degenerates within a few million years by accumulating deleterious mutations, while the other duplicate retains the original function. This model further predicts that on rare occasions, one duplicate may acquire a new adaptive function, resulting in the preservation of both members of the pair, one with the new function and the other retaining the old. However, empirical data suggest that a much greater proportion of gene duplicates is preserved than predicted by the classical model. Here we present a new conceptual framework for understanding the evolution of duplicate genes that may help explain this conundrum. Focusing on the regulatory complexity of eukaryotic genes, we show how complementary degenerative mutations in different regulatory elements of duplicated genes can facilitate the preservation of both duplicates, thereby increasing long-term opportunities for the evolution of new gene functions. The duplication-degeneration-complementation (DDC) model predicts that (1) degenerative mutations in regulatory elements can increase rather than reduce the probability of duplicate gene preservation and (2) the usual mechanism of duplicate gene preservation is the partitioning of ancestral functions rather than the evolution of new functions. We present several examples (including analysis of a new engrailed gene in zebrafish) that appear to be consistent with the DDC model, and we suggest several analytical and experimental approaches for determining whether the complementary loss of gene subfunctions or the acquisition of novel functions are likely to be the primary mechanisms for the preservation of gene duplicates. For a newly duplicated paralog, survival depends on the outcome of the race between

  14. Phylogenetics of Lophotrochozoan bHLH Genes and the Evolution of Lineage-Specific Gene Duplicates

    PubMed Central

    Bao, Yongbo

    2017-01-01

    The gain and loss of genes encoding transcription factors is of importance to understanding the evolution of gene regulatory complexity. The basic helix–loop–helix (bHLH) genes encode a large superfamily of transcription factors. We systematically classify the bHLH genes from five mollusc, two annelid and one brachiopod genomes, tracing the pattern of bHLH gene evolution across these poorly studied Phyla. In total, 56–88 bHLH genes were identified in each genome, with most identifiable as members of previously described bilaterian families, or of new families we define. Of such families only one, Mesp, appears lost by all these species. Additional duplications have also played a role in the evolution of the bHLH gene repertoire, with many new lophotrochozoan-, mollusc-, bivalve-, or gastropod-specific genes defined. Using a combination of transcriptome mining, RT-PCR, and in situ hybridization we compared the expression of several of these novel genes in tissues and embryos of the molluscs Crassostrea gigas and Patella vulgata, finding both conserved expression and evidence for neofunctionalization. We also map the positions of the genes across these genomes, identifying numerous gene linkages. Some reflect recent paralog divergence by tandem duplication, others are remnants of ancient tandem duplications dating to the lophotrochozoan or bilaterian common ancestors. These data are built into a model of the evolution of bHLH genes in molluscs, showing formidable evolutionary stasis at the family level but considerable within-family diversification by tandem gene duplication. PMID:28338988

  15. Duplicate gene divergence by changes in microRNA binding sites in Arabidopsis and Brassica.

    PubMed

    Wang, Sishuo; Adams, Keith L

    2015-02-02

    Gene duplication provides large numbers of new genes that can lead to the evolution of new functions. Duplicated genes can diverge by changes in sequences, expression patterns, and functions. MicroRNAs play an important role in the regulation of gene expression in many eukaryotes. After duplication, two paralogs may diverge in their microRNA binding sites, which might impact their expression and function. Little is known about conservation and divergence of microRNA binding sites in duplicated genes in plants. We analyzed microRNA binding sites in duplicated genes in Arabidopsis thaliana and Brassica rapa. We found that duplicates are more often targeted by microRNAs than singletons. The vast majority of duplicated genes in A. thaliana with microRNA binding sites show divergence in those sites between paralogs. Analysis of microRNA binding sites in genes derived from the ancient whole-genome triplication in B. rapa also revealed extensive divergence. Paralog pairs with divergent microRNA binding sites show more divergence in expression patterns compared with paralog pairs with the same microRNA binding sites in Arabidopsis. Close to half of the cases of binding site divergence are caused by microRNAs that are specific to the Arabidopsis genus, indicating evolutionarily recent gain of binding sites after target gene duplication. We also show rapid evolution of microRNA binding sites in a jacalin gene family. Our analyses reveal a dynamic process of changes in microRNA binding sites after gene duplication in Arabidopsis and highlight the role of microRNA regulation in the divergence and contrasting evolutionary fates of duplicated genes.

  16. Duplicate Gene Divergence by Changes in MicroRNA Binding Sites in Arabidopsis and Brassica

    PubMed Central

    Wang, Sishuo; Adams, Keith L.

    2015-01-01

    Gene duplication provides large numbers of new genes that can lead to the evolution of new functions. Duplicated genes can diverge by changes in sequences, expression patterns, and functions. MicroRNAs play an important role in the regulation of gene expression in many eukaryotes. After duplication, two paralogs may diverge in their microRNA binding sites, which might impact their expression and function. Little is known about conservation and divergence of microRNA binding sites in duplicated genes in plants. We analyzed microRNA binding sites in duplicated genes in Arabidopsis thaliana and Brassica rapa. We found that duplicates are more often targeted by microRNAs than singletons. The vast majority of duplicated genes in A. thaliana with microRNA binding sites show divergence in those sites between paralogs. Analysis of microRNA binding sites in genes derived from the ancient whole-genome triplication in B. rapa also revealed extensive divergence. Paralog pairs with divergent microRNA binding sites show more divergence in expression patterns compared with paralog pairs with the same microRNA binding sites in Arabidopsis. Close to half of the cases of binding site divergence are caused by microRNAs that are specific to the Arabidopsis genus, indicating evolutionarily recent gain of binding sites after target gene duplication. We also show rapid evolution of microRNA binding sites in a jacalin gene family. Our analyses reveal a dynamic process of changes in microRNA binding sites after gene duplication in Arabidopsis and highlight the role of microRNA regulation in the divergence and contrasting evolutionary fates of duplicated genes. PMID:25644246

  17. Impact of recurrent gene duplication on adaptation of plant genomes

    PubMed Central

    2014-01-01

    Background Recurrent gene duplication and retention played an important role in angiosperm genome evolution. It has been hypothesized that these processes contribute significantly to plant adaptation but so far this hypothesis has not been tested at the genome scale. Results We studied available sequenced angiosperm genomes to assess the frequency of positive selection footprints in lineage specific expanded (LSE) gene families compared to single-copy genes using a dN/dS-based test in a phylogenetic framework. We found 5.38% of alignments in LSE genes with codons under positive selection. In contrast, we found no evidence for codons under positive selection in the single-copy reference set. An analysis at the branch level shows that purifying selection acted more strongly on single-copy genes than on LSE gene clusters. Moreover we detect significantly more branches indicating evolution under positive selection and/or relaxed constraint in LSE genes than in single-copy genes. Conclusions In this – to our knowledge –first genome-scale study we provide strong empirical support for the hypothesis that LSE genes fuel adaptation in angiosperms. Our conservative approach for detecting selection footprints as well as our results can be of interest for further studies on (plant) gene family evolution. PMID:24884640

  18. Effect of Incomplete Lineage Sorting On Tree-Reconciliation-Based Inference of Gene Duplication.

    PubMed

    Zheng, Yu; Zhang, Louxin

    2014-01-01

    In the tree reconciliation approach to infer the duplication history of a gene family, the gene (family) tree is compared to the corresponding species tree. Incomplete lineage sorting (ILS) gives rise to stochastic variation in the topology of a gene tree and hence likely introduces false duplication events when a tree reconciliation method is used. We quantify the effect of ILS on gene duplication inference in a species tree in terms of the expected number of false duplication events inferred from reconciling a random gene tree, which occurs with a probability predicted in coalescent theory, and the species tree. We computationally examine the relationship between the effect of ILS on duplication inference in a species tree and its topological parameters. Our findings suggest that ILS may cause non-negligible bias on duplication inference, particularly on an asymmetric species tree. Hence, when gene duplication is inferred via tree reconciliation or any other approach that takes gene tree topology into account, the ILS-induced bias should be examined cautiously.

  19. Duplication of chicken defensin7 gene generated by gene conversion and homologous recombination

    PubMed Central

    Lee, Mi Ok; Bornelöv, Susanne; Andersson, Leif; Lamont, Susan J.; Chen, Junfeng; Womack, James E.

    2016-01-01

    Defensins constitute an evolutionary conserved family of cationic antimicrobial peptides that play a key role in host innate immune responses to infection. Defensin genes generally reside in complex genomic regions that are prone to structural variation, and defensin genes exhibit extensive copy number variation in humans and in other species. Copy number variation of defensin genes was examined in inbred lines of Leghorn and Fayoumi chickens, and a duplication of defensin7 was discovered in the Fayoumi breed. Analysis of junction sequences confirmed the occurrence of a simple tandem duplication of defensin7 with sequence identity at the junction, suggesting nonallelic homologous recombination between defensin7 and defensin6. The duplication event generated two chimeric promoters that are best explained by gene conversion followed by homologous recombination. Expression of defensin7 was not elevated in animals with two genes despite both genes being transcribed in the tissues examined. Computational prediction of promoter regions revealed the presence of several putative transcription factor binding sites generated by the duplication event. These data provide insight into the evolution and possible function of large gene families and specifically, the defensins. PMID:27849592

  20. Duplication of chicken defensin7 gene generated by gene conversion and homologous recombination.

    PubMed

    Lee, Mi Ok; Bornelöv, Susanne; Andersson, Leif; Lamont, Susan J; Chen, Junfeng; Womack, James E

    2016-11-29

    Defensins constitute an evolutionary conserved family of cationic antimicrobial peptides that play a key role in host innate immune responses to infection. Defensin genes generally reside in complex genomic regions that are prone to structural variation, and defensin genes exhibit extensive copy number variation in humans and in other species. Copy number variation of defensin genes was examined in inbred lines of Leghorn and Fayoumi chickens, and a duplication of defensin7 was discovered in the Fayoumi breed. Analysis of junction sequences confirmed the occurrence of a simple tandem duplication of defensin7 with sequence identity at the junction, suggesting nonallelic homologous recombination between defensin7 and defensin6 The duplication event generated two chimeric promoters that are best explained by gene conversion followed by homologous recombination. Expression of defensin7 was not elevated in animals with two genes despite both genes being transcribed in the tissues examined. Computational prediction of promoter regions revealed the presence of several putative transcription factor binding sites generated by the duplication event. These data provide insight into the evolution and possible function of large gene families and specifically, the defensins.

  1. Matrix Gla protein and osteocalcin: from gene duplication to neofunctionalization.

    PubMed

    Cancela, M Leonor; Laizé, Vincent; Conceição, Natércia

    2014-11-01

    Osteocalcin (OC or bone Gla protein, BGP) and matrix Gla protein (MGP) are two members of the growing family of vitamin K-dependent (VKD) proteins. They were the first VKD proteins found not to be involved in coagulation and synthesized outside the liver. Both proteins were isolated from bone although it is now known that only OC is synthesized by bone cells under normal physiological conditions, but since both proteins can bind calcium and hydroxyapatite, they can also accumulate in bone. Both OC and MGP share similar structural features, both in terms of protein domains and gene organization. OC gene is likely to have appeared from MGP through a tandem gene duplication that occurred concomitantly with the appearance of the bony vertebrates. Despite their relatively close relationship and the fact that both can bind calcium and affect mineralization, their functions are not redundant and they also have other unrelated functions. Interestingly, these two proteins appear to have followed quite different evolutionary strategies in order to acquire novel functionalities, with OC following a gene duplication strategy while MGP variability was obtained mostly by the use of multiple promoters and alternative splicing, leading to proteins with additional functional characteristics and alternative gene regulatory pathways.

  2. On the retention of gene duplicates prone to dominant deleterious mutations.

    PubMed

    Malaguti, Giulia; Singh, Param Priya; Isambert, Hervé

    2014-05-01

    Recent studies have shown that gene families from different functional categories have been preferentially expanded either by small scale duplication (SSD) or by whole-genome duplication (WGD). In particular, gene families prone to dominant deleterious mutations and implicated in cancers and other genetic diseases in human have been greatly expanded through two rounds of WGD dating back from early vertebrates. Here, we strengthen this intriguing observation, showing that human oncogenes involved in different primary tumors have retained many WGD duplicates compared to other human genes. In order to rationalize this evolutionary outcome, we propose a consistent population genetics model to analyze the retention of SSD and WGD duplicates taking into account their propensity to acquire dominant deleterious mutations. We solve a deterministic haploid model including initial duplicated loci, their retention through sub-functionalization or their neutral loss-of-function or deleterious gain-of-function at one locus. Extensions to diploid genotypes are presented and population size effects are analyzed using stochastic simulations. The only difference between the SSD and WGD scenarios is the initial number of individuals with duplicated loci. While SSD duplicates need to spread through the entire population from a single individual to reach fixation, WGD duplicates are de facto fixed in the small initial post-WGD population arising through the ploidy incompatibility between post-WGD individuals and the rest of the pre-WGD population. WGD duplicates prone to dominant deleterious mutations are then shown to be indirectly selected through purifying selection in post-WGD species, whereas SSD duplicates typically require positive selection. These results highlight the long-term evolution mechanisms behind the surprising accumulation of WGD duplicates prone to dominant deleterious mutations and are shown to be consistent with cancer genome data on the prevalence of human

  3. Differential retention and divergent resolution of duplicate genes following whole-genome duplication

    PubMed Central

    McGrath, Casey L.; Gout, Jean-Francois; Johri, Parul; Doak, Thomas G.

    2014-01-01

    The Paramecium aurelia complex is a group of 15 species that share at least three past whole-genome duplications (WGDs). The macronuclear genome sequences of P. biaurelia and P. sexaurelia are presented and compared to the published sequence of P. tetraurelia. Levels of duplicate-gene retention from the recent WGD differ by >10% across species, with P. sexaurelia losing significantly more genes than P. biaurelia or P. tetraurelia. In addition, historically high rates of gene conversion have homogenized WGD paralogs, probably extending the paralogs’ lifetimes. The probability of duplicate retention is positively correlated with GC content and expression level; ribosomal proteins, transcription factors, and intracellular signaling proteins are overrepresented among maintained duplicates. Finally, multiple sources of evidence indicate that P. sexaurelia diverged from the two other lineages immediately following, or perhaps concurrent with, the recent WGD, with approximately half of gene losses between P. tetraurelia and P. sexaurelia representing divergent gene resolutions (i.e., silencing of alternative paralogs), as expected for random duplicate loss between these species. Additionally, though P. biaurelia and P. tetraurelia diverged from each other much later, there are still more than 100 cases of divergent resolution between these two species. Taken together, these results indicate that divergent resolution of duplicate genes between lineages acts to reinforce reproductive isolation between species in the Paramecium aurelia complex. PMID:25085612

  4. The probability of duplicate gene preservation by subfunctionalization.

    PubMed Central

    Lynch, M; Force, A

    2000-01-01

    It has often been argued that gene-duplication events are most commonly followed by a mutational event that silences one member of the pair, while on rare occasions both members of the pair are preserved as one acquires a mutation with a beneficial function and the other retains the original function. However, empirical evidence from genome duplication events suggests that gene duplicates are preserved in genomes far more commonly and for periods far in excess of the expectations under this model, and whereas some gene duplicates clearly evolve new functions, there is little evidence that this is the most common mechanism of duplicate-gene preservation. An alternative hypothesis is that gene duplicates are frequently preserved by subfunctionalization, whereby both members of a pair experience degenerative mutations that reduce their joint levels and patterns of activity to that of the single ancestral gene. We consider the ways in which the probability of duplicate-gene preservation by such complementary mutations is modified by aspects of gene structure, degree of linkage, mutation rates and effects, and population size. Even if most mutations cause complete loss-of-subfunction, the probability of duplicate-gene preservation can be appreciable if the long-term effective population size is on the order of 10(5) or smaller, especially if there are more than two independently mutable subfunctions per locus. Even a moderate incidence of partial loss-of-function mutations greatly elevates the probability of preservation. The model proposed herein leads to quantitative predictions that are consistent with observations on the frequency of long-term duplicate gene preservation and with observations that indicate that a common fate of the members of duplicate-gene pairs is the partitioning of tissue-specific patterns of expression of the ancestral gene. PMID:10629003

  5. Recurrent tandem gene duplication gave rise to functionally divergent genes in Drosophila.

    PubMed

    Fan, Chuanzhu; Chen, Ying; Long, Manyuan

    2008-07-01

    Tandem gene duplication is one of the major gene duplication mechanisms in eukaryotes, as illustrated by the prevalence of gene family clusters. Tandem duplicated paralogs usually share the same regulatory element, and as a consequence, they are likely to perform similar biological functions. Here, we provide an example of a newly evolved tandem duplicate acquiring novel functions, which were driven by positive selection. CG32708, CG32706, and CG6999 are 3 clustered genes residing in the X chromosome of Drosophila melanogaster. CG6999 and CG32708 have been examined for their molecular population genetic properties (Thornton and Long 2005). We further investigated the evolutionary forces acting on these genes with greater sample sizes and a broader approach that incorporate between-species divergence, using more variety of statistical methods. We explored the possible functional implications by characterizing the tissue-specific and developmental expression patterns of these genes. Sequence comparison of species within D. melanogaster subgroup reveals that this 3-gene cluster was created by 2 rounds of tandem gene duplication in the last 5 Myr. Based on phylogenetic analysis, CG32708 is clearly the parental copy that is shared by all species. CG32706 appears to have originated in the ancestor of Drosophila simulans and D. melanogaster about 5 Mya, and CG6999 is the newest duplicate that is unique to D. melanogaster. All 3 genes have different expression profiles, and CG6999 has in addition acquired a novel transcript. Biased polymorphism frequency spectrum, linkage disequilibrium, nucleotide substitution, and McDonald-Kreitman analyses suggested that the evolution of CG6999 and CG32706 were driven by positive Darwinian selection.

  6. Whole Genome and Tandem Duplicate Retention Facilitated Glucosinolate Pathway Diversification in the Mustard Family

    PubMed Central

    Hofberger, Johannes A.; Lyons, Eric; Edger, Patrick P.; Chris Pires, J.; Eric Schranz, M.

    2013-01-01

    Plants share a common history of successive whole-genome duplication (WGD) events retaining genomic patterns of duplicate gene copies (ohnologs) organized in conserved syntenic blocks. Duplication was often proposed to affect the origin of novel traits during evolution. However, genetic evidence linking WGD to pathway diversification is scarce. We show that WGD and tandem duplication (TD) accelerated genetic versatility of plant secondary metabolism, exemplified with the glucosinolate (GS) pathway in the mustard family. GS biosynthesis is a well-studied trait, employing at least 52 biosynthetic and regulatory genes in the model plant Arabidopsis. In a phylogenomics approach, we identified 67 GS loci in Aethionema arabicum of the tribe Aethionemae, sister group to all mustard family members. All but one of the Arabidopsis GS gene families evolved orthologs in Aethionema and all but one of the orthologous sequence pairs exhibit synteny. The 45% fraction of duplicates among all protein-coding genes in Arabidopsis was increased to 95% and 97% for Arabidopsis and Aethionema GS pathway inventory, respectively. Compared with the 22% average for all protein-coding genes in Arabidopsis, 52% and 56% of Aethionema and Arabidopsis GS loci align to ohnolog copies dating back to the last common WGD event. Although 15% of all Arabidopsis genes are organized in tandem arrays, 45% and 48% of GS loci in Arabidopsis and Aethionema descend from TD, respectively. We describe a sequential combination of TD and WGD events driving gene family extension, thereby expanding the evolutionary playground for functional diversification and thus potential novelty and success. PMID:24171911

  7. Gene duplication models for directed networks with limits on growth

    NASA Astrophysics Data System (ADS)

    Enemark, Jakob; Sneppen, Kim

    2007-11-01

    Background: Duplication of genes is important for evolution of molecular networks. Many authors have therefore considered gene duplication as a driving force in shaping the topology of molecular networks. In particular it has been noted that growth via duplication would act as an implicit means of preferential attachment, and thereby provide the observed broad degree distributions of molecular networks. Results: We extend current models of gene duplication and rewiring by including directions and the fact that molecular networks are not a result of unidirectional growth. We introduce upstream sites and downstream shapes to quantify potential links during duplication and rewiring. We find that this in itself generates the observed scaling of transcription factors for genome sites in prokaryotes. The dynamical model can generate a scale-free degree distribution, p(k)\\propto 1/k^{\\gamma } , with exponent γ = 1 in the non-growing case, and with γ>1 when the network is growing. Conclusions: We find that duplication of genes followed by substantial recombination of upstream regions could generate features of genetic regulatory networks. Our steady state degree distribution is however too broad to be consistent with data, thereby suggesting that selective pruning acts as a main additional constraint on duplicated genes. Our analysis shows that gene duplication can only be a main cause for the observed broad degree distributions if there are also substantial recombinations between upstream regions of genes.

  8. Familial lipoprotein lipase deficiency: a case of compound heterozygosity of a novel duplication (R44Kfs*4) and a common mutation (N291S) in the lipoprotein lipase gene.

    PubMed

    Overgaard, Martin; Brasen, Claus Lohman; Svaneby, Dea; Feddersen, Søren; Nybo, Mads

    2013-07-01

    Familial lipoprotein lipase (LPL) deficiency (FLLD) is a rare autosomal recessive genetic disorder caused by homozygous or compound heterozygous mutations in the LPL gene. FLLD individuals usually express an impaired or non-functional LPL enzyme with low or absent triglyceride (TG) hydrolysis activity causing severe hypertriglyceridaemia. Here we report a case of FLLD in a 29-year-old man, who initially presented with eruptive cutaneous xanthomata, elevated plasma TG concentration but no other co-morbidities. Subsequent genetic testing of the patient revealed compound heterozygosity of a novel duplication (p.R44Kfs*4) leading to a premature stop codon in exon 2 and a known mutation (N291S) in exon 5 of the LPL gene. Further biochemical analysis of the patient's postheparin plasma confirmed a reduction of total lipase activity compared with his heterozygous father carrying the common N291S mutation and to a healthy control. Also the patient showed increased (1.85-fold) activity of hepatic lipase (HL), indicating a functional link between HL and LPL. In summary, we report a case of FLLD caused by compound heterozygosity of a new duplication and a common mutation in the LPL gene, resulting in residual LPL activity. With such mutations, individuals may not receive a diagnosis before classical FLLD symptoms appear later in adulthood. Nevertheless, early diagnosis and lipid-lowering treatment may favour a reduced risk of premature cardiovascular disease or acute pancreatitis in such individuals.

  9. An Approximation Algorithm for Computing a Parsimonious First Speciation in the Gene Duplication Model

    NASA Astrophysics Data System (ADS)

    Ouangraoua, Aïda; Swenson, Krister M.; Chauve, Cedric

    We consider the following problem: given a forest of gene family trees on a set of genomes, find a first speciation which splits these genomes into two subsets and minimizes the number of gene duplications that happened before this speciation. We call this problem the Minimum Duplication Bipartition Problem. Using a generalization of the Minimum Edge-Cut Problem, known as Submodular Function Minimization, we propose a polynomial time and space 2-approximation algorithm for the Minimum Duplication Bipartition Problem. We illustrate the potential of this algorithm on both synthetic and real data.

  10. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution.

    PubMed

    Clarke, Thomas H; Garb, Jessica E; Hayashi, Cheryl Y; Arensburger, Peter; Ayoub, Nadia A

    2015-06-08

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae).

  11. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution

    PubMed Central

    Clarke, Thomas H.; Garb, Jessica E.; Hayashi, Cheryl Y.; Arensburger, Peter; Ayoub, Nadia A.

    2015-01-01

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae). PMID:26058392

  12. Evolution of pigment synthesis pathways by gene and genome duplication in fish

    PubMed Central

    Braasch, Ingo; Schartl, Manfred; Volff, Jean-Nicolas

    2007-01-01

    Background Coloration and color patterning belong to the most diverse phenotypic traits in animals. Particularly, teleost fishes possess more pigment cell types than any other group of vertebrates. As the result of an ancient fish-specific genome duplication (FSGD), teleost genomes might contain more copies of genes involved in pigment cell development than tetrapods. No systematic genomic inventory allowing to test this hypothesis has been drawn up so far for pigmentation genes in fish, and almost nothing is known about the evolution of these genes in different fish lineages. Results Using a comparative genomic approach including phylogenetic reconstructions and synteny analyses, we have studied two major pigment synthesis pathways in teleost fish, the melanin and the pteridine pathways, with respect to different types of gene duplication. Genes encoding three of the four enzymes involved in the synthesis of melanin from tyrosine have been retained as duplicates after the FSGD. In the pteridine pathway, two cases of duplicated genes originating from the FSGD as well as several lineage-specific gene duplications were observed. In both pathways, genes encoding the rate-limiting enzymes, tyrosinase and GTP-cyclohydrolase I (GchI), have additional paralogs in teleosts compared to tetrapods, which have been generated by different modes of duplication. We have also observed a previously unrecognized diversity of gchI genes in vertebrates. In addition, we have found evidence for divergent resolution of duplicated pigmentation genes, i.e., differential gene loss in divergent teleost lineages, particularly in the tyrosinase gene family. Conclusion Mainly due to the FSGD, teleost fishes apparently have a greater repertoire of pigment synthesis genes than any other vertebrate group. Our results support an important role of the FSGD and other types of duplication in the evolution of pigmentation in fish. PMID:17498288

  13. Gene duplication is infrequent in the recent evolutionary history of RNA viruses.

    PubMed

    Simon-Loriere, Etienne; Holmes, Edward C

    2013-06-01

    Gene duplication generates genetic novelty and redundancy and is a major mechanism of evolutionary change in bacteria and eukaryotes. To date, however, gene duplication has been reported only rarely in RNA viruses. Using a conservative BLAST approach we systematically screened for the presence of duplicated (i.e., paralogous) proteins in all RNA viruses for which full genome sequences are publicly available. Strikingly, we found only nine significantly supported cases of gene duplication, two of which are newly described here--in the 25 and 26 kDa proteins of Beet necrotic yellow vein virus (genus Benyvirus) and in the U1 and U2 proteins of Wongabel virus (family Rhabdoviridae). Hence, gene duplication has occurred at a far lower frequency in the recent evolutionary history of RNA viruses than in other organisms. Although the rapidity of RNA virus evolution means that older gene duplication events will be difficult to detect through sequence-based analyses alone, it is likely that specific features of RNA virus biology, and particularly intrinsic constraints on genome size, reduce the likelihood of the fixation and maintenance of duplicated genes.

  14. Processes of fungal proteome evolution and gain of function: gene duplication and domain rearrangement

    NASA Astrophysics Data System (ADS)

    Cohen-Gihon, Inbar; Sharan, Roded; Nussinov, Ruth

    2011-06-01

    During evolution, organisms have gained functional complexity mainly by modifying and improving existing functioning systems rather than creating new ones ab initio. Here we explore the interplay between two processes which during evolution have had major roles in the acquisition of new functions: gene duplication and protein domain rearrangements. We consider four possible evolutionary scenarios: gene families that have undergone none of these event types; only gene duplication; only domain rearrangement, or both events. We characterize each of the four evolutionary scenarios by functional attributes. Our analysis of ten fungal genomes indicates that at least for the fungi clade, species significantly appear to gain complexity by gene duplication accompanied by the expansion of existing domain architectures via rearrangements. We show that paralogs gaining new domain architectures via duplication tend to adopt new functions compared to paralogs that preserve their domain architectures. We conclude that evolution of protein families through gene duplication and domain rearrangement is correlated with their functional properties. We suggest that in general, new functions are acquired via the integration of gene duplication and domain rearrangements rather than each process acting independently.

  15. The probability of preservation of a newly arisen gene duplicate.

    PubMed Central

    Lynch, M; O'Hely, M; Walsh, B; Force, A

    2001-01-01

    Newly emerging data from genome sequencing projects suggest that gene duplication, often accompanied by genetic map changes, is a common and ongoing feature of all genomes. This raises the possibility that differential expansion/contraction of various genomic sequences may be just as important a mechanism of phenotypic evolution as changes at the nucleotide level. However, the population-genetic mechanisms responsible for the success vs. failure of newly arisen gene duplicates are poorly understood. We examine the influence of various aspects of gene structure, mutation rates, degree of linkage, and population size (N) on the joint fate of a newly arisen duplicate gene and its ancestral locus. Unless there is active selection against duplicate genes, the probability of permanent establishment of such genes is usually no less than 1/(4N) (half of the neutral expectation), and it can be orders of magnitude greater if neofunctionalizing mutations are common. The probability of a map change (reassignment of a key function of an ancestral locus to a new chromosomal location) induced by a newly arisen duplicate is also generally >1/(4N) for unlinked duplicates, suggesting that recurrent gene duplication and alternative silencing may be a common mechanism for generating microchromosomal rearrangements responsible for postreproductive isolating barriers among species. Relative to subfunctionalization, neofunctionalization is expected to become a progressively more important mechanism of duplicate-gene preservation in populations with increasing size. However, even in large populations, the probability of neofunctionalization scales only with the square of the selective advantage. Tight linkage also influences the probability of duplicate-gene preservation, increasing the probability of subfunctionalization but decreasing the probability of neofunctionalization. PMID:11779815

  16. The probability of preservation of a newly arisen gene duplicate.

    PubMed

    Lynch, M; O'Hely, M; Walsh, B; Force, A

    2001-12-01

    Newly emerging data from genome sequencing projects suggest that gene duplication, often accompanied by genetic map changes, is a common and ongoing feature of all genomes. This raises the possibility that differential expansion/contraction of various genomic sequences may be just as important a mechanism of phenotypic evolution as changes at the nucleotide level. However, the population-genetic mechanisms responsible for the success vs. failure of newly arisen gene duplicates are poorly understood. We examine the influence of various aspects of gene structure, mutation rates, degree of linkage, and population size (N) on the joint fate of a newly arisen duplicate gene and its ancestral locus. Unless there is active selection against duplicate genes, the probability of permanent establishment of such genes is usually no less than 1/(4N) (half of the neutral expectation), and it can be orders of magnitude greater if neofunctionalizing mutations are common. The probability of a map change (reassignment of a key function of an ancestral locus to a new chromosomal location) induced by a newly arisen duplicate is also generally >1/(4N) for unlinked duplicates, suggesting that recurrent gene duplication and alternative silencing may be a common mechanism for generating microchromosomal rearrangements responsible for postreproductive isolating barriers among species. Relative to subfunctionalization, neofunctionalization is expected to become a progressively more important mechanism of duplicate-gene preservation in populations with increasing size. However, even in large populations, the probability of neofunctionalization scales only with the square of the selective advantage. Tight linkage also influences the probability of duplicate-gene preservation, increasing the probability of subfunctionalization but decreasing the probability of neofunctionalization.

  17. Three neuropeptide Y receptor genes in the spiny dogfish, Squalus acanthias, support en bloc duplications in early vertebrate evolution.

    PubMed

    Salaneck, Erik; Ardell, David H; Larson, Earl T; Larhammar, Dan

    2003-08-01

    It has been debated whether the increase in gene number during early vertebrate evolution was due to multiple independent gene duplications or synchronous duplications of many genes. We describe here the cloning of three neuropeptide Y (NPY) receptor genes belonging to the Y1 subfamily in the spiny dogfish, Squalus acanthias, a cartilaginous fish. The three genes are orthologs of the mammalian subtypes Y1, Y4, and Y6, which are located in paralogous gene regions on different chromosomes in mammals. Thus, these genes arose by duplications of a chromosome region before the radiation of gnathostomes (jawed vertebrates). Estimates of duplication times from linearized trees together with evidence from other gene families supports two rounds of chromosome duplications or tetraploidizations early in vertebrate evolution. The anatomical distribution of mRNA was determined by reverse-transcriptase PCR and was found to differ from mammals, suggesting differential functional diversification of the new gene copies during the radiation of the vertebrate classes.

  18. Gene duplication, genome duplication, and the functional diversification of vertebrate globins

    PubMed Central

    Storz, Jay F.; Opazo, Juan C.; Hoffmann, Federico G.

    2015-01-01

    The functional diversification of the vertebrate globin gene superfamily provides an especially vivid illustration of the role of gene duplication and whole-genome duplication in promoting evolutionary innovation. For example, key globin proteins that evolved specialized functions in various aspects of oxidative metabolism and oxygen signaling pathways (hemoglobin [Hb], myoglobin [Mb], and cytoglobin [Cygb]) trace their origins to two whole-genome duplication events in the stem lineage of vertebrates. The retention of the proto-Hb and Mb genes in the ancestor of jawed vertebrates permitted a physiological division of labor between the oxygen-carrier function of Hb and the oxygen-storage function of Mb. In the Hb gene lineage, a subsequent tandem gene duplication gave rise to the proto α- and β-globin genes, which permitted the formation of multimeric Hbs composed of unlike subunits (α2β2). The evolution of this heteromeric quaternary structure was central to the emergence of Hb as a specialized oxygen-transport protein because it provided a mechanism for cooperative oxygen-binding and allosteric regulatory control. Subsequent rounds of duplication and divergence have produced diverse repertoires of α- and β-like globin genes that are ontogenetically regulated such that functionally distinct Hb isoforms are expressed during different stages of prenatal development and postnatal life. In the ancestor of jawless fishes, the proto Mb and Hb genes appear to have been secondarily lost, and the Cygb homolog evolved a specialized respiratory function in blood-oxygen transport. Phylogenetic and comparative genomic analyses of the vertebrate globin gene superfamily have revealed numerous instances in which paralogous globins have convergently evolved similar expression patterns and/or similar functional specializations in different organismal lineages. PMID:22846683

  19. Gene duplication, genome duplication, and the functional diversification of vertebrate globins.

    PubMed

    Storz, Jay F; Opazo, Juan C; Hoffmann, Federico G

    2013-02-01

    The functional diversification of the vertebrate globin gene superfamily provides an especially vivid illustration of the role of gene duplication and whole-genome duplication in promoting evolutionary innovation. For example, key globin proteins that evolved specialized functions in various aspects of oxidative metabolism and oxygen signaling pathways (hemoglobin [Hb], myoglobin [Mb], and cytoglobin [Cygb]) trace their origins to two whole-genome duplication events in the stem lineage of vertebrates. The retention of the proto-Hb and Mb genes in the ancestor of jawed vertebrates permitted a physiological division of labor between the oxygen-carrier function of Hb and the oxygen-storage function of Mb. In the Hb gene lineage, a subsequent tandem gene duplication gave rise to the proto α- and β-globin genes, which permitted the formation of multimeric Hbs composed of unlike subunits (α(2)β(2)). The evolution of this heteromeric quaternary structure was central to the emergence of Hb as a specialized oxygen-transport protein because it provided a mechanism for cooperative oxygen-binding and allosteric regulatory control. Subsequent rounds of duplication and divergence have produced diverse repertoires of α- and β-like globin genes that are ontogenetically regulated such that functionally distinct Hb isoforms are expressed during different stages of prenatal development and postnatal life. In the ancestor of jawless fishes, the proto Mb and Hb genes appear to have been secondarily lost, and the Cygb homolog evolved a specialized respiratory function in blood-oxygen transport. Phylogenetic and comparative genomic analyses of the vertebrate globin gene superfamily have revealed numerous instances in which paralogous globins have convergently evolved similar expression patterns and/or similar functional specializations in different organismal lineages.

  20. Explosive Tandem and Segmental Duplications of Multigenic Families in Eucalyptus grandis

    PubMed Central

    Li, Qiang; Yu, Hong; Cao, Phi Bang; Fawal, Nizar; Mathé, Catherine; Azar, Sahar; Cassan-Wang, Hua; Myburg, Alexander A.; Grima-Pettenati, Jacqueline; Marque, Christiane; Teulières, Chantal; Dunand, Christophe

    2015-01-01

    Plant organisms contain a large number of genes belonging to numerous multigenic families whose evolution size reflects some functional constraints. Sequences from eight multigenic families, involved in biotic and abiotic responses, have been analyzed in Eucalyptus grandis and compared with Arabidopsis thaliana. Two transcription factor families APETALA 2 (AP2)/ethylene responsive factor and GRAS, two auxin transporter families PIN-FORMED and AUX/LAX, two oxidoreductase families (ascorbate peroxidases [APx] and Class III peroxidases [CIII Prx]), and two families of protective molecules late embryogenesis abundant (LEA) and DNAj were annotated in expert and exhaustive manner. Many recent tandem duplications leading to the emergence of species-specific gene clusters and the explosion of the gene numbers have been observed for the AP2, GRAS, LEA, PIN, and CIII Prx in E. grandis, while the APx, the AUX/LAX and DNAj are conserved between species. Although no direct evidence has yet demonstrated the roles of these recent duplicated genes observed in E. grandis, this could indicate their putative implications in the morphological and physiological characteristics of E. grandis, and be the key factor for the survival of this nondormant species. Global analysis of key families would be a good criterion to evaluate the capabilities of some organisms to adapt to environmental variations. PMID:25769696

  1. A Young Drosophila Duplicate Gene Plays Essential Roles in Spermatogenesis by Regulating Several Y-Linked Male Fertility Genes

    PubMed Central

    Yang, Shuang; Jiang, Yu; Chen, Yuan; Zhao, Ruoping; Zhang, Yue; Zhang, Guojie; Dong, Yang; Yu, Haijing; Zhou, Qi; Wang, Wen

    2010-01-01

    Gene duplication is supposed to be the major source for genetic innovations. However, how a new duplicate gene acquires functions by integrating into a pathway and results in adaptively important phenotypes has remained largely unknown. Here, we investigated the biological roles and the underlying molecular mechanism of the young kep1 gene family in the Drosophila melanogaster species subgroup to understand the origin and evolution of new genes with new functions. Sequence and expression analysis demonstrates that one of the new duplicates, nsr (novel spermatogenesis regulator), exhibits positive selection signals and novel subcellular localization pattern. Targeted mutagenesis and whole-transcriptome sequencing analysis provide evidence that nsr is required for male reproduction associated with sperm individualization, coiling, and structural integrity of the sperm axoneme via regulation of several Y chromosome fertility genes post-transcriptionally. The absence of nsr-like expression pattern and the presence of the corresponding cis-regulatory elements of the parental gene kep1 in the pre-duplication species Drosophila yakuba indicate that kep1 might not be ancestrally required for male functions and that nsr possibly has experienced the neofunctionalization process, facilitated by changes of trans-regulatory repertories. These findings not only present a comprehensive picture about the evolution of a new duplicate gene but also show that recently originated duplicate genes can acquire multiple biological roles and establish novel functional pathways by regulating essential genes. PMID:21203494

  2. Divergence of recently duplicated M{gamma}-type MADS-box genes in Petunia.

    PubMed

    Bemer, Marian; Gordon, Jonathan; Weterings, Koen; Angenent, Gerco C

    2010-02-01

    The MADS-box transcription factor family has expanded considerably in plants via gene and genome duplications and can be subdivided into type I and MIKC-type genes. The two gene classes show a different evolutionary history. Whereas the MIKC-type genes originated during ancient genome duplications, as well as during more recent events, the type I loci appear to experience high turnover with many recent duplications. This different mode of origin also suggests a different fate for the type I duplicates, which are thought to have a higher chance to become silenced or lost from the genome. To get more insight into the evolution of the type I MADS-box genes, we isolated nine type I genes from Petunia, which belong to the Mgamma subclass, and investigated the divergence of their coding and regulatory regions. The isolated genes could be subdivided into two categories: two genes were highly similar to Arabidopsis Mgamma-type genes, whereas the other seven genes showed less similarity to Arabidopsis genes and originated more recently. Two of the recently duplicated genes were found to contain deleterious mutations in their coding regions, and expression analysis revealed that a third paralog was silenced by mutations in its regulatory region. However, in addition to the three genes that were subjected to nonfunctionalization, we also found evidence for neofunctionalization of one of the Petunia Mgamma-type genes. Our study shows a rapid divergence of recently duplicated Mgamma-type MADS-box genes and suggests that redundancy among type I paralogs may be less common than expected.

  3. High fitness costs and instability of gene duplications reduce rates of evolution of new genes by duplication-divergence mechanisms.

    PubMed

    Adler, Marlen; Anjum, Mehreen; Berg, Otto G; Andersson, Dan I; Sandegren, Linus

    2014-06-01

    An important mechanism for generation of new genes is by duplication-divergence of existing genes. Duplication-divergence includes several different submodels, such as subfunctionalization where after accumulation of neutral mutations the original function is distributed between two partially functional and complementary genes, and neofunctionalization where a new function evolves in one of the duplicated copies while the old function is maintained in another copy. The likelihood of these mechanisms depends on the longevity of the duplicated state, which in turn depends on the fitness cost and genetic stability of the duplications. Here, we determined the fitness cost and stability of defined gene duplications/amplifications on a low copy number plasmid. Our experimental results show that the costs of carrying extra gene copies are substantial and that each additional kilo base pairs of DNA reduces fitness by approximately 0.15%. Furthermore, gene amplifications are highly unstable and rapidly segregate to lower copy numbers in absence of selection. Mathematical modeling shows that the fitness costs and instability strongly reduces the likelihood of both sub- and neofunctionalization, but that these effects can be offset by positive selection for novel beneficial functions.

  4. Assessment and Reconstruction of Novel HSP90 Genes: Duplications, Gains and Losses in Fungal and Animal Lineages

    PubMed Central

    Pantzartzi, Chrysoula N.; Drosopoulou, Elena; Scouras, Zacharias G.

    2013-01-01

    Hsp90s, members of the Heat Shock Protein class, protect the structure and function of proteins and play a significant task in cellular homeostasis and signal transduction. In order to determine the number of hsp90 gene copies and encoded proteins in fungal and animal lineages and through that key duplication events that this family has undergone, we collected and evaluated Hsp90 protein sequences and corresponding Expressed Sequence Tags and analyzed available genomes from various taxa. We provide evidence for duplication events affecting either single species or wider taxonomic groups. With regard to Fungi, duplicated genes have been detected in several lineages. In invertebrates, we demonstrate key duplication events in certain clades of Arthropoda and Mollusca, and a possible gene loss event in a hymenopteran family. Finally, we infer that the duplication event responsible for the two (a and b) isoforms in vertebrates occurred probably shortly after the split of Hyperoartia and Gnathostomata. PMID:24066039

  5. Evidence of duplicated Hox genes in the most recent common ancestor of extant scorpions.

    PubMed

    Sharma, Prashant P; Santiago, Marc A; González-Santillán, Edmundo; Monod, Lionel; Wheeler, Ward C

    2015-01-01

    Scorpions (order Scorpiones) are unusual among arthropods, both for the extreme heteronomy of their bauplan and for the high gene family turnover exhibited in their genomes. These phenomena appear to be correlated, as two scorpion species have been shown to possess nearly twice the number of Hox genes present in most arthropods. Segmentally offset anterior expression boundaries of a subset of Hox paralogs have been shown to correspond to transitions in segmental identities in the scorpion posterior tagmata, suggesting that posterior heteronomy in scorpions may have been achieved by neofunctionalization of Hox paralogs. However, both the first scorpion genome sequenced and the developmental genetic data are based on exemplars of Buthidae, one of 19 families of scorpions. It is therefore not known whether Hox paralogy is limited to Buthidae or widespread among scorpions. We surveyed 24 high throughput transcriptomes and the single whole genome available for scorpions, in order to test the prediction that Hox gene duplications are common to the order. We used gene tree parsimony to infer whether the paralogy was consistent with a duplication event in the scorpion common ancestor. Here we show that duplicated Hox genes in non-buthid scorpions occur in six of the ten Hox classes. Gene tree topologies and parsimony-based reconciliation of the gene trees are consistent with a duplication event in the most recent common ancestor of scorpions. These results suggest that a Hox paralogy, and by extension the model of posterior patterning established in a buthid, can be extended to non-Buthidae scorpions.

  6. Prevertebrate Local Gene Duplication Facilitated Expansion of the Neuropeptide GPCR Superfamily.

    PubMed

    Yun, Seongsik; Furlong, Michael; Sim, Mikang; Cho, Minah; Park, Sumi; Cho, Eun Bee; Reyes-Alcaraz, Arfaxad; Hwang, Jong-Ik; Kim, Jaebum; Seong, Jae Young

    2015-11-01

    In humans, numerous genes encode neuropeptides that comprise a superfamily of more than 70 genes in approximately 30 families and act mainly through rhodopsin-like G protein-coupled receptors (GPCRs). Two rounds of whole-genome duplication (2R WGD) during early vertebrate evolution greatly contributed to proliferation within gene families; however, the mechanisms underlying the initial emergence and diversification of these gene families before 2R WGD are largely unknown. In this study, we analyzed 25 vertebrate rhodopsin-like neuropeptide GPCR families and their cognate peptides using phylogeny, synteny, and localization of these genes on reconstructed vertebrate ancestral chromosomes (VACs). Based on phylogeny, these GPCR families can be divided into five distinct clades, and members of each clade tend to be located on the same VACs. Similarly, their neuropeptide gene families also tend to reside on distinct VACs. Comparison of these GPCR genes with those of invertebrates including Drosophila melanogaster, Caenorhabditis elegans, Branchiostoma floridae, and Ciona intestinalis indicates that these GPCR families emerged through tandem local duplication during metazoan evolution prior to 2R WGD. Our study describes a presumptive evolutionary mechanism and development pathway of the vertebrate rhodopsin-like GPCR and cognate neuropeptide families from the urbilaterian ancestor to modern vertebrates.

  7. Multiple bursts of pancreatic ribonuclease gene duplication in insect-eating bats.

    PubMed

    Xu, Huihui; Liu, Yang; Meng, Fanxing; He, Beibei; Han, Naijian; Li, Gang; Rossiter, Stephen J; Zhang, Shuyi

    2013-09-10

    Pancreatic ribonuclease gene (RNASE1) was previously shown to have undergone duplication and adaptive evolution related to digestive efficiency in several mammalian groups that have evolved foregut fermentation, including ruminants and some primates. RNASE1 gene duplications thought to be linked to diet have also been recorded in some carnivores. Of all mammals, bats have evolved the most diverse dietary specializations, mainly including frugivory and insectivory. Here we cloned, sequenced and analyzed RNASE1 gene sequences from a range of bat species to determine whether their dietary adaptation is mirrored by molecular adaptation. We found that seven insect-eating members of the families Vespertilionidae and Molossidae possessed two or more duplicates, and we also detected three pseudogenes. Reconstructed RNASE1 gene trees based on both Bayesian and maximum likelihood methods supported independent duplication events in these two families. Selection tests revealed that RNASE1 gene duplicates have undergone episodes of positive selection indicative of functional modification, and lineage-specific tests revealed strong adaptive evolution in the Tadarida β clade. However, unlike the RNASE1 duplicates that function in digestion in some mammals, the bat RNASE1 sequences were found to be characterized by relatively high isoelectric points, a feature previously suggested to promote defense against viruses via the breakdown of double-stranded RNA. Taken together, our findings point to an adaptive diversification of RNASE1 in these two bat families, although we find no clear evidence that this was driven by diet. Future experimental assays are needed to resolve the functions of these enzymes in bats.

  8. Paralogue Interference Affects the Dynamics after Gene Duplication.

    PubMed

    Kaltenegger, Elisabeth; Ober, Dietrich

    2015-12-01

    Proteins tend to form homomeric complexes of identical subunits, which act as functional units. By definition, the subunits are encoded from a single genetic locus. When such a gene is duplicated, the gene products are suggested initially to cross-interact when coexpressed, thus resulting in the phenomenon of paralogue interference. In this opinion article, we explore how paralogue interference can shape the fate of a duplicated gene. One important outcome is a prolonged time window in which both copies remain under selection increasing the chance to accumulate mutations and to develop new properties. Thereby, paralogue interference can mediate the coevolution of duplicates and here we illustrate the potential of this phenomenon in light of recent new studies.

  9. Prevalent role of gene features in determining evolutionary fates of whole-genome duplication duplicated genes in flowering plants.

    PubMed

    Jiang, Wen-kai; Liu, Yun-long; Xia, En-hua; Gao, Li-zhi

    2013-04-01

    The evolution of genes and genomes after polyploidization has been the subject of extensive studies in evolutionary biology and plant sciences. While a significant number of duplicated genes are rapidly removed during a process called fractionation, which operates after the whole-genome duplication (WGD), another considerable number of genes are retained preferentially, leading to the phenomenon of biased gene retention. However, the evolutionary mechanisms underlying gene retention after WGD remain largely unknown. Through genome-wide analyses of sequence and functional data, we comprehensively investigated the relationships between gene features and the retention probability of duplicated genes after WGDs in six plant genomes, Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), soybean (Glycine max), rice (Oryza sativa), sorghum (Sorghum bicolor), and maize (Zea mays). The results showed that multiple gene features were correlated with the probability of gene retention. Using a logistic regression model based on principal component analysis, we resolved evolutionary rate, structural complexity, and GC3 content as the three major contributors to gene retention. Cluster analysis of these features further classified retained genes into three distinct groups in terms of gene features and evolutionary behaviors. Type I genes are more prone to be selected by dosage balance; type II genes are possibly subject to subfunctionalization; and type III genes may serve as potential targets for neofunctionalization. This study highlights that gene features are able to act jointly as primary forces when determining the retention and evolution of WGD-derived duplicated genes in flowering plants. These findings thus may help to provide a resolution to the debate on different evolutionary models of gene fates after WGDs.

  10. Alternative Transposition Generates New Chimeric Genes and Segmental Duplications at the Maize p1 Locus

    PubMed Central

    Wang, Dafang; Yu, Chuanhe; Zuo, Tao; Zhang, Jianbo; Weber, David F.; Peterson, Thomas

    2015-01-01

    The maize Ac/Ds transposon family was the first transposable element system identified and characterized by Barbara McClintock. Ac/Ds transposons belong to the hAT family of class II DNA transposons. We and others have shown that Ac/Ds elements can undergo a process of alternative transposition in which the Ac/Ds transposase acts on the termini of two separate, nearby transposons. Because these termini are present in different elements, alternative transposition can generate a variety of genome alterations such as inversions, duplications, deletions, and translocations. Moreover, Ac/Ds elements transpose preferentially into genic regions, suggesting that structural changes arising from alternative transposition may potentially generate chimeric genes at the rearrangement breakpoints. Here we identified and characterized 11 independent cases of gene fusion induced by Ac alternative transposition. In each case, a functional chimeric gene was created by fusion of two linked, paralogous genes; moreover, each event was associated with duplication of the ∼70-kb segment located between the two paralogs. An extant gene in the maize B73 genome that contains an internal duplication apparently generated by an alternative transposition event was also identified. Our study demonstrates that alternative transposition-induced duplications may be a source for spontaneous creation of diverse genome structures and novel genes in maize. PMID:26434719

  11. Effects of Gene Duplication, Positive Selection, and Shifts in Gene Expression on the Evolution of the Venom Gland Transcriptome in Widow Spiders

    PubMed Central

    Haney, Robert A.; Clarke, Thomas H.; Gadgil, Rujuta; Fitzpatrick, Ryan; Hayashi, Cheryl Y.; Ayoub, Nadia A.; Garb, Jessica E.

    2016-01-01

    Gene duplication and positive selection can be important determinants of the evolution of venom, a protein-rich secretion used in prey capture and defense. In a typical model of venom evolution, gene duplicates switch to venom gland expression and change function under the action of positive selection, which together with further duplication produces large gene families encoding diverse toxins. Although these processes have been demonstrated for individual toxin families, high-throughput multitissue sequencing of closely related venomous species can provide insights into evolutionary dynamics at the scale of the entire venom gland transcriptome. By assembling and analyzing multitissue transcriptomes from the Western black widow spider and two closely related species with distinct venom toxicity phenotypes, we do not find that gene duplication and duplicate retention is greater in gene families with venom gland biased expression in comparison with broadly expressed families. Positive selection has acted on some venom toxin families, but does not appear to be in excess for families with venom gland biased expression. Moreover, we find 309 distinct gene families that have single transcripts with venom gland biased expression, suggesting that the switching of genes to venom gland expression in numerous unrelated gene families has been a dominant mode of evolution. We also find ample variation in protein sequences of venom gland–specific transcripts, lineage-specific family sizes, and ortholog expression among species. This variation might contribute to the variable venom toxicity of these species. PMID:26733576

  12. Effects of Gene Duplication, Positive Selection, and Shifts in Gene Expression on the Evolution of the Venom Gland Transcriptome in Widow Spiders.

    PubMed

    Haney, Robert A; Clarke, Thomas H; Gadgil, Rujuta; Fitzpatrick, Ryan; Hayashi, Cheryl Y; Ayoub, Nadia A; Garb, Jessica E

    2016-01-05

    Gene duplication and positive selection can be important determinants of the evolution of venom, a protein-rich secretion used in prey capture and defense. In a typical model of venom evolution, gene duplicates switch to venom gland expression and change function under the action of positive selection, which together with further duplication produces large gene families encoding diverse toxins. Although these processes have been demonstrated for individual toxin families, high-throughput multitissue sequencing of closely related venomous species can provide insights into evolutionary dynamics at the scale of the entire venom gland transcriptome. By assembling and analyzing multitissue transcriptomes from the Western black widow spider and two closely related species with distinct venom toxicity phenotypes, we do not find that gene duplication and duplicate retention is greater in gene families with venom gland biased expression in comparison with broadly expressed families. Positive selection has acted on some venom toxin families, but does not appear to be in excess for families with venom gland biased expression. Moreover, we find 309 distinct gene families that have single transcripts with venom gland biased expression, suggesting that the switching of genes to venom gland expression in numerous unrelated gene families has been a dominant mode of evolution. We also find ample variation in protein sequences of venom gland-specific transcripts, lineage-specific family sizes, and ortholog expression among species. This variation might contribute to the variable venom toxicity of these species.

  13. Compensatory Drift and the Evolutionary Dynamics of Dosage-Sensitive Duplicate Genes.

    PubMed

    Thompson, Ammon; Zakon, Harold H; Kirkpatrick, Mark

    2016-02-01

    Dosage-balance selection preserves functionally redundant duplicates (paralogs) at the optimum for their combined expression. Here we present a model of the dynamics of duplicate genes coevolving under dosage-balance selection. We call this the compensatory drift model. Results show that even when strong dosage-balance selection constrains total expression to the optimum, expression of each duplicate can diverge by drift from its original level. The rate of divergence slows as the strength of stabilizing selection, the size of the mutation effect, and/or the size of the population increases. We show that dosage-balance selection impedes neofunctionalization early after duplication but can later facilitate it. We fit this model to data from sodium channel duplicates in 10 families of teleost fish; these include two convergent lineages of electric fish in which one of the duplicates neofunctionalized. Using the model, we estimated the strength of dosage-balance selection for these genes. The results indicate that functionally redundant paralogs still may undergo radical functional changes after a prolonged period of compensatory drift.

  14. Rapid bursts of androgen-binding protein (Abp) gene duplication occurred independently in diverse mammals

    PubMed Central

    2008-01-01

    Background The draft mouse (Mus musculus) genome sequence revealed an unexpected proliferation of gene duplicates encoding a family of secretoglobin proteins including the androgen-binding protein (ABP) α, β and γ subunits. Further investigation of 14 α-like (Abpa) and 13 β- or γ-like (Abpbg) undisrupted gene sequences revealed a rich diversity of developmental stage-, sex- and tissue-specific expression. Despite these studies, our understanding of the evolution of this gene family remains incomplete. Questions arise from imperfections in the initial mouse genome assembly and a dearth of information about the gene family structure in other rodents and mammals. Results Here, we interrogate the latest 'finished' mouse (Mus musculus) genome sequence assembly to show that the Abp gene repertoire is, in fact, twice as large as reported previously, with 30 Abpa and 34 Abpbg genes and pseudogenes. All of these have arisen since the last common ancestor with rat (Rattus norvegicus). We then demonstrate, by sequencing homologs from species within the Mus genus, that this burst of gene duplication occurred very recently, within the past seven million years. Finally, we survey Abp orthologs in genomes from across the mammalian clade and show that bursts of Abp gene duplications are not specific to the murid rodents; they also occurred recently in the lagomorph (rabbit, Oryctolagus cuniculus) and ruminant (cattle, Bos taurus) lineages, although not in other mammalian taxa. Conclusion We conclude that Abp genes have undergone repeated bursts of gene duplication and adaptive sequence diversification driven by these genes' participation in chemosensation and/or sexual identification. PMID:18269759

  15. PGDD: a database of gene and genome duplication in plants

    PubMed Central

    Lee, Tae-Ho; Tang, Haibao; Wang, Xiyin; Paterson, Andrew H.

