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1

Increased sex chromosome expression and epigenetic abnormalities in spermatids from male mice with Y chromosome deletions.  

PubMed

During male meiosis, the X and Y chromosomes are transcriptionally silenced, a process termed meiotic sex chromosome inactivation (MSCI). Recent studies have shown that the sex chromosomes remain substantially transcriptionally repressed after meiosis in round spermatids, but the mechanisms involved in this later repression are poorly understood. Mice with deletions of the Y chromosome long arm (MSYq-) have increased spermatid expression of multicopy X and Y genes, and so represent a model for studying post-meiotic sex chromosome repression. Here, we show that the increase in sex chromosome transcription in spermatids from MSYq- mice affects not only multicopy but also single-copy XY genes, as well as an X-linked reporter gene. This increase in transcription is accompanied by specific changes in the sex chromosome histone code, including almost complete loss of H4K8Ac and reduction of H3K9me3 and CBX1. Together, these data show that an MSYq gene regulates sex chromosome gene expression as well as chromatin remodelling in spermatids. PMID:19861498

Reynard, Louise N; Turner, James M A

2009-10-27

2

Sex Chromosome  

NSDL National Science Digital Library

A sex chromosome is one of the two chromosomes that specify an organism's genetic sex. Humans have two kinds of sex chromosomes, one called X and the other Y. Normal females possess two X chromosomes and normal males one X and one Y.

Darryl Leja (National Human Genome Research Institute REV)

2005-04-14

3

PCR-PRINS-FISH analysis of structurally abnormal sex chromosomes in eight patients with Turner phenotype.  

PubMed

According to cytogenetic analysis, about 50% of Turner individuals are 45,X. The remaining cases have a structurally abnormal X chromosome or are mosaics with a second cell line containing a normal or abnormal sex chromosome. In these mosaics, approximately 20% have a sex marker chromosome whose identity cannot usually be determined by classical cytogenetic methods, requiring the use of molecular techniques. Polymerase chain reaction (PCR), primed in situ labeling (PRINS), and fluorescence in situ hybridization (FISH) analyses were performed in 8 patients with Turner syndrome and 45,X mosaic karyotypes to determine the origin and structure of the marker chromosome in the second cell line. Our data showed that markers were Y-derived in 2 patients and X-derived in the remaining 6 patients. We were also able to determine the breakpoints in the two Y chromosomes. The use of cytogenetic and molecular techniques allowed us to establish unequivocally the origin, X or Y, of the marker chromosomes in the 8 patients with Turner phenotype. This study illustrates the power of resolution and utility of combined cytogenetic and molecular approaches in some clinical cases. PMID:11903342

Cervantes, A; Guevara-Yáñez, R; López, M; Monroy, N; Aguinaga, M; Valdez, H; Sierra, C; Canún, S; Guízar, J; Navarrete, C; Zafra, G; Salamanca, F; Kofman-Alfaro, S

2001-11-01

4

Epilepsy and chromosomal abnormalities  

PubMed Central

Background Many chromosomal abnormalities are associated with Central Nervous System (CNS) malformations and other neurological alterations, among which seizures and epilepsy. Some of these show a peculiar epileptic and EEG pattern. We describe some epileptic syndromes frequently reported in chromosomal disorders. Methods Detailed clinical assessment, electrophysiological studies, survey of the literature. Results In some of these congenital syndromes the clinical presentation and EEG anomalies seems to be quite typical, in others the manifestations appear aspecific and no strictly linked with the chromosomal imbalance. The onset of seizures is often during the neonatal period of the infancy. Conclusions A better characterization of the electro clinical patterns associated with specific chromosomal aberrations could give us a valuable key in the identification of epilepsy susceptibility of some chromosomal loci, using the new advances in molecular cytogenetics techniques - such as fluorescent in situ hybridization (FISH), subtelomeric analysis and CGH (comparative genomic hybridization) microarray. However further studies are needed to understand the mechanism of epilepsy associated with chromosomal abnormalities.

2010-01-01

5

Chromosome abnormalities in glioma  

SciTech Connect

Cytogenetic studies were performed in 25 patients with gliomas. An interesting finding was a seemingly identical abnormality, an extra band on the tip of the short arm of chromosome 1, add(1)(p36), in two cases. The abnormality was present in all cells from a patient with a glioblastoma and in 27% of the tumor cells from a patient with a recurrent irradiated anaplastic astrocytoma; in the latter case, 7 unrelated abnormal clones were identified except 4 of those clones shared a common change, -Y. Three similar cases have been described previously. In a patient with pleomorphic astrocytoma, the band 1q42 in both homologues of chromosome 1 was involved in two different rearrangements. A review of the literature revealed that deletion of the long arm of chromosome 1 including 1q42 often occurs in glioma. This may indicate a possible tumor suppressor gene in this region. Cytogenetic follow-up studies were carried out in two patients and emergence of unrelated clones were noted in both. A total of 124 clonal breakpoints were identified in the 25 patients. The breakpoints which occurred three times or more were: 1p36, 1p22, 1q21, 1q25, 3q21, 7q32, 8q22, 9q22, 16q22, and 22q13.

Li, Y.S.; Ramsay, D.A.; Fan, Y.S. [Victoria Hospital, London, Ontario (Canada)] [and others

1994-09-01

6

Chromosomal abnormalities and mental illness  

Microsoft Academic Search

Linkage studies of mental illness have provided suggestive evidence of susceptibility loci over many broad chromosomal regions. Pinpointing causative gene mutations by conventional linkage strategies alone is problematic. The breakpoints of chromosomal abnormalities occurring in patients with mental illness may be more direct pointers to the relevant gene locus. Publications that describe patients where chromosomal abnormalities co-exist with mental illness

D J MacIntyre; D H R Blackwood; D J Porteous; B S Pickard; W J Muir

2003-01-01

7

Sex Chromosomes and Speciation  

Microsoft Academic Search

Studies of reproductive isolation between animal species have shown (i) that if one sex of the hybrids between two species is sterile or inviable, it is usually the heterogametic sex (Haldane's rule), and (ii) the genes on the sex chromosomes play a particularly large role in hybrid sterility and inviability. We propose an explanation for these two observations which is

Eva Jablonka; Marion J. Lamb

1991-01-01

8

Abnormalities of sex differentiation.  

PubMed

Sex differentiation is determined by a cascade of events proceeding from chromosomal sex to the completion of sexual maturation at puberty. Many factors involved in this cascade have been identified. Here we focus on DAX-1, androgen receptor and cytochrome P450c17, and discuss their functions in sex differentiation. We analyzed the DAX-1 genes of two unrelated Japanese patients with congenital adrenal hypoplasia and hypogonadotropic hypogonadism using PCR amplification of genomic DNA and complete exonic sequencing, and established that congenital adrenal hypoplasia and hypogonadotropic hypogonadism result from not only inherited but also de novo mutation in the DAX-1 gene. Androgen insensitivity syndrome (AIS) is a good model to clarify the relationship between the structure and function of androgen receptor, the androgen receptor gene mutation and clinical phenotype. We analyzed 15 cases of AIS and demonstrate the structural and functional relationships of the androgen receptor. We have sequenced the CYP17 (P450c17) gene in DNA from several patients with 17 alpha-hydroxylase deficiency, reconstructed the mutations in a human P450c17 cDNA and expressed the mutant P450c17 in COSl cells to characterize the kinetic properties of 17 alpha-hydroxylase and 17,20-lyase activities. The molecular bases of cases clinically reported as 17 alpha-hydroxylase deficiency have turned out to be complete or partial combined deficiencies of 17 alpha-hydroxylase/17,20-lyase. PMID:8864743

Nawata, H; Takayanagi, R; Yanase, T; Ikuyama, S; Okabe, T

1996-01-01

9

Chromosomal abnormalities and embryo development in recurrent miscarriage couples  

Microsoft Academic Search

BACKGROUND: Chromosomal abnormalities are an important cause of spontaneous abortion and recurrent mis- carriage (RM). Therefore, we have analysed the incidence of chromosomal abnormalities and embryo development in patients with RM. METHODS: Preimplantation genetic diagnosis (PGD) was performed on 71 couples with RM and 28 couples undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X

C. Rubio; C. Simon; F. Vidal; L. Rodrigo; T. Pehlivan; J. Remohi; A. Pellicer

2003-01-01

10

Genomics of Sex and Sex Chromosomes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sex chromosomes are distinctive, not only because of their gender determining role, but also for genomic features that reflect their evolutionary history. The genomic sequences in the ancient sex chromosomes of humans and in the incipient sex chromosomes of medaka, stickleback, and papaya exhibit u...

11

[Sex chromosomes and meiosis].  

PubMed

Sex chromosome behaviour fundamentally differs between male and female meiosis. In oocyte, X chromosomes synapse giving a XX bivalent which is not recognizable in their morphology and behaviour from autosomal bivalents. In human male, X and Y chromosomes differ from one another in their morphology and their genetic content, leading to a limited pairing and preventing genetic recombination, excepted in homologous region PAR1. During pachytene stage of the first meiotic prophase, X and Y chromosomes undergo a progressive condensation and form a transcriptionally silenced peripheral XY body. The condensation of the XY bivalent during pachytene stage led us to describe four pachytene substages and to localize the pachytene checkpoint between substages 2 and 3. We also defined the pachytene index (PI=P1+P2/P1+P2+P3+P4) which is always less than 0.50 in normal meiosis. XY body undergoes decondensation at diplotene stage, but transcriptional inactivation of the two sex chromosomes or Meiotic Sex Chromosome Inactivation (MSCI) persists through to the end of spermatogenesis. Sex chromosome inactivation involves several proteins, some of them were now identified. Two isoforms of the HP1 protein, HP1beta and HP1gamma, are involved in the facultative heterochromatinization of the XY body, but the initiation of this process involves the phosphorylation of the protein H2AX by the kinase ATR whose recruitment depends on BRCA1. Extensive researches on the inactivation of the sex chromosomes during male meiosis will allow to a better understanding of some male infertilities. PMID:19819743

Guichaoua, M-R; Geoffroy-Siraudin, C; Tassistro, V; Ghalamoun-Slaimi, R; Perrin, J; Metzler-Guillemain, C

2009-10-12

12

Function of the sex chromosomes in mammalian fertility.  