    2013-01-01

    Genome duplication (GD) has permanently shaped the architecture and function of many higher eukaryotic genomes. The angiosperms (flowering plants) are outstanding models in which to elucidate consequences of GD for higher eukaryotes, owing to their propensity for chromosomal duplication or even triplication in a few cases. Duplicated genome structures often require both intra- and inter-genome alignments to unravel their evolutionary history, also providing the means to deduce both obvious and otherwise-cryptic orthology, paralogy and other relationships among genes. The burgeoning sets of angiosperm genome sequences provide the foundation for a host of investigations into the functional and evolutionary consequences of gene and GD. To provide genome alignments from a single resource based on uniform standards that have been validated by empirical studies, we built the Plant Genome Duplication Database (PGDD; freely available at http://chibba.agtec.uga.edu/duplication/), a web service providing synteny information in terms of colinearity between chromosomes. At present, PGDD contains data for 26 plants including bryophytes and chlorophyta, as well as angiosperms with draft genome sequences. In addition to the inclusion of new genomes as they become available, we are preparing new functions to enhance PGDD. PMID:23180799

  16. Duplication of the ZIC2 gene is not associated with holoprosencephaly.

    PubMed

    Jobanputra, Vaidehi; Burke, Alanna; Kwame, Anyane-Yeboa; Shanmugham, Anita; Shirazi, Maryam; Brown, Stephen; Warburton, Peter E; Levy, Brynn; Warburton, Dorothy

    2012-01-01

    Cytogenetic testing using genomic microarrays presents a clinical challenge when data regarding the phenotypic consequences of the genomic alteration are not available. We describe a chromosome 13q32.3 duplication discovered by microarray testing in a fetus with a prenatally detected apparently balanced de novo translocation 46,XY,t(2;13)(q37;q32). Microarray analysis on the fetal DNA showed duplications of 384 and 564 kb at the breakpoint regions on chromosomes 2q37.3 and 13q32.3, respectively. There were no disease-associated genes in the duplicated region on chromosome 2q37. The duplicated region on chromosome 13q contains the ZIC2 gene. Haploinsufficiency of ZIC2 is known to cause holoprosencephaly and other brain malformations. Studies in the mouse models have suggested that over expression of ZIC2 may also lead to brain malformations. Fetal MRI of the brain was normal and the family elected to continue the pregnancy. An apparently normal baby was born at term. At 3 months of age a physical exam showed no abnormalities and no developmental delay. This report shows that duplication of ZIC2 is not necessarily associated with brain malformations. We also describe the phenotype from four additional patients with duplications of the region of chromosome 13 containing ZIC2 and three previously described patients with supernumerary marker chromosomes derived from distal chromosome 13. None of the eight patients had holoprosencephaly or brain malformations, indicating that duplication of ZIC2 is not associated with brain anomalies. This information will be useful for counseling in other occurrences of this duplication identified by microarray.

  17. Evaluating and Characterizing Ancient Whole-Genome Duplications in Plants with Gene Count Data

    PubMed Central

    Tiley, George P.; Ané, Cécile; Burleigh, J. Gordon

    2016-01-01

    Whole-genome duplications (WGDs) have helped shape the genomes of land plants, and recent evidence suggests that the genomes of all angiosperms have experienced at least two ancient WGDs. In plants, WGDs often are followed by rapid fractionation, in which many homeologous gene copies are lost. Thus, it can be extremely difficult to identify, let alone characterize, ancient WGDs. In this study, we use a new maximum likelihood estimator to test for evidence of ancient WGDs in land plants and estimate the fraction of new genes copies that are retained following a WGD using gene count data, the number of gene copies in gene families. We identified evidence of many putative ancient WGDs in land plants and found that the genome fractionation rates vary tremendously among ancient WGDs. Analyses of WGDs within Brassicales also indicate that background gene duplication and loss rates vary across land plants, and different gene families have different probabilities of being retained following a WGD. Although our analyses are largely robust to errors in duplication and loss rates and the choice of priors, simulations indicate that this method can have trouble detecting multiple WGDs that occur on the same branch, especially when the gene retention rates for ancient WGDs are very low. They also suggest that we should carefully evaluate evidence for some ancient plant WGD hypotheses. PMID:26988251

  18. Evaluating and Characterizing Ancient Whole-Genome Duplications in Plants with Gene Count Data.

    PubMed

    Tiley, George P; Ané, Cécile; Burleigh, J Gordon

    2016-04-11

    Whole-genome duplications (WGDs) have helped shape the genomes of land plants, and recent evidence suggests that the genomes of all angiosperms have experienced at least two ancient WGDs. In plants, WGDs often are followed by rapid fractionation, in which many homeologous gene copies are lost. Thus, it can be extremely difficult to identify, let alone characterize, ancient WGDs. In this study, we use a new maximum likelihood estimator to test for evidence of ancient WGDs in land plants and estimate the fraction of new genes copies that are retained following a WGD using gene count data, the number of gene copies in gene families. We identified evidence of many putative ancient WGDs in land plants and found that the genome fractionation rates vary tremendously among ancient WGDs. Analyses of WGDs within Brassicales also indicate that background gene duplication and loss rates vary across land plants, and different gene families have different probabilities of being retained following a WGD. Although our analyses are largely robust to errors in duplication and loss rates and the choice of priors, simulations indicate that this method can have trouble detecting multiple WGDs that occur on the same branch, especially when the gene retention rates for ancient WGDs are very low. They also suggest that we should carefully evaluate evidence for some ancient plant WGD hypotheses.

  19. Functional divergence in tandemly duplicated Arabidopsis thaliana trypsin inhibitor genes.

    PubMed Central

    Clauss, M J; Mitchell-Olds, T

    2004-01-01

    In multigene families, variation among loci and alleles can contribute to trait evolution. We explored patterns of functional and genetic variation in six duplicated Arabidopsis thaliana trypsin inhibitor (ATTI) loci. We demonstrate significant variation in constitutive and herbivore-induced transcription among ATTI loci that show, on average, 65% sequence divergence. Significant variation in ATTI expression was also found between two molecularly defined haplotype classes. Population genetic analyses for 17 accessions of A. thaliana showed that six ATTI loci arranged in tandem within 10 kb varied 10-fold in nucleotide diversity, from 0.0009 to 0.0110, and identified a minimum of six recombination events throughout the tandem array. We observed a significant peak in nucleotide and indel polymorphism spanning ATTI loci in the interior of the array, due primarily to divergence between the two haplotype classes. Significant deviation from the neutral equilibrium model for individual genes was interpreted within the context of intergene linkage disequilibrium and correlated patterns of functional differentiation. In contrast to the outcrosser Arabidopsis lyrata for which recombination is observed even within ATTI loci, our data suggest that response to selection was slowed in the inbreeding, annual A. thaliana because of interference among functionally divergent ATTI loci. PMID:15082560

  20. Gene duplication, silencing and expression alteration govern the molecular evolution of PRC2 genes in plants.

    PubMed

    Furihata, Hazuka Y; Suenaga, Kazuya; Kawanabe, Takahiro; Yoshida, Takanori; Kawabe, Akira

    2016-10-13

    PRC2 genes were analyzed for their number of gene duplications, dN/dS ratios and expression patterns among Brassicaceae and Gramineae species. Although both amino acid sequences and copy number of the PRC2 genes were generally well conserved in both Brassicaceae and Gramineae species, we observed that some rapidly evolving genes experienced duplications and expression pattern changes. After multiple duplication events, all but one or two of the duplicated copies tend to be silenced. Silenced copies were reactivated in the endosperm and showed ectopic expression in developing seeds. The results indicated that rapid evolution of some PRC2 genes is initially caused by a relaxation of selective constraint following the gene duplication events. Several loci could become maternally expressed imprinted genes and acquired functional roles in the endosperm.

  1. On the origins of Mendelian disease genes in man: the impact of gene duplication.

    PubMed

    Dickerson, Jonathan E; Robertson, David L

    2012-01-01

    Over 3,000 human diseases are known to be linked to heritable genetic variation, mapping to over 1,700 unique genes. Dating of the evolutionary age of these disease-associated genes has suggested that they have a tendency to be ancient, specifically coming into existence with early metazoa. The approach taken by past studies, however, assumes that the age of a disease is the same as the age of its common ancestor, ignoring the fundamental contribution of duplication events in the evolution of new genes and function. Here, we date both the common ancestor and the duplication history of known human disease-associated genes. We find that the majority of disease genes (80%) are genes that have been duplicated in their evolutionary history. Periods for which there are more disease-associated genes, for example, at the origins of bony vertebrates, are explained by the emergence of more genes at that time, and the majority of these are duplicates inferred to have arisen by whole-genome duplication. These relationships are similar for different disease types and the disease-associated gene's cellular function. This indicates that the emergence of duplication-associated diseases has been ongoing and approximately constant (relative to the retention of duplicate genes) throughout the evolution of life. This continued until approximately 390 Ma from which time relatively fewer novel genes came into existence on the human lineage, let alone disease genes. For single-copy genes associated with disease, we find that the numbers of disease genes decreases with recency. For the majority of duplicates, the disease-associated mutation is associated with just one of the duplicate copies. A universal explanation for heritable disease is, thus, that it is merely a by-product of the evolutionary process; the evolution of new genes (de novo or by duplication) results in the potential for new diseases to emerge.

  2. Insight into transcription factor gene duplication from Caenorhabditis elegans Promoterome-driven expression patterns

    PubMed Central

    Reece-Hoyes, John S; Shingles, Jane; Dupuy, Denis; Grove, Christian A; Walhout, Albertha JM; Vidal, Marc; Hope, Ian A

    2007-01-01

    Background The C. elegans Promoterome is a powerful resource for revealing the regulatory mechanisms by which transcription is controlled pan-genomically. Transcription factors will form the core of any systems biology model of genome control and therefore the promoter activity of Promoterome inserts for C. elegans transcription factor genes was examined, in vivo, with a reporter gene approach. Results Transgenic C. elegans strains were generated for 366 transcription factor promoter/gfp reporter gene fusions. GFP distributions were determined, and then summarized with reference to developmental stage and cell type. Reliability of these data was demonstrated by comparison to previously described gene product distributions. A detailed consideration of the results for one C. elegans transcription factor gene family, the Six family, comprising ceh-32, ceh-33, ceh-34 and unc-39 illustrates the value of these analyses. The high proportion of Promoterome reporter fusions that drove GFP expression, compared to previous studies, led to the hypothesis that transcription factor genes might be involved in local gene duplication events less frequently than other genes. Comparison of transcription factor genes of C. elegans and Caenorhabditis briggsae was therefore carried out and revealed very few examples of functional gene duplication since the divergence of these species for most, but not all, transcription factor gene families. Conclusion Examining reporter expression patterns for hundreds of promoters informs, and thereby improves, interpretation of this data type. Genes encoding transcription factors involved in intrinsic developmental control processes appear acutely sensitive to changes in gene dosage through local gene duplication, on an evolutionary time scale. PMID:17244357

  3. The Phenotypic Plasticity of Duplicated Genes in Saccharomyces cerevisiae and the Origin of Adaptations

    PubMed Central

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Toft, Christina; Fares, Mario A.

    2016-01-01

    Gene and genome duplication are the major sources of biological innovations in plants and animals. Functional and transcriptional divergence between the copies after gene duplication has been considered the main driver of innovations . However, here we show that increased phenotypic plasticity after duplication plays a more major role than thought before in the origin of adaptations. We perform an exhaustive analysis of the transcriptional alterations of duplicated genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with five different environmental stresses. Analysis of the transcriptomes of yeast shows that gene duplication increases the transcriptional response to environmental changes, with duplicated genes exhibiting signatures of adaptive transcriptional patterns in response to stress. The mechanism of duplication matters, with whole-genome duplicates being more transcriptionally altered than small-scale duplicates. The predominant transcriptional pattern follows the classic theory of evolution by gene duplication; with one gene copy remaining unaltered under stress, while its sister copy presents large transcriptional plasticity and a prominent role in adaptation. Moreover, we find additional transcriptional profiles that are suggestive of neo- and subfunctionalization of duplicate gene copies. These patterns are strongly correlated with the functional dependencies and sequence divergence profiles of gene copies. We show that, unlike singletons, duplicates respond more specifically to stress, supporting the role of natural selection in the transcriptional plasticity of duplicates. Our results reveal the underlying transcriptional complexity of duplicated genes and its role in the origin of adaptations. PMID:27799339

  4. The Phenotypic Plasticity of Duplicated Genes in Saccharomyces cerevisiae and the Origin of Adaptations.

    PubMed

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Toft, Christina; Fares, Mario A

    2017-01-05

    Gene and genome duplication are the major sources of biological innovations in plants and animals. Functional and transcriptional divergence between the copies after gene duplication has been considered the main driver of innovations . However, here we show that increased phenotypic plasticity after duplication plays a more major role than thought before in the origin of adaptations. We perform an exhaustive analysis of the transcriptional alterations of duplicated genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with five different environmental stresses. Analysis of the transcriptomes of yeast shows that gene duplication increases the transcriptional response to environmental changes, with duplicated genes exhibiting signatures of adaptive transcriptional patterns in response to stress. The mechanism of duplication matters, with whole-genome duplicates being more transcriptionally altered than small-scale duplicates. The predominant transcriptional pattern follows the classic theory of evolution by gene duplication; with one gene copy remaining unaltered under stress, while its sister copy presents large transcriptional plasticity and a prominent role in adaptation. Moreover, we find additional transcriptional profiles that are suggestive of neo- and subfunctionalization of duplicate gene copies. These patterns are strongly correlated with the functional dependencies and sequence divergence profiles of gene copies. We show that, unlike singletons, duplicates respond more specifically to stress, supporting the role of natural selection in the transcriptional plasticity of duplicates. Our results reveal the underlying transcriptional complexity of duplicated genes and its role in the origin of adaptations.

  5. Species-specific duplications of NBS-encoding genes in Chinese chestnut (Castanea mollissima)

    PubMed Central

    Zhong, Yan; Li, Yingjun; Huang, Kaihui; Cheng, Zong-Ming

    2015-01-01

    The disease resistance (R) genes play an important role in protecting plants from infection by diverse pathogens in the environment. The nucleotide-binding site (NBS)-leucine-rich repeat (LRR) class of genes is one of the largest R gene families. Chinese chestnut (Castanea mollissima) is resistant to Chestnut Blight Disease, but relatively little is known about the resistance mechanism. We identified 519 NBS-encoding genes, including 374 NBS-LRR genes and 145 NBS-only genes. The majority of Ka/Ks were less than 1, suggesting the purifying selection operated during the evolutionary history of NBS-encoding genes. A minority (4/34) of Ka/Ks in non-TIR gene families were greater than 1, showing that some genes were under positive selection pressure. Furthermore, Ks peaked at a range of 0.4 to 0.5, indicating that ancient duplications arose during the evolution. The relationship between Ka/Ks and Ks indicated greater selective pressure on the newer and older genes with the critical value of Ks = 0.4–0.5. Notably, species-specific duplications were detected in NBS-encoding genes. In addition, the group of RPW8-NBS-encoding genes clustered together as an independent clade located at a relatively basal position in the phylogenetic tree. Many cis-acting elements related to plant defense responses were detected in promoters of NBS-encoding genes. PMID:26559332

  6. Gene duplication, tissue-specific gene expression and sexual conflict in stalk-eyed flies (Diopsidae).

    PubMed

    Baker, Richard H; Narechania, Apurva; Johns, Philip M; Wilkinson, Gerald S

    2012-08-19

    Gene duplication provides an essential source of novel genetic material to facilitate rapid morphological evolution. Traits involved in reproduction and sexual dimorphism represent some of the fastest evolving traits in nature, and gene duplication is intricately involved in the origin and evolution of these traits. Here, we review genomic research on stalk-eyed flies (Diopsidae) that has been used to examine the extent of gene duplication and its role in the genetic architecture of sexual dimorphism. Stalk-eyed flies are remarkable because of the elongation of the head into long stalks, with the eyes and antenna laterally displaced at the ends of these stalks. Many species are strongly sexually dimorphic for eyespan, and these flies have become a model system for studying sexual selection. Using both expressed sequence tag and next-generation sequencing, we have established an extensive database of gene expression in the developing eye-antennal imaginal disc, the adult head and testes. Duplicated genes exhibit narrower expression patterns than non-duplicated genes, and the testes, in particular, provide an abundant source of gene duplication. Within somatic tissue, duplicated genes are more likely to be differentially expressed between the sexes, suggesting gene duplication may provide a mechanism for resolving sexual conflict.

  7. A rare case of plastid protein-coding gene duplication in the chloroplast genome of Euglena archaeoplastidiata (Euglenophyta).

    PubMed

    Bennett, Matthew S; Shiu, Shin-Han; Triemer, Richard E

    2017-03-12

    Gene duplication is an important evolutionary process that allows duplicate functions to diverge, or, in some cases, allows for new functional gains. However, in contrast to the nuclear genome, gene duplications within the chloroplast are extremely rare. Here, we present the chloroplast genome of the photosynthetic protist Euglena archaeoplastidiata. Upon annotation, it was found that the chloroplast genome contained a novel tandem direct duplication that encoded a portion of RuBisCO large subunit (rbcL) followed by a complete copy of ribosomal protein L32 (rpl32), as well as the associated intergenic sequences. Analyses of the duplicated rpl32 were inconclusive regarding selective pressures, although it was found that substitutions in the duplicated region, all non-synonymous, likely had a neutral functional effect. The duplicated region did not exhibit patterns consistent with previously described mechanisms for tandem direct duplications, and demonstrated an unknown mechanism of duplication. In addition, a comparison of this chloroplast genome to other previously characterized chloroplast genomes from the same family revealed characteristics that indicated E. archaeoplastidiata was probably more closely related to taxa in the genera Monomorphina, Cryptoglena, and Euglenaria than it was to other Euglena taxa. Taken together, the chloroplast genome of E. archaeoplastidiata demonstrated multiple characteristics unique to the euglenoid world, and has justified the longstanding curiosity regarding this enigmatic taxon.

  8. Divergence in Enzymatic Activities in the Soybean GST Supergene Family Provides New Insight into the Evolutionary Dynamics of Whole-Genome Duplicates.

    PubMed

    Liu, Hai-Jing; Tang, Zhen-Xin; Han, Xue-Min; Yang, Zhi-Ling; Zhang, Fu-Min; Yang, Hai-Ling; Liu, Yan-Jing; Zeng, Qing-Yin

    2015-11-01

    Whole-genome duplication (WGD), or polyploidy, is a major force in plant genome evolution. A duplicate of all genes is present in the genome immediately following a WGD event. However, the evolutionary mechanisms responsible for the loss of, or retention and subsequent functional divergence of polyploidy-derived duplicates remain largely unknown. In this study we reconstructed the evolutionary history of the glutathione S-transferase (GST) gene family from the soybean genome, and identified 72 GST duplicated gene pairs formed by a recent Glycine-specific WGD event occurring approximately 13 Ma. We found that 72% of duplicated GST gene pairs experienced gene losses or pseudogenization, whereas 28% of GST gene pairs have been retained in the soybean genome. The GST pseudogenes were under relaxed selective constraints, whereas functional GSTs were subject to strong purifying selection. Plant GST genes play important roles in stress tolerance and detoxification metabolism. By examining the gene expression responses to abiotic stresses and enzymatic properties of the ancestral and current proteins, we found that polyploidy-derived GST duplicates show the divergence in enzymatic activities. Through site-directed mutagenesis of ancestral proteins, this study revealed that nonsynonymous substitutions of key amino acid sites play an important role in the divergence of enzymatic functions of polyploidy-derived GST duplicates. These findings provide new insights into the evolutionary and functional dynamics of polyploidy-derived duplicate genes.

  9. Six Subgroups and Extensive Recent Duplications Characterize the Evolution of the Eukaryotic Tubulin Protein Family

    PubMed Central

    Findeisen, Peggy; Mühlhausen, Stefanie; Dempewolf, Silke; Hertzog, Jonny; Zietlow, Alexander; Carlomagno, Teresa; Kollmar, Martin

    2014-01-01

    Tubulins belong to the most abundant proteins in eukaryotes providing the backbone for many cellular substructures like the mitotic and meiotic spindles, the intracellular cytoskeletal network, and the axonemes of cilia and flagella. Homologs have even been reported for archaea and bacteria. However, a taxonomically broad and whole-genome-based analysis of the tubulin protein family has never been performed, and thus, the number of subfamilies, their taxonomic distribution, and the exact grouping of the supposed archaeal and bacterial homologs are unknown. Here, we present the analysis of 3,524 tubulins from 504 species. The tubulins formed six major subfamilies, α to ζ. Species of all major kingdoms of the eukaryotes encode members of these subfamilies implying that they must have already been present in the last common eukaryotic ancestor. The proposed archaeal homologs grouped together with the bacterial TubZ proteins as sister clade to the FtsZ proteins indicating that tubulins are unique to eukaryotes. Most species contained α- and/or β-tubulin gene duplicates resulting from recent branch- and species-specific duplication events. This shows that tubulins cannot be used for constructing species phylogenies without resolving their ortholog–paralog relationships. The many gene duplicates and also the independent loss of the δ-, ε-, or ζ-tubulins, which have been shown to be part of the triplet microtubules in basal bodies, suggest that tubulins can functionally substitute each other. PMID:25169981

  10. A duplication/paracentric inversion associated with familial X-linked deafness (DFN3) suggests the presence of a regulatory element more than 400 kb upstream of the POU3F4 gene.

    PubMed

    de Kok, Y J; Merkx, G F; van der Maarel, S M; Huber, I; Malcolm, S; Ropers, H H; Cremers, F P

    1995-11-01

    X-linked deafness with stapes fixation (DFN3) is caused by mutations in the POU3F4 gene at Xq21.1. By employing pulsed field gel electrophoresis (PFGE) we identified a chromosomal aberration in the DNA of a DFN3 patient who did not show alterations in the open reading frame (ORF) of POU3F4. Southern blot analysis indicated that a DNA segment of 150 kb, located 170 kb proximal to the POU3F4 gene, was duplicated. Fluorescence in situ hybridization (FISH) analysis, PFGE, and detailed Southern analysis revealed that this duplication is part of a more complex rearrangement including a paracentric inversion involving the Xq21.1 region, and presumably the Xq21.3 region. Since at least two DFN3-associated minideletions are situated proximal to the duplicated segment, the inversion most likely disconnects the POU3F4 gene from a regulatory element which is located at a distance of at least 400 kb upstream of the POU3F4 gene.

  11. Recurrent duplications of the annexin A1 gene (ANXA1) in autism spectrum disorders

    PubMed Central

    2014-01-01

    Background Validating the potential pathogenicity of copy number variants (CNVs) identified in genome-wide studies of autism spectrum disorders (ASD) requires detailed assessment of case/control frequencies, inheritance patterns, clinical correlations, and functional impact. Here, we characterize a small recurrent duplication in the annexin A1 (ANXA1) gene, identified by the Autism Genome Project (AGP) study. Methods From the AGP CNV genomic screen in 2,147 ASD individuals, we selected for characterization an ANXA1 gene duplication that was absent in 4,964 population-based controls. We further screened the duplication in a follow-up sample including 1,496 patients and 410 controls, and evaluated clinical correlations and family segregation. Sequencing of exonic/downstream ANXA1 regions was performed in 490 ASD patients for identification of additional variants. Results The ANXA1 duplication, overlapping the last four exons and 3’UTR region, had an overall prevalence of 11/3,643 (0.30%) in unrelated ASD patients but was not identified in 5,374 controls. Duplication carriers presented no distinctive clinical phenotype. Family analysis showed neuropsychiatric deficits and ASD traits in multiple relatives carrying the duplication, suggestive of a complex genetic inheritance. Sequencing of exonic regions and the 3’UTR identified 11 novel changes, but no obvious variants with clinical significance. Conclusions We provide multilevel evidence for a role of ANXA1 in ASD etiology. Given its important role as mediator of glucocorticoid function in a wide variety of brain processes, including neuroprotection, apoptosis, and control of the neuroendocrine system, the results add ANXA1 to the growing list of rare candidate genetic etiological factors for ASD. PMID:24720851

  12. Impact of whole-genome and tandem duplications in the expansion and functional diversification of the F-box family in legumes (Fabaceae).

    PubMed

    Bellieny-Rabelo, Daniel; Oliveira, Antônia Elenir Amâncio; Venancio, Thiago Motta

    2013-01-01

    F-box proteins constitute a large gene family that regulates processes from hormone signaling to stress response. F-box proteins are the substrate recognition modules of SCF E3 ubiquitin ligases. Here we report very distinct trends in family size, duplication, synteny and transcription of F-box genes in two nitrogen-fixing legumes, Glycine max (soybean) and Medicago truncatula (alfafa). While the soybean FBX genes emerged mainly through segmental duplications (including whole-genome duplications), M. truncatula genome is dominated by locally-duplicated (tandem) F-box genes. Many of these young FBX genes evolved complex transcriptional patterns, including preferential transcription in different tissues, suggesting that they have probably been recruited to important biochemical pathways (e.g. nodulation and seed development).

  13. Evidence showing duplication and recombination of cel genes in tandem from hyperthermophilic Thermotoga sp.

    PubMed

    Kim, Min Keun; Kang, Tae Ho; Kim, Jungho; Kim, Hoon; Yun, Han Dae

    2012-12-01

    This study was conducted to assess the gene duplication and diversification of tandem cellulase genes in thermophilic bacteria. The tandem cellulase genes cel5C and cel5D were cloned from Thermotoga maritima MSB8, and a survey of the thermophilic bacterial genome for tandem cel genes from the databases was carried out. A clone having 2.3 kb fragment from T. maritima MSB8 showed cellulase activity, which had two open reading frames in tandem (cel5C and cel5D). The cel5C gene has 954 bp, which encodes a protein of 317 amino acid residues with a signal peptide of 23 amino acids, and the other gene cel5D consisting of 990 bp encoding a protein of 329 amino acid residues. These two proteins have similarity with the enzymes of glycosyl hydrolase family 5. From the enzyme assay, it was observed that Cel5C was extracellular and Cel5D was intracellular cellulase. Phylogenetic and homology matrix analyses of DNA and protein sequences revealed that family 12 cellulase enzymes Cel12A and Cel12B displayed higher homology (>50 %), but Cel5C and Cel5D enzymes belong to family 5 displayed lower homology (<30 %). In addition, repeated and mirror sequences in tandem genes are supposed to show the existence of gene duplication and recombination.

  14. Evidence for the fixation of gene duplications by positive selection in Drosophila

    PubMed Central

    Cardoso-Moreira, Margarida; Arguello, J. Roman; Gottipati, Srikanth; Harshman, L.G.; Grenier, Jennifer K.; Clark, Andrew G.

    2016-01-01

    Gene duplications play a key role in the emergence of novel traits and in adaptation. But despite their centrality to evolutionary processes, it is still largely unknown how new gene duplicates are initially fixed within populations and later maintained in genomes. Long-standing debates on the evolution of gene duplications could be settled by determining the relative importance of genetic drift vs. positive selection in the fixation of new gene duplicates. Using the Drosophila Global Diversity Lines (GDL), we have combined genome-wide SNP polymorphism data with a novel set of copy number variant calls and gene expression profiles to characterize the polymorphic phase of new genes. We found that approximately half of the roughly 500 new complete gene duplications segregating in the GDL lead to significant increases in the expression levels of the duplicated genes and that these duplications are more likely to be found at lower frequencies, suggesting a negative impact on fitness. However, we also found that six of the nine gene duplications that are fixed or close to fixation in at least one of the five populations in our study show signs of being under positive selection, and that these duplications are likely beneficial because of dosage effects, with a possible role for additional mutations in two duplications. Our work suggests that in Drosophila, theoretical models that posit that gene duplications are immediately beneficial and fixed by positive selection are most relevant to explain the long-term evolution of gene duplications in this species. PMID:27197209

  15. Origin and evolution of eukaryotic chaperonins: phylogenetic evidence for ancient duplications in CCT genes.

    PubMed

    Archibald, J M; Logsdon, J M; Doolittle, W F

    2000-10-01

    Chaperonins are oligomeric protein-folding complexes which are divided into two distantly related structural classes. Group I chaperonins (called GroEL/cpn60/hsp60) are found in bacteria and eukaryotic organelles, while group II chaperonins are present in archaea and the cytoplasm of eukaryotes (called CCT/TriC). While archaea possess one to three chaperonin subunit-encoding genes, eight distinct CCT gene families (paralogs) have been characterized in eukaryotes. We are interested in determining when during eukaryotic evolution the multiple gene duplications producing the CCT subunits occurred. We describe the sequence and phylogenetic analysis of five CCT genes from TRICHOMONAS: vaginalis and seven from GIARDIA: lamblia, representatives of amitochondriate protist lineages thought to have diverged early from other eukaryotes. Our data show that the gene duplications producing the eight CCT paralogs took place prior to the organismal divergence of TRICHOMONAS: and GIARDIA: from other eukaryotes. Thus, these divergent protists likely possess completely hetero-oligomeric CCT complexes like those in yeast and mammalian cells. No close phylogenetic relationship between the archaeal chaperonins and specific CCT subunits was observed, suggesting that none of the CCT gene duplications predate the divergence of archaea and eukaryotes. The duplications producing the CCTdelta and CCTepsilon subunits, as well as CCTalpha, CCTbeta, and CCTeta, are the most recent in the CCT gene family. Our analyses show significant differences in the rates of evolution of archaeal chaperonins compared with the eukaryotic CCTs, as well as among the different CCT subunits themselves. We discuss these results in light of current views on the origin, evolution, and function of CCT complexes.

  16. The human VK locus. Characterization of a duplicated region encoding 28 different immunoglobulin genes.

    PubMed

    Straubinger, B; Huber, E; Lorenz, W; Osterholzer, E; Pargent, W; Pech, M; Pohlenz, H D; Zimmer, F J; Zachau, H G

    1988-01-05

    Two large regions of the human multigene family coding for the variable parts of the immunoglobulin light chains of the K type (VK) have been characterized on cosmid clones. The two germline regions, called Aa and Ab, span together 250,000 base-pairs and comprise 28 different VK gene segments, nine of which have been sequenced. There is a preponderance of VKII genes but genes belonging to subgroups I and III, and genes that cannot be easily assigned to one of the known subgroups, are interspersed within the VKII gene clusters. A number of pseudogenes have been identified. Within the Aa and Ab regions, all gene segments are organized in the same transcriptional orientation. The regions Aa and Ab, whose restriction maps are highly homologous, were shown not to be allelic structures; they must have arisen by a duplication event. Taken together with previous results, one can conclude that the major part of the VK locus exists in duplicated form. One individual has been found who has only one copy of some of the duplicated regions. By chromosomal walking, the A regions could be linked to the O regions, an analysis of which has been reported. The A regions contribute about one-third of the VK genes so far identified.

  17. Hox gene duplications correlate with posterior heteronomy in scorpions

    PubMed Central

    Sharma, Prashant P.; Schwager, Evelyn E.; Extavour, Cassandra G.; Wheeler, Ward C.

    2014-01-01

    The evolutionary success of the largest animal phylum, Arthropoda, has been attributed to tagmatization, the coordinated evolution of adjacent metameres to form morphologically and functionally distinct segmental regions called tagmata. Specification of regional identity is regulated by the Hox genes, of which 10 are inferred to be present in the ancestor of arthropods. With six different posterior segmental identities divided into two tagmata, the bauplan of scorpions is the most heteronomous within Chelicerata. Expression domains of the anterior eight Hox genes are conserved in previously surveyed chelicerates, but it is unknown how Hox genes regionalize the three tagmata of scorpions. Here, we show that the scorpion Centruroides sculpturatus has two paralogues of all Hox genes except Hox3, suggesting cluster and/or whole genome duplication in this arachnid order. Embryonic anterior expression domain boundaries of each of the last four pairs of Hox genes (two paralogues each of Antp, Ubx, abd-A and Abd-B) are unique and distinguish segmental groups, such as pectines, book lungs and the characteristic tail, while maintaining spatial collinearity. These distinct expression domains suggest neofunctionalization of Hox gene paralogues subsequent to duplication. Our data reconcile previous understanding of Hox gene function across arthropods with the extreme heteronomy of scorpions. PMID:25122224

  18. Hox gene duplications correlate with posterior heteronomy in scorpions.

    PubMed

    Sharma, Prashant P; Schwager, Evelyn E; Extavour, Cassandra G; Wheeler, Ward C

    2014-10-07

    The evolutionary success of the largest animal phylum, Arthropoda, has been attributed to tagmatization, the coordinated evolution of adjacent metameres to form morphologically and functionally distinct segmental regions called tagmata. Specification of regional identity is regulated by the Hox genes, of which 10 are inferred to be present in the ancestor of arthropods. With six different posterior segmental identities divided into two tagmata, the bauplan of scorpions is the most heteronomous within Chelicerata. Expression domains of the anterior eight Hox genes are conserved in previously surveyed chelicerates, but it is unknown how Hox genes regionalize the three tagmata of scorpions. Here, we show that the scorpion Centruroides sculpturatus has two paralogues of all Hox genes except Hox3, suggesting cluster and/or whole genome duplication in this arachnid order. Embryonic anterior expression domain boundaries of each of the last four pairs of Hox genes (two paralogues each of Antp, Ubx, abd-A and Abd-B) are unique and distinguish segmental groups, such as pectines, book lungs and the characteristic tail, while maintaining spatial collinearity. These distinct expression domains suggest neofunctionalization of Hox gene paralogues subsequent to duplication. Our data reconcile previous understanding of Hox gene function across arthropods with the extreme heteronomy of scorpions.

  19. Multiple paleopolyploidizations during the evolution of the Compositae reveal parallel patterns of duplicate gene retention after millions of years.

    PubMed

    Barker, Michael S; Kane, Nolan C; Matvienko, Marta; Kozik, Alexander; Michelmore, Richard W; Knapp, Steven J; Rieseberg, Loren H

    2008-11-01

    Of the approximately 250,000 species of flowering plants, nearly one in ten are members of the Compositae (Asteraceae), a diverse family found in almost every habitat on all continents except Antarctica. With an origin in the mid Eocene, the Compositae is also a relatively young family with remarkable diversifications during the last 40 My. Previous cytologic and systematic investigations suggested that paleopolyploidy may have occurred in at least one Compositae lineage, but a recent analysis of genomic data was equivocal. We tested for evidence of paleopolyploidy in the evolutionary history of the family using recently available expressed sequence tag (EST) data from the Compositae Genome Project. Combined with data available on GenBank, we analyzed nearly 1 million ESTs from 18 species representing seven genera and four tribes. Our analyses revealed at least three ancient whole-genome duplications in the Compositae-a paleopolyploidization shared by all analyzed taxa and placed near the origin of the family just prior to the rapid radiation of its tribes and independent genome duplications near the base of the tribes Mutisieae and Heliantheae. These results are consistent with previous research implicating paleopolyploidy in the evolution and diversification of the Heliantheae. Further, we observed parallel retention of duplicate genes from the basal Compositae genome duplication across all tribes, despite divergence times of 33-38 My among these lineages. This pattern of retention was also repeated for the paleologs from the Heliantheae duplication. Intriguingly, the categories of genes retained in duplicate were substantially different from those in Arabidopsis. In particular, we found that genes annotated to structural components or cellular organization Gene Ontology categories were significantly enriched among paleologs, whereas genes associated with transcription and other regulatory functions were significantly underrepresented. Our results suggest that

  20. Multiple Paleopolyploidizations during the Evolution of the Compositae Reveal Parallel Patterns of Duplicate Gene Retention after Millions of Years

    PubMed Central

    Barker, Michael S.; Kane, Nolan C.; Matvienko, Marta; Kozik, Alexander; Michelmore, Richard W.; Knapp, Steven J.; Rieseberg, Loren H.

    2008-01-01

    Of the approximately 250,000 species of flowering plants, nearly one in ten are members of the Compositae (Asteraceae), a diverse family found in almost every habitat on all continents except Antarctica. With an origin in the mid Eocene, the Compositae is also a relatively young family with remarkable diversifications during the last 40 My. Previous cytologic and systematic investigations suggested that paleopolyploidy may have occurred in at least one Compositae lineage, but a recent analysis of genomic data was equivocal. We tested for evidence of paleopolyploidy in the evolutionary history of the family using recently available expressed sequence tag (EST) data from the Compositae Genome Project. Combined with data available on GenBank, we analyzed nearly 1 million ESTs from 18 species representing seven genera and four tribes. Our analyses revealed at least three ancient whole-genome duplications in the Compositae—a paleopolyploidization shared by all analyzed taxa and placed near the origin of the family just prior to the rapid radiation of its tribes and independent genome duplications near the base of the tribes Mutisieae and Heliantheae. These results are consistent with previous research implicating paleopolyploidy in the evolution and diversification of the Heliantheae. Further, we observed parallel retention of duplicate genes from the basal Compositae genome duplication across all tribes, despite divergence times of 33–38 My among these lineages. This pattern of retention was also repeated for the paleologs from the Heliantheae duplication. Intriguingly, the categories of genes retained in duplicate were substantially different from those in Arabidopsis. In particular, we found that genes annotated to structural components or cellular organization Gene Ontology categories were significantly enriched among paleologs, whereas genes associated with transcription and other regulatory functions were significantly underrepresented. Our results suggest

  1. New genes from old: asymmetric divergence of gene duplicates and the evolution of development.

    PubMed

    Holland, Peter W H; Marlétaz, Ferdinand; Maeso, Ignacio; Dunwell, Thomas L; Paps, Jordi

    2017-02-05

    Gene duplications and gene losses have been frequent events in the evolution of animal genomes, with the balance between these two dynamic processes contributing to major differences in gene number between species. After gene duplication, it is common for both daughter genes to accumulate sequence change at approximately equal rates. In some cases, however, the accumulation of sequence change is highly uneven with one copy radically diverging from its paralogue. Such 'asymmetric evolution' seems commoner after tandem gene duplication than after whole-genome duplication, and can generate substantially novel genes. We describe examples of asymmetric evolution in duplicated homeobox genes of moths, molluscs and mammals, in each case generating new homeobox genes that were recruited to novel developmental roles. The prevalence of asymmetric divergence of gene duplicates has been underappreciated, in part, because the origin of highly divergent genes can be difficult to resolve using standard phylogenetic methods.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.

  2. A salmonid EST genomic study: genes, duplications, phylogeny and microarrays

    PubMed Central

    Koop, Ben F; von Schalburg, Kristian R; Leong, Jong; Walker, Neil; Lieph, Ryan; Cooper, Glenn A; Robb, Adrienne; Beetz-Sargent, Marianne; Holt, Robert A; Moore, Richard; Brahmbhatt, Sonal; Rosner, Jamie; Rexroad, Caird E; McGowan, Colin R; Davidson, William S

    2008-01-01

    Background Salmonids are of interest because of their relatively recent genome duplication, and their extensive use in wild fisheries and aquaculture. A comprehensive gene list and a comparison of genes in some of the different species provide valuable genomic information for one of the most widely studied groups of fish. Results 298,304 expressed sequence tags (ESTs) from Atlantic salmon (69% of the total), 11,664 chinook, 10,813 sockeye, 10,051 brook trout, 10,975 grayling, 8,630 lake whitefish, and 3,624 northern pike ESTs were obtained in this study and have been deposited into the public databases. Contigs were built and putative full-length Atlantic salmon clones have been identified. A database containing ESTs, assemblies, consensus sequences, open reading frames, gene predictions and putative annotation is available. The overall similarity between Atlantic salmon ESTs and those of rainbow trout, chinook, sockeye, brook trout, grayling, lake whitefish, northern pike and rainbow smelt is 93.4, 94.2, 94.6, 94.4, 92.5, 91.7, 89.6, and 86.2% respectively. An analysis of 78 transcript sets show Salmo as a sister group to Oncorhynchus and Salvelinus within Salmoninae, and Thymallinae as a sister group to Salmoninae and Coregoninae within Salmonidae. Extensive gene duplication is consistent with a genome duplication in the common ancestor of salmonids. Using all of the available EST data, a new expanded salmonid cDNA microarray of 32,000 features was created. Cross-species hybridizations to this cDNA microarray indicate that this resource will be useful for studies of all 68 salmonid species. Conclusion An extensive collection and analysis of salmonid RNA putative transcripts indicate that Pacific salmon, Atlantic salmon and charr are 94–96% similar while the more distant whitefish, grayling, pike and smelt are 93, 92, 89 and 86% similar to salmon. The salmonid transcriptome reveals a complex history of gene duplication that is consistent with an ancestral

  3. The structure and early evolution of recently arisen gene duplicates in the Caenorhabditis elegans genome.

    PubMed Central

    Katju, Vaishali; Lynch, Michael

    2003-01-01

    The significance of gene duplication in provisioning raw materials for the evolution of genomic diversity is widely recognized, but the early evolutionary dynamics of duplicate genes remain obscure. To elucidate the structural characteristics of newly arisen gene duplicates at infancy and their subsequent evolutionary properties, we analyzed gene pairs with < or =10% divergence at synonymous sites within the genome of Caenorhabditis elegans. Structural heterogeneity between duplicate copies is present very early in their evolutionary history and is maintained over longer evolutionary timescales, suggesting that duplications across gene boundaries in conjunction with shuffling events have at least as much potential to contribute to long-term evolution as do fully redundant (complete) duplicates. The median duplication span of 1.4 kb falls short of the average gene length in C. elegans (2.5 kb), suggesting that partial gene duplications are frequent. Most gene duplicates reside close to the parent copy at inception, often as tandem inverted loci, and appear to disperse in the genome as they age, as a result of reduced survivorship of duplicates located in proximity to the ancestral copy. We propose that illegitimate recombination events leading to inverted duplications play a disproportionately large role in gene duplication within this genome in comparison with other mechanisms. PMID:14704166

  4. The structure and early evolution of recently arisen gene duplicates in the Caenorhabditis elegans genome.

    PubMed

    Katju, Vaishali; Lynch, Michael

    2003-12-01

    The significance of gene duplication in provisioning raw materials for the evolution of genomic diversity is widely recognized, but the early evolutionary dynamics of duplicate genes remain obscure. To elucidate the structural characteristics of newly arisen gene duplicates at infancy and their subsequent evolutionary properties, we analyzed gene pairs with < or =10% divergence at synonymous sites within the genome of Caenorhabditis elegans. Structural heterogeneity between duplicate copies is present very early in their evolutionary history and is maintained over longer evolutionary timescales, suggesting that duplications across gene boundaries in conjunction with shuffling events have at least as much potential to contribute to long-term evolution as do fully redundant (complete) duplicates. The median duplication span of 1.4 kb falls short of the average gene length in C. elegans (2.5 kb), suggesting that partial gene duplications are frequent. Most gene duplicates reside close to the parent copy at inception, often as tandem inverted loci, and appear to disperse in the genome as they age, as a result of reduced survivorship of duplicates located in proximity to the ancestral copy. We propose that illegitimate recombination events leading to inverted duplications play a disproportionately large role in gene duplication within this genome in comparison with other mechanisms.

  5. Mitochondrial genomes of praying mantises (Dictyoptera, Mantodea): rearrangement, duplication, and reassignment of tRNA genes

    PubMed Central

    Ye, Fei; Lan, Xu-e; Zhu, Wen-bo; You, Ping

    2016-01-01

    Insect mitochondrial genomes (mitogenomes) contain a conserved set of 37 genes for an extensive diversity of lineages. Previously reported dictyopteran mitogenomes share this conserved mitochondrial gene arrangement, although surprisingly little is known about the mitogenome of Mantodea. We sequenced eight mantodean mitogenomes including the first representatives of two families: Hymenopodidae and Liturgusidae. Only two of these genomes retain the typical insect gene arrangement. In three Liturgusidae species, the trnM genes have translocated. Four species of mantis (Creobroter gemmata, Mantis religiosa, Statilia sp., and Theopompa sp.-HN) have multiple identical tandem duplication of trnR, and Statilia sp. additionally includes five extra duplicate trnW. These extra trnR and trnW in Statilia sp. are erratically arranged and form another novel gene order. Interestingly, the extra trnW is converted from trnR by the process of point mutation at anticodon, which is the first case of tRNA reassignment for an insect. Furthermore, no significant differences were observed amongst mantodean mitogenomes with variable copies of tRNA according to comparative analysis of codon usage. Combined with phylogenetic analysis, the characteristics of tRNA only possess limited phylogenetic information in this research. Nevertheless, these features of gene rearrangement, duplication, and reassignment provide valuable information toward understanding mitogenome evolution in insects. PMID:27157299

  6. Domain loss facilitates accelerated evolution and neofunctionalization of duplicate snake venom metalloproteinase toxin genes.

    PubMed

    Casewell, Nicholas R; Wagstaff, Simon C; Harrison, Robert A; Renjifo, Camila; Wüster, Wolfgang

    2011-09-01

    Gene duplication is a key mechanism for the adaptive evolution and neofunctionalization of gene families. Large multigene families often exhibit complex evolutionary histories as a result of frequent gene duplication acting in concordance with positive selection pressures. Alterations in the domain structure of genes, causing changes in the molecular scaffold of proteins, can also result in a complex evolutionary history and has been observed in functionally diverse multigene toxin families. Here, we investigate the role alterations in domain structure have on the tempo of evolution and neofunctionalization of multigene families using the snake venom metalloproteinases (SVMPs) as a model system. Our results reveal that the evolutionary history of viperid (Serpentes: Viperidae) SVMPs is repeatedly punctuated by domain loss, with the single loss of the cysteine-rich domain, facilitating the formation of P-II class SVMPs, occurring prior to the convergent loss of the disintegrin domain to form multiple P-I SVMP structures. Notably, the majority of phylogenetic branches where domain loss was inferred to have occurred exhibited highly significant evidence of positive selection in surface-exposed amino acid residues, resulting in the neofunctionalization of P-II and P-I SVMP classes. These results provide a valuable insight into the mechanisms by which complex gene families evolve and detail how the loss of domain structures can catalyze the accelerated evolution of novel gene paralogues. The ensuing generation of differing molecular scaffolds encoded by the same multigene family facilitates gene neofunctionalization while presenting an evolutionary advantage through the retention of multiple genes capable of encoding functionally distinct proteins.

  7. [Duplication of DNA--a mechanism for the development of new functionality of genes].

    PubMed

    Maślanka, Roman; Zadrąg-Tęcza, Renata

    2015-01-01

    The amplification of DNA is considered as a mechanism for rapid evolution of organisms. Duplication can be especially advantageous in the case of changing environmental conditions. Whole genome duplication maintains the proper balance between gene expression. This seems to be the main reason why WGD is more favorable than duplication of the fragments of DNA. The polyploidy status disappear as a result of the loss of the majority of duplicated genes. The preservation of duplicated genes is associated with the development of their new functions. Polyploidization is often noted for plants. However due to sequencing technique, the duplications episodes are more frequently reports also for the other systematic taxa, including animals. The occurrence of ancient genome duplication is also considered for yeast Saccharomyces cerevisiae. The existence of two active copies of ribosomal protein genes can be a confirmation of this process. Development of the fermentation process might be one of the probable causes of the yeast genome duplication.

  8. Insertion of the IL1RAPL1 gene into the duplication junction of the dystrophin gene.

    PubMed

    Zhang, Zhujun; Yagi, Mariko; Okizuka, Yo; Awano, Hiroyuki; Takeshima, Yasuhiro; Matsuo, Masafumi

    2009-08-01

    Duplications of one or more exons of the dystrophin gene are the second most common mutation in dystrophinopathies. Even though duplications are suggested to occur with greater complexity than thought earlier, they have been considered an intragenic event. Here, we report the insertion of a part of the IL1RAPL1 (interleukin-1 receptor accessory protein-like 1) gene into the duplication junction site. When the actual exon junction was examined in 15 duplication mutations in the dystrophin gene by analyzing dystrophin mRNA, one patient was found to have an unknown 621 bp insertion at the junction of duplication of exons from 56 to 62. Unexpectedly, the inserted sequence was found completely identical to sequences of exons 3-5 of the IL1RAPL1 gene that is nearly 100 kb distal from the dystrophin gene. Accordingly, the insertion of IL1RAPL1 exons 3-5 between dystrophin exons 62 and 56 was confirmed at the genomic sequence level. One junction between the IL1RAPL1 intron 5 and dystrophin intron 55 was localized within an Alu sequence. These results showed that a fragment of the IL1RAPL1 gene was inserted into the duplication junction of the dystrophin gene in the same direction as the dystrophin gene. This suggests the novel possibility of co-occurrence of complex genomic rearrangements in dystrophinopathy.

  9. A limited role for gene duplications in the evolution of platypus venom.

    PubMed

    Wong, Emily S W; Papenfuss, Anthony T; Whittington, Camilla M; Warren, Wesley C; Belov, Katherine

    2012-01-01

    Gene duplication followed by adaptive selection is believed to be the primary driver of venom evolution. However, to date, no studies have evaluated the importance of gene duplications for venom evolution using a genomic approach. The availability of a sequenced genome and a venom gland transcriptome for the enigmatic platypus provides a unique opportunity to explore the role that gene duplication plays in venom evolution. Here, we identify gene duplication events and correlate them with expressed transcripts in an in-season venom gland. Gene duplicates (1,508) were identified. These duplicated pairs (421), including genes that have undergone multiple rounds of gene duplications, were expressed in the venom gland. The majority of these genes are involved in metabolism and protein synthesis not toxin functions. Twelve secretory genes including serine proteases, metalloproteinases, and protease inhibitors likely to produce symptoms of envenomation such as vasodilation and pain were detected. Only 16 of 107 platypus genes with high similarity to known toxins evolved through gene duplication. Platypus venom C-type natriuretic peptides and nerve growth factor do not possess lineage-specific gene duplicates. Extensive duplications, believed to increase the potency of toxic content and promote toxin diversification, were not found. This is the first study to take a genome-wide approach in order to examine the impact of gene duplication on venom evolution. Our findings support the idea that adaptive selection acts on gene duplicates to drive the independent evolution and functional diversification of similar venom genes in venomous species. However, gene duplications alone do not explain the "venome" of the platypus. Other mechanisms, such as alternative splicing and mutation, may be important in venom innovation.

  10. Gene duplication and speciation in Drosophila: evidence from the Odysseus locus.

    PubMed

    Ting, Chau-Ti; Tsaur, Shun-Chern; Sun, Sha; Browne, William E; Chen, Yung-Chia; Patel, Nipam H; Wu, Chung-I

    2004-08-17

    The importance of gene duplication in evolution has long been recognized. Because duplicated genes are prone to diverge in function, gene duplication could plausibly play a role in species differentiation. However, experimental evidence linking gene duplication with speciation is scarce. Here, we show that a hybrid-male sterility gene, Odysseus (OdsH), arose by gene duplication in the Drosophila genome. OdsH has evolved at a very high rate, whereas its most immediate paralog, unc-4, is nearly identical among species in the Drosophila melanogaster subgroup. The disparity in their sequence evolution is echoed by the divergence in their expression patterns in both soma and reproductive tissues. We suggest that duplicated genes that have yet to evolve a stable function at the time of speciation may be candidates for "speciation genes," which is broadly defined as genes that contribute to differential adaptation between species.

  11. Modelling the evolution of multi-gene families.

    PubMed

    Nye, Tom M W

    2009-10-01

    A number of biological processes can lead to genes being copied within the genome of some given species. Duplicate genes of this form are called paralogs and such genes share a high degree sequence similarity as well as often having closely related functions. Some genes have become widely duplicated to form multigene families in which the copies are distributed both within the genomes of individual species and across different species. Statistical modelling of gene duplication and the evolution of multi-gene families currently lags behind well-established models of DNA sequence evolution despite an increasing volume of available data, but the analysis of multi-gene families is important as part of a wider effort to understand evolution at the genomic level. This article reviews existing approaches to modelling multi-gene families and presents various challenges and possibilities for this exciting area of research.

  12. Coregulation of tandem duplicate genes slows evolution of subfunctionalization in mammals

    PubMed Central

    Lan, Xun; Pritchard, Jonathan K.

    2016-01-01

    Gene duplication is a fundamental process in genome evolution. However, most young duplicates are degraded by loss-of-function mutations, and the factors that allow some duplicate pairs to survive long-term remain controversial. One class of models to explain duplicate retention invokes sub- or neofunctionalization, whereas others focus on sharing of gene dosage. RNA-sequencing data from 46 human and 26 mouse tissues indicate that subfunctionalization of expression evolves slowly and is rare among duplicates that arose within the placental mammals, possibly because tandem duplicates are coregulated by shared genomic elements. Instead, consistent with the dosage-sharing hypothesis, most young duplicates are down-regulated to match expression levels of single-copy genes. Thus, dosage sharing of expression allows for the initial survival of mammalian duplicates, followed by slower functional adaptation enabling long-term preservation. PMID:27199432

  13. Imbalanced positive selection maintains the functional divergence of duplicated DIHYDROKAEMPFEROL 4-REDUCTASE genes

    PubMed Central

    Huang, Bing-Hong; Chen, Yi-Wen; Huang, Chia-Lung; Gao, Jian; Liao, Pei-Chun

    2016-01-01

    Gene duplication could be beneficial by functional division but might increase the risk of genetic load. The dynamics of duplicated paralogs number could involve recombination, positive selection, and functional divergence. Duplication of DIHYDROFLAVONOL 4-REDUCTASE (DFR) has been reported in several organisms and may have been retained by escape from adaptive conflict (EAC). In this study, we screened the angiosperm DFR gene focusing on a diversified genus Scutellaria to investigate how these duplicated genes are retained. We deduced that gene duplication involved multiple independent events in angiosperms, but the duplication of DFR was before the divergence of Scutellaria. Asymmetric positive selective pressures resulted in different evolutionary rates between the duplicates. Different numbers of regulatory elements, differential codon usages, radical amino acid changes, and differential gene expressions provide evidences of functional divergence between the two DFR duplicates in Scutellaria, implying adaptive subfunctionalization between duplicates. The discovery of pseudogenes accompanying a reduced replacement rate in one DFR paralogous gene suggested possibly leading to “loss of function” due to dosage imbalance after the transient adaptive subfunctionalization in the early stage of duplication. Notwithstanding, episodic gene duplication and functional divergence may be relevant to the diversification of ecological function of DFR gene in Scutellaria. PMID:27966614

  14. The HOPA Gene Dodecamer Duplication Is Not a Significant Etiological Factor in Autism.

    ERIC Educational Resources Information Center

    Michaelis, Ron C.; Copeland-Yates, Susan A.; Sossey-Alaoui, Khalid; Skinner, Cindy; Friez, Michael J.; Longshore, John W.; Simensen, Richard J.; Schroer, Richard J.; Stevenson, Roger E.

    2000-01-01

    A study of 202 patients with autism found the incidence of a dodecamer duplication in the HOPA gene was not significantly different between patients and controls. Three female patients inherited the duplication from nonautistic fathers. Also, there was no systematic skewing of X inactivation in female patients with the duplication. (Contains…

  15. Evolution by gene duplication of Medicago truncatula PISTILLATA-like transcription factors.

    PubMed

    Roque, Edelín; Fares, Mario A; Yenush, Lynne; Rochina, Mari Cruz; Wen, Jiangqi; Mysore, Kirankumar S; Gómez-Mena, Concepción; Beltrán, José Pío; Cañas, Luis A

    2016-03-01

    PISTILLATA (PI) is a member of the B-function MADS-box gene family, which controls the identity of both petals and stamens in Arabidopsis thaliana. In Medicago truncatula (Mt), there are two PI-like paralogs, known as MtPI and MtNGL9. These genes differ in their expression patterns, but it is not known whether their functions have also diverged. Describing the evolution of certain duplicated genes, such as transcription factors, remains a challenge owing to the complex expression patterns and functional divergence between the gene copies. Here, we report a number of functional studies, including analyses of gene expression, protein-protein interactions, and reverse genetic approaches designed to demonstrate the respective contributions of each M. truncatula PI-like paralog to the B-function in this species. Also, we have integrated molecular evolution approaches to determine the mode of evolution of Mt PI-like genes after duplication. Our results demonstrate that MtPI functions as a master regulator of B-function in M. truncatula, maintaining the overall ancestral function, while MtNGL9 does not seem to have a role in this regard, suggesting that the pseudogenization could be the functional evolutionary fate for this gene. However, we provide evidence that purifying selection is the primary evolutionary force acting on this paralog, pinpointing the conservation of its biochemical function and, alternatively, the acquisition of a new role for this gene.

  16. Divergence of Gene Body DNA Methylation and Evolution of Plant Duplicate Genes

    PubMed Central

    Wang, Jun; Marowsky, Nicholas C.; Fan, Chuanzhu

    2014-01-01

    It has been shown that gene body DNA methylation is associated with gene expression. However, whether and how deviation of gene body DNA methylation between duplicate genes can influence their divergence remains largely unexplored. Here, we aim to elucidate the potential role of gene body DNA methylation in the fate of duplicate genes. We identified paralogous gene pairs from Arabidopsis and rice (Oryza sativa ssp. japonica) genomes and reprocessed their single-base resolution methylome data. We show that methylation in paralogous genes nonlinearly correlates with several gene properties including exon number/gene length, expression level and mutation rate. Further, we demonstrated that divergence of methylation level and pattern in paralogs indeed positively correlate with their sequence and expression divergences. This result held even after controlling for other confounding factors known to influence the divergence of paralogs. We observed that methylation level divergence might be more relevant to the expression divergence of paralogs than methylation pattern divergence. Finally, we explored the mechanisms that might give rise to the divergence of gene body methylation in paralogs. We found that exonic methylation divergence more closely correlates with expression divergence than intronic methylation divergence. We show that genomic environments (e.g., flanked by transposable elements and repetitive sequences) of paralogs generated by various duplication mechanisms are associated with the methylation divergence of paralogs. Overall, our results suggest that the changes in gene body DNA methylation could provide another avenue for duplicate genes to develop differential expression patterns and undergo different evolutionary fates in plant genomes. PMID:25310342

  17. Duplication and Diversification of Dipteran Argonaute Genes, and the Evolutionary Divergence of Piwi and Aubergine

    PubMed Central

    Lewis, Samuel H.; Salmela, Heli; Obbard, Darren J.