PubMed

The sex chromosomes play a highly specialized role in germ cell development in mammals, being enriched in genes expressed in the testis and ovary. Sex chromosome abnormalities (e.g., Klinefelter [XXY] and Turner [XO] syndrome) constitute the largest class of chromosome abnormalities and the commonest genetic cause of infertility in humans. Understanding how sex-gene expression is regulated is therefore critical to our understanding of human reproduction. Here, we describe how the expression of sex-linked genes varies during germ cell development; in females, the inactive X chromosome is reactivated before meiosis, whereas in males the X and Y chromosomes are inactivated at this stage. We discuss the epigenetics of sex chromosome inactivation and how this process has influenced the gene content of the mammalian X and Y chromosomes. We also present working models for how perturbations in sex chromosome inactivation or reactivation result in subfertility in the major classes of sex chromosome abnormalities. PMID:21730045

Heard, Edith; Turner, James

2011-10-01

13

Function of the Sex Chromosomes in Mammalian Fertility  

PubMed Central

The sex chromosomes play a highly specialized role in germ cell development in mammals, being enriched in genes expressed in the testis and ovary. Sex chromosome abnormalities (e.g., Klinefelter [XXY] and Turner [XO] syndrome) constitute the largest class of chromosome abnormalities and the commonest genetic cause of infertility in humans. Understanding how sex-gene expression is regulated is therefore critical to our understanding of human reproduction. Here, we describe how the expression of sex-linked genes varies during germ cell development; in females, the inactive X chromosome is reactivated before meiosis, whereas in males the X and Y chromosomes are inactivated at this stage. We discuss the epigenetics of sex chromosome inactivation and how this process has influenced the gene content of the mammalian X and Y chromosomes. We also present working models for how perturbations in sex chromosome inactivation or reactivation result in subfertility in the major classes of sex chromosome abnormalities.

Heard, Edith; Turner, James

2011-01-01

14

Meiotic sex chromosome inactivation.  

PubMed

X chromosome inactivation is most commonly studied in the context of female mammalian development, where it performs an essential role in dosage compensation. However, another form of X-inactivation takes place in the male, during spermatogenesis, as germ cells enter meiosis. This second form of X-inactivation, called meiotic sex chromosome inactivation (MSCI) has emerged as a novel paradigm for studying the epigenetic regulation of gene expression. New studies have revealed that MSCI is a special example of a more general mechanism called meiotic silencing of unsynapsed chromatin (MSUC), which silences chromosomes that fail to pair with their homologous partners and, in doing so, may protect against aneuploidy in subsequent generations. Furthermore, failure in MSCI is emerging as an important etiological factor in meiotic sterility. PMID:17329371

Turner, James M A

2007-02-28

15

Dosage Compensation of the Sex Chromosomes  

PubMed Central

Differentiated sex chromosomes evolved because of suppressed recombination once sex became genetically controlled. In XX/XY and ZZ/ZW systems, the heterogametic sex became partially aneuploid after degeneration of the Y or W. Often, aneuploidy causes abnormal levels of gene expression throughout the entire genome. Dosage compensation mechanisms evolved to restore balanced expression of the genome. These mechanisms include upregulation of the heterogametic chromosome as well as repression in the homogametic sex. Remarkably, strategies for dosage compensation differ between species. In organisms where more is known about molecular mechanisms of dosage compensation, specific protein complexes containing noncoding RNAs are targeted to the X chromosome. In addition, the dosage-regulated chromosome often occupies a specific nuclear compartment. Some genes escape dosage compensation, potentially resulting in sex-specific differences in gene expression. This review focuses on dosage compensation in mammals, with comparisons to fruit flies, nematodes, and birds.

Disteche, Christine M.

2013-01-01

16

Metabolic impact of sex chromosomes  

PubMed Central

Obesity and associated metabolic diseases are sexually dimorphic. To provide better diagnosis and treatment for both sexes, it is of interest to identify the factors that underlie male/female differences in obesity. Traditionally, sexual dimorphism has been attributed to effects of gonadal hormones, which influence numerous metabolic processes. However, the XX/XY sex chromosome complement is an additional factor that may play a role. Recent data using the four core genotypes mouse model have revealed that sex chromosome complement—independently from gonadal sex—plays a role in adiposity, feeding behavior, fatty liver and glucose homeostasis. Potential mechanisms for the effects of sex chromosome complement include differential gene dosage from X chromosome genes that escape inactivation, and distinct genomic imprints on X chromosomes inherited from maternal or paternal parents. Here we review recent data in mice and humans concerning the potential impact of sex chromosome complement on obesity and metabolic disease.

Link, Jenny C.; Chen, Xuqi; Arnold, Arthur P.; Reue, Karen

2013-01-01

17

Metabolic impact of sex chromosomes.  

PubMed

Obesity and associated metabolic diseases are sexually dimorphic. To provide better diagnosis and treatment for both sexes, it is of interest to identify the factors that underlie male/female differences in obesity. Traditionally, sexual dimorphism has been attributed to effects of gonadal hormones, which influence numerous metabolic processes. However, the XX/XY sex chromosome complement is an additional factor that may play a role. Recent data using the four core genotypes mouse model have revealed that sex chromosome complement-independently from gonadal sex-plays a role in adiposity, feeding behavior, fatty liver and glucose homeostasis. Potential mechanisms for the effects of sex chromosome complement include differential gene dosage from X chromosome genes that escape inactivation, and distinct genomic imprints on X chromosomes inherited from maternal or paternal parents. Here we review recent data in mice and humans concerning the potential impact of sex chromosome complement on obesity and metabolic disease. PMID:23805402

Link, Jenny C; Chen, Xuqi; Arnold, Arthur P; Reue, Karen

2013-04-01

18

Plant sex determination and sex chromosomes  

Microsoft Academic Search

Sex determination systems in plants have evolved many times from hermaphroditic ancestors (including monoecious plants with separate male and female flowers on the same individual), and sex chromosome systems have arisen several times in flowering plant evolution. Consistent with theoretical models for the evolutionary transition from hermaphroditism to monoecy, multiple sex determining genes are involved, including male-sterility and female-sterility factors.