    2016-01-01

    Genetic studies of Drosophila melanogaster have provided a paradigm for RNA interference (RNAi) in arthropods, in which the microRNA and antiviral pathways are each mediated by a single Argonaute (Ago1 and Ago2) and germline suppression of transposable elements is mediated by a trio of Piwi-subfamily Argonaute proteins (Ago3, Aub, and Piwi). Without a suitable evolutionary context, deviations from this can be interpreted as derived or idiosyncratic. Here we analyze the evolution of Argonaute genes across the genomes and transcriptomes of 86 Dipteran species, showing that variation in copy number can occur rapidly, and that there is constant flux in some RNAi mechanisms. The lability of the RNAi pathways is illustrated by the divergence of Aub and Piwi (182–156 Ma), independent origins of multiple Piwi-family genes in Aedes mosquitoes (less than 25Ma), and the recent duplications of Ago2 and Ago3 in the tsetse fly Glossina morsitans. In each case the tissue specificity of these genes has altered, suggesting functional divergence or innovation, and consistent with the action of dynamic selection pressures across the Argonaute gene family. We find there are large differences in evolutionary rates and gene turnover between pathways, and that paralogs of Ago2, Ago3, and Piwi/Aub show contrasting rates of evolution after duplication. This suggests that Argonautes undergo frequent evolutionary expansions that facilitate functional divergence. PMID:26868596

  18. Evolution history of duplicated smad3 genes in teleost: insights from Japanese flounder, Paralichthys olivaceus

    PubMed Central

    Du, Xinxin; Liu, Yuezhong; Liu, Jinxiang; Zhang, Quanqi

    2016-01-01

    Following the two rounds of whole-genome duplication (WGD) during deuterosome evolution, a third genome duplication occurred in the ray-fined fish lineage and is considered to be responsible for the teleost-specific lineage diversification and regulation mechanisms. As a receptor-regulated SMAD (R-SMAD), the function of SMAD3 was widely studied in mammals. However, limited information of its role or putative paralogs is available in ray-finned fishes. In this study, two SMAD3 paralogs were first identified in the transcriptome and genome of Japanese flounder (Paralichthys olivaceus). We also explored SMAD3 duplication in other selected species. Following identification, genomic structure, phylogenetic reconstruction, and synteny analyses performed by MrBayes and online bioinformatic tools confirmed that smad3a/3b most likely originated from the teleost-specific WGD. Additionally, selection pressure analysis and expression pattern of the two genes performed by PAML and quantitative real-time PCR (qRT-PCR) revealed evidence of subfunctionalization of the two SMAD3 paralogs in teleost. Our results indicate that two SMAD3 genes originate from teleost-specific WGD, remain transcriptionally active, and may have likely undergone subfunctionalization. This study provides novel insights to the evolution fates of smad3a/3b and draws attentions to future function analysis of SMAD3 gene family. PMID:27703851

  19. Accelerated evolution after gene duplication: a time-dependent process affecting just one copy.

    PubMed

    Pegueroles, Cinta; Laurie, Steve; Albà, M Mar

    2013-08-01

    Gene duplication is widely regarded as a major mechanism modeling genome evolution and function. However, the mechanisms that drive the evolution of the two, initially redundant, gene copies are still ill defined. Many gene duplicates experience evolutionary rate acceleration, but the relative contribution of positive selection and random drift to the retention and subsequent evolution of gene duplicates, and for how long the molecular clock may be distorted by these processes, remains unclear. Focusing on rodent genes that duplicated before and after the mouse and rat split, we find significantly increased sequence divergence after duplication in only one of the copies, which in nearly all cases corresponds to the novel daughter copy, independent of the mechanism of duplication. We observe that the evolutionary rate of the accelerated copy, measured as the ratio of nonsynonymous to synonymous substitutions, is on average 5-fold higher in the period spanning 4-12 My after the duplication than it was before the duplication. This increase can be explained, at least in part, by the action of positive selection according to the results of the maximum likelihood-based branch-site test. Subsequently, the rate decelerates until purifying selection completely returns to preduplication levels. Reversion to the original rates has already been accomplished 40.5 My after the duplication event, corresponding to a genetic distance of about 0.28 synonymous substitutions per site. Differences in tissue gene expression patterns parallel those of substitution rates, reinforcing the role of neofunctionalization in explaining the evolution of young gene duplicates.

  20. Evolution of the ability to modulate host chemokine networks via gene duplication in human cytomegalovirus (HCMV).

    PubMed

    Scarborough, Jessica A; Paul, John R; Spencer, Juliet V

    2017-03-14

    Human cytomegalovirus (HCMV) is a widespread pathogen that is particularly skillful at evading immune detection and defense mechanisms, largely due to extensive co-evolution with its host. One aspect of this co-evolution involves the acquisition of virally encoded G protein-coupled receptors (GPCRs) with homology to the chemokine receptor family. GPCRs are the largest family of cell surface proteins, found in organisms from yeast to humans, and they regulate a variety of cellular processes including development, sensory perception, and immune cell trafficking. The US27 and US28 genes are encoded by human and primate CMVs, but homologs are not found in the genomes of viruses infecting rodents or other species. Phylogenetic analysis was used to investigate the US27 and US28 genes, which are adjacent in the unique short (US) region of the HCMV genome, and their relationship to one another and to human chemokine receptor genes. The results indicate that both US27 and US28 share the same common ancestor with human chemokine receptor CX3CR1, suggesting that a single host gene was captured and a subsequent viral gene duplication event occurred. The US28 gene product (pUS28) has maintained the function of the ancestral gene and has the ability to bind and signal in response to CX3CL1/fractalkine, the natural ligand for CX3CR1. In contrast, pUS27 does not bind to any known chemokine ligand, and the sequence has diverged significantly, highlighted by the fact that pUS27 currently exhibits greater sequence similarity to human CCR1. While the evolutionary advantage of the gene duplication and neofunctionalization event remains unclear, the US27 and US28 genes are highly conserved among different HCMV strains and retained even in laboratory strains that have lost many virulence genes, suggesting that US27 and US28 have each evolved distinct, important functions during virus infection.

  1. Did homeobox gene duplications contribute to the Cambrian explosion?

    PubMed

    Holland, Peter W H

    2015-01-01

    The Cambrian explosion describes an apparently rapid increase in the diversity of bilaterian animals around 540-515 million years ago. Bilaterian animals explore the world in three-dimensions deploying forward-facing sense organs, a brain, and an anterior mouth; they possess muscle blocks enabling efficient crawling and burrowing in sediments, and they typically have an efficient 'through-gut' with separate mouth and anus to process bulk food and eject waste, even when burrowing in sediment. A variety of ecological, environmental, genetic, and developmental factors have been proposed as possible triggers and correlates of the Cambrian explosion, and it is likely that a combination of factors were involved. Here, I focus on a set of developmental genetic changes and propose these are part of the mix of permissive factors. I describe how ANTP-class homeobox genes, which encode transcription factors involved in body patterning, increased in number in the bilaterian stem lineage and earlier. These gene duplications generated a large array of ANTP class genes, including three distinct gene clusters called NK, Hox, and ParaHox. Comparative data supports the idea that NK genes were deployed primarily to pattern the bilaterian mesoderm, Hox genes coded position along the central nervous system, and ParaHox genes most likely originally specified the mouth, midgut, and anus of the newly evolved through-gut. It is proposed that diversification of ANTP class genes played a role in the Cambrian explosion by contributing to the patterning systems used to build animal bodies capable of high-energy directed locomotion, including active burrowing.

  2. North Carolina macular dystrophy (MCDR1) caused by a novel tandem duplication of the PRDM13 gene

    PubMed Central

    Sullivan, Lori S.; Wheaton, Dianna K.; Locke, Kirsten G.; Jones, Kaylie D.; Koboldt, Daniel C.; Fulton, Robert S.; Wilson, Richard K.; Blanton, Susan H.; Birch, David G.; Daiger, Stephen P.

    2016-01-01

    Purpose To identify the underlying cause of disease in a large family with North Carolina macular dystrophy (NCMD). Methods A large four-generation family (RFS355) with an autosomal dominant form of NCMD was ascertained. Family members underwent comprehensive visual function evaluations. Blood or saliva from six affected family members and three unaffected spouses was collected and DNA tested for linkage to the MCDR1 locus on chromosome 6q12. Three affected family members and two unaffected spouses underwent whole exome sequencing (WES) and subsequently, custom capture of the linkage region followed by next-generation sequencing (NGS). Standard PCR and dideoxy sequencing were used to further characterize the mutation. Results Of the 12 eyes examined in six affected individuals, all but two had Gass grade 3 macular degeneration features. Large central excavation of the retinal and choroid layers, referred to as a macular caldera, was seen in an age-independent manner in the grade 3 eyes. The calderas are unique to affected individuals with MCDR1. Genome-wide linkage mapping and haplotype analysis of markers from the chromosome 6q region were consistent with linkage to the MCDR1 locus. Whole exome sequencing and custom-capture NGS failed to reveal any rare coding variants segregating with the phenotype. Analysis of the custom-capture NGS sequencing data for copy number variants uncovered a tandem duplication of approximately 60 kb on chromosome 6q. This region contains two genes, CCNC and PRDM13. The duplication creates a partial copy of CCNC and a complete copy of PRDM13. The duplication was found in all affected members of the family and is not present in any unaffected members. The duplication was not seen in 200 ethnically matched normal chromosomes. Conclusions The cause of disease in the original family with MCDR1 and several others has been recently reported to be dysregulation of the PRDM13 gene, caused by either single base substitutions in a DNase 1

  3. Gene duplication, population genomics, and species-level differentiation within a tropical mountain shrub.

    PubMed

    Mastretta-Yanes, Alicia; Zamudio, Sergio; Jorgensen, Tove H; Arrigo, Nils; Alvarez, Nadir; Piñero, Daniel; Emerson, Brent C

    2014-09-14

    Gene duplication leads to paralogy, which complicates the de novo assembly of genotyping-by-sequencing (GBS) data. The issue of paralogous genes is exacerbated in plants, because they are particularly prone to gene duplication events. Paralogs are normally filtered from GBS data before undertaking population genomics or phylogenetic analyses. However, gene duplication plays an important role in the functional diversification of genes and it can also lead to the formation of postzygotic barriers. Using populations and closely related species of a tropical mountain shrub, we examine 1) the genomic differentiation produced by putative orthologs, and 2) the distribution of recent gene duplication among lineages and geography. We find high differentiation among populations from isolated mountain peaks and species-level differentiation within what is morphologically described as a single species. The inferred distribution of paralogs among populations is congruent with taxonomy and shows that GBS could be used to examine recent gene duplication as a source of genomic differentiation of nonmodel species.

  4. Are duplicated genes responsible for anthracnose resistance in common bean?

    PubMed

    Costa, Larissa Carvalho; Nalin, Rafael Storto; Ramalho, Magno Antonio Patto; de Souza, Elaine Aparecida

    2017-01-01

    The race 65 of Colletotrichum lindemuthianum, etiologic agent of anthracnose in common bean, is distributed worldwide, having great importance in breeding programs for anthracnose resistance. Several resistance alleles have been identified promoting resistance to this race. However, the variability that has been detected within race has made it difficult to obtain cultivars with durable resistance, because cultivars may have different reactions to each strain of race 65. Thus, this work aimed at studying the resistance inheritance of common bean lines to different strains of C. lindemuthianum, race 65. We used six C. lindemuthianum strains previously characterized as belonging to the race 65 through the international set of differential cultivars of anthracnose and nine commercial cultivars, adapted to the Brazilian growing conditions and with potential ability to discriminate the variability within this race. To obtain information on the resistance inheritance related to nine commercial cultivars to six strains of race 65, these cultivars were crossed two by two in all possible combinations, resulting in 36 hybrids. Segregation in the F2 generations revealed that the resistance to each strain is conditioned by two independent genes with the same function, suggesting that they are duplicated genes, where the dominant allele promotes resistance. These results indicate that the specificity between host resistance genes and pathogen avirulence genes is not limited to races, it also occurs within strains of the same race. Further research may be carried out in order to establish if the alleles identified in these cultivars are different from those described in the literature.

  5. Are duplicated genes responsible for anthracnose resistance in common bean?

    PubMed Central

    2017-01-01

    The race 65 of Colletotrichum lindemuthianum, etiologic agent of anthracnose in common bean, is distributed worldwide, having great importance in breeding programs for anthracnose resistance. Several resistance alleles have been identified promoting resistance to this race. However, the variability that has been detected within race has made it difficult to obtain cultivars with durable resistance, because cultivars may have different reactions to each strain of race 65. Thus, this work aimed at studying the resistance inheritance of common bean lines to different strains of C. lindemuthianum, race 65. We used six C. lindemuthianum strains previously characterized as belonging to the race 65 through the international set of differential cultivars of anthracnose and nine commercial cultivars, adapted to the Brazilian growing conditions and with potential ability to discriminate the variability within this race. To obtain information on the resistance inheritance related to nine commercial cultivars to six strains of race 65, these cultivars were crossed two by two in all possible combinations, resulting in 36 hybrids. Segregation in the F2 generations revealed that the resistance to each strain is conditioned by two independent genes with the same function, suggesting that they are duplicated genes, where the dominant allele promotes resistance. These results indicate that the specificity between host resistance genes and pathogen avirulence genes is not limited to races, it also occurs within strains of the same race. Further research may be carried out in order to establish if the alleles identified in these cultivars are different from those described in the literature. PMID:28296933

  6. Evolution of Chaperonin Gene Duplication in Stigonematalean Cyanobacteria (Subsection V)

    PubMed Central

    Weissenbach, Julia; Ilhan, Judith; Hülter, Nils; Stucken, Karina; Dagan, Tal

    2017-01-01

    Chaperonins promote protein folding and are known to play a role in the maintenance of cellular stability under stress conditions. The group I bacterial chaperonin complex comprises GroEL, that forms a barrel-like oligomer, and GroES that forms the lid. In most eubacteria the GroES/GroEL chaperonin is encoded by a single-copy bicistronic operon, whereas in cyanobacteria up to three groES/groEL paralogs have been documented. Here we study the evolution and functional diversification of chaperonin paralogs in the heterocystous, multi-seriate filament forming cyanobacterium Chlorogloeopsis fritschii PCC 6912. The genome of C. fritschii encodes two groES/groEL operons (groESL1, groESL1.2) and a monocistronic groEL gene (groEL2). A phylogenetic reconstruction reveals that the groEL2 duplication is as ancient as cyanobacteria, whereas the groESL1.2 duplication occurred at the ancestor of heterocystous cyanobacteria. A comparison of the groEL paralogs transcription levels under different growth conditions shows that they have adapted distinct transcriptional regulation. Our results reveal that groEL1 and groEL1.2 are upregulated during diazotrophic conditions and the localization of their promoter activity points towards a role in heterocyst differentiation. Furthermore, protein–protein interaction assays suggest that paralogs encoded in the two operons assemble into hybrid complexes. The monocistronic encoded GroEL2 is not forming oligomers nor does it interact with the co-chaperonins. Interaction between GroES1.2 and GroEL1.2 could not be documented, suggesting that the groESL1.2 operon does not encode a functional chaperonin complex. Functional complementation experiments in Escherichia coli show that only GroES1/GroEL1 and GroES1/GroEL1.2 can substitute the native operon. In summary, the evolutionary consequences of chaperonin duplication in cyanobacteria include the retention of groESL1 as a housekeeping gene, subfunctionalization of groESL1.2 and

  7. Evolution of Chaperonin Gene Duplication in Stigonematalean Cyanobacteria (Subsection V).

    PubMed

    Weissenbach, Julia; Ilhan, Judith; Bogumil, David; Hülter, Nils; Stucken, Karina; Dagan, Tal

    2017-01-12

    Chaperonins promote protein folding and are known to play a role in the maintenance of cellular stability under stress conditions. The group I bacterial chaperonin complex comprises GroEL, that forms a barrel-like oligomer, and GroES that forms the lid. In most eubacteria the GroES/GroEL chaperonin is encoded by a single-copy bicistronic operon, whereas in cyanobacteria up to three groES/groEL paralogs have been documented. Here we study the evolution and functional diversification of chaperonin paralogs in the heterocystous, multi-seriate filament forming cyanobacterium Chlorogloeopsis fritschii PCC 6912. The genome of C. fritschii encodes two groES/groEL operons (groESL1, groESL1.2) and a monocistronic groEL gene (groEL2). A phylogenetic reconstruction reveals that the groEL2 duplication is as ancient as cyanobacteria, whereas the groESL1.2 duplication occurred at the ancestor of heterocystous cyanobacteria. A comparison of the groEL paralogs transcription levels under different growth conditions shows that they have adapted distinct transcriptional regulation. Our results reveal that groEL1 and groEL1.2 are upregulated during diazotrophic conditions and the localization of their promoter activity points towards a role in heterocyst differentiation. Furthermore, protein-protein interaction assays suggest that paralogs encoded in the two operons assemble into hybrid complexes. The monocistronic GroEL2 is not forming oligomers nor does it interact with the co-chaperonins. Interaction between GroES1.2 and GroEL1.2 could not be documented, suggesting that the groESL1.2 operon does not encode a functional chaperonin complex. Functional complementation experiments in Escherichia coli show that only GroES1/GroEL1 and GroES1/GroEL1.2 can substitute the native operon. In summary, the evolutionary consequences of chaperonin duplication in cyanobacteria include the retention of groESL1 as a housekeeping gene, subfunctionalization of groESL1.2 and neofunctionalization of the

  8. Definition of minimal duplicated region encompassing the XIAP and STAG2 genes in the Xq25 microduplication syndrome.

    PubMed

    Di Benedetto, Daniela; Musumeci, Sebastiano Antonino; Avola, Emanuela; Alberti, Antonino; Buono, Serafino; Scuderi, Carmela; Grillo, Lucia; Galesi, Ornella; Spalletta, Angela; Giudice, Mariangela Lo; Luciano, Daniela; Vinci, Mirella; Bianca, Sebastiano; Romano, Corrado; Fichera, Marco

    2014-08-01

    Typical Xq25 duplications are large and associated with heterogeneous phenotypes. Recently, small duplications involving this genomic region and encompassing the GRIA3 and STAG2 genes have been reported. These Xq25 microduplications are associated with a recognizable syndrome including intellectual disability and distinctive facial appearance. We report on Xq25 microduplications in two unrelated families identified by array comparative genomic hybridization. In both families, the genomic imbalances segregated with the disease in male individuals, while the phenotypes of the heterozygous females appeared to be modulated by their X-inactivation pattern. These rearrangements of about 600 kb involved only three genes: THOC2, XIAP, and STAG2. Further characterization by FISH analyses showed tandem duplication in the Xq25 locus of these genes. These data refine the Xq25 candidate region, identifying a minimal duplicated region of about 270 kb encompassing the XIAP and STAG2 genes. We discuss the function of the genes in the rearrangements and their involvement in the pathogenesis of this disorder.

  9. Adaptive evolution of genes duplicated from the Drosophila pseudoobscura neo-X chromosome.

    PubMed

    Meisel, Richard P; Hilldorfer, Benedict B; Koch, Jessica L; Lockton, Steven; Schaeffer, Stephen W

    2010-08-01

    Drosophila X chromosomes are disproportionate sources of duplicated genes, and these duplications are usually the result of retrotransposition of X-linked genes to the autosomes. The excess duplication is thought to be driven by natural selection for two reasons: X chromosomes are inactivated during spermatogenesis, and the derived copies of retroposed duplications tend to be testis expressed. Therefore, autosomal derived copies of retroposed genes provide a mechanism for their X-linked paralogs to "escape" X inactivation. Once these duplications have fixed, they may then be selected for male-specific functions. Throughout the evolution of the Drosophila genus, autosomes have fused with X chromosomes along multiple lineages giving rise to neo-X chromosomes. There has also been excess duplication from the two independent neo-X chromosomes that have been examined--one that occurred prior to the common ancestor of the willistoni species group and another that occurred along the lineage leading to Drosophila pseudoobscura. To determine what role natural selection plays in the evolution of genes duplicated from the D. pseudoobscura neo-X chromosome, we analyzed DNA sequence divergence between paralogs, polymorphism within each copy, and the expression profiles of these duplicated genes. We found that the derived copies of all duplicated genes have elevated nonsynonymous polymorphism, suggesting that they are under relaxed selective constraints. The derived copies also tend to have testis- or male-biased expression profiles regardless of their chromosome of origin. Genes duplicated from the neo-X chromosome appear to be under less constraints than those duplicated from other chromosome arms. We also find more evidence for historical adaptive evolution in genes duplicated from the neo-X chromosome, suggesting that they are under a unique selection regime in which elevated nonsynonymous polymorphism provides a large reservoir of functional variants, some of which are fixed

  10. Multiple tandem duplication of the phenylalanine ammonia-lyase genes in Cucumis sativus L.

    PubMed

    Shang, Qing-Mao; Li, Liang; Dong, Chun-Juan

    2012-10-01

    Phenylalanine ammonia-lyase (PAL) is the first entry enzyme of the phenylpropanoid pathway, and therefore plays a key role in both plant development and stress defense. In many plants, PAL is encoded by a multi-gene family, and each member is differentially regulated in response to environmental stimuli. In the present study, we report that PAL in cucumber (Cucumis sativus L.) is encoded for by a family of seven genes (designated as CsPAL1-7). All seven CsPALs are arranged in tandem in two duplication blocks, which are located on chromosomes 4 and 6, respectively. The cDNA and protein sequences of the CsPALs share an overall high identity to each other. Homology modeling reveals similarities in their protein structures, besides several slight differences, implying the different activities in conversion of phenylalanine. Phylogenic analysis places CsPAL1-7 in a separate cluster rather than clustering with other plant PALs. Analyses of expression profiles in different cucumber tissues or in response to various stress or plant hormone treatments indicate that CsPAL1-7 play redundant, but divergent roles in cucumber development and stress response. This is consistent with our finding that CsPALs possess overlapping but different cis-elements in their promoter regions. Finally, several duplication events are discussed to explain the evolution of the cucumber PAL genes.

  11. The glutamine synthetase gene family in Populus

    PubMed Central

    2011-01-01

    Background Glutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming) is a key enzyme in ammonium assimilation and metabolism of higher plants. The current work was undertaken to develop a more comprehensive understanding of molecular and biochemical features of GS gene family in poplar, and to characterize the developmental regulation of GS expression in various tissues and at various times during the poplar perennial growth. Results The GS gene family consists of 8 different genes exhibiting all structural and regulatory elements consistent with their roles as functional genes. Our results indicate that the family members are organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1) and 1 which codes for the choroplastic GS isoform (GS2). Our analysis shows that Populus trichocarpa is the first plant species in which it was observed the complete GS family duplicated. Detailed expression analyses have revealed specific spatial and seasonal patterns of GS expression in poplar. These data provide insights into the metabolic function of GS isoforms in poplar and pave the way for future functional studies. Conclusions Our data suggest that GS duplicates could have been retained in order to increase the amount of enzyme in a particular cell type. This possibility could contribute to the homeostasis of nitrogen metabolism in functions associated to changes in glutamine-derived metabolic products. The presence of duplicated GS genes in poplar could also contribute to diversification of the enzymatic properties for a particular GS isoform through the assembly of GS polypeptides into homo oligomeric and/or hetero oligomeric holoenzymes in specific cell types. PMID:21867507

  12. Afrobatrachian mitochondrial genomes: genome reorganization, gene rearrangement mechanisms, and evolutionary trends of duplicated and rearranged genes

    PubMed Central

    2013-01-01

    Background Mitochondrial genomic (mitogenomic) reorganizations are rarely found in closely-related animals, yet drastic reorganizations have been found in the Ranoides frogs. The phylogenetic relationships of the three major ranoid taxa (Natatanura, Microhylidae, and Afrobatrachia) have been problematic, and mitogenomic information for afrobatrachians has not been available. Several molecular models for mitochondrial (mt) gene rearrangements have been proposed, but observational evidence has been insufficient to evaluate them. Furthermore, evolutionary trends in rearranged mt genes have not been well understood. To gain molecular and phylogenetic insights into these issues, we analyzed the mt genomes of four afrobatrachian species (Breviceps adspersus, Hemisus marmoratus, Hyperolius marmoratus, and Trichobatrachus robustus) and performed molecular phylogenetic analyses. Furthermore we searched for two evolutionary patterns expected in the rearranged mt genes of ranoids. Results Extensively reorganized mt genomes having many duplicated and rearranged genes were found in three of the four afrobatrachians analyzed. In fact, Breviceps has the largest known mt genome among vertebrates. Although the kinds of duplicated and rearranged genes differed among these species, a remarkable gene rearrangement pattern of non-tandemly copied genes situated within tandemly-copied regions was commonly found. Furthermore, the existence of concerted evolution was observed between non-neighboring copies of triplicated 12S and 16S ribosomal RNA regions. Conclusions Phylogenetic analyses based on mitogenomic data support a close relationship between Afrobatrachia and Microhylidae, with their estimated divergence 100 million years ago consistent with present-day endemism of afrobatrachians on the African continent. The afrobatrachian mt data supported the first tandem and second non-tandem duplication model for mt gene rearrangements and the recombination-based model for concerted

  13. The Evolutionary Relationship between Alternative Splicing and Gene Duplication

    PubMed Central

    Iñiguez, Luis P.; Hernández, Georgina

    2017-01-01

    The protein diversity that exists today has resulted from various evolutionary processes. It is well known that gene duplication (GD) along with the accumulation of mutations are responsible, among other factors, for an increase in the number of different proteins. The gene structure in eukaryotes requires the removal of non-coding sequences, introns, to produce mature mRNAs. This process, known as cis-splicing, referred to here as splicing, is regulated by several factors which can lead to numerous splicing arrangements, commonly designated as alternative splicing (AS). AS, producing several transcripts isoforms form a single gene, also increases the protein diversity. However, the evolution and manner for increasing protein variation differs between AS and GD. An important question is how are patterns of AS affected after a GD event. Here, we review the current knowledge of AS and GD, focusing on their evolutionary relationship. These two processes are now considered the main contributors to the increasing protein diversity and therefore their relationship is a relevant, yet understudied, area of evolutionary study. PMID:28261262

  14. Two secretory protein genes in Chironomus tentans have arisen by gene duplication and exhibit different developmental expression patterns.

    PubMed

    Galli, J; Wieslander, L

    1993-05-20

    The salivary gland cells in the dipteran Chironomus tentans produce approximately 15 different secretory proteins, with relative molecular masses ranging between 1 x 10(4) and 1 x 10(6). Together these proteins form two types of extra corporal tubes, a larval protective housing and feeding tube or a pupation tube. The developmental change in tube formation is accompanied by a switch in production from one combination of secretory proteins to another. Here we characterize two genes, the sp38-40.A and B genes, which encode secretory proteins with relative molecular masses of 38,000 to 40,000. The two genes are located 346 base-pairs apart in the same orientation and have presumably arisen by gene duplication as the result of an illegitimate recombination event. Both genes contain two regions with cysteine codons, surrounded by regions with short repeats coding for proline and charged amino acid residues. The two genes and alleles of the genes differ in their number of repeats. This structure resembles the structure of the Balbiani ring (BR) genes, which encode the four largest salivary gland secretory proteins. The sp38-40.A and B genes are therefore likely to belong to a BR multigene family containing all or most of the 15 salivary gland secretory protein genes. The expression of the sp38-40.A and B genes are different: the A gene is expressed throughout the larval fourth instar but considerably less in the prepupal stage, while the B gene shows the opposite expression pattern. The developmental regulation of the expression of the two genes has therefore diverged after the gene duplication event.

  15. Analyses of nuclearly encoded mitochondrial genes suggest gene duplication as a mechanism for resolving intralocus sexually antagonistic conflict in Drosophila.

    PubMed

    Gallach, Miguel; Chandrasekaran, Chitra; Betrán, Esther

    2010-01-01

    Gene duplication is probably the most important mechanism for generating new gene functions. However, gene duplication has been overlooked as a potentially effective way to resolve genetic conflicts. Here, we analyze the entire set of Drosophila melanogaster nuclearly encoded mitochondrial duplicate genes and show that both RNA- and DNA-mediated mitochondrial gene duplications exhibit an unexpectedly high rate of relocation (change in location between parental and duplicated gene) as well as an extreme tendency to avoid the X chromosome. These trends are likely related to our observation that relocated genes tend to have testis-specific expression. We also infer that these trends hold across the entire Drosophila genus. Importantly, analyses of gene ontology and functional interaction networks show that there is an overrepresentation of energy production-related functions in these mitochondrial duplicates. We discuss different hypotheses to explain our results and conclude that our findings substantiate the hypothesis that gene duplication for male germline function is likely a mechanism to resolve intralocus sexually antagonistic conflicts that we propose are common in testis. In the case of nuclearly encoded mitochondrial duplicates, our hypothesis is that past sexually antagonistic conflict related to mitochondrial energy function in Drosophila was resolved by gene duplication.

  16. Rice pollen hybrid incompatibility caused by reciprocal gene loss of duplicated genes.

    PubMed

    Mizuta, Yoko; Harushima, Yoshiaki; Kurata, Nori

    2010-11-23

    Genetic incompatibility is a barrier contributing to species isolation and is caused by genetic interactions. We made a whole genome survey of two-way interacting loci acting within the gametophyte or zygote using independence tests of marker segregations in an F(2) population from an intersubspecific cross between O. sativa subspecies indica and japonica. We detected only one reproducible interaction, and identified paralogous hybrid incompatibility genes, DOPPELGANGER1 (DPL1) and DOPPELGANGER2 (DPL2), by positional cloning. Independent disruptions of DPL1 and DPL2 occurred in indica and japonica, respectively. DPLs encode highly conserved, plant-specific small proteins (∼10 kDa) and are highly expressed in mature anther. Pollen carrying two defective DPL alleles became nonfunctional and did not germinate, suggesting an essential role for DPLs in pollen germination. Although rice has many duplicated genes resulting from ancient whole genome duplication, the origin of this gene duplication was in recent small-scale gene duplication, occurring after Oryza-Brachypodium differentiation. Comparative analyses suggested the geographic and phylogenetic distribution of these two defective alleles, showing that loss-of-function mutations of DPL1 genes emerged multiple times in indica and its wild ancestor, O. rufipogon, and that the DPL2 gene defect is specific to japonica cultivars.

  17. Lineage-Specific Expansion of IFIT Gene Family: An Insight into Coevolution with IFN Gene Family

    PubMed Central

    Liu, Ying; Zhang, Yi-Bing; Liu, Ting-Kai; Gui, Jian-Fang

    2013-01-01

    In mammals, IFIT (Interferon [IFN]-induced proteins with Tetratricopeptide Repeat [TPR] motifs) family genes are involved in many cellular and viral processes, which are tightly related to mammalian IFN response. However, little is known about non-mammalian IFIT genes. In the present study, IFIT genes are identified in the genome databases from the jawed vertebrates including the cartilaginous elephant shark but not from non-vertebrates such as lancelet, sea squirt and acorn worm, suggesting that IFIT gene family originates from a vertebrate ancestor about 450 million years ago. IFIT family genes show conserved gene structure and gene arrangements. Phylogenetic analyses reveal that this gene family has expanded through lineage-specific and species-specific gene duplication. Interestingly, IFN gene family seem to share a common ancestor and a similar evolutionary mechanism; the function link of IFIT genes to IFN response is present early since the origin of both gene families, as evidenced by the finding that zebrafish IFIT genes are upregulated by fish IFNs, poly(I:C) and two transcription factors IRF3/IRF7, likely via the IFN-stimulated response elements (ISRE) within the promoters of vertebrate IFIT family genes. These coevolution features creates functional association of both family genes to fulfill a common biological process, which is likely selected by viral infection during evolution of vertebrates. Our results are helpful for understanding of evolution of vertebrate IFN system. PMID:23818968

  18. Phylogenetic dating and characterization of gene duplications in vertebrates: the cartilaginous fish reference.

    PubMed

    Robinson-Rechavi, Marc; Boussau, Bastien; Laudet, Vincent

    2004-03-01

    Vertebrates originated in the lower Cambrian. Their diversification and morphological innovations have been attributed to large-scale gene or genome duplications at the origin of the group. These duplications are predicted to have occurred in two rounds, the "2R" hypothesis, or they may have occurred in one genome duplication plus many segmental duplications, although these hypotheses are disputed. Under such models, most genes that are duplicated in all vertebrates should have originated during the same period. Previous work has shown that indeed duplications started after the speciation between vertebrates and the closest invertebrate, amphioxus, but have not set a clear ending. Consideration of chordate phylogeny immediately shows the key position of cartilaginous vertebrates (Chondrichthyes) to answer this question. Did gene duplications occur as frequently during the 45 Myr between the cartilaginous/bony vertebrate split and the fish/tetrapode split as in the previous approximately 100 Myr? Although the time interval is relatively short, it is crucial to understanding the events at the origin of vertebrates. By a systematic appraisal of gene phylogenies, we show that significantly more duplications occurred before than after the cartilaginous/bony vertebrate split. Our results support rounds of gene or genome duplications during a limited period of early vertebrate evolution and allow a better characterization of these events.

  19. First evidence of a large CHEK2 duplication involved in cancer predisposition in an Italian family with hereditary breast cancer

    PubMed Central

    2014-01-01

    Background CHEK2 is a multi-cancer susceptibility gene whose common germline mutations are known to contribute to the risk of developing breast and prostate cancer. Case presentation Here, we describe an Italian family with a high number of cases of breast cancer and other types of tumour subjected to the MLPA test to verify the presence of BRCA1, BRCA2 and CHEK2 deletions and duplications. We identified a new 23-kb duplication in the CHEK2 gene extending from intron 5 to 13 that was associated with breast cancer in the family. The presence and localisation of the alteration was confirmed by a second analysis by Next-Generation Sequencing. Conclusions This finding suggests that CHEK2 mutations are heterogeneous and that techniques other than sequencing, such as MLPA, are needed to identify CHEK2 mutations. It also indicates that CHEK2 rare variants, such as duplications, can confer a high susceptibility to cancer development and should thus be studied in depth as most of our knowledge of CHEK2 concerns common mutations. PMID:24986639

  20. CG gene body DNA methylation changes and evolution of duplicated genes in cassava.

    PubMed

    Wang, Haifeng; Beyene, Getu; Zhai, Jixian; Feng, Suhua; Fahlgren, Noah; Taylor, Nigel J; Bart, Rebecca; Carrington, James C; Jacobsen, Steven E; Ausin, Israel

    2015-11-03

    DNA methylation is important for the regulation of gene expression and the silencing of transposons in plants. Here we present genome-wide methylation patterns at single-base pair resolution for cassava (Manihot esculenta, cultivar TME 7), a crop with a substantial impact in the agriculture of subtropical and tropical regions. On average, DNA methylation levels were higher in all three DNA sequence contexts (CG, CHG, and CHH, where H equals A, T, or C) than those of the most well-studied model plant Arabidopsis thaliana. As in other plants, DNA methylation was found both on transposons and in the transcribed regions (bodies) of many genes. Consistent with these patterns, at least one cassava gene copy of all of the known components of Arabidopsis DNA methylation pathways was identified. Methylation of LTR transposons (GYPSY and COPIA) was found to be unusually high compared with other types of transposons, suggesting that the control of the activity of these two types of transposons may be especially important. Analysis of duplicated gene pairs resulting from whole-genome duplication showed that gene body DNA methylation and gene expression levels have coevolved over short evolutionary time scales, reinforcing the positive relationship between gene body methylation and high levels of gene expression. Duplicated genes with the most divergent gene body methylation and expression patterns were found to have distinct biological functions and may have been under natural or human selection for cassava traits.

  1. CG gene body DNA methylation changes and evolution of duplicated genes in cassava

    PubMed Central

    Wang, Haifeng; Beyene, Getu; Zhai, Jixian; Feng, Suhua; Fahlgren, Noah; Taylor, Nigel J.; Bart, Rebecca; Carrington, James C.; Jacobsen, Steven E.; Ausin, Israel

    2015-01-01

    DNA methylation is important for the regulation of gene expression and the silencing of transposons in plants. Here we present genome-wide methylation patterns at single-base pair resolution for cassava (Manihot esculenta, cultivar TME 7), a crop with a substantial impact in the agriculture of subtropical and tropical regions. On average, DNA methylation levels were higher in all three DNA sequence contexts (CG, CHG, and CHH, where H equals A, T, or C) than those of the most well-studied model plant Arabidopsis thaliana. As in other plants, DNA methylation was found both on transposons and in the transcribed regions (bodies) of many genes. Consistent with these patterns, at least one cassava gene copy of all of the known components of Arabidopsis DNA methylation pathways was identified. Methylation of LTR transposons (GYPSY and COPIA) was found to be unusually high compared with other types of transposons, suggesting that the control of the activity of these two types of transposons may be especially important. Analysis of duplicated gene pairs resulting from whole-genome duplication showed that gene body DNA methylation and gene expression levels have coevolved over short evolutionary time scales, reinforcing the positive relationship between gene body methylation and high levels of gene expression. Duplicated genes with the most divergent gene body methylation and expression patterns were found to have distinct biological functions and may have been under natural or human selection for cassava traits. PMID:26483493

  2. Consensus properties and their large-scale applications for the gene duplication problem.

    PubMed

    Moon, Jucheol; Lin, Harris T; Eulenstein, Oliver

    2016-06-01

    Solving the gene duplication problem is a classical approach for species tree inference from gene trees that are confounded by gene duplications. This problem takes a collection of gene trees and seeks a species tree that implies the minimum number of gene duplications. Wilkinson et al. posed the conjecture that the gene duplication problem satisfies the desirable Pareto property for clusters. That is, for every instance of the problem, all clusters that are commonly present in the input gene trees of this instance, called strict consensus, will also be found in every solution to this instance. We prove that this conjecture does not generally hold. Despite this negative result we show that the gene duplication problem satisfies a weaker version of the Pareto property where the strict consensus is found in at least one solution (rather than all solutions). This weaker property contributes to our design of an efficient scalable algorithm for the gene duplication problem. We demonstrate the performance of our algorithm in analyzing large-scale empirical datasets. Finally, we utilize the algorithm to evaluate the accuracy of standard heuristics for the gene duplication problem using simulated datasets.

  3. The evolutionary fate of alternatively spliced homologous exons after gene duplication.

    PubMed

    Abascal, Federico; Tress, Michael L; Valencia, Alfonso

    2015-04-29

    Alternative splicing and gene duplication are the two main processes responsible for expanding protein functional diversity. Although gene duplication can generate new genes and alternative splicing can introduce variation through alternative gene products, the interplay between the two processes is complex and poorly understood. Here, we have carried out a study of the evolution of alternatively spliced exons after gene duplication to better understand the interaction between the two processes. We created a manually curated set of 97 human genes with mutually exclusively spliced homologous exons and analyzed the evolution of these exons across five distantly related vertebrates (lamprey, spotted gar, zebrafish, fugu, and coelacanth). Most of these exons had an ancient origin (more than 400 Ma). We found examples supporting two extreme evolutionary models for the behaviour of homologous axons after gene duplication. We observed 11 events in which gene duplication was accompanied by splice isoform separation, that is, each paralog specifically conserved just one distinct ancestral homologous exon. At other extreme, we identified genes in which the homologous exons were always conserved within paralogs, suggesting that the alternative splicing event cannot easily be separated from the function in these genes. That many homologous exons fall in between these two extremes highlights the diversity of biological systems and suggests that the subtle balance between alternative splicing and gene duplication is adjusted to the specific cellular context of each gene.

  4. The Roles of Whole-Genome and Small-Scale Duplications in the Functional Specialization of Saccharomyces cerevisiae Genes

    PubMed Central

    Fares, Mario A.; Keane, Orla M.; Toft, Christina; Carretero-Paulet, Lorenzo; Jones, Gary W.

    2013-01-01

    Researchers have long been enthralled with the idea that gene duplication can generate novel functions, crediting this process with great evolutionary importance. Empirical data shows that whole-genome duplications (WGDs) are more likely to be retained than small-scale duplications (SSDs), though their relative contribution to the functional fate of duplicates remains unexplored. Using the map of genetic interactions and the re-sequencing of 27 Saccharomyces cerevisiae genomes evolving for 2,200 generations we show that SSD-duplicates lead to neo-functionalization while WGD-duplicates partition ancestral functions. This conclusion is supported by: (a) SSD-duplicates establish more genetic interactions than singletons and WGD-duplicates; (b) SSD-duplicates copies share more interaction-partners than WGD-duplicates copies; (c) WGD-duplicates interaction partners are more functionally related than SSD-duplicates partners; (d) SSD-duplicates gene copies are more functionally divergent from one another, while keeping more overlapping functions, and diverge in their sub-cellular locations more than WGD-duplicates copies; and (e) SSD-duplicates complement their functions to a greater extent than WGD–duplicates. We propose a novel model that uncovers the complexity of evolution after gene duplication. PMID:23300483

  5. Gene duplication and divergence affecting drug content in Cannabis sativa.

    PubMed

    Weiblen, George D; Wenger, Jonathan P; Craft, Kathleen J; ElSohly, Mahmoud A; Mehmedic, Zlatko; Treiber, Erin L; Marks, M David

    2015-12-01

    Cannabis sativa is an economically important source of durable fibers, nutritious seeds, and psychoactive drugs but few economic plants are so poorly understood genetically. Marijuana and hemp were crossed to evaluate competing models of cannabinoid inheritance and to explain the predominance of tetrahydrocannabinolic acid (THCA) in marijuana compared with cannabidiolic acid (CBDA) in hemp. Individuals in the resulting F2 population were assessed for differential expression of cannabinoid synthase genes and were used in linkage mapping. Genetic markers associated with divergent cannabinoid phenotypes were identified. Although phenotypic segregation and a major quantitative trait locus (QTL) for the THCA/CBDA ratio were consistent with a simple model of codominant alleles at a single locus, the diversity of THCA and CBDA synthase sequences observed in the mapping population, the position of enzyme coding loci on the map, and patterns of expression suggest multiple linked loci. Phylogenetic analysis further suggests a history of duplication and divergence affecting drug content. Marijuana is distinguished from hemp by a nonfunctional CBDA synthase that appears to have been positively selected to enhance psychoactivity. An unlinked QTL for cannabinoid quantity may also have played a role in the recent escalation of drug potency.

  6. Gene duplication of type-B ARR transcription factors systematically extends transcriptional regulatory structures in Arabidopsis

    PubMed Central

    Choi, Seung Hee; Hyeon, Do Young; Lee, ll Hwan; Park, Su Jin; Han, Seungmin; Lee, In Chul; Hwang, Daehee; Nam, Hong Gil

    2014-01-01

    Many of duplicated genes are enriched in signaling pathways. Recently, gene duplication of kinases has been shown to provide genetic buffering and functional diversification in cellular signaling. Transcription factors (TFs) are also often duplicated. However, how duplication of TFs affects their regulatory structures and functions of target genes has not been explored at the systems level. Here, we examined regulatory and functional roles of duplication of three major ARR TFs (ARR1, 10, and 12) in Arabidopsis cytokinin signaling using wild-type and single, double, and triple deletion mutants of the TFs. Comparative analysis of gene expression profiles obtained from Arabidopsis roots in wild-type and these mutants showed that duplication of ARR TFs systematically extended their transcriptional regulatory structures, leading to enhanced robustness and diversification in functions of target genes, as well as in regulation of cellular networks of target genes. Therefore, our results suggest that duplication of TFs contributes to robustness and diversification in functions of target genes by extending transcriptional regulatory structures. PMID:25425016

  7. Gene duplication of type-B ARR transcription factors systematically extends transcriptional regulatory structures in Arabidopsis.

    PubMed

    Choi, Seung Hee; Hyeon, Do Young; Lee, Ll Hwan; Park, Su Jin; Han, Seungmin; Lee, In Chul; Hwang, Daehee; Nam, Hong Gil

    2014-11-26

    Many of duplicated genes are enriched in signaling pathways. Recently, gene duplication of kinases has been shown to provide genetic buffering and functional diversification in cellular signaling. Transcription factors (TFs) are also often duplicated. However, how duplication of TFs affects their regulatory structures and functions of target genes has not been explored at the systems level. Here, we examined regulatory and functional roles of duplication of three major ARR TFs (ARR1, 10, and 12) in Arabidopsis cytokinin signaling using wild-type and single, double, and triple deletion mutants of the TFs. Comparative analysis of gene expression profiles obtained from Arabidopsis roots in wild-type and these mutants showed that duplication of ARR TFs systematically extended their transcriptional regulatory structures, leading to enhanced robustness and diversification in functions of target genes, as well as in regulation of cellular networks of target genes. Therefore, our results suggest that duplication of TFs contributes to robustness and diversification in functions of target genes by extending transcriptional regulatory structures.

  8. Exon duplications in the ATP7A gene: Frequency and Transcriptional Behaviour

    PubMed Central

    2011-01-01

    Background Menkes disease (MD) is an X-linked, fatal neurodegenerative disorder of copper metabolism, caused by mutations in the ATP7A gene. Thirty-three Menkes patients in whom no mutation had been detected with standard diagnostic tools were screened for exon duplications in the ATP7A gene. Methods The ATP7A gene was screened for exon duplications using multiplex ligation-dependent probe amplification (MLPA). The expression level of ATP7A was investigated by real-time PCR and detailed analysis of the ATP7A mRNA was performed by RT-PCR followed by sequencing. In order to investigate whether the identified duplicated fragments originated from a single or from two different X-chromosomes, polymorphic markers located in the duplicated fragments were analyzed. Results Partial ATP7A gene duplication was identified in 20 unrelated patients including one patient with Occipital Horn Syndrome (OHS). Duplications in the ATP7A gene are estimated from our material to be the disease causing mutation in 4% of the Menkes disease patients. The duplicated regions consist of between 2 and 15 exons. In at least one of the cases, the duplication was due to an intra-chromosomal event. Characterization of the ATP7A mRNA transcripts in 11 patients revealed that the duplications were organized in tandem, in a head to tail direction. The reading frame was disrupted in all 11 cases. Small amounts of wild-type transcript were found in all patients as a result of exon-skipping events occurring in the duplicated regions. In the OHS patient with a duplication of exon 3 and 4, the duplicated out-of-frame transcript coexists with an almost equally represented wild-type transcript, presumably leading to the milder phenotype. Conclusions In general, patients with duplication of only 2 exons exhibit a milder phenotype as compared to patients with duplication of more than 2 exons. This study provides insight into exon duplications in the ATP7A gene. PMID:22074552

  9. Extensive Local Gene Duplication and Functional Divergence among Paralogs in Atlantic Salmon

    PubMed Central

    Warren, Ian A.; Ciborowski, Kate L.; Casadei, Elisa; Hazlerigg, David G.; Martin, Sam; Jordan, William C.; Sumner, Seirian

    2014-01-01

    Many organisms can generate alternative phenotypes from the same genome, enabling individuals to exploit diverse and variable environments. A prevailing hypothesis is that such adaptation has been favored by gene duplication events, which generate redundant genomic material that may evolve divergent functions. Vertebrate examples of recent whole-genome duplications are sparse although one example is the salmonids, which have undergone a whole-genome duplication event within the last 100 Myr. The life-cycle of the Atlantic salmon, Salmo salar, depends on the ability to produce alternating phenotypes from the same genome, to facilitate migration and maintain its anadromous life history. Here, we investigate the hypothesis that genome-wide and local gene duplication events have contributed to the salmonid adaptation. We used high-throughput sequencing to characterize the transcriptomes of three key organs involved in regulating migration in S. salar: Brain, pituitary, and olfactory epithelium. We identified over 10,000 undescribed S. salar sequences and designed an analytic workflow to distinguish between paralogs originating from local gene duplication events or from whole-genome duplication events. These data reveal that substantial local gene duplications took place shortly after the whole-genome duplication event. Many of the identified paralog pairs have either diverged in function or become noncoding. Future functional genomics studies will reveal to what extent this rich source of divergence in genetic sequence is likely to have facilitated the evolution of extreme phenotypic plasticity required for an anadromous life-cycle. PMID:24951567

  10. Extensive local gene duplication and functional divergence among paralogs in Atlantic salmon.

    PubMed

    Warren, Ian A; Ciborowski, Kate L; Casadei, Elisa; Hazlerigg, David G; Martin, Sam; Jordan, William C; Sumner, Seirian

    2014-06-19

    Many organisms can generate alternative phenotypes from the same genome, enabling individuals to exploit diverse and variable environments. A prevailing hypothesis is that such adaptation has been favored by gene duplication events, which generate redundant genomic material that may evolve divergent functions. Vertebrate examples of recent whole-genome duplications are sparse although one example is the salmonids, which have undergone a whole-genome duplication event within the last 100 Myr. The life-cycle of the Atlantic salmon, Salmo salar, depends on the ability to produce alternating phenotypes from the same genome, to facilitate migration and maintain its anadromous life history. Here, we investigate the hypothesis that genome-wide and local gene duplication events have contributed to the salmonid adaptation. We used high-throughput sequencing to characterize the transcriptomes of three key organs involved in regulating migration in S. salar: Brain, pituitary, and olfactory epithelium. We identified over 10,000 undescribed S. salar sequences and designed an analytic workflow to distinguish between paralogs originating from local gene duplication events or from whole-genome duplication events. These data reveal that substantial local gene duplications took place shortly after the whole-genome duplication event. Many of the identified paralog pairs have either diverged in function or become noncoding. Future functional genomics studies will reveal to what extent this rich source of divergence in genetic sequence is likely to have facilitated the evolution of extreme phenotypic plasticity required for an anadromous life-cycle.

  11. Investigating different duplication pattern of essential genes in mouse and human.

    PubMed

    Acharya, Debarun; Mukherjee, Dola; Podder, Soumita; Ghosh, Tapash C

    2015-01-01

    Gene duplication is one of the major driving forces shaping genome and organism evolution and thought to be itself regulated by some intrinsic properties of the gene. Comparing the essential genes among mouse and human, we observed that the essential genes avoid duplication in mouse while prefer to remain duplicated in humans. In this study, we wanted to explore the reasons behind such differences in gene essentiality by cross-species comparison of human and mouse. Moreover, we examined essential genes that are duplicated in humans are functionally more redundant than that in mouse. The proportion of paralog pseudogenization of essential genes is higher in mouse than that of humans. These duplicates of essential genes are under stringent dosage regulation in human than in mouse. We also observed slower evolutionary rate in the paralogs of human essential genes than the mouse counterpart. Together, these results clearly indicate that human essential genes are retained as duplicates to serve as backed up copies that may shield themselves from harmful mutations.

  12. Capillary electrophoresis for the detection of PMP22 gene duplication: study in Mexican patients.

    PubMed

    Hernández-Zamora, Edgar; de la Luz Arenas-Sordo, María; Maldonado-Rodríguez, Rogelio

    2008-04-01

    Charcot-Marie-Tooth (CMT) disease is the most common inherited disorder of the human peripheral nerve, with an estimated overall prevalence of 17-40/10 000 [1]. The typical phenotype presents peroneal muscular atrophy and pes cavus [2]. CMT is usually divided into two large types, about two-thirds of the patients have CMT type 1 (CMT1), that affects the layer of myelin (demyelination). In type 2 (CMT2) the nerve fibers are affected (axonal). CMT diseases have autosomal dominant, autosomal recessive, and X-linked inheritance [1]. The most frequent subtype is 1A (CMT1A) with autosomal dominant transmission, secondary in most cases to a tandem duplication of a 1.5 Mb DNA fragment on chromosome 17p11.2-p12 [4-7]. In this region, the codification of the peripheral myelin protein 22 (PMP22) takes place. The severity of the disease varies among patients, even within the same family, from almost no symptoms to severe foot-drop and sensory loss. The PMP22 gene has four exons and is regulated by two promoters located toward the extreme 5'. The origin of the duplication that causes the disease is an uneven exchange of the chromatids during the meiosis. This unequal recombination occurs between two regions that limit the PMP22 gene, described as REP places of 24 kb, proximal and distal [3, 4].

  13. New organelles by gene duplication in a biophysical model of eukaryote endomembrane evolution.

    PubMed

    Ramadas, Rohini; Thattai, Mukund

    2013-06-04

    Extant eukaryotic cells have a dynamic traffic network that consists of diverse membrane-bound organelles exchanging matter via vesicles. This endomembrane system arose and diversified during a period characterized by massive expansions of gene families involved in trafficking after the acquisition of a mitochondrial endosymbiont by a prokaryotic host cell >1.8 billion years ago. Here we investigate the mechanistic link between gene duplication and the emergence of new nonendosymbiotic organelles, using a minimal biophysical model of traffic. Our model incorporates membrane-bound compartments, coat proteins and adaptors that drive vesicles to bud and segregate cargo from source compartments, and SNARE proteins and associated factors that cause vesicles to fuse into specific destination compartments. In simulations, arbitrary numbers of compartments with heterogeneous initial compositions segregate into a few compositionally distinct subsets that we term organelles. The global structure of the traffic system (i.e., the number, composition, and connectivity of organelles) is determined completely by local molecular interactions. On evolutionary timescales, duplication of the budding and fusion machinery followed by loss of cross-interactions leads to the emergence of new organelles, with increased molecular specificity being necessary to maintain larger organellar repertoires. These results clarify potential modes of early eukaryotic evolution as well as more recent eukaryotic diversification.

  14. Preservation of Gene Duplication Increases the Regulatory Spectrum of Ribosomal Protein Genes and Enhances Growth under Stress.

    PubMed

    Parenteau, Julie; Lavoie, Mathieu; Catala, Mathieu; Malik-Ghulam, Mustafa; Gagnon, Jules; Abou Elela, Sherif

    2015-12-22

    In baker's yeast, the majority of ribosomal protein genes (RPGs) are duplicated, and it was recently proposed that such duplications are preserved via the functional specialization of the duplicated genes. However, the origin and nature of duplicated RPGs' (dRPGs) functional specificity remain unclear. In this study, we show that differences in dRPG functions are generated by variations in the modality of gene expression and, to a lesser extent, by protein sequence. Analysis of the sequence and expression patterns of non-intron-containing RPGs indicates that each dRPG is controlled by specific regulatory sequences modulating its expression levels in response to changing growth conditions. Homogenization of dRPG sequences reduces cell tolerance to growth under stress without changing the number of expressed genes. Together, the data reveal a model where duplicated genes provide a means for modulating the expression of ribosomal proteins in response to stress.

  15. An ancient genome duplication contributed to the abundance of metabolic genes in the moss Physcomitrella patens

    PubMed Central

    Rensing, Stefan A; Ick, Julia; Fawcett, Jeffrey A; Lang, Daniel; Zimmer, Andreas; Van de Peer, Yves; Reski, Ralf

    2007-01-01

    Background: Analyses of complete genomes and large collections of gene transcripts have shown that most, if not all seed plants have undergone one or more genome duplications in their evolutionary past. Results: In this study, based on a large collection of EST sequences, we provide evidence that the haploid moss Physcomitrella patens is a paleopolyploid as well. Based on the construction of linearized phylogenetic trees we infer the genome duplication to have occurred between 30 and 60 million years ago. Gene Ontology and pathway association of the duplicated genes in P. patens reveal different biases of gene retention compared with seed plants. Conclusion: Metabolic genes seem to have been retained in excess following the genome duplication in P. patens. This might, at least partly, explain the versatility of metabolism, as described for P. patens and other mosses, in comparison to other land plants. PMID:17683536

  16. Duplication and functional diversification of HAP3 genes leading to the origin of the seed-developmental regulatory gene, LEAFY COTYLEDON1 (LEC1), in nonseed plant genomes.

    PubMed

    Xie, Zengyan; Li, Xia; Glover, Beverley J; Bai, Shunong; Rao, Guang-Yuan; Luo, Jingchu; Yang, Ji

    2008-08-01

    The HAP3 gene encodes a subunit of the CCAAT-box-binding factor (CBF), a highly conserved trimeric activator that recognizes and binds the ubiquitous CCAAT promoter element with high affinity. Two types of HAP3 gene have been identified in plant genomes. The LEAFY COTYLEDON1 (LEC1)-type HAP3 genes encode a functionally specialized subunit of CBF, which is expressed specifically in developing seeds. In contrast, most non-LEC1-type HAP3 genes are expressed in various tissues. It has been proposed that the LEC1-type HAP3 genes originated from the duplication and functional divergence of non-LEC1-type HAP3 genes. However, it is not yet known when this duplication event took place or whether the LEC1-type HAP3 genes appeared at the same time as the origin of seed plants. Here we describe a comprehensive comparison of the duplication patterns of HAP3 genes in different plant genomes. We recognize a major expansion of the HAP3 gene family accompanying the origin and early diversification of land plants and postulate that retrotransposition and other mechanisms of gene duplication have been involved in the expansion of the plant HAP3 gene family. We provide evidence that the LEC1-type HAP3 genes originated in nonseed vascular plant genomes and demonstrate that they are inductively expressed under drought stress in nonseed plants. These genes, however, were recruited to a novel regulatory network in the early stages of seed plant evolution and steadily expressed during seed development and maturation.