D Charlesworth

2002-01-01

19

Disorders caused by chromosome abnormalities  

PubMed Central

Many human genetic disorders result from unbalanced chromosome abnormalities, in which there is a net gain or loss of genetic material. Such imbalances often disrupt large numbers of dosage-sensitive, developmentally important genes and result in specific and complex phenotypes. Alternately, some chromosomal syndromes may be caused by a deletion or duplication of a single gene with pleiotropic effects. Traditionally, chromosome abnormalities were identified by visual inspection of the chromosomes under a microscope. The use of molecular cytogenetic technologies, such as fluorescence in situ hybridization and microarrays, has allowed for the identification of cryptic or submicroscopic imbalances, which are not visible under the light microscope. Microarrays have allowed for the identification of numerous new syndromes through a genotype-first approach in which patients with the same or overlapping genomic alterations are identified and then the phenotypes are described. Because many chromosomal alterations are large and encompass numerous genes, the ascertainment of individuals with overlapping deletions and varying clinical features may allow researchers to narrow the region in which to search for candidate genes.

Theisen, Aaron; Shaffer, Lisa G

2010-01-01

20

Sex chromosomes and brain gender  

Microsoft Academic Search

In birds and mammals, differences in development between the sexes arise from the differential actions of genes that are encoded on the sex chromosomes. These genes are differentially represented in the cells of males and females, and have been selected for sex-specific roles. The brain is a sexually dimorphic organ and is also shaped by sex-specific selection pressures. Genes on

Arthur P. Arnold

2004-01-01

21

Advances in Understanding Paternally Transmitted Chromosomal Abnormalities.  

National Technical Information Service (NTIS)

Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnorma...

F. Marchetti E. Sloter A. J. Wyrobek

2002-01-01

22

Chromosome abnormalities in Indonesian patients with short stature  

PubMed Central

Background Short stature is associated with several disorders including wide variations of chromosomal disorders and single gene disorders. The objective of this report is to present the cytogenetic findings in Indonesian patients with short stature. Methods G-banding and interphase/metaphase FISH were performed on short stature patients with and without other clinical features who were referred by clinicians all over Indonesia to our laboratory during the year 2003–2009. Results The results of chromosomal analysis of ninety seven patients (mean age: 10.7 years old) were collected. The group of patients with other clinical features showed sex chromosome abnormalities in 45% (18/40) and autosomal abnormalities in 10% (4/40), whereas those with short stature only, 42.1% (24/57) had sex chromosome abnormalities and 1.75% (1/57) had autosomal abnormalities. The autosomal chromosomal abnormalities involved mostly subtelomeric regions. Results discrepancies between karyotype and FISH were found in 10 patients, including detection of low-level monosomy X mosaicism in 6 patients with normal karyotype, and detection of mosaic aneuploidy chromosome 18 in 1 patient with 45,XX,rob(13;14)(q10;q10). Statistical analysis showed no significant association between the groups and the type of chromosomal abnormalities. Conclusion Chromosome abnormalities account for about 50% of the short stature patients. Wide variations of both sex and autosomal chromosomes abnormalities were detected in the study. Since three out of five patients had autosomal structural abnormalities involving the subtelomeric regions, thus in the future, subtelomeric FISH or even a more sensitive method such as genomic/SNP microarray is needed to confirm deletions of subtelomeric regions of chromosome 9, 11 and 18. Low-level mosaicism in normal karyotype patients indicates interphase FISH need to be routinely carried out in short stature patients as an adjunct to karyotyping.

2012-01-01

23

Isolation and characterization of sex chromosome rearrangements generating male muscle dystrophy and female abnormal oogenesis in the silkworm, Bombyx mori  

Microsoft Academic Search

In deletion-mapping of W-specific RAPD (W-RAPD) markers and putative female determinant gene (Fem), we used X-ray irradiation to break the translocation-carrying W chromosome (W\\u000a Ze\\u000a ). We succeeded in obtaining a fragment of the W\\u000a Ze\\u000a chromosome designated as Ze\\u000a W, having 3 of 12 W-RAPD markers (W-Bonsai, W-Yukemuri-S, W-Yukemuri-L). Inheritance of the Ze\\u000a W fragment by males indicates that

T. Fujii; T. Yokoyama; O. Ninagi; K. Kakehashi; Y. Obara; M. Nenoi; T. Ishikawa; K. Mita; T. Shimada; H. Abe

2007-01-01

24

Chromosome X numerical abnormalities in patients with Non-Hodgkin's Lymphoma  

Microsoft Academic Search

Chromosome X numerical abnormalities are frequently observed in non-Hodgkin's lymphoma (NHL), with an incidence of 3% to 14% for chromosomal loss and 7% to 33% for chromosomal gain. Because sex chromosome numerical abnormalities are thought to be due to aging, little information is known about their relation to gender, therapy, and prognosis. Therefore, to determine the incidence and clinical relevance