  17. Gene duplication, exon gain and neofunctionalization of OEP16-related genes in land plants.

    PubMed

    Drea, Sinéad C; Lao, Nga T; Wolfe, Kenneth H; Kavanagh, Tony A

    2006-06-01

    OEP16, a channel protein of the outer membrane of chloroplasts, has been implicated in amino acid transport and in the substrate-dependent import of protochlorophyllide oxidoreductase A. Two major clades of OEP16-related sequences were identified in land plants (OEP16-L and OEP16-S), which arose by a gene duplication event predating the divergence of seed plants and bryophytes. Remarkably, in angiosperms, OEP16-S genes evolved by gaining an additional exon that extends an interhelical loop domain in the pore-forming region of the protein. We analysed the sequence, structure and expression of the corresponding Arabidopsis genes (atOEP16-S and atOEP16-L) and demonstrated that following duplication, both genes diverged in terms of expression patterns and coding sequence. AtOEP16-S, which contains multiple G-box ABA-responsive elements (ABREs) in the promoter region, is regulated by ABI3 and ABI5 and is strongly expressed during the maturation phase in seeds and pollen grains, both desiccation-tolerant tissues. In contrast, atOEP-L, which lacks promoter ABREs, is expressed predominantly in leaves, is induced strongly by low-temperature stress and shows weak induction in response to osmotic stress, salicylic acid and exogenous ABA. Our results indicate that gene duplication, exon gain and regulatory sequence evolution each played a role in the divergence of OEP16 homologues in plants.

  18. Interchromosomal segmental duplications explain the unusual structure of PRSS3, the gene for an inhibitor-resistant trypsinogen.

    PubMed

    Rowen, Lee; Williams, Eleanor; Glusman, Gustavo; Linardopoulou, Elena; Friedman, Cynthia; Ahearn, Mary Ellen; Seto, Jason; Boysen, Cecilie; Qin, Shizhen; Wang, Kai; Kaur, Amardeep; Bloom, Scott; Hood, Leroy; Trask, Barbara J

    2005-08-01

    Homo sapiens possess several trypsinogen or trypsinogen-like genes of which three (PRSS1, PRSS2, and PRSS3) produce functional trypsins in the digestive tract. PRSS1 and PRSS2 are located on chromosome 7q35, while PRSS3 is found on chromosome 9p13. Here, we report a variation of the theme of new gene creation by duplication: the PRSS3 gene was formed by segmental duplications originating from chromosomes 7q35 and 11q24. As a result, PRSS3 transcripts display two variants of exon 1. The PRSS3 transcript whose gene organization most resembles PRSS1 and PRSS2 encodes a functional protein originally named mesotrypsinogen. The other variant is a fusion transcript, called trypsinogen IV. We show that the first exon of trypsinogen IV is derived from the noncoding first exon of LOC120224, a chromosome 11 gene. LOC120224 codes for a widely conserved transmembrane protein of unknown function. Comparative analyses suggest that these interchromosomal duplications occurred after the divergence of Old World monkeys and hominids. PRSS3 transcripts consist of a mixed population of mRNAs, some expressed in the pancreas and encoding an apparently functional trypsinogen and others of unknown function expressed in brain and a variety of other tissues. Analysis of the selection pressures acting on the trypsinogen gene family shows that, while the apparently functional genes are under mild to strong purifying selection overall, a few residues appear under positive selection. These residues could be involved in interactions with inhibitors.

  19. Gene duplication in the major insecticide target site, Rdl, in Drosophila melanogaster.

    PubMed

    Remnant, Emily J; Good, Robert T; Schmidt, Joshua M; Lumb, Christopher; Robin, Charles; Daborn, Phillip J; Batterham, Philip

    2013-09-03

    The Resistance to Dieldrin gene, Rdl, encodes a GABA-gated chloride channel subunit that is targeted by cyclodiene and phenylpyrazole insecticides. The gene was first characterized in Drosophila melanogaster by genetic mapping of resistance to the cyclodiene dieldrin. The 4,000-fold resistance observed was due to a single amino acid replacement, Ala(301) to Ser. The equivalent change was subsequently identified in Rdl orthologs of a large range of resistant insect species. Here, we report identification of a duplication at the Rdl locus in D. melanogaster. The 113-kb duplication contains one WT copy of Rdl and a second copy with two point mutations: an Ala(301) to Ser resistance mutation and Met(360) to Ile replacement. Individuals with this duplication exhibit intermediate dieldrin resistance compared with single copy Ser(301) homozygotes, reduced temperature sensitivity, and altered RNA editing associated with the resistant allele. Ectopic recombination between Roo transposable elements is involved in generating this genomic rearrangement. The duplication phenotypes were confirmed by construction of a transgenic, artificial duplication integrating the 55.7-kb Rdl locus with a Ser(301) change into an Ala(301) background. Gene duplications can contribute significantly to the evolution of insecticide resistance, most commonly by increasing the amount of gene product produced. Here however, duplication of the Rdl target site creates permanent heterozygosity, providing unique potential for adaptive mutations to accrue in one copy, without abolishing the endogenous role of an essential gene.

  20. Genesis of the vertebrate FoxP subfamily member genes occurred during two ancestral whole genome duplication events.

    PubMed

    Song, Xiaowei; Tang, Yezhong; Wang, Yajun

    2016-08-22

    The vertebrate FoxP subfamily genes play important roles in the construction of essential functional modules involved in physiological and developmental processes. To explore the adaptive evolution of functional modules associated with the FoxP subfamily member genes, it is necessary to study the gene duplication process. We detected four member genes of the FoxP subfamily in sea lampreys (a representative species of jawless vertebrates) through genome screenings and phylogenetic analyses. Reliable paralogons (i.e. paralogous chromosome segments) have rarely been detected in scaffolds of FoxP subfamily member genes in sea lampreys due to the considerable existence of HTH_Tnp_Tc3_2 transposases. However, these transposases did not alter gene numbers of the FoxP subfamily in sea lampreys. The coincidence between the "1-4" gene duplication pattern of FoxP subfamily genes from invertebrates to vertebrates and two rounds of ancestral whole genome duplication (1R- and 2R-WGD) events reveal that the FoxP subfamily of vertebrates was quadruplicated in the 1R- and 2R-WGD events. Furthermore, we deduced that a synchronous gene duplication process occurred for the FoxP subfamily and for three linked gene families/subfamilies (i.e. MIT family, mGluR group III and PLXNA subfamily) in the 1R- and 2R-WGD events using phylogenetic analyses and mirror-dendrogram methods (i.e. algorithms to test protein-protein interactions). Specifically, the ancestor of FoxP1 and FoxP3 and the ancestor of FoxP2 and FoxP4 were generated in 1R-WGD event. In the subsequent 2R-WGD event, these two ancestral genes were changed into FoxP1, FoxP2, FoxP3 and FoxP4. The elucidation of these gene duplication processes shed light on the phylogenetic relationships between functional modules of the FoxP subfamily member genes.

  1. Distinct Defects in Spine Formation or Pruning in Two Gene Duplication Mouse Models of Autism.

    PubMed

    Wang, Miao; Li, Huiping; Takumi, Toru; Qiu, Zilong; Xu, Xiu; Yu, Xiang; Bian, Wen-Jie

    2017-04-01

    Autism spectrum disorder (ASD) encompasses a complex set of developmental neurological disorders, characterized by deficits in social communication and excessive repetitive behaviors. In recent years, ASD is increasingly being considered as a disease of the synapse. One main type of genetic aberration leading to ASD is gene duplication, and several mouse models have been generated mimicking these mutations. Here, we studied the effects of MECP2 duplication and human chromosome 15q11-13 duplication on synaptic development and neural circuit wiring in the mouse sensory cortices. We showed that mice carrying MECP2 duplication had specific defects in spine pruning, while the 15q11-13 duplication mouse model had impaired spine formation. Our results demonstrate that spine pathology varies significantly between autism models and that distinct aspects of neural circuit development may be targeted in different ASD mutations. Our results further underscore the importance of gene dosage in normal development and function of the brain.

  2. Gene-Family Extension Measures and Correlations

    PubMed Central

    Carmi, Gon; Bolshoy, Alexander

    2016-01-01

    The existence of multiple copies of genes is a well-known phenomenon. A gene family is a set of sufficiently similar genes, formed by gene duplication. In earlier works conducted on a limited number of completely sequenced and annotated genomes it was found that size of gene family and size of genome are positively correlated. Additionally, it was found that several atypical microbes deviated from the observed general trend. In this study, we reexamined these associations on a larger dataset consisting of 1484 prokaryotic genomes and using several ranking approaches. We applied ranking methods in such a way that genomes with lower numbers of gene copies would have lower rank. Until now only simple ranking methods were used; we applied the Kemeny optimal aggregation approach as well. Regression and correlation analysis were utilized in order to accurately quantify and characterize the relationships between measures of paralog indices and genome size. In addition, boxplot analysis was employed as a method for outlier detection. We found that, in general, all paralog indexes positively correlate with an increase of genome size. As expected, different groups of atypical prokaryotic genomes were found for different types of paralog quantities. Mycoplasmataceae and Halobacteria appeared to be among the most interesting candidates for further research of evolution through gene duplication. PMID:27527218

  3. Duplicative activation mechanisms of two trypanosome telomeric VSG genes with structurally simple 5' flanks.

    PubMed

    Matthews, K R; Shiels, P G; Graham, S V; Cowan, C; Barry, J D

    1990-12-25

    In the mammalian bloodstream, African trypanosomes express variant surface glycoprotein (VSG) genes from a family of long and complex telomeric expression sites. VSG switching generally occurs by the duplication of different VSG genes into these sites by gene conversion involving a series of 70 base pair (70bp) repeats in the 5' flank. In contrast, when VSG is first synthesised by trypanosomes in the tsetse fly at the metacyclic stage, a separate set of telomeric expression sites is activated. These latter telomeres appear not to act as recipients in gene conversion. We have found that the structure of two such expression sites is simple, with very short 70bp repeat regions and very little other sequence in common with bloodstream expression sites. However, the two telomeres readily act as donors in VSG gene conversion in the bloodstream and we show for one a consistent association of the conversion 5' end point with the short 70bp repeat region. These findings help explain why a very predictable set of VSGs is expressed in the tsetse fly and have implications for VSG gene conversion mechanisms.

  4. Characterizing gene family evolution

    PubMed Central

    Liberles, David A.

    2008-01-01

    Gene families are widely used in comparative genomics, molecular evolution, and in systematics. However, they are constructed in different manners, their data analyzed and interpreted differently, with different underlying assumptions, leading to sometimes divergent conclusions. In systematics, concepts like monophyly and the dichotomy between homoplasy and homology have been central to the analysis of phylogenies. We critique the traditional use of such concepts as applied to gene families and give examples of incorrect inferences they may lead to. Operational definitions that have emerged within functional genomics are contrasted with the common formal definitions derived from systematics. Lastly, we question the utility of layers of homology and the meaning of homology at the character state level in the context of sequence evolution. From this, we move forward to present an idealized strategy for characterizing gene family evolution for both systematic and functional purposes, including recent methodological improvements. PMID:19461954

  5. beta. amyloid gene duplication in Alzheimer's disease and karyotypically normal Down syndrome

    SciTech Connect

    Delabar, J.; Goldgaber, D.; Lamour, Y.; Nicole, A.; Huret, J.; De Groucy, J.; Brown, P.; Gajdusek, D.C.; Sinet, P.

    1987-03-13

    With the recently cloned complementary DNA probe, lambdaAm4 for the chromosome 21 gene encoding brain amyloid polypeptide (..beta.. amyloid protein) of Alzheimer's disease, leukocyte DNA from three patients with sporadic Alzheimer's disease and two patients with karyotypically normal Down syndrome was found to contain three copies of this bene. Because a small region of chromosome 21 containing the ets-2 gene is duplicated in patients with Alzheimer's disease, as well as in karyotypically normal Down syndrome, duplication of a subsection of the critical segment of chromosome 21 that is duplicated in Down syndrome may be the genetic defect in Alzeimer's disease.

  6. Dynamics of gene duplication in the genomes of chlorophyll d-producing cyanobacteria: implications for the ecological niche.

    PubMed

    Miller, Scott R; Wood, A Michelle; Blankenship, Robert E; Kim, Maria; Ferriera, Steven

    2011-01-01

    Gene duplication may be an important mechanism for the evolution of new functions and for the adaptive modulation of gene expression via dosage effects. Here, we analyzed the fate of gene duplicates for two strains of a novel group of cyanobacteria (genus Acaryochloris) that produces the far-red light absorbing chlorophyll d as its main photosynthetic pigment. The genomes of both strains contain an unusually high number of gene duplicates for bacteria. As has been observed for eukaryotic genomes, we find that the demography of gene duplicates can be well modeled by a birth-death process. Most duplicated Acaryochloris genes are of comparatively recent origin, are strain-specific, and tend to be located on different genetic elements. Analyses of selection on duplicates of different divergence classes suggest that a minority of paralogs exhibit near neutral evolutionary dynamics immediately following duplication but that most duplicate pairs (including those which have been retained for long periods) are under strong purifying selection against amino acid change. The likelihood of duplicate retention varied among gene functional classes, and the pronounced differences between strains in the pool of retained recent duplicates likely reflects differences in the nutrient status and other characteristics of their respective environments. We conclude that most duplicates are quickly purged from Acaryochloris genomes and that those which are retained likely make important contributions to organism ecology by conferring fitness benefits via gene dosage effects. The mechanism of enhanced duplication may involve homologous recombination between genetic elements mediated by paralogous copies of recA.

  7. Extensive horizontal gene transfer, duplication, and loss of chlorophyll synthesis genes in the algae

    DOE PAGES

    Hunsperger, Heather M.; Randhawa, Tejinder; Cattolico, Rose Ann

    2015-02-10

    Two non-homologous, isofunctional enzymes catalyze the penultimate step of chlorophyll a synthesis in oxygenic photosynthetic organisms such as cyanobacteria, eukaryotic algae and land plants: the light independent (LIPOR) and light-dependent (POR) protochlorophyllide oxidoreductases. Whereas the distribution of these enzymes in cyanobacteria and land plants is well understood, the presence, loss, duplication, and replacement of these genes have not been surveyed in the polyphyletic and remarkably diverse eukaryotic algal lineages.

  8. Restriction and Recruitment—Gene Duplication and the Origin and Evolution of Snake Venom Toxins

    PubMed Central

    Hargreaves, Adam D.; Swain, Martin T.; Hegarty, Matthew J.; Logan, Darren W.; Mulley, John F.

    2014-01-01

    Snake venom has been hypothesized to have originated and diversified through a process that involves duplication of genes encoding body proteins with subsequent recruitment of the copy to the venom gland, where natural selection acts to develop or increase toxicity. However, gene duplication is known to be a rare event in vertebrate genomes, and the recruitment of duplicated genes to a novel expression domain (neofunctionalization) is an even rarer process that requires the evolution of novel combinations of transcription factor binding sites in upstream regulatory regions. Therefore, although this hypothesis concerning the evolution of snake venom is very unlikely and should be regarded with caution, it is nonetheless often assumed to be established fact, hindering research into the true origins of snake venom toxins. To critically evaluate this hypothesis, we have generated transcriptomic data for body tissues and salivary and venom glands from five species of venomous and nonvenomous reptiles. Our comparative transcriptomic analysis of these data reveals that snake venom does not evolve through the hypothesized process of duplication and recruitment of genes encoding body proteins. Indeed, our results show that many proposed venom toxins are in fact expressed in a wide variety of body tissues, including the salivary gland of nonvenomous reptiles and that these genes have therefore been restricted to the venom gland following duplication, not recruited. Thus, snake venom evolves through the duplication and subfunctionalization of genes encoding existing salivary proteins. These results highlight the danger of the elegant and intuitive “just-so story” in evolutionary biology. PMID:25079342

  9. Restriction and recruitment-gene duplication and the origin and evolution of snake venom toxins.

    PubMed

    Hargreaves, Adam D; Swain, Martin T; Hegarty, Matthew J; Logan, Darren W; Mulley, John F

    2014-08-01

    Snake venom has been hypothesized to have originated and diversified through a process that involves duplication of genes encoding body proteins with subsequent recruitment of the copy to the venom gland, where natural selection acts to develop or increase toxicity. However, gene duplication is known to be a rare event in vertebrate genomes, and the recruitment of duplicated genes to a novel expression domain (neofunctionalization) is an even rarer process that requires the evolution of novel combinations of transcription factor binding sites in upstream regulatory regions. Therefore, although this hypothesis concerning the evolution of snake venom is very unlikely and should be regarded with caution, it is nonetheless often assumed to be established fact, hindering research into the true origins of snake venom toxins. To critically evaluate this hypothesis, we have generated transcriptomic data for body tissues and salivary and venom glands from five species of venomous and nonvenomous reptiles. Our comparative transcriptomic analysis of these data reveals that snake venom does not evolve through the hypothesized process of duplication and recruitment of genes encoding body proteins. Indeed, our results show that many proposed venom toxins are in fact expressed in a wide variety of body tissues, including the salivary gland of nonvenomous reptiles and that these genes have therefore been restricted to the venom gland following duplication, not recruited. Thus, snake venom evolves through the duplication and subfunctionalization of genes encoding existing salivary proteins. These results highlight the danger of the elegant and intuitive "just-so story" in evolutionary biology.

  10. The enrichment of TATA box and the scarcity of depleted proximal nucleosome in the promoters of duplicated yeast genes.

    PubMed

    Kim, Yuseob; Lee, Jang H; Babbitt, Gregory A

    2010-01-01

    Population genetic theory of gene duplication suggests that the preservation of duplicate copies requires functional divergence upon duplication. Genes that can be readily modified to produce new gene expression patterns may thus be duplicated often. In yeast, genes exhibit dichotomous expression patterns based on their promoter architectures. The expression of genes that contain TATA box or occupied proximal nucleosome (OPN) tends to be variable and respond to external signals. On the other hand, genes without TATA box or with depleted proximal nucleosome (DPN) are expressed constitutively. We find that recent duplicates in the yeast genome are heavily biased to be TATA box containing genes and not to be DPN genes. This suggests that variably expressed genes, due to the functional organization in their promoters, have higher duplicability than constitutively expressed genes.

  11. Predicting the Stability of Homologous Gene Duplications in a Plant RNA Virus.

    PubMed

    Willemsen, Anouk; Zwart, Mark P; Higueras, Pablo; Sardanyés, Josep; Elena, Santiago F

    2016-10-12

    One of the striking features of many eukaryotes is the apparent amount of redundancy in coding and non-coding elements of their genomes. Despite the possible evolutionary advantages, there are fewer examples of redundant sequences in viral genomes, particularly those with RNA genomes. The factors constraining the maintenance of redundant sequences in present-day RNA virus genomes are not well known. Here, we use Tobacco etch virus, a plant RNA virus, to investigate the stability of genetically redundant sequences by generating viruses with potentially beneficial gene duplications. Subsequently, we tested the viability of these viruses and performed experimental evolution. We found that all gene duplication events resulted in a loss of viability or in a significant reduction in viral fitness. Moreover, upon analyzing the genomes of the evolved viruses, we always observed the deletion of the duplicated gene copy and maintenance of the ancestral copy. Interestingly, there were clear differences in the deletion dynamics of the duplicated gene associated with the passage duration and the size and position of the duplicated copy. Based on the experimental data, we developed a mathematical model to characterize the stability of genetically redundant sequences, and showed that fitness effects are not enough to predict genomic stability. A context-dependent recombination rate is also required, with the context being the duplicated gene and its position. Our results therefore demonstrate experimentally the deleterious nature of gene duplications in RNA viruses. Beside previously described constraints on genome size, we identified additional factors that reduce the likelihood of the maintenance of duplicated genes.

  12. Evolution of Vertebrate Adam Genes; Duplication of Testicular Adams from Ancient Adam9/9-like Loci

    PubMed Central

    Wei, Shuo

    2015-01-01

    Members of the disintegrin metalloproteinase (ADAM) family have important functions in regulating cell-cell and cell-matrix interactions as well as cell signaling. There are two major types of ADAMs: the somatic ADAMs (sADAMs) that have a significant presence in somatic tissues, and the testicular ADAMs (tADAMs) that are expressed predominantly in the testis. Genes encoding tADAMs can be further divided into two groups: group I (intronless) and group II (intron-containing). To date, tAdams have only been reported in placental mammals, and their evolutionary origin and relationship to sAdams remain largely unknown. Using phylogenetic and syntenic tools, we analyzed the Adam genes in various vertebrates ranging from fishes to placental mammals. Our analyses reveal duplication and loss of some sAdams in certain vertebrate species. In particular, there exists an Adam9-like gene in non-mammalian vertebrates but not mammals. We also identified putative group I and group II tAdams in all amniote species that have been examined. These tAdam homologues are more closely related to Adams 9 and 9-like than to other sAdams. In all amniote species examined, group II tAdams lie in close vicinity to Adam9 and hence likely arose from tandem duplication, whereas group I tAdams likely originated through retroposition because of their lack of introns. Clusters of multiple group I tAdams are also common, suggesting tandem duplication after retroposition. Therefore, Adam9/9-like and some of the derived tAdam loci are likely preferred targets for tandem duplication and/or retroposition. Consistent with this hypothesis, we identified a young retroposed gene that duplicated recently from Adam9 in the opossum. As a result of gene duplication, some tAdams were pseudogenized in certain species, whereas others acquired new expression patterns and functions. The rapid duplication of Adam genes has a major contribution to the diversity of ADAMs in various vertebrate species. PMID:26308360

  13. Evolution of Vertebrate Adam Genes; Duplication of Testicular Adams from Ancient Adam9/9-like Loci.

    PubMed

    Bahudhanapati, Harinath; Bhattacharya, Shashwati; Wei, Shuo

    2015-01-01

    Members of the disintegrin metalloproteinase (ADAM) family have important functions in regulating cell-cell and cell-matrix interactions as well as cell signaling. There are two major types of ADAMs: the somatic ADAMs (sADAMs) that have a significant presence in somatic tissues, and the testicular ADAMs (tADAMs) that are expressed predominantly in the testis. Genes encoding tADAMs can be further divided into two groups: group I (intronless) and group II (intron-containing). To date, tAdams have only been reported in placental mammals, and their evolutionary origin and relationship to sAdams remain largely unknown. Using phylogenetic and syntenic tools, we analyzed the Adam genes in various vertebrates ranging from fishes to placental mammals. Our analyses reveal duplication and loss of some sAdams in certain vertebrate species. In particular, there exists an Adam9-like gene in non-mammalian vertebrates but not mammals. We also identified putative group I and group II tAdams in all amniote species that have been examined. These tAdam homologues are more closely related to Adams 9 and 9-like than to other sAdams. In all amniote species examined, group II tAdams lie in close vicinity to Adam9 and hence likely arose from tandem duplication, whereas group I tAdams likely originated through retroposition because of their lack of introns. Clusters of multiple group I tAdams are also common, suggesting tandem duplication after retroposition. Therefore, Adam9/9-like and some of the derived tAdam loci are likely preferred targets for tandem duplication and/or retroposition. Consistent with this hypothesis, we identified a young retroposed gene that duplicated recently from Adam9 in the opossum. As a result of gene duplication, some tAdams were pseudogenized in certain species, whereas others acquired new expression patterns and functions. The rapid duplication of Adam genes has a major contribution to the diversity of ADAMs in various vertebrate species.

  14. Inverted duplication of histone genes in chicken and disposition of regulatory sequences.

    PubMed Central

    Wang, S W; Robins, A J; d'Andrea, R; Wells, J R

    1985-01-01

    Sequence analysis of an 8.4 kb fragment containing five chicken histone genes shows that an H4-H2A gene pair is duplicated and inverted around a central H3 gene. A left and right region, each of 2.1 kb are 97% homologous and the boundaries of homology coincide with ten base pair repeats. These boundary regions also contain highly conserved gene promoter elements, suggesting that interaction of transcriptional machinery with histone genes may be connected with recombination in promoter regions, resulting in the inverted duplication structure seen in this cluster. PMID:4000938

  15. Additional duplicated Hox genes in the earthworm: Perionyx excavatus Hox genes consist of eleven paralog groups.

    PubMed

    Cho, Sung-Jin; Vallès, Yvonne; Kim, Kyong Min; Ji, Seong Chul; Han, Seock Jung; Park, Soon Cheol

    2012-02-10

    Annelida is a lophotrochozoan phylum whose members have a high degree of diversity in body plan morphology, reproductive strategies and ecological niches among others. Of the two traditional classes pertaining to the phylum Annelida (Polychaete and Clitellata), the structure and function of the Hox genes has not been clearly defined within the Oligochaeta class. Using a PCR-based survey, we were able to identify five new Hox genes from the earthworm Perionyx excavatus: a Hox3 gene (Pex-Hox3b), two Dfd genes (Pex-Lox6 and Pex-Lox18), and two posterior genes (Pex-post1 and -post2a). Our result suggests that the eleven earthworm Hox genes contain at least four paralog groups (PG) that have duplicated. We found the clitellates-diagnostic signature residues and annelid signature motif. Also, we show by semi-quantitative RT-PCR that duplicated Hox gene orthologs are differentially expressed in six different anterior-posterior body regions. These results provide essential data for comparative evolution of the Hox cluster within the Annelida.

  16. Human-specific evolution of novel SRGAP2 genes by incomplete segmental duplication

    PubMed Central

    Dennis, Megan Y.; Nuttle, Xander; Sudmant, Peter H.; Antonacci, Francesca; Graves, Tina A.; Nefedov, Mikhail; Rosenfeld, Jill A.; Sajjadian, Saba; Malig, Maika; Kotkiewicz, Holland; Curry, Cynthia J.; Shafer, Susan; Shaffer, Lisa G.; de Jong, Pieter J.; Wilson, Richard K.; Eichler, Evan E.

    2012-01-01

    SUMMARY Gene duplication is an important source of phenotypic change and adaptive evolution. We use a novel genomic approach to identify highly identical sequence missing from the reference genome, confirming the cortical development gene Slit-Robo Rho GTPase activating protein 2 (SRGAP2) duplicated three times in humans. We show that the promoter and first nine exons of SRGAP2 duplicated from 1q32.1 (SRGAP2A) to 1q21.1 (SRGAP2B) ~3.4 million years ago (mya). Two larger duplications later copied SRGAP2B to chromosome 1p12 (SRGAP2C) and to proximal 1q21.1 (SRGAP2D), ~2.4 and ~1 mya, respectively. Sequence and expression analysis shows SRGAP2C is the most likely duplicate to encode a functional protein and among the most fixed human-specific duplicate genes. Our data suggest a mechanism where incomplete duplication created a novel function —at birth, antagonizing parental SRGAP2 function 2–3 mya a time corresponding to the transition from Australopithecus to Homo and the beginning of neocortex expansion. PMID:22559943

  17. Genetic defects causing familial hypercholesterolaemia: identification of deletions and duplications in the LDL-receptor gene and summary of all mutations found in patients attending the Hammersmith Hospital Lipid Clinic.

    PubMed

    Tosi, Isabella; Toledo-Leiva, Paola; Neuwirth, Clare; Naoumova, Rossi P; Soutar, Anne K

    2007-09-01

    Familial hypercholesterolaemia (FH) results from defective catabolism of low density lipoproteins (LDL), leading to premature atherosclerosis and early coronary heart disease. It is commonly caused by mutations in LDLR, encoding the LDL receptor that mediates hepatic uptake of LDL, or in APOB, encoding its major ligand. More rarely, dominant mutations in PCSK9 or recessive mutations in LDLRAP1 (ARH) cause FH, gene defects that also affect the LDL-receptor pathway. We have used multiplex ligation-dependent probe amplification (MLPA) to identify deletions and rearrangements in LDLR, some not detectable by Southern blotting, thus completing our screening for mutations causing FH in a group of FH patients referred to a Lipid Clinic in London. To summarise, mutations in LDLR were found in 153 unrelated heterozygous FH patients and 24 homozygotes/compound heterozygotes, and in over 200 relatives of 80 index patients. LDLR mutations included 85 different point mutations (7 not previously described) and 13 different large rearrangements. The APOB R3500Q mutation was present in 14 heterozygous patients and a mutation in PCSK9 in another 4; LDLRAP1 mutations were found in 4 "homozygous" FH patients. Our data confirm that DNA-based diagnosis provides information that is important for management of FH in a considerable number of families.

  18. Extensive divergence in alternative splicing patterns after gene and genome duplication during the evolutionary history of Arabidopsis.

    PubMed

    Zhang, Peter G; Huang, Suzanne Z; Pin, Anne-Laure; Adams, Keith L

    2010-07-01

    Gene duplication at various scales, from single gene duplication to whole-genome (WG) duplication, has occurred throughout eukaryotic evolution and contributed greatly to the large number of duplicated genes in the genomes of many eukaryotes. Previous studies have shown divergence in expression patterns of many duplicated genes at various evolutionary time scales and cases of gain of a new function or expression pattern by one duplicate or partitioning of functions or expression patterns between duplicates. Alternative splicing (AS) is a fundamental aspect of the expression of many genes that can increase gene product diversity and affect gene regulation. However, the evolution of AS patterns of genes duplicated by polyploidy, as well as in a sizable number of duplicated gene pairs in plants, has not been examined. Here, we have characterized conservation and divergence in AS patterns in genes duplicated by a polyploidy event during the evolutionary history of Arabidopsis thaliana. We used reverse transcription-polymerase chain reaction to assay 104 WG duplicates in six organ types and in plants grown under three abiotic stress treatments to detect organ- and stress-specific patterns of AS. Differences in splicing patterns in one or more organs, or under stress conditions, were found between the genes in a large majority of the duplicated pairs. In a few cases, AS patterns were the same between duplicates only under one or more abiotic stress treatments and not under normal growing conditions or vice versa. We also examined AS in 42 tandem duplicates and we found patterns of AS roughly comparable with the genes duplicated by polyploidy. The alternatively spliced forms in some of the genes created premature stop codons that would result in missing or partial functional domains if the transcripts are translated, which could affect gene function and cause functional divergence between duplicates. Our results indicate that AS patterns have diverged considerably after

  19. The sulfatase gene family.

    PubMed

    Parenti, G; Meroni, G; Ballabio, A

    1997-06-01

    During the past few years, molecular analyses have provided important insights into the biochemistry and genetics of the sulfatase family of enzymes, identifying the molecular bases of inherited diseases caused by sulfatase deficiencies. New members of the sulfatase gene family have been identified in man and other species using a genomic approach. These include the gene encoding arylsulfatase E, which is involved in X-linked recessive chondrodysplasia punctata, a disorder of cartilage and bone development. Another important breakthrough has been the discovery of the biochemical basis of multiple sulfatase deficiency, an autosomal recessive disorder characterized by a severe of all sulfatase activities. These discoveries, together with the resolution of the crystallographic structure of sulfatases, have improved our understanding of the function and evolution of this fascinating family of enzymes.

  20. Detecting Functional Divergence after Gene Duplication through Evolutionary Changes in Posttranslational Regulatory Sequences

    PubMed Central

    Nguyen Ba, Alex N.; Strome, Bob; Hua, Jun Jie; Desmond, Jonathan; Gagnon-Arsenault, Isabelle; Weiss, Eric L.; Landry, Christian R.; Moses, Alan M.

    2014-01-01

    Gene duplication is an important evolutionary mechanism that can result in functional divergence in paralogs due to neo-functionalization or sub-functionalization. Consistent with functional divergence after gene duplication, recent studies have shown accelerated evolution in retained paralogs. However, little is known in general about the impact of this accelerated evolution on the molecular functions of retained paralogs. For example, do new functions typically involve changes in enzymatic activities, or changes in protein regulation? Here we study the evolution of posttranslational regulation by examining the evolution of important regulatory sequences (short linear motifs) in retained duplicates created by the whole-genome duplication in budding yeast. To do so, we identified short linear motifs whose evolutionary constraint has relaxed after gene duplication with a likelihood-ratio test that can account for heterogeneity in the evolutionary process by using a non-central chi-squared null distribution. We find that short linear motifs are more likely to show changes in evolutionary constraints in retained duplicates compared to single-copy genes. We examine changes in constraints on known regulatory sequences and show that for the Rck1/Rck2, Fkh1/Fkh2, Ace2/Swi5 paralogs, they are associated with previously characterized differences in posttranslational regulation. Finally, we experimentally confirm our prediction that for the Ace2/Swi5 paralogs, Cbk1 regulated localization was lost along the lineage leading to SWI5 after gene duplication. Our analysis suggests that changes in posttranslational regulation mediated by short regulatory motifs systematically contribute to functional divergence after gene duplication. PMID:25474245

  1. Detecting functional divergence after gene duplication through evolutionary changes in posttranslational regulatory sequences.

    PubMed

    Nguyen Ba, Alex N; Strome, Bob; Hua, Jun Jie; Desmond, Jonathan; Gagnon-Arsenault, Isabelle; Weiss, Eric L; Landry, Christian R; Moses, Alan M

    2014-12-01

    Gene duplication is an important evolutionary mechanism that can result in functional divergence in paralogs due to neo-functionalization or sub-functionalization. Consistent with functional divergence after gene duplication, recent studies have shown accelerated evolution in retained paralogs. However, little is known in general about the impact of this accelerated evolution on the molecular functions of retained paralogs. For example, do new functions typically involve changes in enzymatic activities, or changes in protein regulation? Here we study the evolution of posttranslational regulation by examining the evolution of important regulatory sequences (short linear motifs) in retained duplicates created by the whole-genome duplication in budding yeast. To do so, we identified short linear motifs whose evolutionary constraint has relaxed after gene duplication with a likelihood-ratio test that can account for heterogeneity in the evolutionary process by using a non-central chi-squared null distribution. We find that short linear motifs are more likely to show changes in evolutionary constraints in retained duplicates compared to single-copy genes. We examine changes in constraints on known regulatory sequences and show that for the Rck1/Rck2, Fkh1/Fkh2, Ace2/Swi5 paralogs, they are associated with previously characterized differences in posttranslational regulation. Finally, we experimentally confirm our prediction that for the Ace2/Swi5 paralogs, Cbk1 regulated localization was lost along the lineage leading to SWI5 after gene duplication. Our analysis suggests that changes in posttranslational regulation mediated by short regulatory motifs systematically contribute to functional divergence after gene duplication.

  2. Origin, duplication and reshuffling of plasmid genes: Insights from Burkholderia vietnamiensis G4 genome.

    PubMed

    Maida, Isabel; Fondi, Marco; Orlandini, Valerio; Emiliani, Giovanni; Papaleo, Maria Cristiana; Perrin, Elena; Fani, Renato

    2014-01-01

    Using a computational pipeline based on similarity networks reconstruction we analysed the 1133 genes of the Burkholderia vietnamiensis (Bv) G4 five plasmids, showing that gene and operon duplication played an important role in shaping the plasmid architecture. Several single/multiple duplications occurring at intra- and/or interplasmids level involving 253 paralogous genes (stand-alone, clustered or operons) were detected. An extensive gene/operon exchange between plasmids and chromosomes was also disclosed. The larger the plasmid, the higher the number and size of paralogous fragments. Many paralogs encoded mobile genetic elements and duplicated very recently, suggesting that the rearrangement of the Bv plastic genome is ongoing. Concerning the "molecular habitat" and the "taxonomical status" (the Preferential Organismal Sharing) of Bv plasmid genes, most of them have been exchanged with other plasmids of bacteria belonging (or phylogenetically very close) to Burkholderia, suggesting that taxonomical proximity of bacterial strains is a crucial issue in plasmid-mediated gene exchange.

  3. Mosquito vitellogenin genes: Comparative sequence analysis, gene duplication, and the role of rare synonymous codon usage in regulating expression.

    PubMed

    Isoe, Jun; Hagedorn, Henry H

    2007-01-01

    Comparative sequence analysis of mosquito vitellogenin (Vg) genes was carried out to gain a better understanding of their evolution. The genomic clones of vitellogenin genes were isolated and sequenced from all three subfamilies of the family Culicidae including Culicinae (Aedes aegypti, Ochlerotatus atropalpus, Ae. polynesiensis, Ae. albopictus, Ochlerotatus triseriatus and Culex quinquefasciatus), Toxorhynchitinae (Toxorhynchites amboinensis), and Anophelinae (Anopheles albimanus). Genomic clones of vitellogenin genes Vg-B and Vg-C were isolated from Ae. aegypti and sequenced. A comparison of Vg-B and Vg-C, with the previously characterized vitellogenin gene, Vg-A1, suggests that Vg-A1 and Vg-B probably arose by a recent gene duplication, and Vg-C apparently diverged from the two other members of the gene family in an earlier gene duplication event. Two vitellogenin genes orthologous to Vg-C were cloned from a Cx. quinquefasciatus DNA library, one of which is truncated at the N-terminal end. Single vitellogenin genes, orthologous to Vg-C, were cloned from the An. albimanus and Tx. amboinensis libraries. Incomplete sequences orthologous to Vg-B and Vg-C were isolated from the Oc. atropalpus library. Only partial sequences were isolated from Ae. polynesiensis, Ae. albopictus and Oc. triseriatus. Inferred phylogenetic relationships based on analysis of these sequences suggest that Vg-C was the ancestral gene and that a recent gene duplication gave rise to Vg-A1 and Vg-B after the separation of the genus Aedes. The deduced amino acid composition of mosquito vitellogenin proteins exhibits higher tyrosine and phenylalanine composition than other mosquito proteins except for the hexamerin storage proteins. Analysis of vitellogenin coding sequences showed that a majority of amino acid substitutions were due to conserved and moderately conserved changes suggesting that the vitellogenins are under moderately selective constrains to maintain tertiary structure. The

  4. Evolution of CONSTANS Regulation and Function after Gene Duplication Produced a Photoperiodic Flowering Switch in the Brassicaceae.

    PubMed

    Simon, Samson; Rühl, Mark; de Montaigu, Amaury; Wötzel, Stefan; Coupland, George

    2015-09-01

    Environmental control of flowering allows plant reproduction to occur under optimal conditions and facilitates adaptation to different locations. At high latitude, flowering of many plants is controlled by seasonal changes in day length. The photoperiodic flowering pathway confers this response in the Brassicaceae, which colonized temperate latitudes after divergence from the Cleomaceae, their subtropical sister family. The CONSTANS (CO) transcription factor of Arabidopsis thaliana, a member of the Brassicaceae, is central to the photoperiodic flowering response and shows characteristic patterns of transcription required for day-length sensing. CO is believed to be widely conserved among flowering plants; however, we show that it arose after gene duplication at the root of the Brassicaceae followed by divergence of transcriptional regulation and protein function. CO has two close homologs, CONSTANS-LIKE1 (COL1) and COL2, which are related to CO by tandem duplication and whole-genome duplication, respectively. The single CO homolog present in the Cleomaceae shows transcriptional and functional features similar to those of COL1 and COL2, suggesting that these were ancestral. We detect cis-regulatory and codon changes characteristic of CO and use transgenic assays to demonstrate their significance in the day-length-dependent activation of the CO target gene FLOWERING LOCUS T. Thus, the function of CO as a potent photoperiodic flowering switch evolved in the Brassicaceae after gene duplication. The origin of CO may have contributed to the range expansion of the Brassicaceae and suggests that in other families CO genes involved in photoperiodic flowering arose by convergent evolution.

  5. Gene Duplication, Population Genomics, and Species-Level Differentiation within a Tropical Mountain Shrub

    PubMed Central

    Mastretta-Yanes, Alicia; Zamudio, Sergio; Jorgensen, Tove H.; Arrigo, Nils; Alvarez, Nadir; Piñero, Daniel; Emerson, Brent C.

    2014-01-01

    Gene duplication leads to paralogy, which complicates the de novo assembly of genotyping-by-sequencing (GBS) data. The issue of paralogous genes is exacerbated in plants, because they are particularly prone to gene duplication events. Paralogs are normally filtered from GBS data before undertaking population genomics or phylogenetic analyses. However, gene duplication plays an important role in the functional diversification of genes and it can also lead to the formation of postzygotic barriers. Using populations and closely related species of a tropical mountain shrub, we examine 1) the genomic differentiation produced by putative orthologs, and 2) the distribution of recent gene duplication among lineages and geography. We find high differentiation among populations from isolated mountain peaks and species-level differentiation within what is morphologically described as a single species. The inferred distribution of paralogs among populations is congruent with taxonomy and shows that GBS could be used to examine recent gene duplication as a source of genomic differentiation of nonmodel species. PMID:25223767

  6. Enhanced fixation and preservation of a newly arisen duplicate gene by masking deleterious loss-of-function mutations.

    PubMed

    Tanaka, Kentaro M; Takahasi, K Ryo; Takano-Shimizu, Toshiyuki

    2009-08-01

    Segmental duplications are enriched within many eukaryote genomes, and their potential consequence is gene duplication. While previous theoretical studies of gene duplication have mainly focused on the gene silencing process after fixation, the process leading to fixation is even more important for segmental duplications, because the majority of duplications would be lost before reaching a significant frequency in a population. Here, by a series of computer simulations, we show that purifying selection against loss-of-function mutations increases the fixation probability of a new duplicate gene, especially when the gene is haplo-insufficient. Theoretically, the probability of simultaneous preservation of both duplicate genes becomes twice the loss-of-function mutation rate (u(c)) when the population size (N), the degree of dominance of mutations (h) and the recombination rate between the duplicate genes (c) are all sufficiently large (Nu(c)>1, h>0.1 and c>u(c)). The preservation probability declines rapidly with h and becomes 0 when h=0 (haplo-sufficiency). We infer that masking deleterious loss-of-function mutations give duplicate genes an immediate selective advantage and, together with effects of increased gene dosage, would predominantly determine the fates of the duplicate genes in the early phase of their evolution.

  7. Evolution dynamics of a model for gene duplication under adaptive conflict

    NASA Astrophysics Data System (ADS)

    Ancliff, Mark; Park, Jeong-Man

    2014-06-01

    We present and solve the dynamics of a model for gene duplication showing escape from adaptive conflict. We use a Crow-Kimura quasispecies model of evolution where the fitness landscape is a function of Hamming distances from two reference sequences, which are assumed to optimize two different gene functions, to describe the dynamics of a mixed population of individuals with single and double copies of a pleiotropic gene. The evolution equations are solved through a spin coherent state path integral, and we find two phases: one is an escape from an adaptive conflict phase, where each copy of a duplicated gene evolves toward subfunctionalization, and the other is a duplication loss of function phase, where one copy maintains its pleiotropic form and the other copy undergoes neutral mutation. The phase is determined by a competition between the fitness benefits of subfunctionalization and the greater mutational load associated with maintaining two gene copies. In the escape phase, we find a dynamics of an initial population of single gene sequences only which escape adaptive conflict through gene duplication and find that there are two time regimes: until a time t* single gene sequences dominate, and after t* double gene sequences outgrow single gene sequences. The time t* is identified as the time necessary for subfunctionalization to evolve and spread throughout the double gene sequences, and we show that there is an optimum mutation rate which minimizes this time scale.

  8. Gene body methylation shows distinct patterns associated with different gene origins and duplication modes and has a heterogeneous relationship with gene expression in Oryza sativa (rice).

    PubMed

    Wang, Yupeng; Wang, Xiyin; Lee, Tae-Ho; Mansoor, Shahid; Paterson, Andrew H

    2013-04-01

    Whole-genome duplication (WGD) has been recurring and single-gene duplication is also widespread in angiosperms. Recent whole-genome DNA methylation maps indicate that gene body methylation (i.e. of coding regions) has a functional role. However, whether gene body methylation is related to gene origins and duplication modes has yet to be reported. In rice (Oryza sativa), we computed a body methylation level (proportion of methylated CpG within coding regions) for each gene in five tissues. Body methylation levels follow a bimodal distribution, but show distinct patterns associated with transposable element-related genes; WGD, tandem, proximal and transposed duplicates; and singleton genes. For pairs of duplicated genes, divergence in body methylation levels increases with physical distance and synonymous (Ks) substitution rates, and WGDs show lower divergence than single-gene duplications of similar Ks levels. Intermediate body methylation tends to be associated with high levels of gene expression, whereas heavy body methylation is associated with lower levels of gene expression. The biological trends revealed here are consistent across five rice tissues, indicating that genes of different origins and duplication modes have distinct body methylation patterns, and body methylation has a heterogeneous relationship with gene expression and may be related to survivorship of duplicated genes.

  9. Evolutionary analyses of non-family genes in plants

    SciTech Connect

    Ye, Chuyu; Li, Ting; Yin, Hengfu; Weston, David; Tuskan, Gerald A; Tschaplinski, Timothy J; Yang, Xiaohan

    2013-01-01

    There are a large number of non-family (NF) genes that do not cluster into families with three or more members per genome. While gene families have been extensively studied, a systematic analysis of NF genes has not been reported. We performed comparative studies on NF genes in 14 plant species. Based on the clustering of protein sequences, we identified ~94 000 NF genes across these species that were divided into five evolutionary groups: Viridiplantae wide, angiosperm specific, monocot specific, dicot specific, and those that were species specific. Our analysis revealed that the NF genes resulted largely from less frequent gene duplications and/or a higher rate of gene loss after segmental duplication relative to genes in both lowcopy- number families (LF; 3 10 copies per genome) and high-copy-number families (HF; >10 copies). Furthermore, we identified functions enriched in the NF gene set as compared with the HF genes. We found that NF genes were involved in essential biological processes shared by all plant lineages (e.g. photosynthesis and translation), as well as gene regulation and stress responses associated with phylogenetic diversification. In particular, our analysis of an Arabidopsis protein protein interaction network revealed that hub proteins with the top 10% most connections were over-represented in the NF set relative to the HF set. This research highlights the roles that NF genes may play in evolutionary and functional genomics research.

  10. Evolutionary analyses of non-family genes in plants

    SciTech Connect

    Ye, Chuyu; Li, Ting; Yin, Hengfu; Weston, David; Tuskan, Gerald A; Tschaplinski, Timothy J; Yang, Xiaohan

    2013-03-01

    There are a large number of non-family (NF) genes that do not cluster into families with three or more members per genome. While gene families have been extensively studied, a systematic analysis of NF genes has not been reported. We performed comparative studies on NF genes in 14 plant species. Based on the clustering of protein sequences, we identified ~94,000 NF genes across these species that were divided into five evolutionary groups: Viridiplantae-wide, angiosperm-specific, monocot-specific, dicot-specific, and those that were species-specific. Our analysis revealed that the NF genes resulted largely from less frequent gene duplications and/or a higher rate of gene loss after segmental duplication relative to genes in both low-copy-number families (LF; 3 10 copies per genome) and high-copy-number families (HF; >10 copies). Furthermore, we identified functions enriched in the NF gene set as compared with the HF genes. We found that NF genes were involved in essential biological processes shared by all plant lineages (e.g., photosynthesis and translation), as well as gene regulation and stress responses associated with phylogenetic diversification. In particular, our analysis of an Arabidopsis protein-protein interaction network revealed that hub proteins with the top 10% most connections were over-represented in the NF set relative to the HF set. This research highlights the roles that NF genes may play in evolutionary and functional genomics research.

  11. Independent Origin and Global Distribution of Distinct Plasmodium vivax Duffy Binding Protein Gene Duplications

    PubMed Central

    Hostetler, Jessica B.; Lo, Eugenia; Kanjee, Usheer; Amaratunga, Chanaki; Suon, Seila; Sreng, Sokunthea; Mao, Sivanna; Yewhalaw, Delenasaw; Mascarenhas, Anjali; Kwiatkowski, Dominic P.; Ferreira, Marcelo U.; Rathod, Pradipsinh K.; Yan, Guiyun; Fairhurst, Rick M.; Duraisingh, Manoj T.; Rayner, Julian C.

    2016-01-01

    Background Plasmodium vivax causes the majority of malaria episodes outside Africa, but remains a relatively understudied pathogen. The pathology of P. vivax infection depends critically on the parasite’s ability to recognize and invade human erythrocytes. This invasion process involves an interaction between P. vivax Duffy Binding Protein (PvDBP) in merozoites and the Duffy antigen receptor for chemokines (DARC) on the erythrocyte surface. Whole-genome sequencing of clinical isolates recently established that some P. vivax genomes contain two copies of the PvDBP gene. The frequency of this duplication is particularly high in Madagascar, where there is also evidence for P. vivax infection in DARC-negative individuals. The functional significance and global prevalence of this duplication, and whether there are other copy number variations at the PvDBP locus, is unknown. Methodology/Principal Findings Using whole-genome sequencing and PCR to study the PvDBP locus in P. vivax clinical isolates, we found that PvDBP duplication is widespread in Cambodia. The boundaries of the Cambodian PvDBP duplication differ from those previously identified in Madagascar, meaning that current molecular assays were unable to detect it. The Cambodian PvDBP duplication did not associate with parasite density or DARC genotype, and ranged in prevalence from 20% to 38% over four annual transmission seasons in Cambodia. This duplication was also present in P. vivax isolates from Brazil and Ethiopia, but not India. Conclusions/Significance PvDBP duplications are much more widespread and complex than previously thought, and at least two distinct duplications are circulating globally. The same duplication boundaries were identified in parasites from three continents, and were found at high prevalence in human populations where DARC-negativity is essentially absent. It is therefore unlikely that PvDBP duplication is associated with infection of DARC-negative individuals, but functional tests

  12. Tandem duplication PCR: an ultra-sensitive assay for the detection of internal tandem duplications of the FLT3 gene

    PubMed Central

    Lin, Ming-Tseh; Tseng, Li-Hui; Beierl, Katie; Hsieh, Antony; Thiess, Michele; Chase, Nadine; Stafford, Amanda; Levis, Mark J.; Eshleman, James R.; Gocke, Christopher D.

    2013-01-01

    Internal tandem duplication (ITD) mutations of the FLT3 gene have been associated with a poor prognosis in acute myeloid leukemia (AML). Detection of ITD-positive minor clones at the initial diagnosis and during the minimal residual disease (MRD) stage may be essential. We previously designed a delta-PCR strategy to improve the sensitivity to 0.1% ITD-positive leukemia cells and showed that minor mutants with an allele burden of less than 1% can be clinically significant. In this study, we report on tandem duplication PCR (TD-PCR), a modified inverse PCR assay, and demonstrate a limit of detection of a few molecules of ITD mutants. The TD-PCR was initially designed to confirm ITD mutation of an amplicon which was undetectable by capillary electrophoresis and was incidentally isolated by a molecular fraction collecting tool. Subsequently, TD-PCR detected ITD mutation in 2 of 77 patients previously reported as negative for ITD mutation by a standard PCR assay. TD-PCR can also potentially be applied to monitor MRD with high analytic sensitivity in a portion of ITD-positive AML patients. Further studies using TD-PCR to detect ITD mutants at diagnosis may clarify the clinical significance of those ITD mutants with extremely low allele burden. PMID:23846441

  13. Mosaic gene conversion after a tandem duplication of mtDNA sequence in Diomedeidae (albatrosses).

    PubMed

    Eda, Masaki; Kuro-o, Masaki; Higuchi, Hiroyoshi; Hasegawa, Hiroshi; Koike, Hiroko

    2010-04-01

    Although the tandem duplication of mitochondrial (mt) sequences, especially those of the control region (CR), has been detected in metazoan species, few studies have focused on the features of the duplicated sequence itself, such as the gene conversion rate, distribution patterns of the variation, and relative rates of evolution between the copies. To investigate the features of duplicated mt sequences, we partially sequenced the mt genome of 16 Phoebastria albatrosses belonging to three species (P. albatrus, P. nigripes, and P. immutabilis). More than 2,300 base pairs of tandemly-duplicated sequence were shared by all three species. The observed gene arrangement was shared in the three Phoebastria albatrosses and suggests that the duplication event occurred in the common ancestor of the three species. Most of the copies in each individual were identical or nearly identical, and were maintained through frequent gene conversions. By contrast, portions of CR domains I and III had different phylogenetic signals, suggesting that gene conversion had not occurred in those sections after the speciation of the three species. Several lines of data, including the heterogeneity of the rate of molecular evolution, nucleotide differences, and putative secondary structures, suggests that the two sequences in CR domain I are maintained through selection; however, additional studies into the mechanisms of gene conversion and mtDNA synthesis are required to confirm this hypothesis.

  14. Two complementary recessive genes in duplicated segments control etiolation in rice.

    PubMed

    Mao, Donghai; Yu, Huihui; Liu, Touming; Yang, Gaiyu; Xing, Yongzhong

    2011-02-01

    The main objective of this study was to identify the genes causing etiolation in a rice mutant, the thylakoids of which were scattered. Three populations were employed to map the genes for etiolation using bulked segregant analysis. Genetic analysis confirmed that etiolation was controlled by two recessive genes, et11 and et12, which were fine mapped to an approximately 147-kb region and an approximately 209-kb region on the short arms of chromosomes 11 and 12, respectively. Both regions were within the duplicated segments on chromosomes 11 and 12. They possessed a highly similar sequence of 38 kb at the locations of a pair of duplicated genes with protein sequences very similar to that of HCF152 in Arabidopsis that are required for the processing of chloroplast RNA. These genes are likely the candidates for et11 and et12. Expression profiling was used to compare the expression patterns of paralogs in the duplicated segments. Expression profiling indicated that the duplicated segments had been undergone concerted evolution, and a large number of the paralogs within the duplicated segments were functionally redundant like et11 and et12.

  15. The Use of Duplication-Generating Rearrangements for Studying Heterokaryon Incompatibility Genes in Neurospora

    PubMed Central

    Perkins, David D.

    1975-01-01

    Heterokaryon (vegetative) incompatibility, governing the fusion of somatic hyphal filaments to form stable heterokaryons, is of interest because of its widespread occurrence in fungi and its bearing on cellular recognition. Conventional investigations of the genetic basis of heterokaryon incompatibility in N. crassa are difficult because in commonly used stocks differences are present at several het loci, all with similar incompatibility phenotypes. This difficulty is overcome by using duplications (partial diploids) that are unlikely to contain more than one het locus. A phenotypically expressed incompatibility reaction occurs when unlike het alleles are present within the same somatic nucleus, and this parallels the heterokaryon incompatibility reaction that occurs when unlike alleles in different haploid nuclei are introduced into the same somatic hypha by mycelial fusion.—Nontandem duplications were used to confirm that the incompatibility reactions in heterokaryons and in duplications are alternate expressions of the same genes. This was demonstrated for three loci which had previously been established by conventional heterokaryon tests—het-e, het-c and mt. These were each obtained in duplications as recombinant meiotic segregants from crosses heterozygous for duplication-generating chromosome rearrangements. The particular method of producing the duplications is irrelevant so long as the incompatibility alleles are heterozygous.—The duplication technique has made it possible to determine easily the het-e and het-c genotypes of numerous laboratory and wild strains of unknown constitution. In laboratory strains both loci are represented simply by two alleles. Analysis of het-c is more complicated in some wild strains, where differences have been demonstrated at one or more additional het loci within the duplication used and multiple allelism is also possible.—The results show that the duplication method can be used to identify and map additional

  16. Heterogeneous expression pattern of tandem duplicated sHsps genes during fruit ripening in two tomato species

    NASA Astrophysics Data System (ADS)

    Arce, DP; Krsticevic, FJ; Ezpeleta, J.; Ponce, SD; Pratta, GR; Tapia, E.

    2016-04-01

    The small heat shock proteins (sHSPs) have been found to play a critical role in physiological stress conditions in protecting proteins from irreversible aggregation. To characterize the gene expression profile of four sHsps with a tandem gene structure arrangement in the domesticated Solanum lycopersicum (Heinz 1706) genome and its wild close relative Solanum pimpinellifolium (LA1589), differential gene expression analysis using RNA-Seq was conducted in three ripening stages in both cultivars fruits. Gene promoter analysis was performed to explain the heterogeneous pattern of gene expression found for these tandem duplicated sHsps. In silico analysis results contribute to refocus wet experiment analysis in tomato sHsp family proteins.