Anas Younes; David Jendiroba; Ruth Katz; Debbie Hill; Fernando Cabanillas; Michael Andreeff

1995-01-01

25

Sex chromosomes, recombination, and chromatin conformation  

Microsoft Academic Search

We review what is known about the transcriptional inactivation and condensation of heteromorphic sex chromosomes in contrast to the activation of homomorphic sex chromosomes during meiotic prephase in animals. We relate these cytological and transcriptional features to the recombination status of the sex chromosomes. We propose that sex chromosome condensation is a meiotic adaptation to prevent the initiation of potentially

Bruce D. McKee; Mary Ann Handel

1993-01-01

26

Specific Chromosomal Abnormalities in Malignant Human Gliomas1  

Microsoft Academic Search

Karyotypic analysis of 54 malignant human gliomas (5 anaplastic asina-)tomas, 43 glioblastoma multiformes, 3 gliosarcomas, 2 giant cell glioblastomas, 1 anaplastic mixed glioma) has demonstrated that 12 tumors contained normal stemlines or only lacked one sex chromosome. The 42 tumors with abnormal karyotypes included 38 tumors which could be completely analyzed. Six of these 38 cases had near-triploid or near-

Sandra H. Bigner; Joachim Mark; Peter C. Burger; M. Stephen; Dennis E. Bullan; Lawrence H. Muhlbaier; Dareil D. Bigner

1988-01-01

27

Advances in understanding paternally transmitted Chromosomal Abnormalities  

SciTech Connect

Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

Marchetti, F; Sloter, E; Wyrobek, A J

2001-03-01

28

Klinefelter syndrome and other sex chromosomal aneuploidies  

Microsoft Academic Search

The term Klinefelter syndrome (KS) describes a group of chromosomal disorder in which there is at least one extra X chromosome to a normal male karyotype, 46,XY. XXY aneuploidy is the most common disorder of sex chromosomes in humans, with prevalence of one in 500 males. Other sex chromosomal aneuploidies have also been described, although they are much less frequent,

Jeannie Visootsak; John M Graham Jr

2006-01-01

29

Ovarian dysgenesis in individuals with chromosomal abnormalities  

Microsoft Academic Search

To understand better the pathogenesis of ovarian dysgenesis in individuals with abnormalities such as 45,X Turner syndrome, trisomy 13, and trisomy 18, we have examined microscopically the ovaries of 36 infants with a number of chromosomal abnormalities confirmed by karyotype analysis. All infants with trisomy 13, trisomy 18, triploidy, and 45,X were found to have severe ovarian dysgenesis characterized by

Christopher Cunniff; Kenneth Lyons Jones; Kurt Benirschke

1991-01-01

30

[Y chromosome structural abnormalities and Turner's syndrome].  

PubMed

Although specifically male, the human Y chromosome may be observed in female karyotypes, mostly in women with Turner syndrome stigmata. In women with isolated gonadal dysgenesis but otherwise normal stature, the testis determining factor or SRY gene may have been removed from the Y chromosome or may be mutated. In other women with Turner syndrome, the karyotype is usually abnormal and shows a frequent 45,X/46,XY mosaicism. In these cases, the phenotype depends on the ratio between Y positive and 45,X cell lines in the body. When in mosaicism, Y chromosomes are likely to carry structural abnormalities which explain mitotic instability, such as the existence of two centromeres. Dicentric Y isochromosomes for the short arm (idic[Yp]) or ring Y chromosomes (r[Y]) are the most frequent abnormal Y chromosomes found in infertile patients and in Turner syndrome in mosaic with 45,X cells. Although monocentric, deleted Y chromosomes for the long arm and those carrying microdeletions in the AZF region are also instable and are frequently associated with a 45,X cell line. Management of infertile patients carrying such abnormal Y chromosomes must take into account the risk and the consequences of a mosaicism in the offspring. PMID:19464936

Ravel, C; Siffroi, J-P

2009-05-22

31

Chromosomal abnormalities in spontaneous abortion after assisted reproductive treatment  

PubMed Central

Background We evaluated cytogenetic results occurring with first trimester pregnancy loss, and assessed the type and frequency of chromosomal abnormalities after assisted reproductive treatment (ART) and compared them with a control group. We also compared the rate of chromosomal abnormalities according to infertility causes in ICSI group. Methods A retrospective cohort analysis was made of all patients who were referred to the Genetics Laboratory of Fertility Center of CHA Gangnam Medical Center from 2005 to 2009 because of clinical abortion with a subsequent dilation and evacuation (D&E) performed, and patients were grouped by type of conception as follows: conventional IVF (in vitro fertilization) (n = 114), ICSI (intracytoplasmic sperm injection) (n = 140), and control (natural conception or intrauterine insemination [IUI]) (n = 128). Statistical analysis was performed using SPSS software. Results A total 406 specimens were referred to laboratory, ten abortuses were excluded, and in 14 cases, we did not get any spontaneous metaphase, chromosomal constitutions of 382 specimens were successfully obtained with conventional cytogenetic methods. Overall, 52.62% of the miscarriages were found to be cytogenetically abnormal among all patients, the frequency was 48.4% in the control group, 54.3% of miscarriages after ICSI and 55.3% after conventional IVF (p = 0.503). The most prevalent abnormalities were autosomal trisomy, however, nine (11.69%) sex chromosome aneuploidy were noted in the ICSI group vs. four (6.45%) and two (3.23%) cases in the conventional IVF group and control group. We compared chromosomal abnormalities of miscarriages after ICSI according to infertility factor. 55.71% underwent ICSI due to male factors, 44.29% due to non-male factors. ICSI group having male factors showed significantly higher risk of chromosomal abnormalities than ICSI group having non-male factors (65.8% vs. 34.2%, p = 0.009, odds ratio = 1.529, 95% CI = 1.092-2.141). Conclusions There is no increased risk of chromosomal abnormalities due to ART was found with the exception of a greater number of sex chromosomal abnormalities in the ICSI group with male factor infertility. Therefore, these alterations could be correlated with the underlying parental risk of abnormalities and not with the ICSI procedure itself.

2010-01-01

32

New Y chromosomes and early stages of sex chromosome differentiation: sex determination in Megaselia  

Microsoft Academic Search

The phorid fly Megaselia scalaris is a laboratory model for the turnover and early differentiation of sex chromosomes. Isolates from the field have an XY sex-determining\\u000a mechanism with chromosome pair 2 acting as X and Y chromosomes. The sex chromosomes are homomorphic but display early signs\\u000a of sex chromosome differentiation: a low level of molecular differences between X and Y.

Walther Traut

2010-01-01

33

Evolution and Survival on Eutherian Sex Chromosomes  

Microsoft Academic Search

Since the two eutherian sex chromosomes diverged from an ancestral autosomal pair, the X has remained relatively gene-rich, while the Y has lost most of its genes through the accumulation of deleterious mutations in nonrecombining regions. Presently, it is unclear what is distinctive about genes that remain on the Y chromosome, when the sex chromosomes acquired their unique evolutionary rates,

Melissa A. Wilson; Kateryna D. Makova

2009-01-01

34

Chromosomal abnormalities associated with cyclopia and synophthalmia.  

PubMed Central

At the present time, essentially all known facts concerning cyclopia are consistent with some chromosomal disease, including clinical features of the pregnancy (fetal wastage, prematurity, intrauterine growth retardation, maternal age factor, complications of pregnancy), the generalized developmental abnormalities, specific ocular dysgenesis, by the high incidence of chromosomal abnormality already demonstrated, and the possibility of error in those cases of cyclopia with normal chromosomes. Even if chromosomal aberrations represent only one group of several different etiologic factors leading to cyclopia, at the present time chromosomal errors would seem to be the most common cause of cyclopia now recognized. Further studies will establish or disprove a chromosomal error in those instances which are now considered to be the result of an environmental factor alone or those with apparent familial patterns of inheritance. This apparent diverse origin of cyclopia can be clarified if future cyclopic specimens are carefully investigated. The evaluation should include a careful gross and microscopic examination of all organs, including the eye, and chromosome banding studies of all organs, including the eye, and chromosome banding studies of at least two cyclopic tissues. Then the presence or absence of multiple causative factors can be better evaluated. Images FIGURE 2 A FIGURE 2 B FIGURE 1 A FIGURE 1 B FIGURE 1 C FIGURE 1 D FIGURE 1 E FIGURE 1 F FIGURE 3 A FIGURE 3 B FIGURE 4 A FIGURE 4 B FIGURE 4 C FIGURE 4 D FIGURE 5 FIGURE 6 FIGURE 7 A FIGURE 7 B

Howard, R O

1977-01-01

35

Chromosomal abnormalities among children born with conotruncal cardiac defects  

PubMed Central

BACKGROUND Conotruncal heart defects comprise 25%-30% of non-syndromic congenital heart defects. This study describes the frequency of chromosome abnormalities and microdeletion 22q11 associated with conotruncal heart malformations. METHODS From a population base of 974,579 infants/fetuses delivered, 622 Californian infants/fetuses were ascertained with a defect of aortico-pulmonary septation. Infants whose primary cardiac defect was tetralogy of Fallot (n=296) or D-transposition of the great vessels (n=189) were screened for microdeletions of 22q11. RESULTS Fourteen (2.3%) of the 622 infants/fetuses had chromosomal abnormalities. Thirty infants, 10% of those whose primary defect was tetralogy of Fallot, had chromosome 22q11 microdeletions. Right aortic arch, abnormal branching patterns of the major arteries arising from the thoracic aorta, and pulmonary artery abnormalities were observed more frequently in these children. CONCLUSIONS We found an unusual number of infants with an extra sex chromosome and a conotruncal defect. Infants with tetralogy of Fallot due to 22q11 microdeletion showed more associated vascular anomalies than infants with tetralogy but no 22q11 microdeletion. Although these associated vascular anomalies provide clues as to which infants with tetralogy of Fallot are more likely to carry the microdeletion, the overall risk of 10% among all infants with tetralogy of Fallot warrants chromosome analysis and FISH testing routinely.

Lammer, Edward J.; Chak, Jacqueline S.; Iovannisci, David M.; Schultz, Kathleen; Osoegawa, Kazutoyo; Yang, Wei; Carmichael, Suzan L.; Shaw, Gary M.