  17. Duplicate gene expression in allopolyploid Gossypium reveals two temporally distinct phases of expression evolution

    PubMed Central

    Flagel, Lex; Udall, Joshua; Nettleton, Dan; Wendel, Jonathan

    2008-01-01

    Background Polyploidy has played a prominent role in shaping the genomic architecture of the angiosperms. Through allopolyploidization, several modern Gossypium (cotton) species contain two divergent, although largely redundant genomes. Owing to this redundancy, these genomes can play host to an array of evolutionary processes that act on duplicate genes. Results We compared homoeolog (genes duplicated by polyploidy) contributions to the transcriptome of a natural allopolyploid and a synthetic interspecific F1 hybrid, both derived from a merger between diploid species from the Gossypium A-genome and D-genome groups. Relative levels of A- and D-genome contributions to the petal transcriptome were determined for 1,383 gene pairs. This comparison permitted partitioning of homoeolog expression biases into those arising from genomic merger and those resulting from polyploidy. Within allopolyploid Gossypium, approximately 24% of the genes with biased (unequal contributions from the two homoeologous copies) expression patterns are inferred to have arisen as a consequence of genomic merger, indicating that a substantial fraction of homoeolog expression biases occur instantaneously with hybridization. The remaining 76% of biased homoeologs reflect long-term evolutionary forces, such as duplicate gene neofunctionalization and subfunctionalization. Finally, we observed a greater number of genes biased toward the paternal D-genome and that expression biases have tended to increases during allopolyploid evolution. Conclusion Our results indicate that allopolyploidization entails significant homoeolog expression modulation, both immediately as a consequence of genomic merger, and secondarily as a result of long-term evolutionary transformations in duplicate gene expression. PMID:18416842

  18. Lineage-Specific Gene Duplication and Loss in Human and Great Ape Evolution

    PubMed Central

    MacLaren, Erik; Marshall, Kriste; Hahn, Gretchen; Meltesen, Lynne; Brenton, Matthew; Hink, Raquel; Burgers, Sonya; Hernandez-Boussard, Tina; Karimpour-Fard, Anis; Glueck, Deborah; McGavran, Loris; Berry, Rebecca

    2004-01-01

    Given that gene duplication is a major driving force of evolutionary change and the key mechanism underlying the emergence of new genes and biological processes, this study sought to use a novel genome-wide approach to identify genes that have undergone lineage-specific duplications or contractions among several hominoid lineages. Interspecies cDNA array-based comparative genomic hybridization was used to individually compare copy number variation for 39,711 cDNAs, representing 29,619 human genes, across five hominoid species, including human. We identified 1,005 genes, either as isolated genes or in clusters positionally biased toward rearrangement-prone genomic regions, that produced relative hybridization signals unique to one or more of the hominoid lineages. Measured as a function of the evolutionary age of each lineage, genes showing copy number expansions were most pronounced in human (134) and include a number of genes thought to be involved in the structure and function of the brain. This work represents, to our knowledge, the first genome-wide gene-based survey of gene duplication across hominoid species. The genes identified here likely represent a significant majority of the major gene copy number changes that have occurred over the past 15 million years of human and great ape evolution and are likely to underlie some of the key phenotypic characteristics that distinguish these species. PMID:15252450

  19. Multispecies Analysis of Expression Pattern Diversification in the Recently Expanded Insect Ly6 Gene Family

    PubMed Central

    Tanaka, Kohtaro; Hazbun, Alexis; Hijazi, Assia; Vreede, Barbara; Sucena, Élio

    2015-01-01

    Gene families often consist of members with diverse expression domains reflecting their functions in a wide variety of tissues. However, how the expression of individual members, and thus their tissue-specific functions, diversified during the course of gene family expansion is not well understood. In this study, we approached this question through the analysis of the duplication history and transcriptional evolution of a rapidly expanding subfamily of insect Ly6 genes. We analyzed different insect genomes and identified seven Ly6 genes that have originated from a single ancestor through sequential duplication within the higher Diptera. We then determined how the original embryonic expression pattern of the founding gene diversified by characterizing its tissue-specific expression in the beetle Tribolium castaneum, the butterfly Bicyclus anynana, and the mosquito Anopheles stephensi and those of its duplicates in three higher dipteran species, representing various stages of the duplication history (Megaselia abdita, Ceratitis capitata, and Drosophila melanogaster). Our results revealed that frequent neofunctionalization episodes contributed to the increased expression breadth of this subfamily and that these events occurred after duplication and speciation events at comparable frequencies. In addition, at each duplication node, we consistently found asymmetric expression divergence. One paralog inherited most of the tissue-specificities of the founder gene, whereas the other paralog evolved drastically reduced expression domains. Our approach attests to the power of combining a well-established duplication history with a comprehensive coverage of representative species in acquiring unequivocal information about the dynamics of gene expression evolution in gene families. PMID:25743545

  20. Gene duplication can impart fragility, not robustness, in the yeast protein interaction network.

    PubMed

    Diss, Guillaume; Gagnon-Arsenault, Isabelle; Dion-Coté, Anne-Marie; Vignaud, Hélène; Ascencio, Diana I; Berger, Caroline M; Landry, Christian R

    2017-02-10

    The maintenance of duplicated genes is thought to protect cells from genetic perturbations, but the molecular basis of this robustness is largely unknown. By measuring the interaction of yeast proteins with their partners in wild-type cells and in cells lacking a paralog, we found that 22 out of 56 paralog pairs compensate for the lost interactions. An equivalent number of pairs exhibit the opposite behavior and require each other's presence for maintaining their interactions. These dependent paralogs generally interact physically, regulate each other's abundance, and derive from ancestral self-interacting proteins. This reveals that gene duplication may actually increase mutational fragility instead of robustness in a large number of cases.

  1. An Efficient Algorithm for Gene/Species Trees Parsimonious Reconciliation with Losses, Duplications and Transfers

    NASA Astrophysics Data System (ADS)

    Doyon, Jean-Philippe; Scornavacca, Celine; Gorbunov, K. Yu.; Szöllősi, Gergely J.; Ranwez, Vincent; Berry, Vincent

    Tree reconciliation methods aim at estimating the evolutionary events that cause discrepancy between gene trees and species trees. We provide a discrete computational model that considers duplications, transfers and losses of genes. The model yields a fast and exact algorithm to infer time consistent and most parsimonious reconciliations. Then we study the conditions under which parsimony is able to accurately infer such events. Overall, it performs well even under realistic rates, transfers being in general less accurately recovered than duplications. An implementation is freely available at http://www.atgc-montpellier.fr/MPR.

  2. New Genes Originated via Multiple Recombinational Pathways in the β-Globin Gene Family of Rodents

    PubMed Central

    Hoffmann, Federico G.; Opazo, Juan C.; Storz, Jay F.

    2008-01-01

    Species differences in the size or membership composition of multigene families can be attributed to lineage-specific additions of new genes via duplication, losses of genes via deletion or inactivation, and the creation of chimeric genes via domain shuffling or gene fusion. In principle, it should be possible to infer the recombinational pathways responsible for each of these different types of genomic change by conducting detailed comparative analyses of genomic sequence data. Here, we report an attempt to unravel the complex evolutionary history of the β-globin gene family in a taxonomically diverse set of rodent species. The main objectives were: 1) to characterize the genomic structure of the β-globin gene cluster of rodents; 2) to assign orthologous and paralogous relationships among duplicate copies of β-like globin genes; and 3) to infer the specific recombinational pathways responsible for gene duplications, gene deletions, and the creation of chimeric fusion genes. Results of our comparative genomic analyses revealed that variation in gene family size among rodent species is mainly attributable to the differential gain and loss of later expressed β-globin genes via unequal crossing-over. However, two distinct recombinational mechanisms were implicated in the creation of chimeric fusion genes. In muroid rodents, a chimeric γ/ε fusion gene was created by unequal crossing-over between the embryonic ε- and γ-globin genes. Interestingly, this γ/ε fusion gene was generated in the same fashion as the “anti-Lepore” 5′-δ-(β/δ)-β-3′ duplication mutant in humans (the reciprocal exchange product of the pathological hemoglobin Lepore deletion mutant). By contrast, in the house mouse, Mus musculus, a chimeric β/δ fusion pseudogene was created by a β-globin → δ-globin gene conversion event. Although the γ/ε and β/δ fusion genes share a similar chimeric gene structure, they originated via completely different recombinational pathways. PMID

  3. Functional Characterization of Duplicated SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1-Like Genes in Petunia

    PubMed Central

    Preston, Jill C.; Jorgensen, Stacy A.; Jha, Suryatapa G.

    2014-01-01

    Flowering time is strictly controlled by a combination of internal and external signals that match seed set with favorable environmental conditions. In the model plant species Arabidopsis thaliana (Brassicaceae), many of the genes underlying development and evolution of flowering have been discovered. However, much remains unknown about how conserved the flowering gene networks are in plants with different growth habits, gene duplication histories, and distributions. Here we functionally characterize three homologs of the flowering gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) in the short-lived perennial Petunia hybrida (petunia, Solanaceae). Similar to A. thaliana soc1 mutants, co-silencing of duplicated petunia SOC1-like genes results in late flowering. This phenotype is most severe when all three SOC1-like genes are silenced. Furthermore, expression levels of the SOC1-like genes UNSHAVEN (UNS) and FLORAL BINDING PROTEIN 21 (FBP21), but not FBP28, are positively correlated with developmental age. In contrast to A. thaliana, petunia SOC1-like gene expression did not increase with longer photoperiods, and FBP28 transcripts were actually more abundant under short days. Despite evidence of functional redundancy, differential spatio-temporal expression data suggest that SOC1-like genes might fine-tune petunia flowering in response to photoperiod and developmental stage. This likely resulted from modification of SOC1-like gene regulatory elements following recent duplication, and is a possible mechanism to ensure flowering under both inductive and non-inductive photoperiods. PMID:24787903

  4. Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses

    PubMed Central

    Mondragón-Palomino, Mariana; Hiese, Luisa; Härter, Andrea; Koch, Marcus A; Theißen, Günter

    2009-01-01

    Background Positive selection is recognized as the prevalence of nonsynonymous over synonymous substitutions in a gene. Models of the functional evolution of duplicated genes consider neofunctionalization as key to the retention of paralogues. For instance, duplicate transcription factors are specifically retained in plant and animal genomes and both positive selection and transcriptional divergence appear to have played a role in their diversification. However, the relative impact of these two factors has not been systematically evaluated. Class B MADS-box genes, comprising DEF-like and GLO-like genes, encode developmental transcription factors essential for establishment of perianth and male organ identity in the flowers of angiosperms. Here, we contrast the role of positive selection and the known divergence in expression patterns of genes encoding class B-like MADS-box transcription factors from monocots, with emphasis on the family Orchidaceae and the order Poales. Although in the monocots these two groups are highly diverse and have a strongly canalized floral morphology, there is no information on the role of positive selection in the evolution of their distinctive flower morphologies. Published research shows that in Poales, class B-like genes are expressed in stamens and in lodicules, the perianth organs whose identity might also be specified by class B-like genes, like the identity of the inner tepals of their lily-like relatives. In orchids, however, the number and pattern of expression of class B-like genes have greatly diverged. Results The DEF-like genes from Orchidaceae form four well-supported, ancient clades of orthologues. In contrast, orchid GLO-like genes form a single clade of ancient orthologues and recent paralogues. DEF-like genes from orchid clade 2 (OMADS3-like genes) are under less stringent purifying selection than the other orchid DEF-like and GLO-like genes. In comparison with orchids, purifying selection was less stringent in DEF

  5. Genome-wide analysis of homeobox genes from Mesobuthus martensii reveals Hox gene duplication in scorpions.

    PubMed

    Di, Zhiyong; Yu, Yao; Wu, Yingliang; Hao, Pei; He, Yawen; Zhao, Huabin; Li, Yixue; Zhao, Guoping; Li, Xuan; Li, Wenxin; Cao, Zhijian

    2015-06-01

    Homeobox genes belong to a large gene group, which encodes the famous DNA-binding homeodomain that plays a key role in development and cellular differentiation during embryogenesis in animals. Here, one hundred forty-nine homeobox genes were identified from the Asian scorpion, Mesobuthus martensii (Chelicerata: Arachnida: Scorpiones: Buthidae) based on our newly assembled genome sequence with approximately 248 × coverage. The identified homeobox genes were categorized into eight classes including 82 families: 67 ANTP class genes, 33 PRD genes, 11 LIM genes, five POU genes, six SINE genes, 14 TALE genes, five CUT genes, two ZF genes and six unclassified genes. Transcriptome data confirmed that more than half of the genes were expressed in adults. The homeobox gene diversity of the eight classes is similar to the previously analyzed Mandibulata arthropods. Interestingly, it is hypothesized that the scorpion M. martensii may have two Hox clusters. The first complete genome-wide analysis of homeobox genes in Chelicerata not only reveals the repertoire of scorpion, arachnid and chelicerate homeobox genes, but also shows some insights into the evolution of arthropod homeobox genes.

  6. Becker Muscular Dystrophy (BMD) caused by duplication of exons 3-6 of the dystrophin gene presenting as dilated cardiomyopathy

    SciTech Connect

    Tsai, A.C.; Allingham-Hawkins, D.J.; Becker, L.

    1994-09-01

    X-linked dilated cardiomyopathy (XLCM) is a progressive myocardial disease presenting with congestive heart failure in teenage males without clinical signs of skeletal myopathy. Tight linkage of XLCM to the DMD locus has been demonstrated; it has been suggested that, at least in some families, XLCM is a {open_quotes}dystrophinopathy.{close_quotes} We report a 14-year-old boy who presented with acute heart failure due to dilated cardiomyopathy. He had no history of muscle weakness, but physical examination revealed pseudohypertrophy of the calf muscles. He subsequently received a heart transplantation. Family history was negative. Serum CK level at the time of diagnosis was 10,416. Myocardial biopsy showed no evidence of carditis. Dystrophin staining of cardiac and skeletal muscle with anti-sera to COOH and NH{sub 2}termini showed a patchy distribution of positivity suggestive of Becker muscular dystrophy. Analysis of 18 of the 79 dystrophin exons detected a duplication that included exons 3-6. The proband`s mother has an elevated serum CK and was confirmed to be a carrier of the same duplication. A mutation in the muscle promotor region of the dystrophin gene has been implicated in the etiology of SLCM. However, Towbin et al. (1991) argued that other 5{prime} mutations in the dystrophin gene could cause selective cardiomyopathy. The findings in our patient support the latter hypothesis. This suggests that there are multiple regions in the dystrophin gene which, when disrupted, can cause isolated dilated cardiomyopathy.

  7. Segmental Duplication, Microinversion, and Gene Loss Associated with a Complex Inversion Breakpoint Region in Drosophila

    PubMed Central

    Calvete, Oriol; González, Josefa; Betrán, Esther; Ruiz, Alfredo

    2012-01-01

    Chromosomal inversions are usually portrayed as simple two-breakpoint rearrangements changing gene order but not gene number or structure. However, increasing evidence suggests that inversion breakpoints may often have a complex structure and entail gene duplications with potential functional consequences. Here, we used a combination of different techniques to investigate the breakpoint structure and the functional consequences of a complex rearrangement fixed in Drosophila buzzatii and comprising two tandemly arranged inversions sharing the middle breakpoint: 2m and 2n. By comparing the sequence in the breakpoint regions between D. buzzatii (inverted chromosome) and D. mojavensis (noninverted chromosome), we corroborate the breakpoint reuse at the molecular level and infer that inversion 2m was associated with a duplication of a ∼13 kb segment and likely generated by staggered breaks plus repair by nonhomologous end joining. The duplicated segment contained the gene CG4673, involved in nuclear transport, and its two nested genes CG5071 and CG5079. Interestingly, we found that other than the inversion and the associated duplication, both breakpoints suffered additional rearrangements, that is, the proximal breakpoint experienced a microinversion event associated at both ends with a 121-bp long duplication that contains a promoter. As a consequence of all these different rearrangements, CG5079 has been lost from the genome, CG5071 is now a single copy nonnested gene, and CG4673 has a transcript ∼9 kb shorter and seems to have acquired a more complex gene regulation. Our results illustrate the complex effects of chromosomal rearrangements and highlight the need of complementing genomic approaches with detailed sequence-level and functional analyses of breakpoint regions if we are to fully understand genome structure, function, and evolutionary dynamics. PMID:22328714

  8. Inferring the Recent Duplication History of a Gene Cluster

    NASA Astrophysics Data System (ADS)

    Song, Giltae; Zhang, Louxin; Vinař, Tomáš; Miller, Webb

    Much important evolutionary activity occurs in gene clusters, where a copy of a gene may be free to evolve new functions. Computational methods to extract evolutionary information from sequence data for such clusters are currently imperfect, in part because accurate sequence data are often lacking in these genomic regions, making the existing methods difficult to apply. We describe a new method for reconstructing the recent evolutionary history of gene clusters. The method’s performance is evaluated on simulated data and on actual human gene clusters.

  9. Gene Duplication and Gene Expression Changes Play a Role in the Evolution of Candidate Pollen Feeding Genes in Heliconius Butterflies.

    PubMed

    Smith, Gilbert; Macias-Muñoz, Aide; Briscoe, Adriana D

    2016-09-02

    Heliconius possess a unique ability among butterflies to feed on pollen. Pollen feeding significantly extends their lifespan, and is thought to have been important to the diversification of the genus. We used RNA sequencing to examine feeding-related gene expression in the mouthparts of four species of Heliconius and one nonpollen feeding species, Eueides isabella We hypothesized that genes involved in morphology and protein metabolism might be upregulated in Heliconius because they have longer proboscides than Eueides, and because pollen contains more protein than nectar. Using de novo transcriptome assemblies, we tested these hypotheses by comparing gene expression in mouthparts against antennae and legs. We first looked for genes upregulated in mouthparts across all five species and discovered several hundred genes, many of which had functional annotations involving metabolism of proteins (cocoonase), lipids, and carbohydrates. We then looked specifically within Heliconius where we found eleven common upregulated genes with roles in morphology (CPR cuticle proteins), behavior (takeout-like), and metabolism (luciferase-like). Closer examination of these candidates revealed that cocoonase underwent several duplications along the lineage leading to heliconiine butterflies, including two Heliconius-specific duplications. Luciferase-like genes also underwent duplication within lepidopterans, and upregulation in Heliconius mouthparts. Reverse-transcription PCR confirmed that three cocoonases, a peptidase, and one luciferase-like gene are expressed in the proboscis with little to no expression in labial palps and salivary glands. Our results suggest pollen feeding, like other dietary specializations, was likely facilitated by adaptive expansions of preexisting genes-and that the butterfly proboscis is involved in digestive enzyme production.

  10. Alcohol Dehydrogenase in the Diploid Plant STEPHANOMERIA EXIGUA (Compositae): Gene Duplication, Mode of Inheritance and Linkage

    PubMed Central

    Roose, M. L.; Gottlieb, L. D.

    1980-01-01

    Study of the biochemical genetics of alcohol dehydrogenase (ADH) in the annual plant Stephanomeria exigua (Compositae) revealed that the isozymes are specified by a small family of tightly linked structural genes. One set of ADH isozymes (ADH-1) was induced in roots by flooding, and was also expressed in thickened unflooded tap roots, stems, ovaries and seeds. As in other plants, the enzymes are dimeric and form homo- and heterodimers. An electrophoretic survey of ADH-1 phenotypes in two natural populations revealed seven different ADH-1 homodimers in various phenotypes having one to eight enzyme bands. Genetic analysis of segregations from crosses involving 59 plants showed that the ADH-1 isozymes are inherited as a single Mendelian unit, Adh1. Adh1 is polymorphic for forms that specify one, two, or three different ADH-1 subunits (which combine to form homo- and heterodimers), and are expressed co-dominantly in all genotypic combinations. Staining intensity of enzymes extracted from various homozygous and heterozygous plants indicated that the different subunit types specified by Adh1 are produced in approximately equal amounts. These observations suggest that Adh1 is a compound locus consisting of one to several tightly linked (0 recombinants among 579 testcross progeny), coordinately expressed structural genes. The genes in the two triplications also occur in various duplicate complexes and thus could have originated via unequal crossing over. The ADH-2 isozyme found in pollen and seeds is apparently specified by a different gene, Adh2. Adh1 and Adh2 are tightly linked (0 recombinants among 81 testcross progeny). PMID:17249032

  11. A possible role of DNA methylation in functional divergence of a fast evolving duplicate gene encoding odorant binding protein 11 in the honeybee.

    PubMed

    Kucharski, R; Maleszka, J; Maleszka, R

    2016-06-29

    Although gene duplication is seen as the main path to evolution of new functions, molecular mechanisms by which selection favours the gain versus loss of newly duplicated genes and minimizes the fixation of pseudo-genes are not well understood. Here, we investigate in detail a duplicate honeybee gene obp11 belonging to a fast evolving insect gene family encoding odorant binding proteins (OBPs). We report that obp11 is expressed only in female bees in rare antennal sensilla basiconica in contrast to its tandem partner obp10 that is expressed in the brain in both females and males (drones). Unlike all other obp genes in the honeybee, obp11 is methylated suggesting that functional diversification of obp11 and obp10 may have been driven by an epigenetic mechanism. We also show that increased methylation in drones near one donor splice site that correlates with higher abundance of a transcript variant encoding a truncated OBP11 protein is one way of controlling its contrasting expression. Our data suggest that like in mammals and plants, DNA methylation in insects may contribute to functional diversification of proteins produced from duplicated genes, in particular to their subfunctionalization by generating complementary patterns of expression.

  12. Gene Duplication and Gene Expression Changes Play a Role in the Evolution of Candidate Pollen Feeding Genes in Heliconius Butterflies

    PubMed Central

    Smith, Gilbert; Macias-Muñoz, Aide; Briscoe, Adriana D.

    2016-01-01

    Heliconius possess a unique ability among butterflies to feed on pollen. Pollen feeding significantly extends their lifespan, and is thought to have been important to the diversification of the genus. We used RNA sequencing to examine feeding-related gene expression in the mouthparts of four species of Heliconius and one nonpollen feeding species, Eueides isabella. We hypothesized that genes involved in morphology and protein metabolism might be upregulated in Heliconius because they have longer proboscides than Eueides, and because pollen contains more protein than nectar. Using de novo transcriptome assemblies, we tested these hypotheses by comparing gene expression in mouthparts against antennae and legs. We first looked for genes upregulated in mouthparts across all five species and discovered several hundred genes, many of which had functional annotations involving metabolism of proteins (cocoonase), lipids, and carbohydrates. We then looked specifically within Heliconius where we found eleven common upregulated genes with roles in morphology (CPR cuticle proteins), behavior (takeout-like), and metabolism (luciferase-like). Closer examination of these candidates revealed that cocoonase underwent several duplications along the lineage leading to heliconiine butterflies, including two Heliconius-specific duplications. Luciferase-like genes also underwent duplication within lepidopterans, and upregulation in Heliconius mouthparts. Reverse-transcription PCR confirmed that three cocoonases, a peptidase, and one luciferase-like gene are expressed in the proboscis with little to no expression in labial palps and salivary glands. Our results suggest pollen feeding, like other dietary specializations, was likely facilitated by adaptive expansions of preexisting genes—and that the butterfly proboscis is involved in digestive enzyme production. PMID:27553646

  13. Expansion of transducin subunit gene families in early vertebrate tetraploidizations.

    PubMed

    Lagman, David; Sundström, Görel; Ocampo Daza, Daniel; Abalo, Xesús M; Larhammar, Dan

    2012-10-01

    Hundreds of gene families expanded in the early vertebrate tetraploidizations including many gene families in the phototransduction cascade. We have investigated the evolution of the heterotrimeric G-proteins of photoreceptors, the transducins, in relation to these events using both phylogenetic analyses and synteny comparisons. Three alpha subunit genes were identified in amniotes and the coelacanth, GNAT1-3; two of these were identified in amphibians and teleost fish, GNAT1 and GNAT2. Most tetrapods have four beta genes, GNB1-4, and teleosts have additional duplicates. Finally, three gamma genes were identified in mammals, GNGT1, GNG11 and GNGT2. Of these, GNGT1 and GNGT2 were found in the other vertebrates. In frog and zebrafish additional duplicates of GNGT2 were identified. Our analyses show all three transducin families expanded during the early vertebrate tetraploidizations and the beta and gamma families gained additional copies in the teleost-specific genome duplication. This suggests that the tetraploidizations contributed to visual specialisations.

  14. Orsomucoid: A new variant and additional duplicated ORM1 gene in Qatari population

    SciTech Connect

    Sebetan, I.M.; Alali, K.A.; Alzaman, A.

    1994-09-01

    A new genetically determined ORM2 variant and additional duplicated ORM1 gene were observed in Qatari population using isoelectric focusing in ultra thin layer polyacrylamide gels. The studied population samples indicate occurence of six ORM1 alleles and three ORM2 ones. A simple reliable method for separation of orsomucoid variations with comparison of different reported methods will be presented.

  15. Gene turnover and differential retention in the relaxin/insulin-like gene family in primates.

    PubMed

    Arroyo, José Ignacio; Hoffmann, Federico G; Opazo, Juan C

    2012-06-01

    The relaxin/insulin-like gene family is related to the insulin gene family, and includes two separate types of peptides: relaxins (RLNs) and insulin-like peptides (INSLs) that perform a variety of physiological roles including testicular descent, growth and differentiation of the mammary glands, trophoblast development, and cell differentiation. In vertebrates, these genes are found on three separate genomic loci, and in mammals, variation in the number and nature of genes in this family is mostly restricted to the Relaxin Family Locus B. For example, this locus contains a single copy of RLN in platypus and opossum, whereas it contains copies of the INSL6, INSL4, RLN2 and RLN1 genes in human and chimp. The main objective of this research is to characterize changes in the size and membership composition of the RLN/INSL gene family in primates, reconstruct the history of the RLN/INSL genes of primates, and test competing evolutionary scenarios regarding the origin of INSL4 and of the duplicated copies of the RLN gene of apes. Our results show that the relaxin/INSL-like gene family of primates has had a more dynamic evolutionary history than previously thought, including several examples of gene duplications and losses which are consistent with the predictions of the birth-and-death model of gene family evolution. In particular, we found that the differential retention of relatively old paralogs played a key role in shaping the gene complement of this family in primates. Two examples of this phenomenon are the origin of the INSL4 gene of catarrhines (the group that includes Old World monkeys and apes), and of the duplicate RLN1 and RLN2 paralogs of apes. In the case of INSL4, comparative genomics and phylogenetic analyses indicate that the origin of this gene, which was thought to represent a catarrhine-specific evolutionary innovation, is as old as the split between carnivores and primates, which took place approximately 97 million years ago. In addition, in the case

  16. Ancestral gene duplication enabled the evolution of multifunctional cellulases in stick insects (Phasmatodea).

    PubMed

    Shelomi, Matan; Heckel, David G; Pauchet, Yannick

    2016-04-01

    The Phasmatodea (stick insects) have multiple, endogenous, highly expressed copies of glycoside hydrolase family 9 (GH9) genes. The purpose for retaining so many was unknown. We cloned and expressed the enzymes in transfected insect cell lines, and tested the individual proteins against different plant cell wall component poly- and oligosaccharides. Nearly all isolated enzymes were active against carboxymethylcellulose, however most could also degrade glucomannan, and some also either xylan or xyloglucan. The latter two enzyme groups were each monophyletic, suggesting the evolution of these novel substrate specificities in an early ancestor of the order. Such enzymes are highly unusual for Metazoa, for which no xyloglucanases had been reported. Phasmatodea gut extracts could degrade multiple plant cell wall components fully into sugar monomers, suggesting that enzymatic breakdown of plant cell walls by the entire Phasmatodea digestome may contribute to the Phasmatodea nutritional budget. The duplication and neofunctionalization of GH9s in the ancestral Phasmatodea may have enabled them to specialize as folivores and diverge from their omnivorous ancestors. The structural changes enabling these unprecedented activities in the cellulases require further study.

  17. Effects of whole genome duplication on cell size and gene expression in mouse embryonic stem cells

    PubMed Central

    IMAI, Hiroyuki; FUJII, Wataru; KUSAKABE, Ken Takeshi; KISO, Yasuo; KANO, Kiyoshi

    2016-01-01

    Alterations in ploidy tend to influence cell physiology, which in the long-term, contribute to species adaptation and evolution. Polyploid cells are observed under physiological conditions in the nerve and liver tissues, and in tumorigenic processes. Although tetraploid cells have been studied in mammalian cells, the basic characteristics and alterations caused by whole genome duplication are still poorly understood. The purpose of this study was to acquire basic knowledge about the effect of whole genome duplication on the cell cycle, cell size, and gene expression. Using flow cytometry, we demonstrate that cell cycle subpopulations in mouse tetraploid embryonic stem cells (TESCs) were similar to those in embryonic stem cells (ESCs). We performed smear preparations and flow cytometric analysis to identify cell size alterations. These indicated that the relative cell volume of TESCs was approximately 2.2–2.5 fold that of ESCs. We also investigated the effect of whole genome duplication on the expression of housekeeping and pluripotency marker genes using quantitative real-time PCR with external RNA. We found that the target transcripts were 2.2 times more abundant in TESCs than those in ESCs. This indicated that gene expression and cell volume increased in parallel. Our findings suggest the existence of a homeostatic mechanism controlling the cytoplasmic transcript levels in accordance with genome volume changes caused by whole genome duplication. PMID:27569766

  18. Duplication and diversification in the APETALA1/FRUITFULL floral homeotic gene lineage: implications for the evolution of floral development.

    PubMed Central

    Litt, Amy; Irish, Vivian F

    2003-01-01

    Phylogenetic analyses of angiosperm MADS-box genes suggest that this gene family has undergone multiple duplication events followed by sequence divergence. To determine when such events have taken place and to understand the relationships of particular MADS-box gene lineages, we have identified APETALA1/FRUITFULL-like MADS-box genes from a variety of angiosperm species. Our phylogenetic analyses show two gene clades within the core eudicots, euAP1 (including Arabidopsis APETALA1 and Antirrhinum SQUAMOSA) and euFUL (including Arabidopsis FRUITFULL). Non-core eudicot species have only sequences similar to euFUL genes (FUL-like). The predicted protein products of euFUL and FUL-like genes share a conserved C-terminal motif. In contrast, predicted products of members of the euAP1 gene clade contain a different C terminus that includes an acidic transcription activation domain and a farnesylation signal. Sequence analyses indicate that the euAP1 amino acid motifs may have arisen via a translational frameshift from the euFUL/FUL-like motif. The euAP1 gene clade includes key regulators of floral development that have been implicated in the specification of perianth identity. However, the presence of euAP1 genes only in core eudicots suggests that there may have been changes in mechanisms of floral development that are correlated with the fixation of floral structure seen in this clade. PMID:14573491

  19. Polytomy refinement for the correction of dubious duplications in gene trees

    PubMed Central

    Lafond, Manuel; El-Mabrouk, Nadia

    2014-01-01

    Motivation: Large-scale methods for inferring gene trees are error-prone. Correcting gene trees for weakly supported features often results in non-binary trees, i.e. trees with polytomies, thus raising the natural question of refining such polytomies into binary trees. A feature pointing toward potential errors in gene trees are duplications that are not supported by the presence of multiple gene copies. Results: We introduce the problem of refining polytomies in a gene tree while minimizing the number of created non-apparent duplications in the resulting tree. We show that this problem can be described as a graph-theoretical optimization problem. We provide a bounded heuristic with guaranteed optimality for well-characterized instances. We apply our algorithm to a set of ray-finned fish gene trees from the Ensembl database to illustrate its ability to correct dubious duplications. Availability and implementation: The C++ source code for the algorithms and simulations described in the article are available at http://www-ens.iro.umontreal.ca/~lafonman/software.php. Contact: lafonman@iro.umontreal.ca or mabrouk@iro.umontreal.ca Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25161242

  20. Evolutionary mechanisms driving the evolution of a large polydnavirus gene family coding for protein tyrosine phosphatases

    PubMed Central

    2012-01-01

    Background Gene duplications have been proposed to be the main mechanism involved in genome evolution and in acquisition of new functions. Polydnaviruses (PDVs), symbiotic viruses associated with parasitoid wasps, are ideal model systems to study mechanisms of gene duplications given that PDV genomes consist of virulence genes organized into multigene families. In these systems the viral genome is integrated in a wasp chromosome as a provirus and virus particles containing circular double-stranded DNA are injected into the parasitoids’ hosts and are essential for parasitism success. The viral virulence factors, organized in gene families, are required collectively to induce host immune suppression and developmental arrest. The gene family which encodes protein tyrosine phosphatases (PTPs) has undergone spectacular expansion in several PDV genomes with up to 42 genes. Results Here, we present strong indications that PTP gene family expansion occurred via classical mechanisms: by duplication of large segments of the chromosomally integrated form of the virus sequences (segmental duplication), by tandem duplications within this form and by dispersed duplications. We also propose a novel duplication mechanism specific to PDVs that involves viral circle reintegration into the wasp genome. The PTP copies produced were shown to undergo conservative evolution along with episodes of adaptive evolution. In particular recently produced copies have undergone positive selection in sites most likely involved in defining substrate selectivity. Conclusion The results provide evidence about the dynamic nature of polydnavirus proviral genomes. Classical and PDV-specific duplication mechanisms have been involved in the production of new gene copies. Selection pressures associated with antagonistic interactions with parasitized hosts have shaped these genes used to manipulate lepidopteran physiology with evidence for positive selection involved in adaptation to host targets. PMID

  1. The dynamics of gene duplication and transposons in microbial genome evolution

    NASA Astrophysics Data System (ADS)

    Chia, Nicholas; Goldenfeld, Nigel

    2010-03-01

    Evidence indicates that new functional genes emerge from a process of gene duplication coupled with selection for a novel function. Recently, Bergthorsson et al. proposed a model of continuous selection in order to describe this process. Here, we examine their proposed evolutionary scheme, by modeling gene evolution using a stochastic simulation. Our results indicate that this model, and a related one that includes horizontal gene transfer, can account for the distribution of transposons in microbial genomes, and reproduce the observed environmentally-driven spatial dependence of transposon density in marine bacteria.

  2. Regulatory circuit rewiring and functional divergence of the duplicate admp genes in dorsoventral axial patterning.

    PubMed

    Chang, Yi-Cheng; Pai, Chih-Yu; Chen, Yi-Chih; Ting, Hsiu-Chi; Martinez, Pedro; Telford, Maximilian J; Yu, Jr-Kai; Su, Yi-Hsien

    2016-02-01

    The spatially opposed expression of Antidorsalizing morphogenetic protein (Admp) and BMP signals controls dorsoventral (DV) polarity across Bilateria and hence represents an ancient regulatory circuit. Here, we show that in addition to the conserved admp1 that constitutes the ancient circuit, a second admp gene (admp2) is present in Ambulacraria (Echinodermata+Hemichordata) and two marine worms belonging to Xenoturbellida and Acoelomorpha. The phylogenetic distribution implies that the two admp genes were duplicated in the Bilaterian common ancestor and admp2 was subsequently lost in chordates and protostomes. We show that the ambulacrarian admp1 and admp2 are under opposite transcriptional control by BMP signals and knockdown of Admps in sea urchins impaired their DV polarity. Over-expression of either Admps reinforced BMP signaling but resulted in different phenotypes in the sea urchin embryo. Our study provides an excellent example of signaling circuit rewiring and protein functional changes after gene duplications.

  3. Duplication of acetylcholinesterase gene in diamondback moth strains with different sensitivities to acephate.

    PubMed

    Sonoda, Shoji; Shi, Xueyan; Song, Dunlun; Liang, Pei; Gao, Xiwu; Zhang, Youjun; Li, Jianhong; Liu, Yong; Li, Ming; Matsumura, Masaya; Sanada-Morimura, Sachiyo; Minakuchi, Chieka; Tanaka, Toshiharu; Miyata, Tadashi

    2014-05-01

    This study examined the acetylcholinesterase 1 gene (AChE1) in Plutella xylostella strains with different sensitivities to acephate. Multiple haplotypes of the gene were found in the field-collected strains including distinct haplotypes carrying one or both previously reported mutations (A298S and G324A). Moreover, sequencing results indicated the presence of duplicated copies of the gene in the field-collected strains. No correlation was found between copy numbers of AChE1 and levels of resistance to acephate suggesting that extensive AChE1 duplication is not a major resistance factor at least in some P. xylostella strains. Proportions of the A298S and G324A mutations showed no correlation with levels of resistance to acephate. This suggests that acephate resistance of P. xylostella is complex and cannot be evaluated based on the AChE1 copy number or proportions of the resistance mutations alone.

  4. Evolution and Expression of Tandem Duplicated Maize Flavonol Synthase Genes

    PubMed Central

    Falcone Ferreyra, María Lorena; Casas, María Isabel; Questa, Julia Irene; Herrera, Andrea Lorena; DeBlasio, Stacy; Wang, Jing; Jackson, David; Grotewold, Erich; Casati, Paula

    2012-01-01

    Flavonoids are specialized compounds widely distributed and with diverse functions throughout the plant kingdom and with several benefits for human health. In particular, flavonols, synthesized by flavonol synthase (FLS), protect plants against UV-B radiation and are essential for male fertility in maize and other plants. We have recently characterized a UV-B inducible ZmFLS1, corresponding to the first to be described in monocot plants. Interestingly, the new assembly of the B73 maize genome revealed the presence of a second putative FLS gene (ZmFLS2), with very high identity with ZmFLS1. ZmFLSs expression was analyzed in different maize tissues, and by combining electrophoretic mobility shift assays and transient expression experiments, we show that both genes are direct targets of anthocyanin (C1/PL1 + R/B) and 3-deoxy flavonoid (P1) transcriptional regulators. ZmFLS expression analyses show higher levels of both transcripts in high altitude landraces than inbred lines, and both genes are regulated by UV-B radiation in all lines analyzed. Moreover, the high sequence conservation of the ZmFLS promoters between maize lines suggests that the differences observed in ZmFLS expression are due to allelic variations in the transcription factors that regulate their activities. Finally, we generated pFLS1::FLS1-RFP transgenic plants and analyzed ZmFLS1 expression in different maize tissues; we found that this enzyme is localized in the ER and the perinuclear region. PMID:22654889

  5. Mitochondrial Genomes of Kinorhyncha: trnM Duplication and New Gene Orders within Animals

    PubMed Central

    Popova, Olga V.; Mikhailov, Kirill V.; Nikitin, Mikhail A.; Logacheva, Maria D.; Penin, Aleksey A.; Muntyan, Maria S.; Kedrova, Olga S.; Petrov, Nikolai B.; Panchin, Yuri V.

    2016-01-01

    Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha—an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the early-branching lineages of Ecdysozoa, and their mitochondrial genomes may be important for resolving evolutionary relations between major animal taxa. Here we present the results of sequencing and analysis of mitochondrial genomes from two members of Kinorhyncha, Echinoderes svetlanae (Cyclorhagida) and Pycnophyes kielensis (Allomalorhagida). Their mitochondrial genomes are circular molecules approximately 15 Kbp in size. The kinorhynch mitochondrial gene sequences are highly divergent, which precludes accurate phylogenetic inference. The mitogenomes of both species encode a typical metazoan complement of 37 genes, which are all positioned on the major strand, but the gene order is distinct and unique among Ecdysozoa or animals as a whole. We predict four types of start codons for protein-coding genes in E. svetlanae and five in P. kielensis with a consensus DTD in single letter code. The mitochondrial genomes of E. svetlanae and P. kielensis encode duplicated methionine tRNA genes that display compensatory nucleotide substitutions. Two distant species of Kinorhyncha demonstrate similar patterns of gene arrangements in their mitogenomes. Both genomes have duplicated methionine tRNA genes; the duplication predates the divergence of two species. The kinorhynchs share a few features pertaining to gene order that align them with Priapulida. Gene order analysis reveals that gene arrangement specific of Priapulida may be ancestral for Scalidophora, Ecdysozoa, and even Protostomia

  6. Mitochondrial Genomes of Kinorhyncha: trnM Duplication and New Gene Orders within Animals.

    PubMed

    Popova, Olga V; Mikhailov, Kirill V; Nikitin, Mikhail A; Logacheva, Maria D; Penin, Aleksey A; Muntyan, Maria S; Kedrova, Olga S; Petrov, Nikolai B; Panchin, Yuri V; Aleoshin, Vladimir V

    2016-01-01

    Many features of mitochondrial genomes of animals, such as patterns of gene arrangement, nucleotide content and substitution rate variation are extensively used in evolutionary and phylogenetic studies. Nearly 6,000 mitochondrial genomes of animals have already been sequenced, covering the majority of animal phyla. One of the groups that escaped mitogenome sequencing is phylum Kinorhyncha-an isolated taxon of microscopic worm-like ecdysozoans. The kinorhynchs are thought to be one of the early-branching lineages of Ecdysozoa, and their mitochondrial genomes may be important for resolving evolutionary relations between major animal taxa. Here we present the results of sequencing and analysis of mitochondrial genomes from two members of Kinorhyncha, Echinoderes svetlanae (Cyclorhagida) and Pycnophyes kielensis (Allomalorhagida). Their mitochondrial genomes are circular molecules approximately 15 Kbp in size. The kinorhynch mitochondrial gene sequences are highly divergent, which precludes accurate phylogenetic inference. The mitogenomes of both species encode a typical metazoan complement of 37 genes, which are all positioned on the major strand, but the gene order is distinct and unique among Ecdysozoa or animals as a whole. We predict four types of start codons for protein-coding genes in E. svetlanae and five in P. kielensis with a consensus DTD in single letter code. The mitochondrial genomes of E. svetlanae and P. kielensis encode duplicated methionine tRNA genes that display compensatory nucleotide substitutions. Two distant species of Kinorhyncha demonstrate similar patterns of gene arrangements in their mitogenomes. Both genomes have duplicated methionine tRNA genes; the duplication predates the divergence of two species. The kinorhynchs share a few features pertaining to gene order that align them with Priapulida. Gene order analysis reveals that gene arrangement specific of Priapulida may be ancestral for Scalidophora, Ecdysozoa, and even Protostomia.

  7. Evidence for posttranslational modification and gene duplication of Campylobacter flagellin.

    PubMed Central

    Logan, S M; Trust, T J; Guerry, P

    1989-01-01

    A gene encoding a flagellin protein of Campylobacter coli VC167 has been cloned and sequenced. The gene was identified in a pBR322 library by hybridization to a synthetic oligonucleotide probe corresponding to amino acids 4 to 9 of the N-terminal sequence obtained by direct chemical analysis (S. M. Logan, L. A. Harris, and T. J. Trust, J. Bacteriol. 169:5072-5077, 1987). The DNA was sequenced and shown to contain an open reading frame encoding a protein with a molecular weight of 58,945 and a length of 572 amino acids. The deduced amino acid sequence was identical to the published N-terminal amino acid sequence of VC167 flagellin and to four internal regions whose partial sequences were obtained by direct chemical analysis of two tryptic and two cyanogen bromide peptides of VC167 flagellin. The C. coli flagellin protein contains posttranslationally modified serine residues, most of which occur within a region containing two 9-amino-acid repeating peptides separated by 34 unique amino acids. Comparisons with the sequences of flagellins from other bacterial species revealed conserved residues at the amino- and carboxy-terminal regions. Hybridization data suggest the presence of a second flagellin copy located adjacent to the first on the VC167 chromosome. Images PMID:2722741

  8. Microevolution of Duplications and Deletions and Their Impact on Gene Expression in the Nematode Pristionchus pacificus

    PubMed Central

    2015-01-01

    The evolution of diversity across the animal kingdom has been accompanied by tremendous gene loss and gain. While comparative genomics has been fruitful to characterize differences in gene content across highly diverged species, little is known about the microevolution of structural variations that cause these differences in the first place. In order to investigate the genomic impact of structural variations, we made use of genomic and transcriptomic data from the nematode Pristionchus pacificus, which has been established as a satellite model to Caenorhabditis elegans for comparative biology. We exploit the fact that P. pacificus is a highly diverse species for which various genomic data including the draft genome of a sister species P. exspectatus is available. Based on resequencing coverage data for two natural isolates we identified large (> 2kb) deletions and duplications relative to the reference strain. By restriction to completely syntenic regions between P. pacificus and P. exspectatus, we were able to polarize the comparison and to assess the impact of structural variations on expression levels. We found that while loss of genes correlates with lack of expression, duplication of genes has virtually no effect on gene expression. Further investigating expression of individual copies at sites that segregate between the duplicates, we found in the majority of cases only one of the copies to be expressed. Nevertheless, we still find that certain gene classes are strongly depleted in deletions as well as duplications, suggesting evolutionary constraint acting on synteny. In summary, our results are consistent with a model, where most structural variations are either deleterious or neutral and provide first insights into the microevolution of structural variations in the P. pacificus genome. PMID:26125626

  9. The large-scale evolution by generating new genes from gene duplication; similarity and difference between monoploid and diploid organisms.

    PubMed

    Otsuka, Jinya

    2011-06-07

    On the basis of the concept of biological activity, the large-scale evolution by generating new genes from gene duplication is theoretically compared between the monoploid organism and the diploid organism. The comparison is carried out not only for the process of generating one new gene but also for the process of generating two or more kinds of new genes from successive gene duplication. This comparison reveals the following difference in evolutionary pattern between the monoploids and diploids. The monoploid organism is more suitable to generate one or two new genes step by step but its successive gene duplication is obliged to generate smaller sizes of genes by the severer lowering of biological activity or self-reproducing rate. This is consistent with the evolutionary pattern of prokaryotes having steadily developed chemical syntheses, O₂-releasing photosynthesis and O₂-respiration in the respective lineages. On the other hand, the diploid organism with the plural number of homologous chromosome pairs has a chance to get together many kinds of new genes by the hybridization of variants having experienced different origins of gene duplication. Although this strategy of hybridization avoids the severe lowering of biological activity, it takes the longer time to establish the homozygotes of the more kinds of new genes. During this long period, furthermore different types of variants are accumulated in the population, and their successive hybridization sometimes yields various styles of new organisms. This evolutionary pattern explains the explosive divergence of body plans that has occasionally occurred in the diploid organisms, because the cell differentiation is a representative character exhibited by many kinds of genes and its evolution to the higher hierarchy constructs body plans.

  10. Cheetahs have 4 serum amyloid a genes evolved through repeated duplication events.

    PubMed

    Chen, Lei; Une, Yumi; Higuchi, Keiichi; Mori, Masayuki

    2012-01-01

    Amyloid A (AA) amyloidosis is a leading cause of mortality in captive cheetahs (Acinonyx jubatus). We performed genome walking and PCR cloning and revealed that cheetahs have 4 SAA genes (provisionally named SAA1A, SAA1B, SAA3A, and SAA3B). In addition, we identified multiple nucleotide polymorphisms in the 4 SAA genes by screening 51 cheetahs. The polymorphisms defined 4, 7, 6, and 4 alleles for SAA1A, SAA3A, SAA1B, and SAA3B, respectively. Pedigree analysis of the inheritance of genotypes for the SAA genes revealed that specific combinations of alleles for the 4 SAA genes cosegregated as a unit (haplotype) in pedigrees, indicating that the 4 genes were linked on the same chromosome. Notably, cheetah SAA1A and SAA1B were highly homologous in their nucleotide sequences. Likewise, SAA3A and SAA3B genes were homologous. These observations suggested a model for the evolution of the 4 SAA genes in cheetahs in which duplication of an ancestral SAA gene first gave rise to SAA1 and SAA3. Subsequently, each gene duplicated one more time, uniquely making 4 genes in the cheetah genome. The monomorphism of the cheetah SAA1A protein might be one of the factors responsible for the high incidence of AA amyloidosis in this species.

  11. Genome-wide identification and characterization of the Dof gene family in Medicago truncatula.

    PubMed

    Shu, Y J; Song, L L; Zhang, J; Liu, Y; Guo, C H

    2015-09-09

    The DNA-binding one zinc finger (Dof) family is a classic plant-specific zinc-finger transcription factor family, which is involved in many important processes, including seed maturation and germination, plant growth and development, and light responses. Investigation of the Medicago truncatula genome revealed 42 putative Dof genes, each of which holds one Dof domain. These genes were classified into four groups based on phylogenetic analysis, which are similar to the groups reported for Arabidopsis and rice. Based on genome duplication analysis, it was found that the MtDof genes were distributed on all chromosomes and had expanded through tandem gene duplication and segmental duplication events. Two main duplication regions were identified, one from tandem duplication and another from segmental duplication. By analyzing high-throughput sequencing data from M. truncatula, we found that most of the MtDof genes showed specific expression patterns in different tissues. According to cis-regulatory element analysis, these MtDof genes are regulated by different cis-acting motifs, which are important for the functional divergence of the MtDof genes in different processes. Thus, using genome-wide identification, evolution, and expression pattern analysis of the Dof genes in M. truncatula, our study provides valuable information for understanding the potential function of the Dof genes in regulating the growth and development of M. truncatula.

  12. A pure familial 6q15q21 split duplication associated with obesity and transmitted with partial reduction.

    PubMed

    Landais, Emilie; Leroy, Camille; Kleinfinger, Pascale; Brunet, Stéphanie; Koubi, Valérie; Pietrement, Christine; Poli-Mérol, Marie-Laurence; Fiquet, Caroline; Souchon, Pierre-François; Beri, Mylène; Jonveaux, Philippe; Garnotel, Roselyne; Gaillard, Dominique; Doco-Fenzy, Martine

    2015-06-01

    Familial transmission of chromosome 6 duplications is rare. We report on the first observation of a maternally-inherited pure segmental 6q duplication split into two segments, 6q15q16.3 and 6q16.3q21, and associated with obesity. Obesity has previously been correlated to chromosome 6 q-arm deletion but has not yet been assessed in duplications. The aim of this study was to characterize the structure of these intrachromosomal insertional translocations by classic cytogenetic banding, array-CGH, FISH, M-banding and genotyping using microsatellites and SNP array analysis, in a mother and four offspring. The duplicated 6q segments, 9.75 Mb (dup 1) and 7.05 Mb (dup 2) in size in the mother, were inserted distally into two distinct chromosome 6q regions. They were transmitted to four offspring. A son and a daughter inherited the two unbalanced insertions and displayed, like the mother, an abnormal phenotype with facial dysmorphism, intellectual disability, and morbid obesity. Curiously, two daughters with a normal phenotype inherited only the smaller segment, 6q16.3q21. The abnormal phenotype was associated with the larger proximal 6q15q16.3 duplication. We hypothesize a mechanism for this exceptional phenomenon of recurrent reduction and transmission of the duplication during meiosis in a family. We expect the interpretation of our findings to be useful for genetic counseling and for understanding the mechanisms underlying these large segmental 6q duplications and their evolution.

  13. Selection shaped the evolution of mouse androgen-binding protein (ABP) function and promoted the duplication of Abp genes.

    PubMed

    Karn, Robert C; Laukaitis, Christina M

    2014-08-01

    In the present article, we summarize two aspects of our work on mouse ABP (androgen-binding protein): (i) the sexual selection function producing incipient reinforcement on the European house mouse hybrid zone, and (ii) the mechanism behind the dramatic expansion of the Abp gene region in the mouse genome. Selection unifies these two components, although the ways in which selection has acted differ. At the functional level, strong positive selection has acted on key sites on the surface of one face of the ABP dimer, possibly to influence binding to a receptor. A different kind of selection has apparently driven the recent and rapid expansion of the gene region, probably by increasing the amount of Abp transcript, in one or both of two ways. We have shown previously that groups of Abp genes behave as LCRs (low-copy repeats), duplicating as relatively large blocks of genes by NAHR (non-allelic homologous recombination). The second type of selection involves the close link between the accumulation of L1 elements and the expansion of the Abp gene family by NAHR. It is probably predicated on an initial selection for increased transcription of existing Abp genes and/or an increase in Abp gene number providing more transcriptional sites. Either or both could increase initial transcript production, a quantitative change similar to increasing the volume of a radio transmission. In closing, we also provide a note on Abp gene nomenclature.

  14. Characterization and expression of two amphioxus DDAH genes originating from an amphioxus-specific gene duplication.

    PubMed

    Chen, Dongyan; Lin, Yushuang; Zhang, Hongwei

    2008-02-29

    Two dimethylarginine dimethylaminohydrolase (DDAH) homologous genes in amphioxus are identified and cloned. The phylogenetic analysis indicates two DDAHs in amphioxus originated by independent duplication specific in cephalochordate lineage. Analysis of AmphiDDAHa and AmphiDDAHb genomic structure shows their comparability with the DDAH in vertebrate and aboriginality which is consistent with animal classification. To explore the function relationship of AmphiDDAHa and AmphiDDAHb with AmphiNOS, the nitric oxide synthase homologue in amphioxus, we investigate the three genes expression patterns in embryos and adult tissues. The results indicate that these three genes possess different spatial and temporal expression patterns during embryogenesis. AmphiDDAHa transcripts are detected extensively in the differentiating ectoderm, mesendoderm in gastrula/early neurula, the developing and newly formed neural tube, somites, notochord, alimentary canal and epidermis at neurula stage, as well as in the differentiating pharynx and tailbud at early larval stage. While AmphiDDAHb is expressed in the differentiating non-neural ectoderm at the gastrla/early neurula stage, then locates abroad in the developing and formed neural tube, notochord, somites and alimentary canal. AmphiNOS is expressed weakly but widely from early neurula stage to at least 72-h larva stage. In adult, AmphiDDAHa and AmphiNOS share similar expression patterns in diverse adult tissues and cells such as the neural cord, gut, midgut diverticulum, wheel organ, gill, blood vessels, endostyle, oocytes and macrophages. But no expression of AmphiDDAHb is detected in tissues mentioned above. The results suggest that AmphiDDAHa and AmphiDDAHb should be two homologous genes with different functions in amphioxus. AmphiDDAHa may play a conserved role in the regulation of NO synthesis and immune defense, whereas AmphiDDAHb may mainly play the roles in the cell movement or differentiation of embryonic non-neural ectoderm

  15. Molecular Evolution of MDM1, a “Duplication-Resistant” Gene in Vertebrates

    PubMed Central

    Leung, Yuk Fai; Yang, Jer-Yen

    2016-01-01

    Background The mouse double minute 1 (Mdm1) gene was first reported and cloned in mouse tumor cell lines as an oncogene candidate. Later, it was found that mutation of Mdm1 might cause age-related retinal degeneration 2 in mice by genetic linkage analysis. Additionally, the MDM1 protein was found to be expressed in the centrosomes, cilia, and the nucleus of multiciliated tracheal epithelial cells in mice. These observations suggest that MDM1 may have some basal functions in cell physiology. However, the evolutionary history of this gene and its expression during embryonic development remain largely unexplored. Results Using molecular phylogenetic analysis, we found that the MDM1 gene encoded an evolutionarily conserved protein across all metazoans. We also found that the MDM1 gene was in a conserved synteny in vertebrates. In almost all the species that were analyzed, there was only one MDM1 gene based on current genome annotations. Since vertebrate genomes underwent two to three rounds of whole-genome duplications around the origin of the vertebrates, it is interesting that only one MDM1 ohnolog was retained. This observation implies that other MDM1 ohnologs were lost after the whole-genome duplications. Furthermore, using whole-mount in situ hybridization, we found that mdm1 was expressed in the forebrain, nephric ducts, and tail buds during zebrafish early embryonic development. Conclusion MDM1 is an evolutionary conserved gene, and its homologous genes can be traced back to basal metazoan lineages. In vertebrates, the MDM1 gene is in a conserved synteny and there is only one MDM1 ohnolog suggesting it is a “duplication-resistant” gene. Its expression patterns in early zebrafish embryos indicate that mdm1 may play important roles in the development of the central nervous system, kidneys, and hematopoietic system. PMID:27658201

  16. The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint

    PubMed Central

    1996-01-01

    M-phase checkpoints inhibit cell division when mitotic spindle function is perturbed. Here we show that the Saccharomyces cerevisiae MPS1 gene product, an essential protein kinase required for spindle pole body (SPB) duplication (Winey et al., 1991; Lauze et al., 1995), is also required for M-phase check-point function. In cdc31-2 and mps2-1 mutants, conditional failure of SPB duplication results in cell cycle arrest with high p34CDC28 kinase activity that depends on the presence of the wild-type MAD1 checkpoint gene, consistent with checkpoint arrest of mitosis. In contrast, mps1 mutant cells fail to duplicate their SPBs and do not arrest division at 37 degrees C, exhibiting a normal cycle of p34CDC28 kinase activity despite the presence of a monopolar spindle. Double mutant cdc31-2, mps1-1 cells also fail to arrest mitosis at 37 degrees C, despite having SPB structures similar to cdc31-2 single mutants as determined by EM analysis. Arrest of mitosis upon microtubule depolymerization by nocodazole is also conditionally absent in mps1 strains. This is observed in mps1 cells synchronized in S phase with hydroxyurea before exposure to nocodazole, indicating that failure of checkpoint function in mps1 cells is independent of SPB duplication failure. In contrast, hydroxyurea arrest and a number of other cdc mutant arrest phenotypes are unaffected by mps1 alleles. We propose that the essential MPS1 protein kinase functions both in SPB duplication and in a mitotic checkpoint monitoring spindle integrity. PMID:8567717

  17. Duplication of amyloid precursor protein (APP), but not prion protein (PRNP) gene is a significant cause of early onset dementia in a large UK series

    PubMed Central

    McNaughton, Daniel; Knight, William; Guerreiro, Rita; Ryan, Natalie; Lowe, Jessica; Poulter, Mark; Nicholl, David J.; Hardy, John; Revesz, Tamas; Lowe, James; Rossor, Martin; Collinge, John; Mead, Simon

    2012-01-01

    Amyloid precursor protein gene (APP) duplications have been identified in screens of selected probands with early onset familial Alzheimer's disease (FAD). A causal role for copy number variation (CNV) in the prion protein gene (PRNP) in prion dementias is not known. We aimed to determine the prevalence of copy number variation in APP and PRNP in a large referral series, test a screening method for detection of the same, and expand knowledge of clinical phenotype. We used a 3-tiered screening assay for APP and PRNP duplication (exonic real-time quantitative polymerase chain reaction [exon-qPCR], fluorescent microsatellite quantitative PCR [fm-q-PCR], and Illumina array [Illumina Inc., San Diego, CA, USA]) for analysis of a heterogeneous referral series comprising 1531 probands. Five of 1531 probands screened showed APP duplication, a similar prevalence to APP missense mutation. Real-time quantitative PCR and fluorescent microsatellite quantitative PCR were similar individually but are theoretically complementary; we used Illumina arrays as our reference assay. Two of 5 probands were from an autosomal dominant early onset Alzheimer's disease (familial Alzheimer's disease) pedigree. One extensive, noncontiguous duplication on chromosome 21 was consistent with an unbalanced translocation not including the Down's syndrome critical region. Seizures were prominent in the other typical APP duplications. A range of imaging, neuropsychological, cerebrospinal fluid, and pathological findings are reported that extend the known phenotype. APP but not PRNP duplication is a significant cause of early onset dementia in the UK. The recognized phenotype may be expanded to include the possibility of early seizures and apparently sporadic disease which, in part, may be due to different mutational mechanisms. The pros and cons of our screening method are discussed. PMID:21193246

  18. The butterfly plant arms-race escalated by gene and genome duplications

    PubMed Central

    Edger, Patrick P.; Heidel-Fischer, Hanna M.; Bekaert, Michaël; Rota, Jadranka; Glöckner, Gernot; Platts, Adrian E.; Heckel, David G.; Der, Joshua P.; Wafula, Eric K.; Tang, Michelle; Hofberger, Johannes A.; Smithson, Ann; Hall, Jocelyn C.; Blanchette, Matthieu; Bureau, Thomas E.; Wright, Stephen I.; dePamphilis, Claude W.; Eric Schranz, M.; Barker, Michael S.; Conant, Gavin C.; Wahlberg, Niklas; Vogel, Heiko; Pires, J. Chris; Wheat, Christopher W.