2010-01-01

36

Chromosome and Molecular Abnormalities in Myelodysplastic Syndromes  

Microsoft Academic Search

Cytogenetic abnormalities are seen in approximately 50% of cases of myelodysplastic syndrome (MDS) and 80% of cases of secondary\\u000a MDS (following chemotherapy or radiotherapy). These abnormalities generally consist of partial or complete chromosome deletion\\u000a or addition (del5q, -7, +8, -Y, del20q), whereas balanced or unbalanced translocations are rarely found in MDS. Fluorescence hybridization techniques (fluorescence\\u000a in situ hybridization [FISH], multiplex

Pierre Fenaux

2001-01-01

37

Chromosome Abnormalities in Patients with Syndactyly  

PubMed Central

Chromosome studies on 105 patients with syndactyly included two trisomy-21 mongols, a chromatin-positive boy with 47, XXY, a chromatin-negative short girl with 45,X0 and a boy with a familial D/D translocation. Chromosome patterns were normal in the other cases which included three patients with acrocephalosyndactyly and one patient with oro-facial-digital syndrome. The incidence of chromosome abnormalies was greater than expected since syndactyly of the fingers is uncommon in the chromosome disorders. This incidence may be related to the increased maternal age (mean: 29.4 years) of the syndactyly group compared to maternal age (mean: 26.64 years) of the control group although, paradoxically, four mothers of the five patients with chromosome abnormalities were young. ImagesFIG. 1FIG. 2FIG. 3

Conen, P. E.; Hampole, M. K.; Thomson, H. G.

1969-01-01

38

Genetic conflict and sex chromosome evolution  

PubMed Central

Chromosomal sex determination systems create the opportunity for the evolution of selfish genetic elements that increase the transmission of one sex chromosome at the expense of its homolog. Because such selfish elements on sex chromosomes can reduce fertility and distort the sex ratio of progeny, unlinked suppressors are expected to evolve, bringing different regions of the genome into conflict over the meiotic transmission of the sex chromosomes. Here we argue that recurrent genetic conflict over sex chromosome transmission is an important evolutionary force that has shaped a wide range of seemingly disparate phenomena including the epigenetic regulation of genes expressed in the germline, the distribution of genes in the genome, and the evolution of hybrid sterility between species.

Meiklejohn, Colin D; Tao, Yun

2009-01-01

39

Chromosomal abnormalities in patients with autism spectrum disorders from taiwan.  

PubMed

Autism spectrum disorders (ASD) are childhood-onset neurodevelopmental disorders characterized by verbal communication impairments, social reciprocity deficits, and the presence of restricted interests and stereotyped behaviors. Genetic factors contribute to the incidence of ASD evidently. However, the genetic spectrum of ASD is highly heterogeneous. Chromosomal abnormalities contribute significantly to the genetic deficits of syndromic and non-syndromic ASD. In this study, we conducted karyotyping analysis in a sample of 500 patients (447 males, 53 females) with ASD from Taiwan, the largest cohort in Asia, to the best of our knowledge. We found three patients having sex chromosome aneuploidy, including two cases of 47, XXY and one case of 47, XYY. In addition, we detected a novel reciprocal chromosomal translocation between long arms of chromosomes 4 and 14, designated t(4;14)(q31.3;q24.1), in a patient with Asperger's disorder. This translocation was inherited from his unaffected father, suggesting it might not be pathogenic or it needs further hits to become pathogenic. In line with other studies, our study revealed that subjects with sex chromosomal aneuploidy are liable to neurodevelopmental disorders, including ASD, and conventional karyotyping analysis is still a useful tool in detecting chromosomal translocation in patients with ASD, given that array-based comparative genomic hybridization technology can provide better resolution in detecting copy number variations of genomic DNA. © 2013 Wiley Periodicals, Inc. PMID:24132905

Liao, Hsiao-Mei; Gau, Susan Shur-Fen; Tsai, Wen-Che; Fang, Jye-Siung; Su, Ying-Cheng; Chou, Miao-Chun; Liu, Shih-Kai; Chou, Wen-Jiun; Wu, Yu-Yu; Chen, Chia-Hsiang

2013-10-01

40

Learning Disorders and Sex Chromosome Aberrations.  

ERIC Educational Resources Information Center

|In a prospective study of 20 adult dyslexic men, no sex chromosome aberrations were detected. A retrospective study of 89 Ss with known sex chromosome aberrations revealed 20 of them to be mentally retarded. Among the 69 Ss of normal intelligence, learning, speech, and attention disorders were frequent. (Author/DLS)|

Hier, D. B.; And Others

1980-01-01

41

Evolution of sex chromosomes in insects.  

PubMed

Sex chromosomes have many unusual features relative to autosomes. Y (or W) chromosomes lack genetic recombination, are male- (female-) limited, and show an abundance of genetically inert heterochromatic DNA but contain few functional genes. X (or Z) chromosomes also show sex-biased transmission (i.e., X chromosomes show female-biased and Z-chromosomes show male-biased inheritance) and are hemizygous in the heterogametic sex. Their unusual ploidy level and pattern of inheritance imply that sex chromosomes play a unique role in many biological processes and phenomena, including sex determination, epigenetic chromosome-wide regulation of gene expression, the distribution of genes in the genome, genomic conflict, local adaptation, and speciation. The vast diversity of sex chromosome systems in insects--ranging from the classical male heterogametic XY system in Drosophila to ZW systems in Lepidoptera or mobile genes determining sex as found in house flies--implies that insects can serve as unique model systems to study various functional and evolutionary aspects of these different processes. PMID:21047257