    2015-01-01

    Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits. PMID:26100883

  19. The butterfly plant arms-race escalated by gene and genome duplications.

    PubMed

    Edger, Patrick P; Heidel-Fischer, Hanna M; Bekaert, Michaël; Rota, Jadranka; Glöckner, Gernot; Platts, Adrian E; Heckel, David G; Der, Joshua P; Wafula, Eric K; Tang, Michelle; Hofberger, Johannes A; Smithson, Ann; Hall, Jocelyn C; Blanchette, Matthieu; Bureau, Thomas E; Wright, Stephen I; dePamphilis, Claude W; Eric Schranz, M; Barker, Michael S; Conant, Gavin C; Wahlberg, Niklas; Vogel, Heiko; Pires, J Chris; Wheat, Christopher W

    2015-07-07

    Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.

  20. Functional conservation between members of an ancient duplicated transcription factor family, LSF/Grainyhead.

    PubMed

    Venkatesan, Kavitha; McManus, Heather R; Mello, Craig C; Smith, Temple F; Hansen, Ulla

    2003-08-01

    The LSF/Grainyhead transcription factor family is involved in many important biological processes, including cell cycle, cell growth and development. In order to investigate the evolutionary conservation of these biological roles, we have characterized two new family members in Caenorhabditis elegans and Xenopus laevis. The C.elegans member, Ce-GRH-1, groups with the Grainyhead subfamily, while the X.laevis member, Xl-LSF, groups with the LSF subfamily. Ce-GRH-1 binds DNA in a sequence-specific manner identical to that of Drosophila melanogaster Grainyhead. In addition, Ce-GRH-1 binds to sequences upstream of the C.elegans gene encoding aromatic L-amino-acid decarboxylase and genes involved in post-embryonic development, mab-5 and dbl-1. All three C.elegans genes are homologs of D.melanogaster Grainyhead-regulated genes. RNA-mediated interference of Ce-grh-1 results in embryonic lethality in worms, accompanied by soft, defective cuticles. These phenotypes are strikingly similar to those observed previously in D.melanogaster grainyhead mutants, suggesting conservation of the developmental role of these family members over the course of evolution. Our phylogenetic analysis of the expanded LSF/GRH family (including other previously unrecognized proteins/ESTs) suggests that the structural and functional dichotomy of this family dates back more than 700 million years, i.e. to the time when the first multicellular organisms are thought to have arisen.

  1. Genes duplicated by polyploidy show unequal contributions to the transcriptome and organ-specific reciprocal silencing

    PubMed Central

    Adams, Keith L.; Cronn, Richard; Percifield, Ryan; Wendel, Jonathan F.

    2003-01-01

    Most eukaryotes have genomes that exhibit high levels of gene redundancy, much of which seems to have arisen from one or more cycles of genome doubling. Polyploidy has been particularly prominent during flowering plant evolution, yielding duplicated genes (homoeologs) whose expression may be retained or lost either as an immediate consequence of polyploidization or on an evolutionary timescale. Expression of 40 homoeologous gene pairs was assayed by cDNA-single-stranded conformation polymorphism in natural (1- to 2-million-yr-old) and synthetic tetraploid cotton (Gossypium) to determine whether homoeologous gene pairs are expressed at equal levels after polyploid formation. Silencing or unequal expression of one homoeolog was documented for 10 of 40 genes examined in ovules of Gossypium hirsutum. Assays of homoeolog expression in 10 organs revealed variable expression levels and silencing, depending on the gene and organ examined. Remarkably, silencing and biased expression of some gene pairs are reciprocal and developmentally regulated, with one homoeolog showing silencing in some organs and the other being silenced in other organs, suggesting rapid subfunctionalization. Duplicate gene expression was examined in additional natural polyploids to characterize the pace at which expression alteration evolves. Analysis of a synthetic tetraploid revealed homoeolog expression and silencing patterns that sometimes mirrored those of the natural tetraploid. Both long-term and immediate responses to polyploidization were implicated. Data suggest that some silencing events are epigenetically induced during the allopolyploidization process. PMID:12665616

  2. Dissecting the structure and mechanism of a complex duplication-triplication rearrangement in the DMD gene.

    PubMed

    Ishmukhametova, Aliya; Chen, Jian-Min; Bernard, Rafaëlle; de Massy, Bernard; Baudat, Frédéric; Boyer, Amandine; Méchin, Déborah; Thorel, Delphine; Chabrol, Brigitte; Vincent, Marie-Claire; Khau Van Kien, Philippe; Claustres, Mireille; Tuffery-Giraud, Sylvie

    2013-08-01

    Pathogenic complex genomic rearrangements are being increasingly characterized at the nucleotide level, providing unprecedented opportunities to evaluate the complexities of mutational mechanisms. Here, we report the molecular characterization of a complex duplication-triplication rearrangement involving exons 45-60 of the DMD gene. Inverted repeats facilitated this complex rearrangement, which shares common genomic organization with the recently described duplication-inverted triplication-duplication (DUP-TRP/INV-DUP) events; specifically, a 690-kb region comprising DMD exons from 45 to 60 was duplicated in tandem, and another 46-kb segment containing exon 51 was inserted inversely in between them. Taking into consideration (1) the presence of a predicted PRDM9 binding site in the near vicinity of the junction involving two inverted L1 elements and (2) the inherent properties of X-Y chromosome recombination during male meiosis, we proposed an alternative two-step model for the generation of this X-linked DMD DUP-TRP/INV-DUP event.

  3. Duplication and expression of CYC2-like genes in the origin and maintenance of corolla zygomorphy in Lamiales.

    PubMed

    Zhong, Jinshun; Kellogg, Elizabeth A

    2015-01-01

    Duplication, retention, and expression of CYCLOIDEA2 (CYC2)-like genes are thought to affect evolution of corolla symmetry. However, exactly what and how changes in CYC2-like genes correlate with the origin of corolla zygomorphy are poorly understood. We inferred and calibrated a densely sampled phylogeny of CYC2-like genes across the Lamiales and examined their expression in early diverging (EDL) and higher core clades (HCL). CYC2-like genes duplicated extensively in Lamiales, at least six times in core Lamiales (CL) around the Cretaceous-Paleogene (K-Pg) boundary, and seven more in EDL relatively more recently. Nested duplications and losses of CYC2-like paralogs are pervasive but may not correlate with transitions in corolla symmetry. We found evidence for dN/dS (ω) variation following gene duplications. CYC2-like paralogs in HCL show differential expression with higher expression in adaxial petals. Asymmetric expression but not recurrent duplication of CYC2-like genes correlates with the origin of corolla zygomorphy. Changes in both cis-regulatory and coding domains of CYC2-like genes are probably crucial for the evolution of corolla zygomorphy. Multiple selection regimes appear likely to play important roles in gene retention. The parallel duplications of CYC2-like genes are after the initial diversification of bumble bees and Euglossine bees.

  4. Comparative genomic organization and tissue-specific transcription of the duplicated fabp7 and fabp10 genes in teleost fishes.

    PubMed

    Parmar, Manoj B; Wright, Jonathan M

    2013-11-01

    A whole-genome duplication (WGD) early in the teleost fish lineage makes fish ideal organisms to study the fate of duplicated genes and underlying evolutionary trajectories that have led to the retention of ohnologous gene duplicates in fish genomes. Here, we compare the genomic organization and tissue-specific transcription of the ohnologous fabp7 and fabp10 genes in medaka, three-spined stickleback, and spotted green pufferfish to the well-studied duplicated fabp7 and fabp10 genes of zebrafish. Teleost fabp7 and fabp10 genes contain four exons interrupted by three introns. Polypeptide sequences of Fabp7 and Fabp10 show the highest sequence identity and similarity with their orthologs from vertebrates. Orthology was evident as the ohnologous Fabp7 and Fabp10 polypeptides of teleost fishes each formed distinct clades and clustered together with their orthologs from other vertebrates in a phylogenetic tree. Furthermore, ohnologous teleost fabp7 and fabp10 genes exhibit conserved gene synteny with human FABP7 and chicken FABP10, respectively, which provides compelling evidence that the duplicated fabp7 and fabp10 genes of teleost fishes most likely arose from the well-documented WGD. The tissue-specific distribution of fabp7a, fabp7b, fabp10a, and fabp10b transcripts provides evidence of diverged spatial transcriptional regulation between ohnologous gene duplicates of fabp7 and fabp10 in teleost fishes.

  5. Balanced Gene Losses, Duplications and Intensive Rearrangements Led to an Unusual Regularly Sized Genome in Arbutus unedo Chloroplasts

    PubMed Central

    Martínez-Alberola, Fernando; del Campo, Eva M.; Lázaro-Gimeno, David; Mezquita-Claramonte, Sergio; Molins, Arantxa; Mateu-Andrés, Isabel; Pedrola-Monfort, Joan; Casano, Leonardo M.; Barreno, Eva

    2013-01-01

    Completely sequenced plastomes provide a valuable source of information about the duplication, loss, and transfer events of chloroplast genes and phylogenetic data for resolving relationships among major groups of plants. Moreover, they can also be useful for exploiting chloroplast genetic engineering technology. Ericales account for approximately six per cent of eudicot diversity with 11,545 species from which only three complete plastome sequences are currently available. With the aim of increasing the number of ericalean complete plastome sequences, and to open new perspectives in understanding Mediterranean plant adaptations, a genomic study on the basis of the complete chloroplast genome sequencing of Arbutus unedo and an updated phylogenomic analysis of Asteridae was implemented. The chloroplast genome of A. unedo shows extensive rearrangements but a medium size (150,897 nt) in comparison to most of angiosperms. A number of remarkable distinct features characterize the plastome of A. unedo: five-fold dismissing of the SSC region in relation to most angiosperms; complete loss or pseudogenization of a number of essential genes; duplication of the ndhH-D operon and its location within the two IRs; presence of large tandem repeats located near highly re-arranged regions and pseudogenes. All these features outline the primary evolutionary split between Ericaceae and other ericalean families. The newly sequenced plastome of A. unedo with the available asterid sequences allowed the resolution of some uncertainties in previous phylogenies of Asteridae. PMID:24260278

  6. Tandem duplication within a type II collagen gene (COL2A1) exon in an individual with spondyloepiphyseal dysplasia

    SciTech Connect

    Tiller, G.E. ); Rimoin, D.L.; Cohn, D.H. Univ. of California, Los Angeles ); Murray, L.W. )

    1990-05-01

    The authors have characterized a mutation in the type II collagen gene (COL2A1) that produces a form of spondyloepiphyseal dysplasia. The mutation is an internal tandem duplication of 45 base pairs within exon 48 and results in the addition of 15 amino acids to the triple-helical domain of the {alpha}1 chains of type II collagen derived from the abnormal allele. Although the repeating (Gly-Xaa-Yaa){sub n} motif that characterizes the triple-helical domain is preserved, type II collagen derived from cartilage of the affected individual contains a population with excessive posttranslational modification, consistent with a disruption in triple-helix structure. The mutation is not carried by either parent, indicating that the phenotype in the affected individual is due to a new dominant mutation. DNA sequence homology in the area of the duplication suggests that the mutation may have arisen by unequal crossover between related sequences, a proposed mechanism in the evolution and diversification of the collagen gene family.

  7. Sub-functionalization to ovule development following duplication of a floral organ identity gene.

    PubMed

    Galimba, Kelsey D; Di Stilio, Verónica S

    2015-09-01

    Gene duplications result in paralogs that may be maintained due to the gain of novel functions (neo-functionalization) or the partitioning of ancestral function (sub-functionalization). Plant genomes are especially prone to duplication; paralogs are particularly widespread in the floral MADS box transcription factors that control organ identity through the ABC model of flower development. C class genes establish stamen and carpel identity and control floral meristem determinacy, and are largely conserved across the angiosperm phylogeny. Originally, an additional D class had been identified as controlling ovule identity; yet subsequent studies indicated that both C and D lineage genes more commonly control ovule development redundantly. The ranunculid Thalictrum thalictroides has two orthologs of the Arabidopsis thaliana C class gene AGAMOUS (AG), ThtAG1 and ThtAG2 (Thalictrum thalictroides AGAMOUS1/2). We previously showed that ThtAG1 exhibits typical C class function; here we examine the role of its paralog, ThtAG2. Our phylogenetic analysis shows that ThtAG2 falls within the C lineage, together with ThtAG1, and is consistent with previous findings of a Ranunculales-specific duplication in this clade. However, ThtAG2 is not expressed in stamens, but rather solely in carpels and ovules. This female-specific expression pattern is consistent with D lineage genes, and with other C lineage genes known to be involved in ovule identity. Given the divergent expression of ThtAG2, we tested the hypothesis that it has acquired ovule identity function. Molecular evolution analyses showed evidence of positive selection on ThtAG2-a pattern that supports divergence of function by sub-functionalization. Down-regulation of ThtAG2 by virus-induced gene silencing resulted in homeotic conversions of ovules into carpel-like structures. Taken together, our results suggest that, although ThtAG2 falls within the C lineage, it has diverged to acquire "D function" as an ovule identity gene

  8. Adaptations to endosymbiosis in a cnidarian-dinoflagellate association: differential gene expression and specific gene duplications.

    PubMed

    Ganot, Philippe; Moya, Aurélie; Magnone, Virginie; Allemand, Denis; Furla, Paola; Sabourault, Cécile

    2011-07-01

    Trophic endosymbiosis between anthozoans and photosynthetic dinoflagellates forms the key foundation of reef ecosystems. Dysfunction and collapse of symbiosis lead to bleaching (symbiont expulsion), which is responsible for the severe worldwide decline of coral reefs. Molecular signals are central to the stability of this partnership and are therefore closely related to coral health. To decipher inter-partner signaling, we developed genomic resources (cDNA library and microarrays) from the symbiotic sea anemone Anemonia viridis. Here we describe differential expression between symbiotic (also called zooxanthellate anemones) or aposymbiotic (also called bleached) A. viridis specimens, using microarray hybridizations and qPCR experiments. We mapped, for the first time, transcript abundance separately in the epidermal cell layer and the gastrodermal cells that host photosynthetic symbionts. Transcriptomic profiles showed large inter-individual variability, indicating that aposymbiosis could be induced by different pathways. We defined a restricted subset of 39 common genes that are characteristic of the symbiotic or aposymbiotic states. We demonstrated that transcription of many genes belonging to this set is specifically enhanced in the symbiotic cells (gastroderm). A model is proposed where the aposymbiotic and therefore heterotrophic state triggers vesicular trafficking, whereas the symbiotic and therefore autotrophic state favors metabolic exchanges between host and symbiont. Several genetic pathways were investigated in more detail: i) a key vitamin K-dependant process involved in the dinoflagellate-cnidarian recognition; ii) two cnidarian tissue-specific carbonic anhydrases involved in the carbon transfer from the environment to the intracellular symbionts; iii) host collagen synthesis, mostly supported by the symbiotic tissue. Further, we identified specific gene duplications and showed that the cnidarian-specific isoform was also up-regulated both in the

  9. Alternative splicing and gene duplication differentially shaped the regulation of isochorismate synthase in Populus and Arabidopsis

    PubMed Central

    Yuan, Yinan; Chung, Jeng-Der; Fu, Xueyan; Johnson, Virgil E.; Ranjan, Priya; Booth, Sarah L.; Harding, Scott A.; Tsai, Chung-Jui

    2009-01-01

    Isochorismate synthase (ICS) converts chorismate to isochorismate for the biosynthesis of phylloquinone, an essential cofactor for photosynthetic electron transport. ICS is also required for salicylic acid (SA) synthesis during Arabidopsis defense. In several other species, including Populus, SA is derived primarily from the phenylpropanoid pathway. We therefore sought to investigate ICS regulation in Populus to learn the extent of ICS involvement in SA synthesis and defense. Arabidopsis harbors duplicated AtICS genes that differ in their exon-intron structure, basal expression, and stress inducibility. In contrast, we found a single ICS gene in Populus and six other sequenced plant genomes, pointing to the AtICS duplication as a lineage-specific event. The Populus ICS encodes a functional plastidic enzyme, and was not responsive to stresses that stimulated phenylpropanoid accumulation. Populus ICS underwent extensive alternative splicing that was rare for the duplicated AtICSs. Sequencing of 184 RT-PCR Populus clones revealed 37 alternative splice variants, with normal transcripts representing ≈50% of the population. When expressed in Arabidopsis, Populus ICS again underwent alternative splicing, but did not produce normal transcripts to complement AtICS1 function. The splice-site sequences of Populus ICS are unusual, suggesting a causal link between junction sequence, alternative splicing, and ICS function. We propose that gene duplication and alternative splicing of ICS evolved independently in Arabidopsis and Populus in accordance with their distinct defense strategies. AtICS1 represents a divergent isoform for inducible SA synthesis during defense. Populus ICS primarily functions in phylloquinone biosynthesis, a process that can be sustained at low ICS transcript levels. PMID:19996170

  10. Evolutionary History of the Cancer Immunity Antigen MAGE Gene Family

    PubMed Central

    Katsura, Yukako; Satta, Yoko

    2011-01-01

    The evolutionary mode of a multi-gene family can change over time, depending on the functional differentiation and local genomic environment of family members. In this study, we demonstrate such a change in the melanoma antigen (MAGE) gene family on the mammalian X chromosome. The MAGE gene family is composed of ten subfamilies that can be categorized into two types. Type I genes are of relatively recent origin, and they encode epitopes for human leukocyte antigen (HLA) in cancer cells. Type II genes are relatively ancient and some of their products are known to be involved in apoptosis or cell proliferation. The evolutionary history of the MAGE gene family can be divided into four phases. In phase I, a single-copy state of an ancestral gene and the evolutionarily conserved mode had lasted until the emergence of eutherian mammals. In phase II, eight subfamily ancestors, with the exception for MAGE-C and MAGE-D subfamilies, were formed via retrotransposition independently. This would coincide with a transposition burst of LINE elements at the eutherian radiation. However, MAGE-C was generated by gene duplication of MAGE-A. Phase III is characterized by extensive gene duplication within each subfamily and in particular the formation of palindromes in the MAGE-A subfamily, which occurred in an ancestor of the Catarrhini. Phase IV is characterized by the decay of a palindrome in most Catarrhini, with the exception of humans. Although the palindrome is truncated by frequent deletions in apes and Old World monkeys, it is retained in humans. Here, we argue that this human-specific retention stems from negative selection acting on MAGE-A genes encoding epitopes of cancer cells, which preserves their ability to bind to highly divergent HLA molecules. These findings are interpreted with consideration of the biological factors shaping recent human MAGE-A genes. PMID:21695252

  11. Genome-wide identification and expression profiling of ankyrin-repeat gene family in maize.

    PubMed

    Jiang, Haiyang; Wu, Qingqing; Jin, Jing; Sheng, Lei; Yan, Hanwei; Cheng, Beijiu; Zhu, Suwen

    2013-09-01

    Members of the ankyrin repeats (ANK) gene family encode ANK domain that are common in diverse organisms and play important roles in cell growth and development, such as cell-cell signal transduction and cell cycle regulation. Recently, genome-wide identification and evolutionary analyses of the ANK gene family have been carried out in Arabidopsis and rice. However, little is known regarding the ANK genes in the entire maize genome. In this study, we described the identification and structural characterization of 71 ANK genes in maize (ZmANK). Then, comprehensive bioinformatics analyses of ZmANK genes family were performed including phylogenetic, domain and motif analysis, chromosomal localization, intron/exon structural patterns, gene duplications and expression profiling. Domain composition analyses showed that ZmANK genes formed ten subfamilies. Five tandem duplications and 14 segmental duplications were identified in ZmANK genes. Furthermore, we took comparative analysis of the total ANK gene family in Arabidopsis, rice and maize, ZmANKs were more closely paired with OsANKs than with AtANKs. At last, expression profile analyses were performed. Forty-one members of ZmANK genes held EST sequences records. Semi-quantitative expression and microarray data analysis of these 41 ZmANK genes demonstrated that ZmANK genes exhibit a various expression pattern, suggesting that functional diversification of ZmANK genes family. The results will present significant insights to explore ANK genes expression and function in future studies in maize.

  12. An Exact Algorithm to Compute the Double-Cut-and-Join Distance for Genomes with Duplicate Genes.

    PubMed

    Shao, Mingfu; Lin, Yu; Moret, Bernard M E

    2015-05-01

    Computing the edit distance between two genomes is a basic problem in the study of genome evolution. The double-cut-and-join (DCJ) model has formed the basis for most algorithmic research on rearrangements over the last few years. The edit distance under the DCJ model can be computed in linear time for genomes without duplicate genes, while the problem becomes NP-hard in the presence of duplicate genes. In this article, we propose an integer linear programming (ILP) formulation to compute the DCJ distance between two genomes with duplicate genes. We also provide an efficient preprocessing approach to simplify the ILP formulation while preserving optimality. Comparison on simulated genomes demonstrates that our method outperforms MSOAR in computing the edit distance, especially when the genomes contain long duplicated segments. We also apply our method to assign orthologous gene pairs among human, mouse, and rat genomes, where once again our method outperforms MSOAR.

  13. Comparative transcriptome analyses reveal core parasitism genes and suggest gene duplication and repurposing as sources of structural novelty.

    PubMed

    Yang, Zhenzhen; Wafula, Eric K; Honaas, Loren A; Zhang, Huiting; Das, Malay; Fernandez-Aparicio, Monica; Huang, Kan; Bandaranayake, Pradeepa C G; Wu, Biao; Der, Joshua P; Clarke, Christopher R; Ralph, Paula E; Landherr, Lena; Altman, Naomi S; Timko, Michael P; Yoder, John I; Westwood, James H; dePamphilis, Claude W

    2015-03-01

    The origin of novel traits is recognized as an important process underlying many major evolutionary radiations. We studied the genetic basis for the evolution of haustoria, the novel feeding organs of parasitic flowering plants, using comparative transcriptome sequencing in three species of Orobanchaceae. Around 180 genes are upregulated during haustorial development following host attachment in at least two species, and these are enriched in proteases, cell wall modifying enzymes, and extracellular secretion proteins. Additionally, about 100 shared genes are upregulated in response to haustorium inducing factors prior to host attachment. Collectively, we refer to these newly identified genes as putative "parasitism genes." Most of these parasitism genes are derived from gene duplications in a common ancestor of Orobanchaceae and Mimulus guttatus, a related nonparasitic plant. Additionally, the signature of relaxed purifying selection and/or adaptive evolution at specific sites was detected in many haustorial genes, and may play an important role in parasite evolution. Comparative analysis of gene expression patterns in parasitic and nonparasitic angiosperms suggests that parasitism genes are derived primarily from root and floral tissues, but with some genes co-opted from other tissues. Gene duplication, often taking place in a nonparasitic ancestor of Orobanchaceae, followed by regulatory neofunctionalization, was an important process in the origin of parasitic haustoria.

  14. Comparative Transcriptome Analyses Reveal Core Parasitism Genes and Suggest Gene Duplication and Repurposing as Sources of Structural Novelty

    PubMed Central

    Yang, Zhenzhen; Wafula, Eric K.; Honaas, Loren A.; Zhang, Huiting; Das, Malay; Fernandez-Aparicio, Monica; Huang, Kan; Bandaranayake, Pradeepa C.G.; Wu, Biao; Der, Joshua P.; Clarke, Christopher R.; Ralph, Paula E.; Landherr, Lena; Altman, Naomi S.; Timko, Michael P.; Yoder, John I.; Westwood, James H.; dePamphilis, Claude W.

    2015-01-01

    The origin of novel traits is recognized as an important process underlying many major evolutionary radiations. We studied the genetic basis for the evolution of haustoria, the novel feeding organs of parasitic flowering plants, using comparative transcriptome sequencing in three species of Orobanchaceae. Around 180 genes are upregulated during haustorial development following host attachment in at least two species, and these are enriched in proteases, cell wall modifying enzymes, and extracellular secretion proteins. Additionally, about 100 shared genes are upregulated in response to haustorium inducing factors prior to host attachment. Collectively, we refer to these newly identified genes as putative “parasitism genes.” Most of these parasitism genes are derived from gene duplications in a common ancestor of Orobanchaceae and Mimulus guttatus, a related nonparasitic plant. Additionally, the signature of relaxed purifying selection and/or adaptive evolution at specific sites was detected in many haustorial genes, and may play an important role in parasite evolution. Comparative analysis of gene expression patterns in parasitic and nonparasitic angiosperms suggests that parasitism genes are derived primarily from root and floral tissues, but with some genes co-opted from other tissues. Gene duplication, often taking place in a nonparasitic ancestor of Orobanchaceae, followed by regulatory neofunctionalization, was an important process in the origin of parasitic haustoria. PMID:25534030

  15. Gene structure variation in segmental duplication block C of human chromosome 7q 11.23 during primate evolution.

    PubMed

    Kim, Yun-Ji; Ahn, Kung; Gim, Jeong-An; Oh, Man Hwan; Han, Kyudong; Kim, Heui-Soo

    2015-12-01

    Segmental duplication, or low-copy repeat (LCR) event, occurs during primate evolution and is an important source of genomic diversity, including gain or loss of gene function. The human chromosome 7q 11.23 is related to the William-Beuren syndrome and contains large region-specific LCRs composed of blocks A, B, and C that have different copy numbers in humans and different primates. We analyzed the structure of POM121, NSUN5, FKBP6, and TRIM50 genes in the LCRs of block C. Based on computational analysis, POM121B created by a segmental duplication acquired a new exonic region, whereas NSUN5B (NSUN5C) showed structural variation by integration of HERV-K LTR after duplication from the original NSUN5 gene. The TRIM50 gene originally consists of seven exons, whereas the duplicated TRIM73 and TRIM74 genes present five exons because of homologous recombination-mediated deletion. In addition, independent duplication events of the FKBP6 gene generated two pseudogenes at different genomic locations. In summary, these clustered genes are created by segmental duplication, indicating that they show dynamic evolutionary events, leading to structure variation in the primate genome.

  16. Protease Gene Duplication and Proteolytic Activity in Drosophila Female Reproductive Tracts

    PubMed Central

    Kelleher, Erin S.; Pennington, James E.

    2009-01-01

    Secreted proteases play integral roles in sexual reproduction in a broad range of taxa. In the genetic model Drosophila melanogaster, these molecules are thought to process peptides and activate enzymes inside female reproductive tracts, mediating critical postmating responses. A recent study of female reproductive tract proteins in the cactophilic fruit fly Drosophila arizonae, identified pervasive, lineage-specific gene duplication amongst secreted proteases. Here, we compare the evolutionary dynamics, biochemical nature, and physiological significance of secreted female reproductive serine endoproteases between D. arizonae and its congener D. melanogaster. We show that D. arizonae lower female reproductive tract (LFRT) proteins are significantly enriched for recently duplicated secreted proteases, particularly serine endoproteases, relative to D. melanogaster. Isolated lumen from D. arizonae LFRTs, furthermore, exhibits significant trypsin-like and elastase-like serine endoprotease acitivity, whereas no such activity is seen in D. melanogaster. Finally, trypsin- and elastase-like activity in D. arizonae female reproductive tracts is negatively regulated by mating. We propose that the intense proteolytic environment of the D. arizonae female reproductive tract relates to the extraordinary reproductive physiology of this species and that ongoing gene duplication amongst these proteases is an evolutionary consequence of sexual conflict. PMID:19546158

  17. Detection of a large duplication mutation in the myosin-binding protein C3 gene in a case of hypertrophic cardiomyopathy.

    PubMed

    Meyer, Thomas; Pankuweit, Sabine; Richter, Anette; Maisch, Bernhard; Ruppert, Volker

    2013-09-15

    Hypertrophic cardiomyopathy (HCM) is a cardiovascular disease with autosomal dominant inheritance caused by mutations in genes coding for sarcomeric and/or regulatory proteins expressed in cardiomyocytes. In a small cohort of HCM patients (n=8), we searched for mutations in the two most common genes responsible for HCM and found four missense mutations in the MYH7 gene encoding cardiac β-myosin heavy chain (R204H, M493V, R719W, and R870H) and three mutations in the myosin-binding protein C3 gene (MYBPC3) including one missense (A848V) and two frameshift mutations (c.3713delTG and c.702ins26bp). The c.702ins26bp insertion resulted from the duplication of a 26-bp fragment in a 54-year-old female HCM patient presenting with clinical signs of heart failure due to diastolic dysfunction. Although such large duplications (>10 bp) in the MYBPC3 gene are very rare and have been identified only in 4 families reported so far, the identical duplication mutation was found earlier in a Dutch patient, demonstrating that it may constitute a hitherto unknown founder mutation in central European populations. This observation underscores the significance of insertions into the coding sequence of the MYBPC3 gene for the development and pathogenesis of HCM.

  18. Concerted Evolution of Duplicate Control Regions in the Mitochondria of Species of the Flatfish Family Bothidae (Teleostei: Pleuronectiformes).

    PubMed

    Li, Dong-He; Shi, Wei; Munroe, Thomas A; Gong, Li; Kong, Xiao-Yu

    2015-01-01

    Mitogenomes of flatfishes (Pleuronectiformes) exhibit the greatest diversity of gene rear-rangements in teleostean fishes. Duplicate control regions (CRs) have been found in the mito-genomes of two flatfishes, Samariscus latus (Samaridae) and Laeops lanceolata (Bothidae), which is rare in teleosts. It has been reported that duplicate CRs have evolved in a concerted fashion in fishes and other animals, however, whether concerted evo-lution exists in flatfishes remains unknown. In this study, based on five newly sequenced and six previously reported mitogenomes of lefteye flounders in the Bothidae, we explored whether duplicate CRs and concerted evolution exist in these species. Results based on the present study and previous reports show that four out of eleven bothid species examined have duplicate CRs of their mitogenomes. The core regions of the duplicate CRs of mitogenomes in the same species have identical, or nearly identical, sequences when compared to each other. This pattern fits the typical characteristics of concerted evolution. Additionally, phylogenetic and ancestral state reconstruction analysis also provided evidence to support the hypothesis that duplicate CRs evolved concertedly. The core region of concerted evolution is situated at the conserved domains of the CR of the mitogenome from the termination associated sequences (TASs) to the conserved sequence blocks (CSBs). Commonly, this region is con-sidered to regulate mitochondrial replication and transcription. Thus, we hypothesize that the cause of concerted evolution of the duplicate CRs in the mtDNAs of these four bothids may be related to some function of the conserved sequences of the CRs during mitochondrial rep-lication and transcription. We hope our results will provide fresh insight into the molecular mechanisms related to replication and evolution of mitogenomes.

  19. Patterns of gene duplication and functional evolution during the diversification of the AGAMOUS subfamily of MADS box genes in angiosperms.

    PubMed Central

    Kramer, Elena M; Jaramillo, M Alejandra; Di Stilio, Verónica S

    2004-01-01

    Members of the AGAMOUS (AG) subfamily of MIKC-type MADS-box genes appear to control the development of reproductive organs in both gymnosperms and angiosperms. To understand the evolution of this subfamily in the flowering plants, we have identified 26 new AG-like genes from 15 diverse angiosperm species. Phylogenetic analyses of these genes within a large data set of AG-like sequences show that ancient gene duplications were critical in shaping the evolution of the subfamily. Before the radiation of extant angiosperms, one event produced the ovule-specific D lineage and the well-characterized C lineage, whose members typically promote stamen and carpel identity as well as floral meristem determinacy. Subsequent duplications in the C lineage resulted in independent instances of paralog subfunctionalization and maintained functional redundancy. Most notably, the functional homologs AG from Arabidopsis and PLENA (PLE) from Antirrhinum are shown to be representatives of separate paralogous lineages rather than simple genetic orthologs. The multiple subfunctionalization events that have occurred in this subfamily highlight the potential for gene duplication to lead to dissociation among genetic modules, thereby allowing an increase in morphological diversity. PMID:15020484

  20. The Expansion of the PRAME Gene Family in Eutheria

    PubMed Central

    Chang, Ti-Cheng; Yang, Yang; Yasue, Hiroshi; Bharti, Arvind K.; Retzel, Ernest F.; Liu, Wan-Sheng

    2011-01-01

    The PRAME gene family belongs to the group of cancer/testis genes whose expression is restricted primarily to the testis and a variety of cancers. The expansion of this gene family as a result of gene duplication has been observed in primates and rodents. We analyzed the PRAME gene family in Eutheria and discovered a novel Y-linked PRAME gene family in bovine, PRAMEY, which underwent amplification after a lineage-specific, autosome-to-Y transposition. Phylogenetic analyses revealed two major evolutionary clades. Clade I containing the amplified PRAMEYs and the unamplified autosomal homologs in cattle and other eutherians is under stronger functional constraints; whereas, Clade II containing the amplified autosomal PRAMEs is under positive selection. Deep-sequencing analysis indicated that eight of the identified 16 PRAMEY loci are active transcriptionally. Compared to the bovine autosomal PRAME that is expressed predominantly in testis, the PRAMEY gene family is expressed exclusively in testis and is up-regulated during testicular maturation. Furthermore, the sense RNA of PRAMEY is expressed specifically whereas the antisense RNA is expressed predominantly in spermatids. This study revealed that the expansion of the PRAME family occurred in both autosomes and sex chromosomes in a lineage-dependent manner. Differential selection forces have shaped the evolution and function of the PRAME family. The positive selection observed on the autosomal PRAMEs (Clade II) may result in their functional diversification in immunity and reproduction. Conversely, selective constraints have operated on the expanded PRAMEYs to preserve their essential function in spermatogenesis. PMID:21347312

  1. Evolution of a symbiotic receptor through gene duplications in the legume-rhizobium mutualism.

    PubMed

    De Mita, Stéphane; Streng, Arend; Bisseling, Ton; Geurts, René

    2014-02-01

    The symbiosis between legumes and nitrogen-fixing rhizobia co-opted pre-existing endomycorrhizal features. In particular, both symbionts release lipo-chitooligosaccharides (LCOs) that are recognized by LysM-type receptor kinases. We investigated the evolutionary history of rhizobial LCO receptor genes MtLYK3-LjNFR1 to gain insight into the evolutionary origin of the rhizobial symbiosis. We performed a phylogenetic analysis integrating gene copies from nonlegumes and legumes, including the non-nodulating, phylogenetically basal legume Cercis chinensis. Signatures of differentiation between copies were investigated through patterns of molecular evolution. We show that two rounds of duplication preceded the evolution of the rhizobial symbiosis in legumes. Molecular evolution patterns indicate that the resulting three paralogous gene copies experienced different selective constraints. In particular, one copy maintained the ancestral function, and another specialized into perception of rhizobial LCOs. It has been suggested that legume LCO receptors evolved from a putative ancestral defense-related chitin receptor through the acquisition of two kinase motifs. However, the phylogenetic analysis shows that these domains are actually ancestral, suggesting that this scenario is unlikely. Our study underlines the evolutionary significance of gene duplication and subsequent neofunctionalization in MtLYK3-LjNFR1 genes. We hypothesize that their ancestor was more likely a mycorrhizal LCO receptor, than a defense-related receptor kinase.

  2. Adaptive evolution after gene duplication in alpha-KT x 14 subfamily from Buthus martensii Karsch.

    PubMed

    Cao, Zhijian; Mao, Xin; Xu, Xiuling; Sheng, Jiqun; Dai, Chao; Wu, Yingliang; Luo, Feng; Sha, Yonggang; Jiang, Dahe; Li, Wenxin

    2005-07-01

    A series of isoforms of alpha-KT x 14 (short chain potassium channel scorpion toxins) were isolated from the venom of Buthus martensii Karsch by RACE and screening cDNA library methods. These isoforms adding BmKK1--3 and BmSKTx1--2 together shared high homology (more than 97%) with each other. The result of genomic sequence analysis showed that a length 79 bp intron is inserted Ala codes between the first and the second base at the 17th amino acid of signal peptide. The introns of these isoforms also share high homology with those of BmKK2 and BmSKT x 1 reported previously. Sequence analysis of many clones of cDNA and genomic DNA showed that a species population or individual polymorphism of alpha-KT x 14 genes took place in scorpion Buthus martensii Karsch and accelerated evolution played an important role in the forming process of alpha-KT x 14 scorpion toxins subfamily. The result of southern hybridization indicated that alpha-KT x 14 toxin genes existed in scorpion chromosome with multicopies. All findings maybe provided an important evidence for an extensive evolutionary process of the scorpion "pharmacological factory": at the early course of evolution, the ancestor toxic gene duplicated into a series of multicopy genes integrated at the different chromosome; at the late course of evolution, subsequent functional divergence of duplicate genes was generated by mutations, deletions and insertion.

  3. Dynamics of gene duplication and transposons in microbial genomes following a sudden environmental change

    NASA Astrophysics Data System (ADS)

    Chia, Nicholas; Goldenfeld, Nigel

    2011-02-01

    A variety of genome transformations can occur as a microbial population adapts to a large environmental change. In particular, genomic surveys indicate that, following the transition to an obligate, host-dependent symbiont, the density of transposons first rises, then subsequently declines over evolutionary time. Here we show that these observations can be accounted for by a class of generic stochastic models for the evolution of genomes in the presence of continuous selection and gene duplication. The models use a fitness function that allows for partial contributions from multiple gene copies, is an increasing but bounded function of copy number, and is optimal for one fully adapted gene copy. We use Monte Carlo simulation to show that the dynamics result in an initial rise in gene copy number followed by a subsequent falloff due to adaptation to the new environmental parameters. These results are robust for reasonable gene duplication and mutation parameters when adapting to a novel target sequence. Our model provides a generic explanation for the dynamics of microbial transposon density following a large environmental change such as host restriction.

  4. Duplications in ADHD patients harbour neurobehavioural genes that are co‐expressed with genes associated with hyperactivity in the mouse

    PubMed Central

    Taylor, Avigail; Steinberg, Julia

    2015-01-01

    Attention deficit/hyperactivity disorder (ADHD) is a childhood onset disorder, prevalent in 5.3% of children and 1–4% of adults. ADHD is highly heritable, with a burden of large (>500 Kb) copy number variants (CNVs) identified among individuals with ADHD. However, how such CNVs exert their effects is poorly understood. We examined the genes affected by 71 large, rare, and predominantly inherited CNVs identified among 902 individuals with ADHD. We applied both mouse‐knockout functional enrichment analyses, exploiting behavioral phenotypes arising from the determined disruption of 1:1 mouse orthologues, and human brain‐specific spatio‐temporal expression data to uncover molecular pathways common among genes contributing to enriched phenotypes. Twenty‐two percent of genes duplicated in individuals with ADHD that had mouse phenotypic information were associated with abnormal learning/memory/conditioning (“l/m/c”) phenotypes. Although not observed in a second ADHD‐cohort, we identified a similar enrichment among genes duplicated by eight de novo CNVs present in eight individuals with Hyperactivity and/or Short attention span (“Hyperactivity/SAS”, the ontologically‐derived phenotypic components of ADHD). In the brain, genes duplicated in patients with ADHD and Hyperactivity/SAS and whose orthologues’ disruption yields l/m/c phenotypes in mouse (“candidate‐genes”), were co‐expressed with one another and with genes whose orthologues’ mouse models exhibit hyperactivity. Moreover, genes associated with hyperactivity in the mouse were significantly more co‐expressed with ADHD candidate‐genes than with similarly identified genes from individuals with intellectual disability. Our findings support an etiology for ADHD distinct from intellectual disability, and mechanistically related to genes associated with hyperactivity phenotypes in other mammalian species. © 2015 The Authors. American Journal of Medical Genetics Part B

  5. Sucrose metabolism gene families and their biological functions

    PubMed Central

    Jiang, Shu-Ye; Chi, Yun-Hua; Wang, Ji-Zhou; Zhou, Jun-Xia; Cheng, Yan-Song; Zhang, Bao-Lan; Ma, Ali; Vanitha, Jeevanandam; Ramachandran, Srinivasan

    2015-01-01

    Sucrose, as the main product of photosynthesis, plays crucial roles in plant development. Although studies on general metabolism pathway were well documented, less information is available on the genome-wide identification of these genes, their expansion and evolutionary history as well as their biological functions. We focused on four sucrose metabolism related gene families including sucrose synthase, sucrose phosphate synthase, sucrose phosphate phosphatase and UDP-glucose pyrophosphorylase. These gene families exhibited different expansion and evolutionary history as their host genomes experienced differentiated rates of the whole genome duplication, tandem and segmental duplication, or mobile element mediated gene gain and loss. They were evolutionarily conserved under purifying selection among species and expression divergence played important roles for gene survival after expansion. However, we have detected recent positive selection during intra-species divergence. Overexpression of 15 sorghum genes in Arabidopsis revealed their roles in biomass accumulation, flowering time control, seed germination and response to high salinity and sugar stresses. Our studies uncovered the molecular mechanisms of gene expansion and evolution and also provided new insight into the role of positive selection in intra-species divergence. Overexpression data revealed novel biological functions of these genes in flowering time control and seed germination under normal and stress conditions. PMID:26616172

  6. Isolation and characterization of three duplicated PISTILLATA genes in Brassica napus.

    PubMed

    Deng, Wei; Zhou, Lin; Zhou, Yuntao; Wang, Yujia; Wang, Maolin; Zhao, Yun

    2011-06-01

    Three coding region cDNAs of duplicated PISTILLATA-like (PI-like) MADS-box genes, BnPI-1, BnPI-2 and BnPI-3, were isolated from B. napus by RT-PCR. The sequence analysis showed that the three PI cDNAs possessed 627, 627 and 625 nucleotides, respectively, and their nucleotide sequences had 96.49-98.72% similarity. Due to a deletion of two nucleotides, the protein sequence in the downstream of the frameshift site was altered in BnPI-3. Therefore, there were only 171 amino acids coded by BnPI-3, while there were 208 ones coded by BnPI-1 or BnPI-2. The deduced amino acid identity between BnPI-1 and BnPI-2 was 97.6% and the amino acid sequence of BnPI-1 and BnPI-2 shared 72.6% identity with BnPI-3. The deduced amino acid sequences of the coded proteins indicated high homology with the members of the PI family of MADS-box proteins. RT-PCR analysis showed that BnPI transcription was only detectable in petals and stamens. The yeast two-hybrid assays results showed that the three BnPI proteins exhibited different dimerization affinities with three BnAP3. BnPI-1 and BnPI-2 could form strong heterodimers with BnAP3. The dimerization affinity of BnPI-1 with BnAP3-4 is the strongest in all the combinations, while the affinity of BnPI-3 with BnAP3-4 is the weakest. The dimerization affinity to BnAP3-4 of BnPI-1 is 3.5 times of that of BnPI-3. The distinguished weak interaction to AP3 of BnPI-3 is probably due to the loss of the PI motif. The divergences of sequence and affinity of protein interaction might reflect some functional divergence of the three PI genes in B. napus.

  7. Specific Duplication and Dorsoventrally Asymmetric Expression Patterns of Cycloidea-Like Genes in Zygomorphic Species of Ranunculaceae

    PubMed Central

    Jabbour, Florian; Cossard, Guillaume; Le Guilloux, Martine; Sannier, Julie; Nadot, Sophie; Damerval, Catherine

    2014-01-01

    Floral bilateral symmetry (zygomorphy) has evolved several times independently in angiosperms from radially symmetrical (actinomorphic) ancestral states. Homologs of the Antirrhinum majus Cycloidea gene (Cyc) have been shown to control floral symmetry in diverse groups in core eudicots. In the basal eudicot family Ranunculaceae, there is a single evolutionary transition from actinomorphy to zygomorphy in the stem lineage of the tribe Delphinieae. We characterized Cyc homologs in 18 genera of Ranunculaceae, including the four genera of Delphinieae, in a sampling that represents the floral morphological diversity of this tribe, and reconstructed the evolutionary history of this gene family in Ranunculaceae. Within each of the two RanaCyL (Ranunculaceae Cycloidea-like) lineages previously identified, an additional duplication possibly predating the emergence of the Delphinieae was found, resulting in up to four gene copies in zygomorphic species. Expression analyses indicate that the RanaCyL paralogs are expressed early in floral buds and that the duration of their expression varies between species and paralog class. At most one RanaCyL paralog was expressed during the late stages of floral development in the actinomorphic species studied whereas all paralogs from the zygomorphic species were expressed, composing a species-specific identity code for perianth organs. The contrasted asymmetric patterns of expression observed in the two zygomorphic species is discussed in relation to their distinct perianth architecture. PMID:24752428

  8. SHOX gene and conserved noncoding element deletions/duplications in Colombian patients with idiopathic short stature

    PubMed Central

    Sandoval, Gloria Tatiana Vinasco; Jaimes, Giovanna Carola; Barrios, Mauricio Coll; Cespedes, Camila; Velasco, Harvy Mauricio

    2014-01-01

    SHOX gene mutations or haploinsufficiency cause a wide range of phenotypes such as Leri Weill dyschondrosteosis (LWD), Turner syndrome, and disproportionate short stature (DSS). However, this gene has also been found to be mutated in cases of idiopathic short stature (ISS) with a 3–15% frequency. In this study, the multiplex ligation-dependent probe amplification (MLPA) technique was employed to determine the frequency of SHOX gene mutations and their conserved noncoding elements (CNE) in Colombian patients with ISS. Patients were referred from different centers around the county. From a sample of 62 patients, 8.1% deletions and insertions in the intragenic regions and in the CNE were found. This result is similar to others published in other countries. Moreover, an isolated case of CNE 9 duplication and a new intron 6b deletion in another patient, associated with ISS, are described. This is one of the first studies of a Latin American population in which deletions/duplications of the SHOX gene and its CNE are examined in patients with ISS. PMID:24689071

  9. The sex-peptide gene (Acp70A) is duplicated in Drosophila subobscura.

    PubMed

    Cirera, S; Aguadé, M

    1998-04-14

    A 3.1-kb region of Drosphila subobscura homologous to the Acp70A region of D. melanogaster, which contains the sex-peptide gene, was cloned and sequenced. This region contains an approximately 600-bp duplication that includes the sex-peptide and its 5' and 3' flanking regions. The preproteins are 54 and 56 amino acids long, respectively (as compared to 55 amino acids in D. melanogaster), and each includes a 19-amino-acid-long signal peptide. The C-terminal part of the mature peptide is highly conserved between D. melanogaster and the two copies of D. subobscura. In this species, both copies of the gene are transcribed and, like in D. melangaster, only expressed in males. The duplicated region includes 300 bp upstream of the gene that would therefore seem sufficient for their expression in males. This region presents at its 5' end a stretch 93-bp that has a high similarity with the corresponding region of D. melanogaster and could be part of a still unidentified regulatory element of these genes.

  10. Rapid Diversification of FoxP2 in Teleosts through Gene Duplication in the Teleost-Specific Whole Genome Duplication Event

    PubMed Central

    Song, Xiaowei; Wang, Yajun; Tang, Yezhong

    2013-01-01

    As one of the most conserved genes in vertebrates, FoxP2 is widely involved in a number of important physiological and developmental processes. We systematically studied the evolutionary history and functional adaptations of FoxP2 in teleosts. The duplicated FoxP2 genes (FoxP2a and FoxP2b), which were identified in teleosts using synteny and paralogon analysis on genome databases of eight organisms, were probably generated in the teleost-specific whole genome duplication event. A credible classification with FoxP2, FoxP2a and FoxP2b in phylogenetic reconstructions confirmed the teleost-specific FoxP2 duplication. The unavailability of FoxP2b in Danio rerio suggests that the gene was deleted through nonfunctionalization of the redundant copy after the Otocephala-Euteleostei split. Heterogeneity in evolutionary rates among clusters consisting of FoxP2 in Sarcopterygii (Cluster 1), FoxP2a in Teleostei (Cluster 2) and FoxP2b in Teleostei (Cluster 3), particularly between Clusters 2 and 3, reveals asymmetric functional divergence after the gene duplication. Hierarchical cluster analyses of hydrophobicity profiles demonstrated significant structural divergence among the three clusters with verification of subsequent stepwise discriminant analysis, in which FoxP2 of Leucoraja erinacea and Lepisosteus oculatus were classified into Cluster 1, whereas FoxP2b of Salmo salar was grouped into Cluster 2 rather than Cluster 3. The simulated thermodynamic stability variations of the forkhead box domain (monomer and homodimer) showed remarkable divergence in FoxP2, FoxP2a and FoxP2b clusters. Relaxed purifying selection and positive Darwinian selection probably were complementary driving forces for the accelerated evolution of FoxP2 in ray-finned fishes, especially for the adaptive evolution of FoxP2a and FoxP2b in teleosts subsequent to the teleost-specific gene duplication. PMID:24349554

  11. Computing the Summed Adjacency Disruption Number between Two Genomes with Duplicate Genes Using Pseudo-Boolean Optimization

    NASA Astrophysics Data System (ADS)

    Delgado, João; Lynce, Inês; Manquinho, Vasco

    The increasing number of fully sequenced genomes has led to the study of genome rearrangements. Several approaches have been proposed to solve this problem, all of them being either too complex to be solved efficiently or too simple to be applied to genomes of complex organisms. The latest challenge has been to overcome the problem of having genomes with duplicate genes. This led to the definition of matching models and similarity measures. The idea is to find a matching between genes in two genomes, in order to disambiguate the data of duplicate genes and calculate a similarity measure. The problem becomes that of finding a matching that best preserves the order of genes in two genomes, where gene order is evaluated by a chosen similarity measure. This paper presents a new pseudo-Boolean encoding for computing the exact summed adjacency disruption number for two genomes with duplicate genes. Experimental results on a γ-Proteobacteria data set illustrate the approach.

  12. The transformer genes in the fig wasp Ceratosolen solmsi provide new evidence for duplications independent of complementary sex determination.

    PubMed

    Jia, L-Y; Xiao, J-H; Xiong, T-L; Niu, L-M; Huang, D-W

    2016-06-01

    Transformer (tra) is the key gene that turns on the sex-determination cascade in Drosophila melanogaster and in some other insects. The honeybee Apis mellifera has two duplicates of tra, one of which (complementary sex determiner, csd) is the primary signal for complementary sex-determination (CSD), regulating the other duplicate (feminizer). Two tra duplicates have been found in some other hymenopteran species, resulting in the assumption that a single ancestral duplication of tra took place in the Hymenoptera. Here, we searched for tra homologues and pseudogenes in the Hymenoptera, focusing on five newly published hymenopteran genomes. We found three tra copies in the fig wasp Ceratosolen solmsi. Further evolutionary and expression analyses also showed that the two duplicates (Csoltra-B and Csoltra-C) are under positive selection, and have female-specific expression, suggesting possible sex-related functions. Moreover, Aculeata species exhibit many pseudogenes generated by lineage-specific duplications. We conclude that phylogenetic reconstruction and pseudogene screening provide novel evidence supporting the hypothesis of independent duplications rather an ancestral origin of multiple tra paralogues in the Hymenoptera. The case of C. solmsi is the first example of a non-CSD species with duplicated tra, contrary to the previous assumption that derived tra paralogues function as the CSD locus.

  13. The narrow sheath duplicate genes: sectors of dual aneuploidy reveal ancestrally conserved gene functions during maize leaf development.

    PubMed Central

    Scanlon, M J; Chen, K D; McKnight CC, I V

    2000-01-01

    The narrow sheath mutant of maize displays a leaf and plant stature phenotype controlled by the duplicate factor mutations narrow sheath1 and narrow sheath2. Mutant leaves fail to develop a lateral domain that includes the leaf margins. Genetic data are presented to show that the narrow sheath mutations map to duplicated chromosomal regions, reflecting an ancestral duplication of the maize genome. Genetic and cytogenetic evidence indicates that the original mutation at narrow sheath2 is associated with a chromosomal inversion on the long arm of chromosome 4. Meristematic sectors of dual aneuploidy were generated, producing plants genetically mosaic for NARROW SHEATH function. These mosaic plants exhibited characteristic half-plant phenotypes, in which leaves from one side of the plant were of nonmutant morphology and leaves from the opposite side were of narrow sheath mutant phenotype. The data suggest that the narrow sheath duplicate genes may perform ancestrally conserved, redundant functions in the development of a lateral domain in the maize leaf. PMID:10880496

  14. Ancient Duplications and Expression Divergence in the Globin Gene Superfamily of Vertebrates: Insights from the Elephant Shark Genome and Transcriptome

    PubMed Central

    Opazo, Juan C.; Toloza-Villalobos, Jessica; Burmester, Thorsten; Venkatesh, Byrappa; Storz, Jay F.

    2015-01-01

    Comparative analyses of vertebrate genomes continue to uncover a surprising diversity of genes in the globin gene superfamily, some of which have very restricted phyletic distributions despite their antiquity. Genomic analysis of the globin gene repertoire of cartilaginous fish (Chondrichthyes) should be especially informative about the duplicative origins and ancestral functions of vertebrate globins, as divergence between Chondrichthyes and bony vertebrates represents the most basal split within the jawed vertebrates. Here, we report a comparative genomic analysis of the vertebrate globin gene family that includes the complete globin gene repertoire of the elephant shark (Callorhinchus milii). Using genomic sequence data from representatives of all major vertebrate classes, integrated analyses of conserved synteny and phylogenetic relationships revealed that the last common ancestor of vertebrates possessed a repertoire of at least seven globin genes: single copies of androglobin and neuroglobin, four paralogous copies of globin X, and the single-copy progenitor of the entire set of vertebrate-specific globins. Combined with expression data, the genomic inventory of elephant shark globins yielded four especially surprising findings: 1) there is no trace of the neuroglobin gene (a highly conserved gene that is present in all other jawed vertebrates that have been examined to date), 2) myoglobin is highly expressed in heart, but not in skeletal muscle (reflecting a possible ancestral condition in vertebrates with single-circuit circulatory systems), 3) elephant shark possesses two highly divergent globin X paralogs, one of which is preferentially expressed in gonads, and 4) elephant shark possesses two structurally distinct α-globin paralogs, one of which is preferentially expressed in the brain. Expression profiles of elephant shark globin genes reveal distinct specializations of function relative to orthologs in bony vertebrates and suggest hypotheses about

  15. Ancient Duplications and Expression Divergence in the Globin Gene Superfamily of Vertebrates: Insights from the Elephant Shark Genome and Transcriptome.

    PubMed

    Opazo, Juan C; Lee, Alison P; Hoffmann, Federico G; Toloza-Villalobos, Jessica; Burmester, Thorsten; Venkatesh, Byrappa; Storz, Jay F

    2015-07-01

    Comparative analyses of vertebrate genomes continue to uncover a surprising diversity of genes in the globin gene superfamily, some of which have very restricted phyletic distributions despite their antiquity. Genomic analysis of the globin gene repertoire of cartilaginous fish (Chondrichthyes) should be especially informative about the duplicative origins and ancestral functions of vertebrate globins, as divergence between Chondrichthyes and bony vertebrates represents the most basal split within the jawed vertebrates. Here, we report a comparative genomic analysis of the vertebrate globin gene family that includes the complete globin gene repertoire of the elephant shark (Callorhinchus milii). Using genomic sequence data from representatives of all major vertebrate classes, integrated analyses of conserved synteny and phylogenetic relationships revealed that the last common ancestor of vertebrates possessed a repertoire of at least seven globin genes: single copies of androglobin and neuroglobin, four paralogous copies of globin X, and the single-copy progenitor of the entire set of vertebrate-specific globins. Combined with expression data, the genomic inventory of elephant shark globins yielded four especially surprising findings: 1) there is no trace of the neuroglobin gene (a highly conserved gene that is present in all other jawed vertebrates that have been examined to date), 2) myoglobin is highly expressed in heart, but not in skeletal muscle (reflecting a possible ancestral condition in vertebrates with single-circuit circulatory systems), 3) elephant shark possesses two highly divergent globin X paralogs, one of which is preferentially expressed in gonads, and 4) elephant shark possesses two structurally distinct α-globin paralogs, one of which is preferentially expressed in the brain. Expression profiles of elephant shark globin genes reveal distinct specializations of function relative to orthologs in bony vertebrates and suggest hypotheses about

  16. Duplication and amplification of antibiotic resistance genes enable increased resistance in isolates of multidrug-resistant Salmonella Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During normal bacterial DNA replication, gene duplication and amplification (GDA) events occur randomly at a low frequency in the genome throughout a population. In the absence of selection, GDA events that increase the number of copies of a bacterial gene (or a set of genes) are lost. Antibiotic ...

  17. Duplication and differentiation of common carp (Cyprinus carpio) myoglobin genes revealed by BAC analysis.

    PubMed

    Zhao, Zi-Xia; Xu, Peng; Cao, Ding-Chen; Kuang, You-Yi; Deng, Hai-Xia; Zhang, Yan; Xu, Li-Ming; Li, Jiong-Tang; Xu, Jian; Sun, Xiao-Wen

    2014-09-15

    Two distinct myoglobin (mb) transcripts have been reported in common carp, Cyprinus carpio, which is a hypoxia-tolerant fish living in habitats with greatly fluctuant dissolved oxygen levels. Recombinant protein analysis has shown functional specialization of the two mb transcripts. In this work, analysis for mb-containing bacterial artificial chromosome (BAC) clones indicated different genome loci for common carp myoglobin-1 (mb-1) and myoglobin-2 (mb-2) genes. Fluorescence in situ hybridization (FISH) revealed that mb-1 and mb-2 are located on separate chromosomes. In both of the mb-1 and mb-2 containing BAC clones, gene synteny was well conserved with the homologous region on zebrafish chromosome 1, supporting that the common carp specific mb-2 gene originated from the recent whole genome duplication event in cyprinid lineage. Transcription factor binding sites search indicated that both common carp mb genes lacked specificity Protein 1 (Sp1) and myocyte enhancer factor-2 (MEF2) binding sites, which mediated muscle-specific and calcium-dependent expression in the well-studied mb promoters. Potential hypoxia response elements (HREs) were predicted in the regulatory region of common carp mb genes. These characteristics of common carp mb gene regulatory region well interpreted the hypoxia-inducible, non-muscle expression pattern of mb-1. In the case of mb-2, a 10 bp insertion to the binding site of upstream stimulatory factor (USF), which was a co-factor of hypoxia inducible factor (HIF), might cause the non-response to hypoxia treatment of mb-2. The case of common carp mb gene duplication and subsequent differentiation in expression pattern and protein function provided an example for adaptive evolution toward aquatic hypoxia tolerance.

  18. Two genes of the anaerobic fungus Orpinomyces sp. strain PC-2 encoding cellulases with endoglucanase activities may have arisen by gene duplication.

    PubMed

    Chen, H; Li, X L; Blum, D L; Ljungdahl, L G

    1998-02-01

    A cDNA designated celE cloned from Orpinomyces PC-2 consisted of an open reading frame encoding a polypeptide (CelE) of 477 amino acids. CelE was highly homologous to CelBs of Orpinomyces (72.3% identity) and neocallimastix (67.9% identity) and like them it had a non-catalytic repeated peptide domain (NCRPD) at the C-terminal end. The catalytic domain of CelE was homologous to glycosyl hydrolases of Family 5, found in several anaerobic bacteria. The gene of celE was devoid of introns. The recombinant proteins CelE and CelB of Orpinomyces PC-2 randomly hydrolyzed carboxymethylcellulose and cello-oligosaccharides in the pattern of endoglucanases. The results indicated that a gene of bacterial origin was duplicated to form celE and celB of Orpinomyces PC-2.

  19. Evolutionary analysis of two complement C4 genes: Ancient duplication and conservation during jawed vertebrate evolution.

    PubMed

    Nonaka, Mayumi I; Terado, Tokio; Kimura, Hiroshi; Nonaka, Masaru

    2017-03-01

    The complement C4 is a thioester-containing protein, and a histidine (H) residue catalyzes the cleavage of the thioester to allow covalent binding to carbohydrates on target cells. Some mammalian and teleost species possess an additional isotype where the catalytic H is replaced by an aspartic acid (D), which binds preferentially to proteins. We found the two C4 isotypes in many other jawed vertebrates, including sharks and birds/reptiles. Phylogenetic analysis suggested that C4 gene duplication occurred in the early days of the jawed vertebrate evolution. The D-type C4 of bony fish except for mammals formed a cluster, termed D-lineage. The D-lineage genes were located in a syntenic region outside MHC, and evolved conservatively. Mammals lost the D-lineage before speciation, but D-type C4 was regenerated by recent gene duplication in some mammalian species or groups. Dual C4 molecules with different substrate specificities would have contributed to development of the antibody-dependent classical pathway.

  20. A Large Palindrome With Interchromosomal Gene Duplications in the Pericentromeric Region of the D. melanogaster Y Chromosome

    PubMed Central

    Méndez-Lago, María; Bergman, Casey M.; de Pablos, Beatriz; Tracey, Alan; Whitehead, Siobhan L.; Villasante, Alfredo

    2011-01-01

    The non-recombining Y chromosome is expected to degenerate over evolutionary time, however, gene gain is a common feature of Y chromosomes of mammals and Drosophila. Here, we report that a large palindrome containing interchromosomal segmental duplications is located in the vicinity of the first amplicon detected in the Y chromosome of D. melanogaster. The recent appearance of such amplicons suggests that duplications to the Y chromosome, followed by the amplification of the segmental duplications, are a mechanism for the continuing evolution of Drosophila Y chromosomes. PMID:21297157

  1. An ace-1 gene duplication resorbs the fitness cost associated with resistance in Anopheles gambiae, the main malaria mosquito

    PubMed Central

    Assogba, Benoît S.; Djogbénou, Luc S.; Milesi, Pascal; Berthomieu, Arnaud; Perez, Julie; Ayala, Diego; Chandre, Fabrice; Makoutodé, Michel; Labbé, Pierrick; Weill, Mylène

    2015-01-01

    Widespread resistance to pyrethroids threatens malaria control in Africa. Consequently, several countries switched to carbamates and organophophates insecticides for indoor residual spraying. However, a mutation in the ace-1 gene conferring resistance to these compounds (ace-1R allele), is already present. Furthermore, a duplicated allele (ace-1D) recently appeared; characterizing its selective advantage is mandatory to evaluate the threat. Our data revealed that a unique duplication event, pairing a susceptible and a resistant copy of the ace-1 gene spread through West Africa. Further investigations revealed that, while ace-1D confers less resistance than ace-1R, the high fitness cost associated with ace-1R is almost completely suppressed by the duplication for all traits studied. ace-1 duplication thus represents a permanent heterozygote phenotype, selected, and thus spreading, due to the mosaic nature of mosquito control. It provides malaria mosquito with a new evolutionary path that could hamper resistance management. PMID:26434951

  2. Fc-receptor and M-protein genes of group A streptococci are products of gene duplication.

    PubMed Central

    Heath, D G; Cleary, P P

    1989-01-01

    The partial nucleotide sequence for an Fc-receptor gene from an M-type 76 group A streptococcus was determined. DNA sequence analysis revealed considerable sequence similarity between the Fc-receptor and M-protein genes in their proposed promoter regions, signal sequences, and 3' termini. Additional analysis indicated that the deduced Fc-receptor protein contains a proline-rich region and membrane anchor region highly similar to that of M protein. In view of these results, we postulated that Fc-receptor and M-protein genes of group A streptococci are the products of gene duplication from a common ancestral gene. It is proposed that DNA sequence similarity between these two genes may allow for extragenic homologous recombination as a means of generating antigenic diversity in these two surface proteins. PMID:2660147

  3. Different evolutionary histories of two cation/proton exchanger gene families in plants

    PubMed Central

    2013-01-01

    Background Gene duplication events have been proposed to be involved in the adaptation of plants to stress conditions; precisely how is unclear. To address this question, we studied the evolution of two families of antiporters. Cation/proton exchangers are important for normal cell function and in plants, Na+,K+/H+ antiporters have also been implicated in salt tolerance. Two well-known plant cation/proton antiporters are NHX1 and SOS1, which perform Na+ and K+ compartmentalization into the vacuole and Na+ efflux from the cell, respectively. However, our knowledge about the evolution of NHX and SOS1 stress responsive gene families is still limited. Results In this study we performed a comprehensive molecular evolutionary analysis of the NHX and SOS1 families. Using available sequences from a total of 33 plant species, we estimated gene family phylogenies and gene duplication histories, as well as examined heterogeneous selection pressure on amino acid sites. Our results show that, while the NHX family expanded and specialized, the SOS1 family remained a low copy gene family that appears to have undergone neofunctionalization during its evolutionary history. Additionally, we found that both families are under purifying selection although SOS1 is less constrained. Conclusions We propose that the different evolution histories are related with the proteins’ function and localization, and that the NHX and SOS1 families are examples of two different evolutionary paths through which duplication events may result in adaptive evolution of stress tolerance. PMID:23822194

  4. Gene duplication and the evolution of hemoglobin isoform differentiation in birds.

    PubMed

    Grispo, Michael T; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E; Storz, Jay F

    2012-11-02

    The majority of bird species co-express two functionally distinct hemoglobin (Hb) isoforms in definitive erythrocytes as follows: HbA (the major adult Hb isoform, with α-chain subunits encoded by the α(A)-globin gene) and HbD (the minor adult Hb isoform, with α-chain subunits encoded by the α(D)-globin gene). The α(D)-globin gene originated via tandem duplication of an embryonic α-like globin gene in the stem lineage of tetrapod vertebrates, which suggests the possibility that functional differentiation between the HbA and HbD isoforms may be attributable to a retained ancestral character state in HbD that harkens back to a primordial, embryonic function. To investigate this possibility, we conducted a combined analysis of protein biochemistry and sequence evolution to characterize the structural and functional basis of Hb isoform differentiation in birds. Functional experiments involving purified HbA and HbD isoforms from 11 different bird species revealed that HbD is characterized by a consistently higher O(2) affinity in the presence of allosteric effectors such as organic phosphates and Cl(-) ions. In the case of both HbA and HbD, analyses of oxygenation properties under the two-state Monod-Wyman-Changeux allosteric model revealed that the pH dependence of Hb-O(2) affinity stems primarily from changes in the O(2) association constant of deoxy (T-state)-Hb. Ancestral sequence reconstructions revealed that the amino acid substitutions that distinguish the adult-expressed Hb isoforms are not attributable to the retention of an ancestral (pre-duplication) character state in the α(D)-globin gene that is shared with the embryonic α-like globin gene.

  5. Gene Duplication and the Evolution of Hemoglobin Isoform Differentiation in Birds*

    PubMed Central

    Grispo, Michael T.; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E.; Storz, Jay F.

    2012-01-01

    The majority of bird species co-express two functionally distinct hemoglobin (Hb) isoforms in definitive erythrocytes as follows: HbA (the major adult Hb isoform, with α-chain subunits encoded by the αA-globin gene) and HbD (the minor adult Hb isoform, with α-chain subunits encoded by the αD-globin gene). The αD-globin gene originated via tandem duplication of an embryonic α-like globin gene in the stem lineage of tetrapod vertebrates, which suggests the possibility that functional differentiation between the HbA and HbD isoforms may be attributable to a retained ancestral character state in HbD that harkens back to a primordial, embryonic function. To investigate this possibility, we conducted a combined analysis of protein biochemistry and sequence evolution to characterize the structural and functional basis of Hb isoform differentiation in birds. Functional experiments involving purified HbA and HbD isoforms from 11 different bird species revealed that HbD is characterized by a consistently higher O2 affinity in the presence of allosteric effectors such as organic phosphates and Cl− ions. In the case of both HbA and HbD, analyses of oxygenation properties under the two-state Monod-Wyman-Changeux allosteric model revealed that the pH dependence of Hb-O2 affinity stems primarily from changes in the O2 association constant of deoxy (T-state)-Hb. Ancestral sequence reconstructions revealed that the amino acid substitutions that distinguish the adult-expressed Hb isoforms are not attributable to the retention of an ancestral (pre-duplication) character state in the αD-globin gene that is shared with the embryonic α-like globin gene. PMID:22962007

  6. Phylogenetic analysis of eukaryotic NEET proteins uncovers a link between a key gene duplication event and the evolution of vertebrates

    PubMed Central

    Inupakutika, Madhuri A.; Sengupta, Soham; Nechushtai, Rachel; Jennings, Patricia A.; Onuchic, Jose’ N.; Azad, Rajeev K.; Padilla, Pamela; Mittler, Ron

    2017-01-01

    NEET proteins belong to a unique family of iron-sulfur proteins in which the 2Fe-2S cluster is coordinated by a CDGSH domain that is followed by the “NEET” motif. They are involved in the regulation of iron and reactive oxygen metabolism, and have been associated with the progression of diabetes, cancer, aging and neurodegenerative diseases. Despite their important biological functions, the evolution and diversification of eukaryotic NEET proteins are largely unknown. Here we used the three members of the human NEET protein family (CISD1, mitoNEET; CISD2, NAF-1 or Miner 1; and CISD3, Miner2) as our guides to conduct a phylogenetic analysis of eukaryotic NEET proteins and their evolution. Our findings identified the slime mold Dictyostelium discoideum’s CISD proteins as the closest to the ancient archetype of eukaryotic NEET proteins. We further identified CISD3 homologs in fungi that were previously reported not to contain any NEET proteins, and revealed that plants lack homolog(s) of CISD3. Furthermore, our study suggests that the mammalian NEET proteins, mitoNEET (CISD1) and NAF-1 (CISD2), emerged via gene duplication around the origin of vertebrates. Our findings provide new insights into the classification and expansion of the NEET protein family, as well as offer clues to the diverged functions of the human mitoNEET and NAF-1 proteins. PMID:28205535

  7. Phylogenetic analysis of eukaryotic NEET proteins uncovers a link between a key gene duplication event and the evolution of vertebrates

    NASA Astrophysics Data System (ADS)

    Inupakutika, Madhuri A.; Sengupta, Soham; Nechushtai, Rachel; Jennings, Patricia A.; Onuchic, Jose’ N.; Azad, Rajeev K.; Padilla, Pamela; Mittler, Ron

    2017-02-01

    NEET proteins belong to a unique family of iron-sulfur proteins in which the 2Fe-2S cluster is coordinated by a CDGSH domain that is followed by the “NEET” motif. They are involved in the regulation of iron and reactive oxygen metabolism, and have been associated with the progression of diabetes, cancer, aging and neurodegenerative diseases. Despite their important biological functions, the evolution and diversification of eukaryotic NEET proteins are largely unknown. Here we used the three members of the human NEET protein family (CISD1, mitoNEET; CISD2, NAF-1 or Miner 1; and CISD3, Miner2) as our guides to conduct a phylogenetic analysis of eukaryotic NEET proteins and their evolution. Our findings identified the slime mold Dictyostelium discoideum’s CISD proteins as the closest to the ancient archetype of eukaryotic NEET proteins. We further identified CISD3 homologs in fungi that were previously reported not to contain any NEET proteins, and revealed that plants lack homolog(s) of CISD3. Furthermore, our study suggests that the mammalian NEET proteins, mitoNEET (CISD1) and NAF-1 (CISD2), emerged via gene duplication around the origin of vertebrates. Our findings provide new insights into the classification and expansion of the NEET protein family, as well as offer clues to the diverged functions of the human mitoNEET and NAF-1 proteins.

  8. Evolution of microRNA genes in Oryza sativa and Arabidopsis thaliana: an update of the inverted duplication model.

    PubMed

    Zhang, Yun; Jiang, Wen-kai; Gao, Li-zhi

    2011-01-01

    The origin and evolution of microRNA (miRNA) genes, which are of significance in tuning and buffering gene expressions in a number of critical cellular processes, have long attracted evolutionary biologists. However, genome-wide perspectives on their origins, potential mechanisms of their de novo generation and subsequent evolution remain largely unsolved in flowering plants. Here, genome-wide analyses of Oryza sativa and Arabidopsis thaliana revealed apparently divergent patterns of miRNA gene origins. A large proportion of miRNA genes in O. sativa were TE-related and MITE-related miRNAs in particular, whereas the fraction of these miRNA genes much decreased in A. thaliana. Our results show that the majority of TE-related and pseudogene-related miRNA genes have originated through inverted duplication instead of segmental or tandem duplication events. Based on the presented findings, we hypothesize and illustrate the four likely molecular mechanisms to de novo generate novel miRNA genes from TEs and pseudogenes. Our rice genome analysis demonstrates that non-MITEs and MITEs mediated inverted duplications have played different roles in de novo generating miRNA genes. It is confirmed that the previously proposed inverted duplication model may give explanations for non-MITEs mediated duplication events. However, many other miRNA genes, known from the earlier proposed model, were rather arisen from MITE transpositions into target genes to yield binding sites. We further investigated evolutionary processes spawned from de novo generated to maturely-formed miRNA genes and their regulatory systems. We found that miRNAs increase the tunability of some gene regulatory systems with low gene copy numbers. The results also suggest that gene balance effects may have largely contributed to the evolution of miRNA regulatory systems.

  9. The Histone Modification H3K27me3 Is Retained after Gene Duplication and Correlates with Conserved Noncoding Sequences in Arabidopsis

    PubMed Central

    Berke, Lidija; Snel, Berend

    2014-01-01

    The histone modification H3K27me3 is involved in repression of transcription and plays a crucial role in developmental transitions in both animals and plants. It is deposited by PRC2 (Polycomb repressive complex 2), a conserved protein complex. In Arabidopsis thaliana, H3K27me3 is found at 15% of all genes. These tend to encode transcription factors and other regulators important for development. However, it is not known how PRC2 is recruited to target loci nor how this set of target genes arose during Arabidopsis evolution. To resolve the latter, we integrated A. thaliana gene families with five independent genome-wide H3K27me3 data sets. Gene families were either significantly enriched or depleted of H3K27me3, showing a strong impact of shared ancestry to H3K27me3 distribution. To quantify this, we performed ancestral state reconstruction of H3K27me3 on phylogenetic trees of gene families. The set of H3K27me3-marked genes changed less than expected by chance, suggesting that H3K27me3 was retained after gene duplication. This retention suggests that the PRC2-recruiting signal could be encoded in the DNA and also conserved among certain duplicated genes. Indeed, H3K27me3-marked genes were overrepresented among paralogs sharing conserved noncoding sequences (CNSs) that are enriched with transcription factor binding sites. The association of upstream CNSs with H3K27me3-marked genes represents the first genome-wide connection between H3K27me3 and potential regulatory elements in plants. Thus, we propose that CNSs likely function as part of the PRC2 recruitment in plants. PMID:24567304

  10. On the origin of protein synthesis factors: a gene duplication/fusion model.

    PubMed

    Cousineau, B; Leclerc, F; Cedergren, R

    1997-12-01

    Sequence similarity has given rise to the proposal that IF-2, EF-G, and EF-Tu are related through a common ancestor. We evaluate this proposition and whether the relationship can be extended to other factors of protein synthesis. Analysis of amino acid sequence similarity gives statistical support for an evolutionary affiliation among IF-1, IF-2, IF-3, EF-Tu, EF-Ts, and EF-G and suggests further that this association is a result of gene duplication/fusion events. In support of this mechanism, the three-dimensional structures of IF-3, EF-Tu, and EF-G display a predictable domain structure and overall conformational similarity. The model that we propose consists of three consecutives duplication/fusion events which would have taken place before the divergence of the three superkingdoms: eubacteria, archaea, and eukaryotes. The root of this protein superfamily tree would be an ancestor of the modern IF-1 gene sequence. The repeated fundamental motif of this protein superfamily is a small RNA binding domain composed of two alpha-helices packed along side of an antiparallel beta-sheet.

  11. Contrasted patterns of selection since maize domestication on duplicated genes encoding a starch pathway enzyme.

    PubMed

    Corbi, J; Debieu, M; Rousselet, A; Montalent, P; Le Guilloux, M; Manicacci, D; Tenaillon, M I

    2011-03-01

    Maize domestication from teosinte (Zea mays ssp. parviglumis) was accompanied by an increase of kernel size in landraces. Subsequent breeding has led to a diversification of kernel size and starch content among major groups of inbred lines. We aim at investigating the effect of domestication on duplicated genes encoding a key enzyme of the starch pathway, the ADP-glucose pyrophosphorylase (AGPase). Three pairs of paralogs encode the AGPase small (SSU) and large (LSU) subunits mainly expressed in the endosperm, the embryo and the leaf. We first validated the putative sequence of LSU(leaf) through a comparative expression assay of the six genes. Second, we investigated the patterns of molecular evolution on a 2 kb coding region homologous among the six genes in three panels: teosintes, landraces, and inbred lines. We corrected for demographic effects by relying on empirical distributions built from 580 previously sequenced ESTs. We found contrasted patterns of selection among duplicates: three genes exhibit patterns of directional selection during domestication (SSU(end), LSU(emb)) or breeding (LSU(leaf)), two exhibit patterns consistent with diversifying (SSU(leaf)) and balancing selection (SSU(emb)) accompanying maize breeding. While patterns of linkage disequilibrium did not reveal sign of coevolution between genes expressed in the same organ, we detected an excess of non-synonymous substitutions in the small subunit functional domains highlighting their role in AGPase evolution. Our results offer a different picture on AGPase evolution than the one depicted at the Angiosperm level and reveal how genetic redundancy can provide flexibility in the response to selection.

  12. Duplication at chromosome 2q31.1-q31.2 in a family presenting syndactyly and nystagmus.

    PubMed

    Ghoumid, Jamal; Andrieux, Joris; Sablonnière, Bernard; Odent, Sylvie; Philippe, Nathalie; Zanlonghi, Xavier; Saugier-Veber, Pascale; Bardyn, Thomas; Manouvrier-Hanu, Sylvie; Holder-Espinasse, Muriel

    2011-11-01

    HOXD genes encode transcription factors involved in the antero-posterior patterning of the limb bud and in the specification of fingers. During the embryo development, HOXD genes are expressed, following a spatio-temporal colinearity that involves at least three regions, centrometric and telomeric to this cluster. Here, we describe a father and a daughter presenting a 3-4 hand bilateral syndactyly associated with a nystagmus. Array-comparative genomic hybridisation showed a 3.8 Mb duplication at 2q31.1-q31.2, comprising 27 genes including the entire HOXD cluster. We performed expression studies in lymphoblasts by reverse transcription-PCR and observed an HOXD13 and HOXD10 overexpression, whereas the HOXD12 expression was decreased. HOXD13 and HOXD10 overexpression, associated with a misregulation of at least HOXD12, may therefore induce the syndactyly. Deletions of the HOXD cluster and its regulatory sequences induce hand malformations and, particularly, finger anomalies. Recently, smaller duplications of the same region have been reported in association with a mesomelic dysplasia, type Kantaputra. We discuss the variable phenotypes associated with such 2q duplications.

  13. Evolution of C, D and S-type cystatins in mammals: an extensive gene duplication in primates.

    PubMed

    de Sousa-Pereira, Patrícia; Abrantes, Joana; Pinheiro, Ana; Colaço, Bruno; Vitorino, Rui; Esteves, Pedro J

    2014-01-01

    Cystatins are a family of inhibitors of cysteine peptidases that comprises the salivary cystatins (D and S-type cystatins) and cystatin C. These cystatins are encoded by a multigene family (CST3, CST5, CST4, CST1 and CST2) organized in tandem in the human genome. Their presence and functional importance in human saliva has been reported, however the distribution of these proteins in other mammals is still unclear. Here, we performed a proteomic analysis of the saliva of several mammals and studied the evolution of this multigene family. The proteomic analysis detected S-type cystatins (S, SA, and SN) in human saliva and cystatin D in rat saliva. The evolutionary analysis showed that the cystatin C encoding gene is present in species of the most representative mammalian groups, i.e. Artiodactyla, Rodentia, Lagomorpha, Carnivora and Primates. On the other hand, D and S-type cystatins are mainly retrieved from Primates, and especially the evolution of S-type cystatins seems to be a dynamic process as seen in Pongo abelii genome where several copies of CST1-like gene (cystatin SN) were found. In Rodents, a group of cystatins previously identified as D and S has also evolved. Despite the high divergence of the amino acid sequence, their position in the phylogenetic tree and their genome organization suggests a common origin with those of the Primates. These results suggest that the D and S type cystatins have emerged before the mammalian radiation and were retained only in Primates and Rodents. Although the mechanisms driving the evolution of cystatins are unknown, it seems to be a dynamic process with several gene duplications evolving according to the birth-and-death model of evolution. The factors that led to the appearance of a group of saliva-specific cystatins in Primates and its rapid evolution remain undetermined, but may be associated with an adaptive advantage.

  14. Resolution and reconciliation of non-binary gene trees with transfers, duplications and losses.

    PubMed

    Jacox, Edwin; Weller, Mathias; Tannier, Eric; Scornavacca, Celine

    2017-01-10

    Gene trees reconstructed from sequence alignments contain poorly supported branches when the phylogenetic signal in the sequences is insufficient to determine them all. When a species tree is available, the signal of gains and losses of genes can be used to correctly resolve the unsupported parts of the gene history. However finding a most parsimonious binary resolution of a non-binary tree obtained by contracting the unsupported branches is NP-hard if transfer events are considered as possible gene scale events, in addition to gene origination, duplication and loss. We propose an exact, parameterized algorithm to solve this problem in single-exponential time, where the parameter is the number of connected branches of the gene tree that show low support from the sequence alignment or, equivalently, the maximum number of children of any node of the gene tree once the low-support branches have been collapsed. This improves on the best known algorithm by an exponential factor. We propose a way to choose among optimal solutions based on the available information. We show the usability of this principle on several simulated and biological datasets. The results are comparable in quality to several other tested methods having similar goals, but our approach provides a lower running time and a guarantee that the produced solution is optimal.

  15. Recommended nomenclature for five mammalian carboxylesterase gene families: human, mouse, and rat genes and proteins.

    PubMed

    Holmes, Roger S; Wright, Matthew W; Laulederkind, Stanley J F; Cox, Laura A; Hosokawa, Masakiyo; Imai, Teruko; Ishibashi, Shun; Lehner, Richard; Miyazaki, Masao; Perkins, Everett J; Potter, Phillip M; Redinbo, Matthew R; Robert, Jacques; Satoh, Tetsuo; Yamashita, Tetsuro; Yan, Bingfan; Yokoi, Tsuyoshi; Zechner, Rudolf; Maltais, Lois J

    2010-10-01

    Mammalian carboxylesterase (CES or Ces) genes encode enzymes that participate in xenobiotic, drug, and lipid metabolism in the body and are members of at least five gene families. Tandem duplications have added more genes for some families, particularly for mouse and rat genomes, which has caused confusion in naming rodent Ces genes. This article describes a new nomenclature system for human, mouse, and rat carboxylesterase genes that identifies homolog gene families and allocates a unique name for each gene. The guidelines of human, mouse, and rat gene nomenclature committees were followed and "CES" (human) and "Ces" (mouse and rat) root symbols were used followed by the family number (e.g., human CES1). Where multiple genes were identified for a family or where a clash occurred with an existing gene name, a letter was added (e.g., human CES4A; mouse and rat Ces1a) that reflected gene relatedness among rodent species (e.g., mouse and rat Ces1a). Pseudogenes were named by adding "P" and a number to the human gene name (e.g., human CES1P1) or by using a new letter followed by ps for mouse and rat Ces pseudogenes (e.g., Ces2d-ps). Gene transcript isoforms were named by adding the GenBank accession ID to the gene symbol (e.g., human CES1_AB119995 or mouse Ces1e_BC019208). This nomenclature improves our understanding of human, mouse, and rat CES/Ces gene families and facilitates research into the structure, function, and evolution of these gene families. It also serves as a model for naming CES genes from other mammalian species.

  16. Gene Family Expansions in Aphids Maintained by Endosymbiotic and Nonsymbiotic Traits

    PubMed Central

    Duncan, Rebecca P.; Feng, Honglin; Nguyen, Douglas M.; Wilson, Alex C. C.

    2016-01-01

    Facilitating the evolution of new gene functions, gene duplication is a major mechanism driving evolutionary innovation. Gene family expansions relevant to host/symbiont interactions are increasingly being discovered in eukaryotes that host endosymbiotic microbes. Such discoveries entice speculation that gene duplication facilitates the evolution of novel, endosymbiotic relationships. Here, using a comparative transcriptomic approach combined with differential gene expression analysis, we investigate the importance of endosymbiosis in retention of amino acid transporter paralogs in aphid genomes. To pinpoint the timing of amino acid transporter duplications we inferred gene phylogenies for five aphid species and three outgroups. We found that while some duplications arose in the aphid common ancestor concurrent with endosymbiont acquisition, others predate aphid divergence from related insects without intracellular symbionts, and still others appeared during aphid diversification. Interestingly, several aphid-specific paralogs have conserved enriched expression in bacteriocytes, the insect cells that host primary symbionts. Conserved bacteriocyte enrichment suggests that the transporters were recruited to the aphid/endosymbiont interface in the aphid common ancestor, consistent with a role for gene duplication in facilitating the evolution of endosymbiosis in aphids. In contrast, the temporal variability of amino acid transporter duplication indicates that endosymbiosis is not the only trait driving selection for retention of amino acid transporter paralogs in sap-feeding insects. This study cautions against simplistic interpretations of the role of gene family expansion in the evolution of novel host/symbiont interactions by further highlighting that multiple complex factors maintain gene family paralogs in the genomes of eukaryotes that host endosymbiotic microbes. PMID:26878871

  17. Gene Family Expansions in Aphids Maintained by Endosymbiotic and Nonsymbiotic Traits.

    PubMed

    Duncan, Rebecca P; Feng, Honglin; Nguyen, Douglas M; Wilson, Alex C C

    2016-02-15

    Facilitating the evolution of new gene functions, gene duplication is a major mechanism driving evolutionary innovation. Gene family expansions relevant to host/symbiont interactions are increasingly being discovered in eukaryotes that host endosymbiotic microbes. Such discoveries entice speculation that gene duplication facilitates the evolution of novel, endosymbiotic relationships. Here, using a comparative transcriptomic approach combined with differential gene expression analysis, we investigate the importance of endosymbiosis in retention of amino acid transporter paralogs in aphid genomes. To pinpoint the timing of amino acid transporter duplications we inferred gene phylogenies for five aphid species and three outgroups. We found that while some duplications arose in the aphid common ancestor concurrent with endosymbiont acquisition, others predate aphid divergence from related insects without intracellular symbionts, and still others appeared during aphid diversification. Interestingly, several aphid-specific paralogs have conserved enriched expression in bacteriocytes, the insect cells that host primary symbionts. Conserved bacteriocyte enrichment suggests that the transporters were recruited to the aphid/endosymbiont interface in the aphid common ancestor, consistent with a role for gene duplication in facilitating the evolution of endosymbiosis in aphids. In contrast, the temporal variability of amino acid transporter duplication indicates that endosymbiosis is not the only trait driving selection for retention of amino acid transporter paralogs in sap-feeding insects. This study cautions against simplistic interpretations of the role of gene family expansion in the evolution of novel host/symbiont interactions by further highlighting that multiple complex factors maintain gene family paralogs in the genomes of eukaryotes that host endosymbiotic microbes.

  18. Sgs1 and Exo1 suppress targeted chromosome duplication during ends-in and ends-out gene targeting.

    PubMed

    Štafa, Anamarija; Miklenić, Marina; Zunar, Bojan; Lisnić, Berislav; Symington, Lorraine S; Svetec, Ivan-Krešimir

    2014-10-01

    Gene targeting is extremely efficient in the yeast Saccharomyces cerevisiae. It is performed by transformation with a linear, non-replicative DNA fragment carrying a selectable marker and containing ends homologous to the particular locus in a genome. However, even in S. cerevisiae, transformation can result in unwanted (aberrant) integration events, the frequency and spectra of which are quite different for ends-out and ends-in transformation assays. It has been observed that gene replacement (ends-out gene targeting) can result in illegitimate integration, integration of the transforming DNA fragment next to the target sequence and duplication of a targeted chromosome. By contrast, plasmid integration (ends-in gene targeting) is often associated with multiple targeted integration events but illegitimate integration is extremely rare and a targeted chromosome duplication has not been reported. Here we systematically investigated the influence of design of the ends-out assay on the success of targeted genetic modification. We have determined transformation efficiency, fidelity of gene targeting and spectra of all aberrant events in several ends-out gene targeting assays designed to insert, delete or replace a particular sequence in the targeted region of the yeast genome. Furthermore, we have demonstrated for the first time that targeted chromosome duplications occur even during ends-in gene targeting. Most importantly, the whole chromosome duplication is POL32 dependent pointing to break-induced replication (BIR) as the underlying mechanism. Moreover, the occurrence of duplication of the targeted chromosome was strikingly increased in the exo1Δ sgs1Δ double mutant but not in the respective single mutants demonstrating that the Exo1 and Sgs1 proteins independently suppress whole chromosome duplication during gene targeting.

  19. Evolutionary History of Chordate PAX Genes: Dynamics of Change in a Complex Gene Family

    PubMed Central

    Paixão-Côrtes, Vanessa Rodrigues; Salzano, Francisco Mauro; Bortolini, Maria Cátira

    2013-01-01

    Paired box (PAX) genes are transcription factors that play important roles in embryonic development. Although the PAX gene family occurs in animals only, it is widely distributed. Among the vertebrates, its 9 genes appear to be the product of complete duplication of an original set of 4 genes, followed by an additional partial duplication. Although some studies of PAX genes have been conducted, no comprehensive survey of these genes across the entire taxonomic unit has yet been attempted. In this study, we conducted a detailed comparison of PAX sequences from 188 chordates, which revealed restricted variation. The absence of PAX4 and PAX8 among some species of reptiles and birds was notable; however, all 9 genes were present in all 74 mammalian genomes investigated. A search for signatures of selection indicated that all genes are subject to purifying selection, with a possible constraint relaxation in PAX4, PAX7, and PAX8. This result indicates asymmetric evolution of PAX family genes, which can be associated with the emergence of adaptive novelties in the chordate evolutionary trajectory. PMID:24023886

  20. Duplication of the NPHP1 gene in patients with autism spectrum disorder and normal intellectual ability: a case series.

    PubMed

    Yasuda, Yuka; Hashimoto, Ryota; Fukai, Ryoko; Okamoto, Nobuhiko; Hiraki, Yoko; Yamamori, Hidenaga; Fujimoto, Michiko; Ohi, Kazutaka; Taniike, Masako; Mohri, Ikuko; Nakashima, Mitsuko; Tsurusaki, Yoshinori; Saitsu, Hirotomo; Matsumoto, Naomichi; Miyake, Noriko; Takeda, Masatoshi

    2014-01-01

    Autism spectrum disorder is a neurodevelopmental disorder characterized by impairments in social interactions, reduced verbal communication abilities, stereotyped repetitive behaviors, and restricted interests. It is a complex condition caused by genetic and environmental factors; the high heritability of this disorder supports the presence of a significant genetic contribution. Many studies have suggested that copy-number variants contribute to the etiology of autism spectrum disorder. Recently, copy-number variants of the nephronophthisis 1 gene have been reported in patients with autism spectrum disorder. To the best of our knowledge, only six autism spectrum disorder cases with duplications of the nephronophthisis 1 gene have been reported. These patients exhibited intellectual dysfunction, including verbal dysfunction in one patient, below-average verbal intellectual ability in one patient, and intellectual disability in four patients. In this study, we identified nephronophthisis 1 duplications in two unrelated Japanese patients with autism spectrum disorder using a high-resolution single-nucleotide polymorphism array. This report is the first to describe a nephronophthisis 1 duplication in an autism spectrum disorder patient with an average verbal intelligence quotient and an average performance intelligence quotient. However, the second autism spectrum disorder patient with a nephronophthisis 1 duplication had a below-average performance intelligence quotient. Neither patient exhibited physical dysfunction, motor developmental delay, or neurological abnormalities. This study supports the clinical observation of nephronophthisis 1 duplication in autism spectrum disorder cases and might contribute to our understanding of the clinical phenotype that arises from this duplication.

  1. Chromosome 15q11-13 duplication syndrome brain reveals epigenetic alterations in gene expression not predicted from copy number

    PubMed Central

    Hogart, Amber; Leung, Karen N.; Wang, Nicholas J.; Wu, David J.; Driscoll, Jennette; Vallero, Roxanne O.; Schanen, N. Carolyn

    2008-01-01

    Background Chromosome 15q11-13 contains a cluster of imprinted genes essential for normal mammalian neurodevelopment. Deficiencies in paternal or maternal 15q11-13 alleles result in Prader-Willi or Angelman syndromes, respectively, and maternal duplications lead to a distinct condition that often includes autism. Overexpression of maternally expressed imprinted genes is predicted to cause 15q11-13-associated autism, but a link between gene dosage and expression has not been experimentally determined in brain. Methods Post-mortem brain tissue was obtained from a male with 15q11-13 hexasomy and a female with 15q11-13 tetrasomy. Quantitative RT-PCR was used to measure ten 15q11-13 transcripts in maternal 15q11-13 duplication, Prader-Willi syndrome, and control brain samples. Southern blot, bisulfite sequencing and fluorescence in situ hybridization were used to investigate epigenetic mechanisms of gene regulation. Results Gene expression and DNA methylation correlated with parental gene dosage in the male 15q11-13 duplication sample with severe cognitive impairment and seizures. Strikingly, the female with autism and milder Prader-Willi-like characteristics demonstrated unexpected deficiencies in the paternally expressed transcripts SNRPN, NDN, HBII85, and HBII52 and unchanged levels of maternally expressed UBE3A compared to controls. Paternal expression abnormalities in the female duplication sample were consistent with elevated DNA methylation of the 15q11-13 imprinting control region (ICR). Expression of nonimprinted 15q11-13 GABA receptor subunit genes was significantly reduced specifically in the female 15q11-13 duplication brain without detectable GABRB3 methylation differences. Conclusion Our findings suggest that genetic copy number changes combined with additional genetic or environmental influences on epigenetic mechanisms impact outcome and clinical heterogeneity of 15q11-13 duplication syndromes. PMID:18835857

  2. The carboxylesterase/cholinesterase gene family in invertebrate deuterostomes.

    PubMed

    Johnson, Glynis; Moore, Samuel W

    2012-06-01

    Carboxylesterase/cholinesterase family members are responsible for controlling the nerve impulse, detoxification and various developmental functions, and are a major target of pesticides and chemical warfare agents. Comparative structural analysis of these enzymes is thus important. The invertebrate deuterostomes (phyla Echinodermata and Hemichordata and subphyla Urochordata and Cephalochordata) lie in the transition zone between invertebrates and vertebrates, and are thus of interest to the study of evolution. Here we have investigated the carboxylesterase/cholinesterase gene family in the sequenced genomes of Strongylocentrotus purpuratus (Echinodermata), Saccoglossus kowalevskii (Hemichordata), Ciona intestinalis (Urochordata) and Branchiostoma floridae (Cephalochordata), using sequence analysis of the catalytic apparatus and oligomerisation domains, and phylogenetic analysis. All four genomes show blurring of structural boundaries between cholinesterases and carboxylesterases, with many intermediate enzymes. Non-enzymatic proteins are well represented. The Saccoglossus and Branchiostoma genomes show evidence of extensive gene duplication and retention. There is also evidence of domain shuffling, resulting in multidomain proteins consisting either of multiple carboxylesterase domains, or of carboxylesterase/cholinesterase domains linked to other domains, including RING finger, chitin-binding, immunoglobulin, fibronectin type 3, CUB, cysteine-rich-Frizzled, caspase activation and 7tm-1, amongst others. Such gene duplication and domain shuffling in the carboxylesterase/cholinesterase family appears to be unique to the invertebrate deuterostomes, and we hypothesise that these factors may have contributed to the evolution of the morphological complexity, particularly of the nervous system and neural crest, of the vertebrates.

  3. Spotting and validation of a genome wide oligonucleotide chip with duplicate measurement of each gene

    SciTech Connect

    Thomassen, Mads . E-mail: mads.thomassen@ouh.fyns-amt.dk; Skov, Vibe; Eiriksdottir, Freyja; Tan, Qihua; Jochumsen, Kirsten; Fritzner, Niels; Brusgaard, Klaus; Dahlgaard, Jesper; Kruse, Torben A.

    2006-06-16

    The quality of DNA microarray based gene expression data relies on the reproducibility of several steps in a microarray experiment. We have developed a spotted genome wide microarray chip with oligonucleotides printed in duplicate in order to minimise undesirable biases, thereby optimising detection of true differential expression. The validation study design consisted of an assessment of the microarray chip performance using the MessageAmp and FairPlay labelling kits. Intraclass correlation coefficient (ICC) was used to demonstrate that MessageAmp was significantly more reproducible than FairPlay. Further examinations with MessageAmp revealed the applicability of the system. The linear range of the chips was three orders of magnitude, the precision was high, as 95% of measurements deviated less than 1.24-fold from the expected value, and the coefficient of variation for relative expression was 13.6%. Relative quantitation was more reproducible than absolute quantitation and substantial reduction of variance was attained with duplicate spotting. An analysis of variance (ANOVA) demonstrated no significant day-to-day variation.

  4. Global transcriptome analysis reveals distinct expression among duplicated genes during sorghum-interaction

    PubMed Central

    2012-01-01

    Background Sorghum (Sorghum bicolor L. Moench) is a rich source of natural phytochemicals. We performed massive parallel sequencing of mRNA to identify differentially expressed genes after sorghum BTx623 had been infected with Bipolaris sorghicola, a necrotrophic fungus causing a sorghum disease called target leaf spot. Result Seventy-six-base-pair reads from mRNAs of mock- or pathogen-infected leaves were sequenced. Unannotated transcripts were predicted on the basis of the piling-up of mapped short reads. Differentially expressed genes were identified statistically; particular genes in tandemly duplicated putative paralogs were highly upregulated. Pathogen infection activated the glyoxylate shunt in the TCA cycle; this changes the role of the TCA cycle from energy production to synthesis of cell components. The secondary metabolic pathways of phytoalexin synthesis and of sulfur-dependent detoxification were activated by upregulation of the genes encoding amino acid metabolizing enzymes located at the branch point between primary and secondary metabolism. Coordinated gene expression could guide the metabolic pathway for accumulation of the sorghum-specific phytochemicals 3-deoxyanthocyanidin and dhurrin. Key enzymes for synthesizing these sorghum-specific phytochemicals were not found in the corresponding region of the rice genome. Conclusion Pathogen infection dramatically changed the expression of particular paralogs that putatively encode enzymes involved in the sorghum-specific metabolic network. PMID:22838966

  5. Subfunctionalization of duplicate mitf genes associated with differential degeneration of alternative exons in fish.

    PubMed Central

    Altschmied, Joachim; Delfgaauw, Jacqueline; Wilde, Brigitta; Duschl, Jutta; Bouneau, Laurence; Volff, Jean-Nicolas; Schartl, Manfred

    2002-01-01

    The microphthalmia-associated transcription factor (MITF) exists in at least four isoforms. These are generated in higher vertebrates using alternative 5' exons and promoters from a single gene. Two separate genes (mitf-m and mitf-b), however, are present in different teleost fish species including the poeciliid Xiphophorus, the pufferfishes Fugu rubripes and Tetraodon nigroviridis, and the zebrafish Danio rerio. Fish proteins MITF-m and MITF-b correspond at both the structural and the expression levels to one particular bird/mammalian MITF isoform. In the teleost lineage subfunctionalization of mitf genes after duplication at least 100 million years ago is associated with the degeneration of alternative exons and, probably, regulatory elements and promoters. For example, a remnant of the first exon specific for MITF-m is detected within the pufferfish gene encoding MITF-b. Retracing the evolutionary history of mitf genes in vertebrates uncovered the differential recruitment of new introns specific for either the teleost or the bird/mammalian lineage. PMID:12019239

  6. Familial complex chromosomal rearrangement resulting in duplication/deletion of 6q14 to 6q16.

    PubMed

    Roland, B; Lowry, R B; Cox, D M; Ferreira, P; Lin, C C

    1993-03-01

    A familial complex chromosomal rearrangement (CCR) was ascertained through a mentally retarded, dysmorphic individual. Carriers of the CCR have the karyotype 46,XX or XY, t(6;15)(q16;q21), ins(3;6)(q12;q14q16), and malsegregation of the CCR resulted in loss of the segment 6q14 to 6q16 in the proband, and in an additional copy of the same segment in three members of the extended family. The proband has features similar to other reported cases with deletion of 6q1. The individuals with duplication of 6q14 to 6q16 have moderate mental retardation, short stature, obesity, microcephaly, brachycephaly, a short smooth philtrum, central hair whorl, simian creases, 5th finger brachydactyly and skeletal disproportion. In the 4-generation family, CCR carriers have a 20% empiric risk of phenotypically abnormal livebirths.

  7. Duplication and Remolding of tRNA Genes in the Mitochondrial Genome of Reduvius tenebrosus (Hemiptera: Reduviidae)

    PubMed Central

    Jiang, Pei; Li, Hu; Song, Fan; Cai, Yao; Wang, Jianyun; Liu, Jinpeng; Cai, Wanzhi

    2016-01-01

    Most assassin bugs are predators that act as important natural enemies of insect pests. Mitochondrial (mt) genomes of these insects are double-strand circular DNAs that encode 37 genes. In the present study, we explore the duplication and rearrangement of tRNA genes in the mt genome of Reduvius tenebrosus, the first mt genome from the subfamily Reduviinae. The gene order rearranges from CR (control region)-trnI-trnQ-trnM-ND2 to CR-trnQ-trnI2-trnI1-trnM-ND2. We identified 23 tRNA genes, including 22 tRNAs commonly found in insects and an additional trnI (trnI2), which has high sequence similarity to trnM. We found several pseudo genes, such as pseudo-trnI, pseudo-CR, and pseudo-ND2, in the hotspot region of gene rearrangement (between the control region and ND2). These features provided evidence that this novel gene order could be explained by the tandem duplication/random loss (TDRL) model. The tRNA duplication/anticodon mutation mechanism further explains the presence of trnI2, which is remolded from a duplicated trnM in the TDRL process (through an anticodon mutation of CAT to GAT). Our study also raises new questions as to whether the two events proceed simultaneously and if the remolded tRNA gene is fully functional. Significantly, the duplicated tRNA gene in the mitochondrial genome has evolved independently at least two times within assassin bugs. PMID:27322247

  8. Duplication and Remolding of tRNA Genes in the Mitochondrial Genome of Reduvius tenebrosus (Hemiptera: Reduviidae).

    PubMed

    Jiang, Pei; Li, Hu; Song, Fan; Cai, Yao; Wang, Jianyun; Liu, Jinpeng; Cai, Wanzhi

    2016-06-16

    Most assassin bugs are predators that act as important natural enemies of insect pests. Mitochondrial (mt) genomes of these insects are double-strand circular DNAs that encode 37 genes. In the present study, we explore the duplication and rearrangement of tRNA genes in the mt genome of Reduvius tenebrosus, the first mt genome from the subfamily Reduviinae. The gene order rearranges from CR (control region)-trnI-trnQ-trnM-ND2 to CR-trnQ-trnI2-trnI1-trnM-ND2. We identified 23 tRNA genes, including 22 tRNAs commonly found in insects and an additional trnI (trnI2), which has high sequence similarity to trnM. We found several pseudo genes, such as pseudo-trnI, pseudo-CR, and pseudo-ND2, in the hotspot region of gene rearrangement (between the control region and ND2). These features provided evidence that this novel gene order could be explained by the tandem duplication/random loss (TDRL) model. The tRNA duplication/anticodon mutation mechanism further explains the presence of trnI2, which is remolded from a duplicated trnM in the TDRL process (through an anticodon mutation of CAT to GAT). Our study also raises new questions as to whether the two events proceed simultaneously and if the remolded tRNA gene is fully functional. Significantly, the duplicated tRNA gene in the mitochondrial genome has evolved independently at least two times within assassin bugs.

  9. An evolutionary screen highlights canonical and noncanonical candidate antiviral genes within the primate TRIM gene family.

    PubMed

    Malfavon-Borja, Ray; Sawyer, Sara L; Wu, Lily I; Emerman, Michael; Malik, Harmit S

    2013-01-01

    Recurrent viral pressure has acted on host-encoded antiviral genes during primate and mammalian evolution. This selective pressure has resulted in dramatic episodes of adaptation in host antiviral genes, often detected via positive selection. These evolutionary signatures of adaptation have the potential to highlight previously unrecognized antiviral genes (also called restriction factors). Although the TRIM multigene family is recognized for encoding several bona fide restriction factors (e.g., TRIM5alpha), most members of this expansive gene family remain uncharacterized. Here, we investigated the TRIM multigene family for signatures of positive selection to identify novel candidate antiviral genes. Our analysis reveals previously undocumented signatures of positive selection in 17 TRIM genes, 10 of which represent novel candidate restriction factors. These include the unusual TRIM52 gene, which has evolved under strong positive selection despite its encoded protein lacking a putative viral recognition (B30.2) domain. We show that TRIM52 arose via gene duplication from the TRIM41 gene. Both TRIM52 and TRIM41 have dramatically expanded RING domains compared with the rest of the TRIM multigene family, yet this domain has evolved under positive selection only in primate TRIM52, suggesting that it represents a novel host-virus interaction interface. Our evolutionary-based screen not only documents positive selection in known TRIM restriction factors but also highlights candidate novel restriction factors, providing insight into the interfaces of host-pathogen interactions mediated by the TRIM multigene family.

  10. The ubiquilin gene family: evolutionary patterns and functional insights

    PubMed Central

    2014-01-01

    Background Ubiquilins are proteins that function as ubiquitin receptors in eukaryotes. Mutations in two ubiquilin-encoding genes have been linked to the genesis of neurodegenerative diseases. However, ubiquilin functions are still poorly understood. Results In this study, evolutionary and functional data are combined to determine the origin and diversification of the ubiquilin gene family and to characterize novel potential roles of ubiquilins in mammalian species, including humans. The analysis of more than six hundred sequences allowed characterizing ubiquilin diversity in all the main eukaryotic groups. Many organisms (e. g. fungi, many animals) have single ubiquilin genes, but duplications in animal, plant, alveolate and excavate species are described. Seven different ubiquilins have been detected in vertebrates. Two of them, here called UBQLN5 and UBQLN6, had not been hitherto described. Significantly, marsupial and eutherian mammals have the most complex ubiquilin gene families, composed of up to 6 genes. This exceptional mammalian-specific expansion is the result of the recent emergence of four new genes, three of them (UBQLN3, UBQLN5 and UBQLNL) with precise testis-specific expression patterns that indicate roles in the postmeiotic stages of spermatogenesis. A gene with related features has independently arisen in species of the Drosophila genus. Positive selection acting on some mammalian ubiquilins has been detected. Conclusions The ubiquilin gene family is highly conserved in eukaryotes. The infrequent lineage-specific amplifications observed may be linked to the emergence of novel functions in particular tissues. PMID:24674348

  11. The Insect SNMP Gene Family

    DTIC Science & Technology

    2009-01-01

    The insect SNMP gene family Richard G. Vogt a,*,1, Natalie E. Miller a, Rachel Litvack a, Richard A. Fandino a, Jackson Sparks a, Jon Staples a...Wallace Beltsville Agricultural Research Center Plant Sciences Institute, Invasive Insect Biocontrol and Behavior Laboratory, Bldg. 007, Rm. 030...keywords: Pheromone Receptors Olfactory Gustatory Chemosensory Gustatory Mosquito Fly a b s t r a c t SNMPs are membrane proteins observed to associate with

  12. Organization of the human lipoprotein lipase gene and evolution of the lipase gene family.

    PubMed Central

    Kirchgessner, T G; Chuat, J C; Heinzmann, C; Etienne, J; Guilhot, S; Svenson, K; Ameis, D; Pilon, C; d'Auriol, L; Andalibi, A

    1989-01-01

    The human lipoprotein lipase gene was cloned and characterized. It is composed of 10 exons spanning approximately equal to 30 kilobases. The first exon encodes the 5'-untranslated region, the signal peptide plus the first two amino acids of the mature protein. The next eight exons encode the remaining 446 amino acids, and the tenth exon encodes the long 3'-untranslated region of 1948 nucleotides. The lipoprotein lipase transcription start site and the sequence of the 5'-flanking region were also determined. We compared the organization of genes for lipoprotein lipase, hepatic lipase, pancreatic lipase, and Drosophila yolk protein 1, which are members of a family of related genes. A model for the evolution of the lipase gene family is presented that involves multiple rounds of gene duplication plus exon-shuffling and intron-loss events. Images PMID:2602366

  13. Duplication and Divergence of Leucine-Rich Repeat Receptor-Like Protein Kinase (LRR-RLK) Genes in Basal Angiosperm Amborella trichopoda

    PubMed Central

    Liu, Ping-Li; Xie, Lu-Lu; Li, Peng-Wei; Mao, Jian-Feng; Liu, Hui; Gao, Shu-Min; Shi, Peng-Hao; Gong, Jun-Qing

    2016-01-01

    Leucine-rich repeat receptor-like protein kinases (LRR-RLKs) are the largest group of receptor-like kinases, which are one of the largest protein superfamilies in plants, and play crucial roles in development and stress responses. Although the evolution of LRR-RLK families has been investigated in some eudicot and monocot plants, no comprehensive evolutionary studies have been performed for these genes in basal angiosperms like Amborella trichopoda. In this study, we identified 94 LRR-RLK genes in the genome of A. trichopoda. The number of LRR-RLK genes in the genome of A. trichopoda is only 17–50% of that of several eudicot and monocot species. Tandem duplication and whole-genome duplication have made limited contributions to the expansion of LRR-RLK genes in A. trichopoda. According to the phylogenetic analysis, all A. trichopoda LRR-RLK genes can be organized into 18 subfamilies, which roughly correspond to the LRR-RLK subfamilies defined in Arabidopsis thaliana. Most LRR-RLK subfamilies are characterized by highly conserved protein structures, motif compositions, and gene structures. The unique gene structure, protein structures, and protein motif compositions of each subfamily provide evidence for functional divergence among LRR-RLK subfamilies. Moreover, the expression data of LRR-RLK genes provided further evidence for the functional diversification of them. In addition, selection analyses showed that most LRR-RLK protein sites are subject to purifying selection. Our results contribute to a better understanding of the evolution of LRR-RLK gene family in angiosperm and provide a framework for further functional investigation on A. trichopoda LRR-RLKs. PMID:28066499

  14. Duplication and Divergence of Leucine-Rich Repeat Receptor-Like Protein Kinase (LRR-RLK) Genes in Basal Angiosperm Amborella trichopoda.

    PubMed

    Liu, Ping-Li; Xie, Lu-Lu; Li, Peng-Wei; Mao, Jian-Feng; Liu, Hui; Gao, Shu-Min; Shi, Peng-Hao; Gong, Jun-Qing

    2016-01-01

    Leucine-rich repeat receptor-like protein kinases (LRR-RLKs) are the largest group of receptor-like kinases, which are one of the largest protein superfamilies in plants, and play crucial roles in development and stress responses. Although the evolution of LRR-RLK families has been investigated in some eudicot and monocot plants, no comprehensive evolutionary studies have been performed for these genes in basal angiosperms like Amborella trichopoda. In this study, we identified 94 LRR-RLK genes in the genome of A. trichopoda. The number of LRR-RLK genes in the genome of A. trichopoda is only 17-50% of that of several eudicot and monocot species. Tandem duplication and whole-genome duplication have made limited contributions to the expansion of LRR-RLK genes in A. trichopoda. According to the phylogenetic analysis, all A. trichopoda LRR-RLK genes can be organized into 18 subfamilies, which roughly correspond to the LRR-RLK subfamilies defined in Arabidopsis thaliana. Most LRR-RLK subfamilies are characterized by highly conserved protein structures, motif compositions, and gene structures. The unique gene structure, protein structures, and protein motif compositions of each subfamily provide evidence for functional divergence among LRR-RLK subfamilies. Moreover, the expression data of LRR-RLK genes provided further evidence for the functional diversification of them. In addition, selection analyses showed that most LRR-RLK protein sites are subject to purifying selection. Our results contribute to a better understanding of the evolution of LRR-RLK gene family in angiosperm and provide a framework for further functional investigation on A. trichopoda LRR-RLKs.

  15. Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates.

    PubMed

    Murray, Shauna A; Diwan, Rutuja; Orr, Russell J S; Kohli, Gurjeet S; John, Uwe

    2015-11-01

    A group of marine dinoflagellates (Alveolata, Eukaryota), consisting of ∼10 species of the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense, produce the toxin saxitoxin and its analogues (STX), which can accumulate in shellfish, leading to ecosystem and human health impacts. The genes, sxt, putatively involved in STX biosynthesis, have recently been identified, however, the evolution of these genes within dinoflagellates is not clear. There are two reasons for this: uncertainty over the phylogeny of dinoflagellates; and that the sxt genes of many species of Alexandrium and other dinoflagellate genera are not known. Here, we determined the phylogeny of STX-producing and other dinoflagellates based on a concatenated eight-gene alignment. We determined the presence, diversity and phylogeny of sxtA, domains A1 and A4 and sxtG in 52 strains of Alexandrium, and a further 43 species of dinoflagellates and thirteen other alveolates. We confirmed the presence and high sequence conservation of sxtA, domain A4, in 40 strains (35 Alexandrium, 1 Pyrodinium, 4 Gymnodinium) of 8 species of STX-producing dinoflagellates, and absence from non-producing species. We found three paralogs of sxtA, domain A1, and a widespread distribution of sxtA1 in non-STX producing dinoflagellates, indicating duplication events in the evolution of this gene. One paralog, clade 2, of sxtA1 may be particularly related to STX biosynthesis. Similarly, sxtG appears to be generally restricted to STX-producing species, while three amidinotransferase gene paralogs were found in dinoflagellates. We investigated the role of positive (diversifying) selection following duplication in sxtA1 and sxtG, and found negative selection in clades of sxtG and sxtA1, clade 2, suggesting they were functionally constrained. Significant episodic diversifying selection was found in some strains in clade 3 of sxtA1, a clade that may not be involved in STX biosynthesis, indicating pressure for diversification

  16. Tandem duplication producing a novel oncogenic BRAF fusion gene defines the majority of pilocytic astrocytomas

    PubMed Central

    Jones, David T. W.; Kocialkowski, Sylvia; Liu, Lu; Pearson, Danita M.; Bäcklund, L. Magnus; Ichimura, Koichi; Collins, V. Peter

    2008-01-01

    Brain tumours are the commonest solid tumours of childhood, and pilocytic astrocytomas (PAs) are the most common central nervous system tumour in 5-19 year-olds. Little is known about the genetic alterations underlying their development. Here we describe a tandem duplication of ∼2Mb at 7q34 occurring in 66% of pilocytic astrocytomas. This rearrangement, which was not observed in a series of 244 higher-grade astrocytomas, results in an in-frame fusion gene incorporating the kinase domain of the BRAF oncogene. We further show that the resulting fusion protein has constitutive BRAF kinase activity, and is able to transform NIH3T3 cells. This is the first report of BRAF activation through rearrangement as a frequent feature in a sporadic tumor. The frequency and specificity of this change underline its potential both as a therapeutic target and a diagnostic tool. PMID:18974108

  17. Conservation, Duplication, and Divergence of Five Opsin Genes in Insect Evolution.

    PubMed

    Feuda, Roberto; Marlétaz, Ferdinand; Bentley, Michael A; Holland, Peter W H

    2016-02-09

    Opsin proteins covalently bind to small molecular chromophores and each protein-chromophore complex is sensitive to particular wavelengths of light. Multiple opsins with different wavelength absorbance peaks are required for color vision. Comparing opsin responses is challenging at low light levels, explaining why color vision is often lost in nocturnal species. Here, we investigated opsin evolution in 27 phylogenetically diverse insect species including several transitions between photic niches (nocturnal, diurnal, and crepuscular). We find widespread conservation of five distinct opsin genes, more than commonly considered. These comprise one c-opsin plus four r-opsins (long wavelength sensitive or LWS, blue sensitive, ultra violet [UV] sensitive and the often overlooked Rh7 gene). Several recent opsin gene duplications are also detected. The diversity of opsin genes is consistent with color vision in diurnal, crepuscular, and nocturnal insects. Tests for positive selection in relation to photic niche reveal evidence for adaptive evolution in UV-sensitive opsins in day-flying insects in general, and in LWS opsins of day-flying Lepidoptera specifically.

  18. Conservation, Duplication, and Divergence of Five Opsin Genes in Insect Evolution

    PubMed Central

    Feuda, Roberto; Marlétaz, Ferdinand; Bentley, Michael A.; Holland, Peter W.H.

    2016-01-01

    Opsin proteins covalently bind to small molecular chromophores and each protein-chromophore complex is sensitive to particular wavelengths of light. Multiple opsins with different wavelength absorbance peaks are required for color vision. Comparing opsin responses is challenging at low light levels, explaining why color vision is often lost in nocturnal species. Here, we investigated opsin evolution in 27 phylogenetically diverse insect species including several transitions between photic niches (nocturnal, diurnal, and crepuscular). We find widespread conservation of five distinct opsin genes, more than commonly considered. These comprise one c-opsin plus four r-opsins (long wavelength sensitive or LWS, blue sensitive, ultra violet [UV] sensitive and the often overlooked Rh7 gene). Several recent opsin gene duplications are also detected. The diversity of opsin genes is consistent with color vision in diurnal, crepuscular, and nocturnal insects. Tests for positive selection in relation to photic niche reveal evidence for adaptive evolution in UV-sensitive opsins in day-flying insects in general, and in LWS opsins of day-flying Lepidoptera specifically. PMID:26865071

  19. Repeated Whole-Genome Duplication, Karyotype Reshuffling, and Biased Retention of Stress-Responding Genes in Buckler Mustard

    PubMed Central

    Geiser, Céline; Mandáková, Terezie; Arrigo, Nils

    2016-01-01

    Whole-genome duplication (WGD) is usually followed by gene loss and karyotype repatterning. Despite evidence of new adaptive traits associated with WGD, the underpinnings and evolutionary significance of such genome fractionation remain elusive. Here, we use Buckler mustard (Biscutella laevigata) to infer processes that have driven the retention of duplicated genes after recurrent WGDs. In addition to the β- and α-WGD events shared by all Brassicaceae, cytogenetic and transcriptome analyses revealed two younger WGD events that occurred at times of environmental changes in the clade of Buckler mustard (Biscutelleae): a mesopolyploidy event from the late Miocene that was followed by considerable karyotype reshuffling and chromosome number reduction and a neopolyploidy event during the Pleistocene. Although a considerable number of the older duplicates presented signatures of retention under positive selection, the majority of retained duplicates arising from the younger mesopolyploidy WGD event matched predictions of the gene balance hypothesis and showed evidence of strong purifying selection as well as enrichment in gene categories responding to abiotic stressors. Retention of large stretches of chromosomes for both genomic copies supported the hypothesis that cycles of WGD and biased fractionation shaped the genome of this stress-tolerant polypolyloid, promoting the adaptive recruitment of stress-responding genes in the face of environmental challenges. PMID:26668305

  20. Open and closed evolutionary paths for drastic morphological changes, involving serial gene duplication, sub-functionalization, and selection

    PubMed Central

    Abe, Gembu; Lee, Shu-Hua; Li, Ing-Jia; Chang, Chun-Ju; Tamura, Koji; Ota, Kinya G.

    2016-01-01

    Twin-tail goldfish strains are examples of drastic morphological alterations that emerged through domestication. Although this mutation is known to be caused by deficiency of one of two duplicated chordin genes, it is unknown why equivalent mutations have not been observed in other domesticated fish species. Here, we compared the chordin gene morphant phenotypes of single-tail goldfish and common carp (close relatives, both of which underwent chordin gene duplication and domestication). Morpholino-induced knockdown depleted chordin gene expression in both species; however, while knockdown reproduced twin-tail morphology in single-tail goldfish, it had no effect on common carp morphology. This difference can be explained by the observation that expression patterns of the duplicated chordin genes overlap completely in common carp, but are sub-functionalized in goldfish. Our finding implies that goldfish drastic morphological changes might be enhanced by the subsequent occurrence of three different types of evolutionary event (duplication, sub-functionalization, and selection) in a certain order. PMID:27220684

  1. Repeated Whole-Genome Duplication, Karyotype Reshuffling, and Biased Retention of Stress-Responding Genes in Buckler Mustard.

    PubMed

    Geiser, Céline; Mandáková, Terezie; Arrigo, Nils; Lysak, Martin A; Parisod, Christian

    2016-01-01

    Whole-genome duplication (WGD) is usually followed by gene loss and karyotype repatterning. Despite evidence of new adaptive traits associated with WGD, the underpinnings and evolutionary significance of such genome fractionation remain elusive. Here, we use Buckler mustard (Biscutella laevigata) to infer processes that have driven the retention of duplicated genes after recurrent WGDs. In addition to the β- and α-WGD events shared by all Brassicaceae, cytogenetic and transcriptome analyses revealed two younger WGD events that occurred at times of environmental changes in the clade of Buckler mustard (Biscutelleae): a mesopolyploidy event from the late Miocene that was followed by considerable karyotype reshuffling and chromosome number reduction and a neopolyploidy event during the Pleistocene. Although a considerable number of the older duplicates presented signatures of retention under positive selection, the majority of retained duplicates arising from the younger mesopolyploidy WGD event matched predictions of the gene balance hypothesis and showed evidence of strong purifying selection as well as enrichment in gene categories responding to abiotic stressors. Retention of large stretches of chromosomes for both genomic copies supported the hypothesis that cycles of WGD and biased fractionation shaped the genome of this stress-tolerant polypolyloid, promoting the adaptive recruitment of stress-responding genes in the face of environmental challenges.

  2. Genome-wide structural and evolutionary analysis of the P450 monooxygenase genes (P450ome) in the white rot fungus Phanerochaete chrysosporium : Evidence for gene duplications and extensive gene clustering

    PubMed Central

    Doddapaneni, Harshavardhan; Chakraborty, Ranajit; Yadav, Jagjit S

    2005-01-01

    Background Phanerochaete chrysosporium, the model white rot basidiomycetous fungus, has the extraordinary ability to mineralize (to CO2) lignin and detoxify a variety of chemical pollutants. Its cytochrome P450 monooxygenases have recently been implied in several of these biotransformations. Our initial P450 cloning efforts in P. chrysosporium and its subsequent whole genome sequencing have revealed an extraordinary P450 repertoire ("P450ome") containing at least 150 P450 genes with yet unknown function. In order to understand the functional diversity and the evolutionary mechanisms and significance of these hemeproteins, here we report a genome-wide structural and evolutionary analysis of the P450ome of this fungus. Results Our analysis showed that P. chrysosporium P450ome could be classified into 12 families and 23 sub-families and is characterized by the presence of multigene families. A genome-level structural analysis revealed 16 organizationally homogeneous and heterogeneous clusters of tandem P450 genes. Analysis of our cloned cDNAs revealed structurally conserved characteristics (intron numbers and locations, and functional domains) among members of the two representative multigene P450 families CYP63 and CYP505 (P450foxy). Considering the unusually complex structural features of the P450 genes in this genome, including microexons (2–10 aa) and frequent small introns (45–55 bp), alternative splicing, as experimentally observed for CYP63, may be a more widespread event in the P450ome of this fungus. Clan-level phylogenetic comparison revealed that P. chrysosporium P450 families fall under 11 fungal clans and the majority of these multigene families appear to have evolved locally in this genome from their respective progenitor genes, as a result of extensive gene duplications and rearrangements. Conclusion P. chrysosporium P450ome, the largest known todate among fungi, is characterized by tandem gene clusters and multigene families. This enormous P450

  3. Familial aggregation analysis of gene expressions

    PubMed Central

    Rao, Shao-Qi; Xu, Liang-De; Zhang, Guang-Mei; Li, Xia; Li, Lin; Shen, Gong-Qing; Jiang, Yang; Yang, Yue-Ying; Gong, Bin-Sheng; Jiang, Wei; Zhang, Fan; Xiao, Yun; Wang, Qing K

    2007-01-01

    Traditional studies of familial aggregation are aimed at defining the genetic (and non-genetic) causes of a disease from physiological or clinical traits. However, there has been little attempt to use genome-wide gene expressions, the direct phenotypic measures of genes, as the traits to investigate several extended issues regarding the distributions of familially aggregated genes on chromosomes or in functions. In this study we conducted a genome-wide familial aggregation analysis by using the in vitro cell gene expressions of 3300 human autosome genes (Problem 1 data provided to Genetic Analysis Workshop 15) in order to answer three basic genetics questions. First, we investigated how gene expressions aggregate among different types (degrees) of relative pairs. Second, we conducted a bioinformatics analysis of highly familially aggregated genes to see how they are distributed on chromosomes. Third, we performed a gene ontology enrichment test of familially aggregated genes to find evidence to support their functional consensus. The results indicated that 1) gene expressions did aggregate in families, especially between sibs. Of 3300 human genes analyzed, there were a total of 1105 genes with one or more significant (empirical p < 0.05) familial correlation; 2) there were several genomic hot spots where highly familially aggregated genes (e.g., the chromosome 6 HLA genes cluster) were clustered; 3) as we expected, gene ontology enrichment tests revealed that the 1105 genes were aggregating not only in families but also in functional categories. PMID:18466548

  4. Identification of coding exon 3 duplication in the BMPR1A gene in a patient with juvenile polyposis syndrome.

    PubMed

    Yamaguchi, Junya; Nagayama, Satoshi; Chino, Akiko; Sakata, Ai; Yamamoto, Noriko; Sato, Yuri; Ashihara, Yuumi; Kita, Mizuho; Nomura, Sachio; Ishikawa, Yuichi; Igarashi, Masahiro; Ueno, Masashi; Arai, Masami

    2014-10-01

    Juvenile polyposis syndrome is an autosomal dominant inherited disorder characterized by multiple juvenile polyps arising in the gastrointestinal tract and an increased risk of gastrointestinal cancers, specifically colon cancer. BMPR1A and SMAD4 germline mutations have been found in patients with juvenile polyposis syndrome. We identified a BMPR1A mutation, which involves a duplication of coding exon 3 (c.230+452_333+441dup1995), on multiple ligation dependent probe amplification in a patient with juvenile polyposis syndrome. The mutation causes a frameshift, producing a truncated protein (p.D112NfsX2). Therefore, the mutation is believed to be pathogenic. We also identified a duplication breakpoint in which Alu sequences are located. These results suggest that the duplication event resulted from recombination between Alu sequences. To our knowledge, partial duplication in the BMPR1A gene has not been reported previously. This is the first case report to document coding exon 3 duplication in the BMPR1A gene in a patient with juvenile polyposis syndrome.

  5. Functional analysis of duplicated Symbiosis Receptor Kinase (SymRK) genes during nodulation and mycorrhizal infection in soybean (Glycine max).

    PubMed

    Indrasumunar, Arief; Wilde, Julia; Hayashi, Satomi; Li, Dongxue; Gresshoff, Peter M

    2015-03-15

    Association between legumes and rhizobia results in the formation of root nodules, where symbiotic nitrogen fixation occurs. The early stages of this association involve a complex of signalling events between the host and microsymbiont. Several genes dealing with early signal transduction have been cloned, and one of them encodes the leucine-rich repeat (LRR) receptor kinase (SymRK; also termed NORK). The Symbiosis Receptor Kinase gene is required by legumes to establish a root endosymbiosis with Rhizobium bacteria as well as mycorrhizal fungi. Using degenerate primer and BAC sequencing, we cloned duplicated SymRK homeologues in soybean called GmSymRKα and GmSymRKβ. These duplicated genes have high similarity of nucleotide (96%) and amino acid sequence (95%). Sequence analysis predicted a malectin-like domain within the extracellular domain of both genes. Several putative cis-acting elements were found in promoter regions of GmSymRKα and GmSymRKβ, suggesting a participation in lateral root development, cell division and peribacteroid membrane formation. The mutant of SymRK genes is not available in soybean; therefore, to know the functions of these genes, RNA interference (RNAi) of these duplicated genes was performed. For this purpose, RNAi construct of each gene was generated and introduced into the soybean genome by Agrobacterium rhizogenes-mediated hairy root transformation. RNAi of GmSymRKβ gene resulted in an increased reduction of nodulation and mycorrhizal infection than RNAi of GmSymRKα, suggesting it has the major activity of the duplicated gene pair. The results from the important crop legume soybean confirm the joint phenotypic action of GmSymRK genes in both mycorrhizal and rhizobial infection seen in model legumes.

  6. Plant Genome Duplication Database.

    PubMed

    Lee, Tae-Ho; Kim, Junah; Robertson, Jon S; Paterson, Andrew H

    2017-01-01

    Genome duplication, widespread in flowering plants, is a driving force in evolution. Genome alignments between/within genomes facilitate identification of homologous regions and individual genes to investigate evolutionary consequences of genome duplication. PGDD (the Plant Genome Duplication Database), a public web service database, provides intra- or interplant genome alignment information. At present, PGDD contains information for 47 plants whose genome sequences have been released. Here, we describe methods for identification and estimation of dates of genome duplication and speciation by functions of PGDD.The database is freely available at http://chibba.agtec.uga.edu/duplication/.

  7. Evolution of the RH gene family in vertebrates revealed by brown hagfish (Eptatretus atami) genome sequences.

    PubMed

    Suzuki, Akinori; Komata, Hidero; Iwashita, Shogo; Seto, Shotaro; Ikeya, Hironobu; Tabata, Mitsutoshi; Kitano, Takashi

    2017-02-01

    In vertebrates, there are four major genes in the RH (Rhesus) gene family, RH, RHAG, RHBG, and RHCG. These genes are thought to have been formed by the two rounds of whole-genome duplication (2R-WGD) in the common ancestor of all vertebrates. In our previous work, where we analyzed details of the gene duplications process of this gene family, three nucleotide sequences belonging to this family were identified in Far Eastern brook lamprey (Lethenteron reissneri), and the phylogenetic positions of the genes were determined. Lampreys, along with hagfishes, are cyclostomata (jawless fishes), which is a sister group of gnathostomata (jawed vertebrates). Although those results suggested that one gene was orthologous to the gnathostome RHCG genes, we did not identify clear orthologues for other genes. In this study, therefore, we identified three novel cDNA sequences that belong to the RH gene family using de novo transcriptome analysis of another cyclostome: the brown hagfish (Eptatretus atami). We also determined the nucleotide sequences for the RHBG and RHCG genes in a red stingray (Dasyatis akajei), which belongs to the cartilaginous fishes. The phylogenetic tree showed that two brown hagfish genes, which were probably duplicated in the cyclostome lineage, formed a cluster with the gnathostome RHAG genes, whereas another brown hagfish gene formed a cluster with the gnathostome RHCG genes. We estimated that the RH genes had a higher evolutionary rate than the RHAG, RHBG, and RHCG genes. Interestingly, in the RHBG genes, only the bird lineage showed a higher rate of nonsynonymous substitutions. It is likely that this higher rate was caused by a state of relaxed functional constraints rather than positive selection nor by pseudogenization.

  8. The evolution and maintenance of Hox gene clusters in vertebrates and the teleost-specific genome duplication.

    PubMed

    Kuraku, Shigehiro; Meyer, Axel

    2009-01-01

    Hox genes are known to specify spatial identities along the anterior-posterior axis during embryogenesis. In vertebrates and most other deuterostomes, they are arranged in sets of uninterrupted clusters on chromosomes, and are in most cases expressed in a "colinear" fashion, in which genes closer to the 3-end of the Hox clusters are expressed earlier and more anteriorly and genes close to the 5-end of the clusters later and more posteriorly. In this review, we summarize the current understanding of how Hox gene clusters have been modified from basal lineages of deuterostomes to diverse taxa of vertebrates. Our parsimony reconstruction of Hox cluster architecture at various stages of vertebrate evolution highlights that the variation in Hox cluster structures among jawed vertebrates is mostly due to secondary lineage-specific gene losses and an additional genome duplication that occurred in the actinopterygian stem lineage, the teleost-specific genome duplication (TSGD).

  9. An increased duplication of ZRS region that caused more than one supernumerary digits preaxial polydactyly in a large Chinese family

    PubMed Central

    Wang, Bin; Diao, Yutao; Liu, Qiji; An, Hongqiang; Ma, Ruiping; Jiang, Guosheng; Lai, Nannan; Li, Ziwei; Zhu, Xiaoxiao; Zhao, Lin; Guo, Qiang; Zhang, Zhen; Sun, Rong; Li, Xia

    2016-01-01

    Preaxial polydactyly (PPD) is inherited in an autosomal dominant fashion and characterized by the presence of one or more supernumerary digits on the thumb side. It had been identified that point mutation or genomic duplications of the long-range limb-specific cis-regulator - zone of polarizing activity regulatory sequence (ZRS) cause PPD or other limb deformities such as syndactyly type IV (SD4) and Triphalangeal thumb-polysyndactyly syndrome (TPTPS). Most previously reported cases involved with no more than one extra finger; however, the role of the point mutation or genomic duplications of ZRS in the case of more than one redundant finger polydactyly remains unclear. In this article, we reported a family case of more than one redundant finger polydactyly on the thumb side for bilateral hands with a pedigree chart of the family. Results of quantitative PCR (qPCR) and sequence analysis suggested that the relative copy number (RCN) of ZRS but not point mutation (including insertion and deletion) was involved in all affected individuals. PMID:27922091

  10. Evolutionary Dynamics of the wnt Gene Family: A Lophotrochozoan Perspective

    PubMed Central

    Cho, Sung-Jin; Vallès, Yvonne; Giani, Vincent C.; Seaver, Elaine C.; Weisblat, David A.

    2010-01-01

    expression analyses. The 36 wnt genes obtained represent 11, 12, and 9 distinct wnt subfamilies in Lottia, Capitella, and Helobdella, respectively. Thus, two of the three analyzed lophotrochozoan genomes retained an almost complete ancestral complement of wnt genes emphasizing the importance and complexity of this gene family across metazoans. The genome of the leech Helobdella reflects significantly more dynamism than those of Lottia and Capitella, as judged by gene duplications and losses, branch length, and changes in genetic linkage. Finally, we performed a detailed expression analysis for all the Helobdella wnt genes during embryonic development. We find that, although the patterns show substantial overlap during early cleavage stages, each wnt gene has a unique expression pattern in the germinal plate and during tissue morphogenesis. Comparisons of the embryonic expression patterns of the duplicated wnt genes in Helobdella with their orthologs in Capitella reveal extensive regulatory diversification of the duplicated leech wnt genes. PMID:20176615

  11. Evolution of an expanded mannose receptor gene family.

    PubMed

    Staines, Karen; Hunt, Lawrence G; Young, John R; Butter, Colin

    2014-01-01

    Sequences of peptides from a protein specifically immunoprecipitated by an antibody, KUL01, that recognises chicken macrophages, identified a homologue of the mammalian mannose receptor, MRC1, which we called MRC1L-B. Inspection of the genomic environment of the chicken gene revealed an array of five paralogous genes, MRC1L-A to MRC1L-E, located between conserved flanking genes found either side of the single MRC1 gene in mammals. Transcripts of all five genes were detected in RNA from a macrophage cell line and other RNAs, whose sequences allowed the precise definition of spliced exons, confirming or correcting existing bioinformatic annotation. The confirmed gene structures were used to locate orthologues of all five genes in the genomes of two other avian species and of the painted turtle, all with intact coding sequences. The lizard genome had only three genes, one orthologue of MRC1L-A and two orthologues of the MRC1L-B antigen gene resulting from a recent duplication. The Xenopus genome, like that of most mammals, had only a single MRC1-like gene at the corresponding locus. MRC1L-A and MRC1L-B genes had similar cytoplasmic regions that may be indicative of similar subcellular migration and functions. Cytoplasmic regions of the other three genes were very divergent, possibly indicating the evolution of a new functional repertoire for this family of molecules, which might include novel interactions with pathogens.

  12. A hotspot of gene order rearrangement by tandem duplication and random loss in the vertebrate mitochondrial genome.

    PubMed

    San Mauro, Diego; Gower, David J; Zardoya, Rafael; Wilkinson, Mark

    2006-01-01

    Most reported examples of change in vertebrate mitochondrial (mt) gene order could be explained by a tandem duplication followed by random loss of redundant genes (tandem duplication-random loss [TDRL] model). Under this model of evolution, independent loss of genes arising from a single duplication in an ancestral species are predicted, and remnant pseudogenes expected, intermediate states that may remain in rearranged genomes. However, evidence for this is rare and largely scattered across vertebrate lineages. Here, we report new derived mt gene orders in the vertebrate "WANCY" region of four closely related caecilian amphibians. The novel arrangements found in this genomic region (one of them is convergent with the derived arrangement of marsupials), presence of pseudogenes, and positions of intergenic spacers fully satisfy predictions from the TDRL model. Our results, together with comparative data for the available vertebrate complete mt genomes, provide further evidence that the WANCY genomic region is a hotspot for gene order rearrangements and support the view that TDRL is the dominant mechanism of gene order rearrangement in vertebrate mt genomes. Convergent gene rearrangements are not unlikely in hotspots of gene order rearrangement by TDRL.

  13. Comparative Mitogenomics of Leeches (Annelida: Clitellata): Genome Conservation and Placobdella-Specific trnD Gene Duplication

    PubMed Central

    Moya, Andrés; Siddall, Mark E.; Latorre, Amparo

    2016-01-01

    Mitochondrial DNA sequences, often in combination with nuclear markers and morphological data, are frequently used to unravel the phylogenetic relationships, population dynamics and biogeographic histories of a plethora of organisms. The information provided by examining complete mitochondrial genomes also enables investigation of other evolutionary events such as gene rearrangements, gene duplication and gene loss. Despite efforts to generate information to represent most of the currently recognized groups, some taxa are underrepresented in mitochondrial genomic databases. One such group is leeches (Annelida: Hirudinea: Clitellata). Herein, we expand our knowledge concerning leech mitochondrial makeup including gene arrangement, gene duplication and the evolution of mitochondrial genomes by adding newly sequenced mitochondrial genomes for three bloodfeeding species: Haementeria officinalis, Placobdella lamothei and Placobdella parasitica. With the inclusion of three new mitochondrial genomes of leeches, a better understanding of evolution for this organelle within the group is emerging. We found that gene order and genomic arrangement in the three new mitochondrial genomes is identical to previously sequenced members of Clitellata. Interestingly, within Placobdella, we recovered a genus-specific duplication of the trnD gene located between cox2 and atp8. We performed phylogenetic analyses using 12 protein-coding genes and expanded our taxon sampling by including GenBank sequences for 39 taxa; the analyses confirm the monophyletic status of Clitellata, yet disagree in several respects with other phylogenetic hypotheses based on morphology and analyses of non-mitochondrial data. PMID:27176910

  14. Comparative Mitogenomics of Leeches (Annelida: Clitellata): Genome Conservation and Placobdella-Specific trnD Gene Duplication.

    PubMed

    Oceguera-Figueroa, Alejandro; Manzano-Marín, Alejandro; Kvist, Sebastian; Moya, Andrés; Siddall, Mark E; Latorre, Amparo

    2016-01-01

    Mitochondrial DNA sequences, often in combination with nuclear markers and morphological data, are frequently used to unravel the phylogenetic relationships, population dynamics and biogeographic histories of a plethora of organisms. The information provided by examining complete mitochondrial genomes also enables investigation of other evolutionary events such as gene rearrangements, gene duplication and gene loss. Despite efforts to generate information to represent most of the currently recognized groups, some taxa are underrepresented in mitochondrial genomic databases. One such group is leeches (Annelida: Hirudinea: Clitellata). Herein, we expand our knowledge concerning leech mitochondrial makeup including gene arrangement, gene duplication and the evolution of mitochondrial genomes by adding newly sequenced mitochondrial genomes for three bloodfeeding species: Haementeria officinalis, Placobdella lamothei and Placobdella parasitica. With the inclusion of three new mitochondrial genomes of leeches, a better understanding of evolution for this organelle within the group is emerging. We found that gene order and genomic arrangement in the three new mitochondrial genomes is identical to previously sequenced members of Clitellata. Interestingly, within Placobdella, we recovered a genus-specific duplication of the trnD gene located between cox2 and atp8. We performed phylogenetic analyses using 12 protein-coding genes and expanded our taxon sampling by including GenBank sequences for 39 taxa; the analyses confirm the monophyletic status of Clitellata, yet disagree in several respects with other phylogenetic hypotheses based on morphology and analyses of non-mitochondrial data.

  15. Niemeyer Virus: A New Mimivirus Group A Isolate Harboring a Set of Duplicated Aminoacyl-tRNA Synthetase Genes

    PubMed Central

    Boratto, Paulo V. M.; Arantes, Thalita S.; Silva, Lorena C. F.; Assis, Felipe L.; Kroon, Erna G.; La Scola, Bernard; Abrahão, Jônatas S.

    2015-01-01

    It is well recognized that gene duplication/acquisition is a key factor for molecular evolution, being directly related to the emergence of new genetic variants. The importance of such phenomena can also be expanded to the viral world, with impacts on viral fitness and environmental adaptations. In this work we describe the isolation and characterization of Niemeyer virus, a new mimivirus isolate obtained from water samples of an urban lake in Brazil. Genomic data showed that Niemeyer harbors duplicated copies of three of its four aminoacyl-tRNA synthetase genes (cysteinyl, methionyl, and tyrosyl RS). Gene expression analysis showed that such duplications allowed significantly increased expression of methionyl and tyrosyl aaRS mRNA by Niemeyer in comparison to APMV. Remarkably, phylogenetic data revealed that Niemeyer duplicated gene pairs are different, each one clustering with a different group of mimivirus strains. Taken together, our results raise new questions about the origins and selective pressures involving events of aaRS gain and loss among mimiviruses. PMID:26635738

  16. A familial complex chromosome translocation resulting in duplication of 6p25.

    PubMed

    Vermeesch, J R; Thoelen, R; Fryns, Jean Pierre

    2004-01-01

    We report on a girl with psychomotor retardation, severe speech developmental delay and mild dysmorphic features. Molecular cytogenetic analysis showed that the patient was carrier of an insertion (6)(p22.5-->22.4) in chromosome 12. Analysis of the chromosomes of the mother revealed the presence of a complex chromosomal rearrangement. In addition to the insertion (6)(p22.5-->22.4) in chromosome 12 and a pericentric inversion in chromosome 12, the 6p subtelomeric region was absent in the mother. This is, to our knowledge, the smallest pure duplication of chromosome 6p as well as the smallest cryptic subtelomeric 6pter deletion thus far reported.

  17. Fifteen million years of evolution in the Oryza genus shows extensive gene family expansion.

    PubMed

    Jacquemin, Julie; Ammiraju, Jetty S S; Haberer, Georg; Billheimer, Dean D; Yu, Yeisoo; Liu, Liana C; Rivera, Luis F; Mayer, Klaus; Chen, Mingsheng; Wing, Rod A

    2014-04-01

    In analyzing gene families in the whole-genome sequences available for O. sativa (AA), O. glaberrima (AA), and O. brachyantha (FF), we observed large size expansions in the AA genomes compared to FF genomes for the super-families F-box and NB-ARC, and five additional families: the Aspartic proteases, BTB/POZ proteins (BTB), Glutaredoxins, Trypsin α-amylase inhibitor proteins, and Zf-Dof proteins. Their evolutionary dynamic was investigated to understand how and why such important size variations are observed between these closely related species. We show that expansions resulted from both amplification, largely by tandem duplications, and contraction by gene losses. For the F-box and NB-ARC gene families, the genes conserved in all species were under strong purifying selection while expanded orthologous genes were under more relaxed purifying selection. In F-box, NB-ARC, and BTB, the expanded groups were enriched in genes with little evidence of expression, in comparison with conserved groups. We also detected 87 loci under positive selection in the expanded groups. These results show that most of the duplicated copies in the expanded groups evolve neutrally after duplication because of functional redundancy but a fraction of these genes were preserved following neofunctionalization. Hence, the lineage-specific expansions observed between Oryza species were partly driven by directional selection.

  18. Molecular Characterization of Duplicate Cytosolic Phosphoglucose Isomerase Genes in Clarkia and Comparison to the Single Gene in Arabidopsis

    PubMed Central

    Thomas, B. R.; Ford, V. S.; Pichersky, E.; Gottlieb, L. D.

    1993-01-01

    The nucleotide sequence of PgiC1-a which encodes a cytosolic isozyme of phosphoglucose isomerase (PGIC; EC 5.3.1.9) in Clarkia lewisii, a wildflower native to California, is described and compared to the previously published sequence of the duplicate PgiC2-a from the same genome. Both genes have the same structure of 23 exons and 22 introns located in identical positions, and they encode proteins of 569 amino acids. Exon and inferred protein sequences of the two genes are 96.4% and 97.2% identical, respectively. Intron sequences are 88.2% identical. The high nucleotide similarity of the two genes is consistent with previous genetic and biosystematic findings that suggest the duplication arose within Clarkia. A partial sequence of PgiC2-b was also obtained. It is 99.5% identical to PgiC2-a in exons and 99.7% in introns. The nucleotide sequence of the single PgiC from Arabidopsis thaliana was also determined for comparison to the Clarkia genes. The A. thaliana PgiC has 21 introns located at positions identical to those in Clarkia PgiC1 and PgiC2, but lacks the intron that divides Clarkia exons 21 and 22. The A. thaliana PGIC protein is shorter, with 560 amino acids, and differs by about 17% from the Clarkia PGICs. The PgiC in A. thaliana was mapped to a site 20 cM from restriction fragment length polymorphism marker 331 on chromosome 5. PMID:8293986

  19. Structure and regulation of the Asr gene family in banana.

    PubMed

    Henry, Isabelle M; Carpentier, Sebastien C; Pampurova, Suzana; Van Hoylandt, Anais; Panis, Bart; Swennen, Rony; Remy, Serge

    2011-10-01

    Abscisic acid, stress, ripening proteins (ASR) are a family of plant-specific small hydrophilic proteins. Studies in various plant species have highlighted their role in increased resistance to abiotic stress, including drought, but their specific function remains unknown. As a first step toward their potential use in crop improvement, we investigated the structure and regulation of the Asr gene family in Musa species (bananas and plantains). We determined that the Musa Asr gene family contained at least four members, all of which exhibited the typical two exons, one intron structure of Asr genes and the "ABA/WDS" (abscisic acid/water deficit stress) domain characteristic of Asr genes. Phylogenetic analyses determined that the Musa Asr genes were closely related to each other, probably as the product of recent duplication events. For two of the four members, two versions corresponding to the two sub-genomes of Musa, acuminata and balbisiana were identified. Gene expression and protein analyses were performed and Asr expression could be detected in meristem cultures, root, pseudostem, leaf and cormus. In meristem cultures, mAsr1 and mAsr3 were induced by osmotic stress and wounding, while mAsr3 and mAsr4 were induced by exposure to ABA. mASR3 exhibited the most variation both in terms of amino acid sequence and expression pattern, making it the most promising candidate for further functional study and use in crop improvement.

  20. Origin and evolution of laminin gene family diversity.

    PubMed

    Fahey, Bryony; Degnan, Bernard M

    2012-07-01

    generated independently from within the laminin family by duplication and domain shuffling and by domain loss. Together, our results suggest that gene duplication and loss and domain shuffling and loss all played a role in the evolution of the laminin family and contributed to the generation of lineage-specific diversity in the laminin gene complements of extant metazoans.

  1. Analysis of the Prefoldin Gene Family in 14 Plant Species

    PubMed Central

    Cao, Jun

    2016-01-01

    Prefoldin is a hexameric molecular chaperone complex present in all eukaryotes and archaea. The evolution of this gene family in plants is unknown. Here, I identified 140 prefoldin genes in 14 plant species. These prefoldin proteins were divided into nine groups through phylogenetic analysis. Highly conserved gene organization and motif distribution exist in each prefoldin group, implying their functional conservation. I also observed the segmental duplication of maize prefoldin gene family. Moreover, a few functional divergence sites were identified within each group pairs. Functional network analyses identified 78 co-expressed genes, and most of them were involved in carrying, binding and kinase activity. Divergent expression profiles of the maize prefoldin genes were further investigated in different tissues and development periods and under auxin and some abiotic stresses. I also found a few cis-elements responding to abiotic stress and phytohormone in the upstream sequences of the maize prefoldin genes. The results provided a foundation for exploring the characterization of the prefoldin genes in plants and will offer insights for additional functional studies. PMID:27014333

  2. Regulatory divergence of homeologous Atlantic salmon elovl5 genes following the salmonid-specific whole-genome duplication.

    PubMed

    Carmona-Antoñanzas, Greta; Zheng, Xiaozhong; Tocher, Douglas R; Leaver, Michael J

    2016-10-10

    Fatty acyl elongase 5 (elovl5) is a critical enzyme in the vertebrate biosynthetic pathway which produces the physiologically essential long-chain polyunsaturated fatty acids (LC-PUFA), docosahexenoic acid (DHA), and eicosapentenoic acid (EPA) from 18 carbon fatty acids precursors. In contrast to most other vertebrates, Atlantic salmon possess two copies of elovl5 (elovl5a and elovl5b) as a result of a whole-genome duplication (WGD) which occurred at the base of the salmonid lineage. WGDs have had a major influence on vertebrate evolution, providing extra genetic material, enabling neofunctionalization to accelerate adaptation and speciation. However, little is known about the mechanisms by which such duplicated homeologous genes diverge. Here we show that homeologous Atlantic salmon elovl5a and elovl5b genes have been asymmetrically colonised by transposon-like elements. Identical locations and identities of insertions are also present in the rainbow trout duplicate elovl5 genes, but not in the nearest extant representative preduplicated teleost, the northern pike. Both elovl5 salmon duplicates possessed conserved regulatory elements that promoted Srebp1- and Srebp2-dependent transcription, and differences in the magnitude of Srebp response between promoters could be attributed to a tandem duplication of SRE and NF-Y cofactor binding sites in elovl5b. Furthermore, an insertion in the promoter region of elovl5a confers responsiveness to Lxr/Rxr transcriptional activation. Our results indicate that most, but not all, transposon mobilisation into elovl5 genes occurred after the split from the common ancestor of pike and salmon, but before more recent salmonid speciations, and that divergence of elovl5 regulatory regions have enabled neofuntionalization by promoting differential expression of these homeologous genes.

  3. Divergent Evolutionary and Expression Patterns between Lineage Specific New Duplicate Genes and Their Parental Paralogs in Arabidopsis thaliana

    PubMed Central

    Wang, Jun; Marowsky, Nicholas C.; Fan, Chuanzhu

    2013-01-01

    Gene duplication is an important mechanism for the origination of functional novelties in organisms. We performed a comparative genome analysis to systematically estimate recent lineage specific gene duplication events in Arabidopsis thaliana and further investigate whether and how these new duplicate genes (NDGs) play a functional role in the evolution and adaption of A. thaliana. We accomplished this using syntenic relationship among four closely related species, A. thaliana, A. lyrata, Capsella rubella and Brassica rapa. We identified 100 NDGs, showing clear origination patterns, whose parental genes are located in syntenic regions and/or have clear orthologs in at least one of three outgroup species. All 100 NDGs were transcribed and under functional constraints, while 24% of the NDGs have differential expression patterns compared to their parental genes. We explored the underlying evolutionary forces of these paralogous pairs through conducting neutrality tests with sequence divergence and polymorphism data. Evolution of about 15% of NDGs appeared to be driven by natural selection. Moreover, we found that 3 NDGs not only altered their expression patterns when compared with parental genes, but also evolved under positive selection. We investigated the underlying mechanisms driving the differential expression of NDGs and their parents, and found a number of NDGs had different cis-elements and methylation patterns from their parental genes. Overall, we demonstrated that NDGs acquired divergent cis-elements and methylation patterns and may experience sub-functionalization or neo-functionalization influencing the evolution and adaption of A. thaliana. PMID:24009676

  4. Identification and functional analysis of novel facial patterning genes in the duplicated beak chicken embryo.

    PubMed

    Nimmagadda, Suresh; Buchtová, Marcela; Fu, Katherine; Geetha-Loganathan, Poongodi; Hosseini-Farahabadi, Sara; Trachtenberg, Alexander J; Kuo, Winston Patrick; Vesela, Iva; Richman, Joy M

    2015-11-15

    Cranial neural crest cells form the majority of the facial skeleton. However exactly when the pattering information and hence jaw identity is established is not clear. We know that premigratory neural crest cells contain a limited amount of information about the lower jaw but the upper jaw and facial midline are specified later by local tissue interactions. The environmental signals leading to frontonasal identity have been explored by our group in the past. Altering the levels of two signaling pathways (Bone Morphogenetic Protein) and retinoic acid (RA) in the chicken embryo creates a duplicated midline on the side of the upper beak complete with egg tooth in place of maxillary derivatives (Lee et al., 2001). Here we analyze the transcriptome 16 h after bead placement in order to identify potential mediators of the identity change in the maxillary prominence. The gene list included RA, BMP and WNT signaling pathway genes as well as transcription factors expressed in craniofacial development. There was also cross talk between Noggin and RA such that Noggin activated the RA pathway. We also observed expression changes in several poorly characterized genes including the upregulation of Peptidase Inhibitor-15 (PI15). We tested the functional effects of PI15 overexpression with a retroviral misexpression strategy. PI15 virus induced a cleft beak analogous to human cleft lip. We next asked whether PI15 effects were mediated by changes in expression of major clefting genes and genes in the retinoid signaling pathway. Expression of TP63, TBX22, BMP4 and FOXE1, all human clefting genes, were upregulated. In addition, ALDH1A2, ALDH1A3 and RA target, RARβ were increased while the degradation enzyme CYP26A1 was decreased. Together these changes were consistent with activation of the RA pathway. Furthermore, PI15 retrovirus injected into the face was able to replace RA and synergize with Noggin to induce beak transformations. We conclude that the microarrays have generated a

  5. Identification of Ohnolog Genes Originating from Whole Genome Duplication in Early Vertebrates, Based on Synteny Comparison across Multiple Genomes.

    PubMed

    Singh, Param Priya; Arora, Jatin; Isambert, Hervé

    2015-07-01

    Whole genome duplications (WGD) have now been firmly established in all major eukaryotic kingdoms. In particular, all vertebrates descend from two rounds of WGDs, that occurred in their jawless ancestor some 500 MY ago. Paralogs retained from WGD, also coined 'ohnologs' after Susumu Ohno, have been shown to be typically associated with development, signaling and gene regulation. Ohnologs, which amount to about 20 to 35% of genes in the human genome, have also been shown to be prone to dominant deleterious mutations and frequently implicated in cancer and genetic diseases. Hence, identifying ohnologs is central to better understand the evolution of vertebrates and their susceptibility to genetic diseases. Early computational analyses to identify vertebrate ohnologs relied on content-based synteny comparisons between the human genome and a single invertebrate outgroup genome or within the human genome itself. These approaches are thus limited by lineage specific rearrangements in individual genomes. We report, in this study, the identification of vertebrate ohnologs based on the quantitative assessment and integration of synteny conservation between six amniote vertebrates and six invertebrate outgroups. Such a synteny comparison across multiple genomes is shown to enhance the statistical power of ohnolog identification in vertebrates compared to earlier approaches, by overcoming lineage specific genome rearrangements. Ohnolog gene families can be browsed and downloaded for three statistical confidence levels or recompiled for specific, user-defined, significance criteria at http://ohnologs.curie.fr/. In the light of the importance of WGD on the genetic makeup of vertebrates, our analysis provides a useful resource for researchers interested in gaining further insights on vertebrate evolution and genetic diseases.

  6. Mirror-image duplication of the primary axis and heart in Xenopus embryos by the overexpression of Msx-1 gene.

    PubMed

    Chen, Y; Solursh, M

    1995-10-01

    The Msx-1 gene (formerly known as Hox-7) is a member of a discrete subclass of homeobox-containing genes. Examination of the expression pattern of Msx-1 in murine and avian embryos suggests that this gene may be involved in the regionalization of the medio-lateral axis during earlier development. We have examined the possible functions of Xenopus Msx-1 during early Xenopus embryonic development by overexpression of the Msx-1 gene. Overexpression of Msx-1 causes a left-right mirror-image duplication of primary axial structures, including notochord, neural tube, somites, suckers, and foregut. The embryonic developing heart is also mirror-image duplicated, including looping directions and polarity. These results indicate that Msx-1 may be involved in the mesoderm formation as well as left-right patterning in the early Xenopus embryonic development.

  7. The insect SNMP gene family.

    PubMed

    Vogt, Richard G; Miller, Natalie E; Litvack, Rachel; Fandino, Richard A; Sparks, Jackson; Staples, Jon; Friedman, Robert; Dickens, Joseph C

    2009-07-01

    SNMPs are membrane proteins observed to associate with chemosensory neurons in insects; in Drosophila melanogaster, SNMP1 has been shown to be essential for the detection of the pheromone cis-vaccenyl acetate (CVA). SNMPs are one of three insect gene clades related to the human fatty acid transporter CD36. We previously characterized the CD36 gene family in 4 insect Orders that effectively cover the Holometabola, or some 80% of known insect species and the 300 million years of evolution since this lineage emerged: Lepidoptera (e.g. Bombyx mori, Antheraea polyphemus, Manduca sexta, Heliothis virescens, Helicoverpa assulta, Helicoverpa armigera, Mamestra brassicae); Diptera (D. melanogaster, Drosophila pseudoobscura, Aedes aegypti, Anopheles gambiae, Culex pipiens quinquefasciatus); Hymenoptera (Apis mellifera); and Coleoptera (Tribolium castaneum). This previous study suggested a complex topography within the SNMP clade including a strongly supported SNMP1 sub-clade plus additional SNMP genes. To further resolve the SNMP clade here, we used cDNA sequences of SNMP1 and SNMP2 from various Lepidoptera species, D. melanogaster and Ae. aegypti, as well as BAC derived genomic sequences from Ae. aegypti as models for proposing corrected sequences of orthologues in the D. pseudoobscura and An. gambiae genomes, and for identifying orthologues in the B. mori and C. pipiens q. genomes. We then used these sequences to analyze the SNMP clade of the insect CD36 gene family, supporting the existence of two well supported sub-clades, SNMP1 and SNMP2, throughout the dipteran and lepidopteran lineages, and plausibly throughout the Holometabola and across a broad evolutionary time scale. We present indirect evidence based on evolutionary selection (dN/dS) that the dipteran SNMPs are expressed as functional proteins. We observed expansions of the SNMP1 sub-clade in C. pipiens q. and T. castaneum suggesting that the SNMP1s may have an expanded functional role in these species.

  8. Host mitochondrial association evolved in the human parasite Toxoplasma gondii via neofunctionalization of a gene duplicate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Toxoplasma gondii, an intracellular parasite of humans and other warm-blooded animals, the ability to associate with host mitochondria (HMA) is driven by a locally expanded gene family that encodes multiple mitochondrial association factor 1 (MAF1) proteins. The importance of copy number in the e...

  9. A 20-basepair duplication in the human thyroid peroxidase gene results in a total iodide organification defect and congenital hypothyroidism

    SciTech Connect

    Bikker, H.; Hartog, M.T. den; Gons, M.H.; Vulsma, T.; Vijlder, J.J.M. de; Baas, F.

    1994-07-01

    In this study, the authors present the molecular basis of a total iodide organification defect causing severe congenital hypothyroidism. In the thyroid gland of the patient, thyroid peroxidase (TPO) activity and the iodination degree of thyroglobulin were below detection limits, and no TPO messenger ribonucleic acid was detectable by Northern blot analysis. Denaturing gradient gel electrophoretic analysis of the TPO gene of the patient revealed a homozygous mutation in exon 2. Sequence analysis showed the presence of a 20-basepair duplication, 47 basepairs down-stream of the ATG start codon. This duplication generates a frame shift, resulting in a termination signal in exon 3, compatible with the complete absence of TPO. Both parents of the patient are heterozygous for the same duplication, confirming the recessive mode of inheritance of the mutation. 32 refs., 4 figs.

  10. Whole-Genome Duplications Spurred the Functional Diversification of the Globin Gene Superfamily in Vertebrates

    PubMed Central

    Hoffmann, Federico G.; Opazo, Juan C.; Storz, Jay F.

    2012-01-01

    It has been hypothesized that two successive rounds of whole-genome duplication (WGD) in the stem lineage of vertebrates provided genetic raw materials for the evolutionary innovation of many vertebrate-specific features. However, it has seldom been possible to trace such innovations to specific functional differences between paralogous gene products that derive from a WGD event. Here, we report genomic evidence for a direct link between WGD and key physiological innovations in the vertebrate oxygen transport system. Specifically, we demonstrate that key globin proteins that evolved specialized functions in different aspects of oxidative metabolism (hemoglobin, myoglobin, and cytoglobin) represent paralogous products of two WGD events in the vertebrate common ancestor. Analysis of conserved macrosynteny between the genomes of vertebrates and amphioxus (subphylum Cephalochordata) revealed that homologous chromosomal segments defined by myoglobin + globin-E, cytoglobin, and the α-globin gene cluster each descend from the same linkage group in the reconstructed proto-karyotype of the chordate common ancestor. The physiological division of labor between the oxygen transport function of hemoglobin and the oxygen storage function of myoglobin played a pivotal role in the evolution of aerobic energy metabolism, supporting the hypothesis that WGDs helped fuel key innovations in vertebrate evolution. PMID:21965344

  11. Collagen duplicate genes of bone and cartilage participate during regeneration of zebrafish fin skeleton.

    PubMed

    Duran, I; Csukasi, F; Taylor, S P; Krakow, D; Becerra, J; Bombarely, A; Marí-Beffa, M

    2015-01-01

    The zebrafish fin is widely used as a model for skeleton regeneration. For years, the nature of the fin skeleton has been controversial as its extracellular matrix shows hybrid characteristics of both bone and cartilage. The presence of co-orthologs genes also increases the complexity of these tissues. In this article, we have identified and described the expression of fibrillar collagens in zebrafish fin skeleton. We found that genes coding for types I, II, V, XI and XXVII collagens are duplicated, showing in several cases, different expression domains. We also identified specific genomic features, such as the presence of type XXIV collagen and the absence of type III collagen in the zebrafish genome. Our study showed that actinotrichia-forming cells and osteoblasts synthesize a wide variety of these fibrillar collagens during fin regeneration. An intertrichial domain expressing most of the collagens was located in the transition between the mesenchyme condensations of actinotrichia and lepidotrichia and may determine an important niche associated with fin skeleton morphogenesis. We also confirmed the hybrid nature of the fin exoskeleton and provided a complete description of those fibrillar collagens expressed during the formation of the fin skeleton.

  12. Evidence for repeated gene duplications in Tritrichomonas foetus supported by EST analysis and comparison with the Trichomonas vaginalis genome.

    PubMed

    Oyhenart, Jorge; Breccia, Javier D

    2014-12-15

    Tritrichomonas foetus causes a venereal infection in cattle; the disease has mild or no clinical manifestation in bulls, while cows may present vaginitis, placentitis, pyometra and abortion in the more severe cases. T. foetus has one of the largest known genomes among trichomonads. However molecular data are fragmentary and have minimally contributed to the understanding of the biology and pathogenesis of this protozoan. In a search of new T. foetus genes, a detailed exploration was performed using recently available expressed sequences. Genes involved in the central carbon metabolism (phosphoenol pyruvate carboxykinase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphosphate aldolase, thioredoxin peroxidase, alpha and beta chains of succinyl CoA synthetase, malate dehydrogenase, malate oxidoreductase and enolase) as well as in cell structure and motility (actin, α-tubulin and β-tubulin) were found duplicated and, in many cases, repeatedly duplicated. Homology analysis suggested that massive expansions might have occurred in the T. foetus genome in a similar way it was also predicted for Trichomonas vaginalis, while conservation assessment showed that duplications have been acquired after differentiation of the two species. Therefore, gene duplications might be common among these parasitic protozoans.

  13. Divergence pattern of animal gene families and relationship with the Cambrian explosion.

    PubMed

    Miyata, T; Suga, H

    2001-11-01

    There are many gene families that are specific to multicellular animals. These have either diverged from ancestral genes that are shared with fungi and/or plants or evolved from an ancestral gene unique to animals. The evolution of gene families involved in cell-cell communication and developmental control has been studied to establish whether the number of member genes increased dramatically immediately prior to or in concert with the Cambrian explosion. A molecular phylogeny-based analysis of several animal-specific gene families has revealed that gene diversification by duplication occurred during two active periods interrupted by a long intervening quiescent period. Intriguingly, the Cambrian explosion is situated in the silent period, indicating that there is no direct link between the first burst of gene diversification and the Cambrian explosion itself. The importance of gene recruitment as a possible molecular mechanism for morphological diversity, and its possible role for the Cambrian explosion, are discussed.

  14. Evolution of the chitin synthase gene family correlates with fungal morphogenesis and adaption to ecological niches

    PubMed Central

    Liu, Ran; Xu, Chuan; Zhang, Qiangqiang; Wang, Shiyi; Fang, Weiguo

    2017-01-01

    The fungal kingdom potentially has the most complex chitin synthase (CHS) gene family, but evolution of the fungal CHS gene family and its diversification to fulfill multiple functions remain to be elucidated. Here, we identified the full complement of CHSs from 231 fungal species. Using the largest dataset to date, we characterized the evolution of the fungal CHS gene family using phylogenetic and domain structure analysis. Gene duplication, domain recombination and accretion are major mechanisms underlying the diversification of the fungal CHS gene family, producing at least 7 CHS classes. Contraction of the CHS gene family is morphology-specific, with significant loss in unicellular fungi, whereas family expansion is lineage-specific with obvious expansion in early-diverging fungi. ClassV and ClassVII CHSs with the same domain structure were produced by the recruitment of domains PF00063 and PF08766 and subsequent duplications. Comparative analysis of their functions in multiple fungal species shows that the emergence of ClassV and ClassVII CHSs is important for the morphogenesis of filamentous fungi, development of pathogenicity in pathogenic fungi, and heat stress tolerance in Pezizomycotina fungi. This work reveals the evolution of the fungal CHS gene family, and its correlation with fungal morphogenesis and adaptation to ecological niches. PMID:28300148

  15. Genome-Wide Investigation of Hsf Genes in Sesame Reveals Their Segmental Duplication Expansion and Their Active Role in Drought Stress Response.

    PubMed

    Dossa, Komivi; Diouf, Diaga; Cissé, Ndiaga

    2016-01-01

    Sesame is a survivor crop cultivated for ages in arid areas under high temperatures and limited water conditions. Since its entire genome has been sequenced, revealing evolution, and functional characterization of its abiotic stress genes became a hot topic. In this study, we performed a whole-genome identification and analysis of Hsf gene family in sesame. Thirty genes encoding Hsf domain were found and classified into 3 major classes A, B, and C. The class A members were the most representative one and Hsf genes were distributed in 12 of the 16 linkage groups (except the LG 8, 9, 13, and 16). Evolutionary analysis revealed that, segmental duplication events which occurred around 67 MYA, were the primary force underlying Hsf genes expansion in sesame. Comparative analysis also suggested that sesame has retained most of its Hsf genes while its relatives viz. tomato and potato underwent extensive gene losses during evolution. Continuous purifying selection has played a key role in the maintenance of Hsf genes in sesame. Expression analysis of the Hsf genes in sesame revealed their putative involvement in multiple tissue-/developmental stages. Time-course expression profiling of Hsf genes in response to drought stress showed that 90% Hsfs are drought responsive. We infer that classes B-Hsfs might be the primary regulators of drought response in sesame by cooperating with some class A genes. This is the first insight into this gene family and the results provide some gene resources for future gene cloning and functional studies toward the improvement in stress tolerance of sesame.

  16. Genome-Wide Investigation of Hsf Genes in Sesame Reveals Their Segmental Duplication Expansion and Their Active Role in Drought Stress Response

    PubMed Central

    Dossa, Komivi; Diouf, Diaga; Cissé, Ndiaga

    2016-01-01

    Sesame is a survivor crop cultivated for ages in arid areas under high temperatures and limited water conditions. Since its entire genome has been sequenced, revealing evolution, and functional characterization of its abiotic stress genes became a hot topic. In this study, we performed a whole-genome identification and analysis of Hsf gene family in sesame. Thirty genes encoding Hsf domain were found and classified into 3 major classes A, B, and C. The class A members were the most representative one and Hsf genes were distributed in 12 of the 16 linkage groups (except the LG 8, 9, 13, and 16). Evolutionary analysis revealed that, segmental duplication events which occurred around 67 MYA, were the primary force underlying Hsf genes expansion in sesame. Comparative analysis also suggested that sesame has retained most of its Hsf genes while its relatives viz. tomato and potato underwent extensive gene losses during evolution. Continuous purifying selection has played a key role in the maintenance of Hsf genes in sesame. Expression analysis of the Hsf genes in sesame revealed their putative involvement in multiple tissue-/developmental stages. Time-course expression profiling of Hsf genes in response to drought stress showed that 90% Hsfs are drought responsive. We infer that classes B-Hsfs might be the primary regulators of drought response in sesame by cooperating with some class A genes. This is the first insight into this gene family and the results provide some gene resources for future gene cloning and functional studies toward the improvement in stress tolerance of sesame. PMID:27790233

  17. A 380-kb Duplication in 7p22.3 Encompassing the LFNG Gene in a Boy with Asperger Syndrome

    PubMed Central

    Vulto-van Silfhout, A.T.; de Brouwer, A.F.M.; de Leeuw, N.; Obihara, C.C.; Brunner, H.G.; de Vries, B.B.A.

    2012-01-01

    De novo genomic aberrations are considered an important cause of autism spectrum disorders. We describe a de novo 380-kb gain in band p22.3 of chromosome 7 in a patient with Asperger syndrome. This duplicated region contains 9 genes including the LNFG gene that is an important regulator of NOTCH signaling. We suggest that this copy number variation has been a contributive factor to the occurrence of Asperger syndrome in this patient. PMID:22822384

  18. FoxO gene family evolution in vertebrates

    PubMed Central

    Wang, Minghui; Zhang, Xiangzhe; Zhao, Hongbo; Wang, Qishan; Pan, Yuchun

    2009-01-01

    Background Forkhead box, class O (FoxO) belongs to the large family of forkhead transcription factors that are characterized by a conserved forkhead box DNA-binding domain. To date, the FoxO group has four mammalian members: FoxO1, FoxO3a, FoxO4 and FoxO6, which are orthologs of DAF16, an insulin-responsive transcription factor involved in regulating longevity of worms and flies. The degree of homology between these four members is high, especially in the forkhead domain, which contains the DNA-binding interface. Yet, mouse FoxO knockouts have revealed that each FoxO gene has its unique role in the physiological process. Whether the functional divergences are primarily due to adaptive selection pressure or relaxed selective constraint remains an open question. As such, this study aims to address the evolutionary mode of FoxO, which may lead to the functional divergence. Results Sequence similarity searches have performed in genome and scaffold data to identify homologues of FoxO in vertebrates. Phylogenetic analysis was used to characterize the family evolutionary history by identifying two duplications early in vertebrate evolution. To determine the mode of evolution in vertebrates, we performed a rigorous statistical analysis with FoxO gene sequences, including relative rate ratio tests, branch-specific dN/dS ratio tests, site-specific dN/dS ratio tests, branch-site dN/dS ratio tests and clade level amino acid conservation/variation patterns analysis. Our results suggest that FoxO is constrained by strong purifying selection except four sites in FoxO6, which have undergone positive Darwinian selection. The functional divergence in this family is best explained by either relaxed purifying selection or positive selection. Conclusion We present a phylogeny describing the evolutionary history of the FoxO gene family and show that the genes have evolved through duplications followed by purifying selection except for four sites in FoxO6 fixed by positive selection lie

  19. Biological Consequences of Ancient Gene