Kaiser, Vera B; Bachtrog, Doris

2010-01-01

42

Chromosomal abnormalities as a cause of recurrent abortions in Egypt  

PubMed Central

BACKGROUND: In 4%-8% of couples with recurrent abortion, at least one of the partners has chromosomal abnormality. Most spontaneous miscarriages which happen in the first and second trimesters are caused by chromosomal abnormalities. These chromosomal abnormalities may be either numerical or structural. MATERIAL AND METHODS: Cytogenetic study was done for 73 Egyptian couples who presented with recurrent abortion at Genetic Unit of Children Hospital, Mansoura University. RESULTS: We found that the frequency of chromosomal abnormalities was not significantly different from that reported worldwide. Chromosomal abnormalities were detected in 9 (6.1%) of 73 couples. Seven of chromosomal abnormalities were structural and two of them were numerical. CONCLUSION: Our results showed that 6.1% of the couples with recurrent abortion had chromosomal abnormalities, with no other abnormalities. We suggest that it is necessary to perform cytogenetic in vestigation for couples who have recurrent abortion.

El-Dahtory, Faeza Abdel Mogib

2011-01-01

43

Chromosome abnormalities in primary ovarian cancer  

SciTech Connect

Chromosome abnormalities that are specific and recurrent may occur in regions of the genome that are involved in the conversion of normal cells to those with tumorigenic potential. Ovarian cancer is the primary cause of death among patients with gynecological malignancies. We have performed cytogenetic analysis of 16 ovarian tumors from women age 28-82. Three tumors of low malignant potential and three granulosa cell tumors had normal karyotypes. To look for the presence of trisomy 12, which has been suggested to be a common aberration in this group of tumors, interphase fluorescence in situ hybridization was performed on direct preparations from three of these tumors using a probe for alpha satellite sequences of chromosome 12. In the 3 preparations, 92-98 percent of the cells contained two copies of chromosome 12, indicating that trisomy 12 is not a universal finding in low grade ovarian tumors. Endometrioid carcinoma of the ovary is histologically indistinguishable from endometial carcinoma of the uterus. We studied 10 endometrioid tumors to determine the degree of genetic similarity between these two carcinomas. Six out of ten endometrioid tumors showed a near-triploid modal number, and one presented with a tetraploid modal number. Eight of the ten contained structural chromosome abnormalities, of which the most frequent were 1p- (5 tumors), 19q+ (3 tumors), 6q- or ins(6) (4 tumors), 3q- or 3q+ (4 tumors). These cytogenetic results resemble those reported for papillary ovarian tumors and differ from those of endometrial carcinoma of the uterus. We conclude that despite the histologic similarities between the endometrioid and endometrial carcinomas, the genetic abnormalities in the genesis of these tumors differ significantly.

Yonescu, R.; Currie, J.; Griffin, C.A. [John Hopkins Univ., Baltimore, MD (United States)

1994-09-01

44

Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution  

PubMed Central

Sex chromosomes originate from autosomes. The accumulation of sexually antagonistic mutations on protosex chromosomes selects for a loss of recombination and sets in motion the evolutionary processes generating heteromorphic sex chromosomes. Recombination suppression and differentiation are generally viewed as the default path of sex chromosome evolution, and the occurrence of old, homomorphic sex chromosomes, such as those of ratite birds, has remained a mystery. Here, we analyze the genome and transcriptome of emu (Dromaius novaehollandiae) and confirm that most genes on the sex chromosome are shared between the Z and W. Surprisingly, however, levels of gene expression are generally sex-biased for all sex-linked genes relative to autosomes, including those in the pseudoautosomal region, and the male-bias increases after gonad formation. This expression bias suggests that the emu sex chromosomes have become masculinized, even in the absence of ZW differentiation. Thus, birds may have taken different evolutionary solutions to minimize the deleterious effects imposed by sexually antagonistic mutations: some lineages eliminate recombination along the protosex chromosomes to physically restrict sexually antagonistic alleles to one sex, whereas ratites evolved sex-biased expression to confine the product of a sexually antagonistic allele to the sex it benefits. This difference in conflict resolution may explain the preservation of recombining, homomorphic sex chromosomes in other lineages and illustrates the importance of sexually antagonistic mutations driving the evolution of sex chromosomes.

Vicoso, Beatriz; Kaiser, Vera B.; Bachtrog, Doris

2013-01-01

45

X Chromosome Abnormalities and Cognitive Development: Implications for Understanding Normal Human Development.  

ERIC Educational Resources Information Center

Argues that knowledge from studies of individuals with sex chromosome abnormalities can further understanding of aspects of normal human development. Studies of XO girls, XXY boys, XXX girls, and males with a fragile X chromosome are summarized to demonstrate how results contribute to knowledge about normal cognitive development and about…

Walzer, Stanley

1985-01-01

46

Sex, sex chromosomes and gene expression.  

PubMed

The X chromosome has fewer testis-specific genes than autosomes in many species. This bias is commonly attributed to X inactivation in spermatogenesis but a recent paper in BMC Biology provides evidence against X inactivation in Drosophila and proposes that somatic tissue- and testis- but not ovary-specific genes tend not to be located on the X chromosome. Here, we discuss possible mechanisms underlying this bias, including sexual antagonism and dosage compensation. PMID:21542945

Lu, Xuemei; Wu, Chung-I

2011-05-04

47

Karyotype heterogeneity and unclassified chromosomal abnormalities.  

PubMed

In a departure from traditional gene-centric thinking with regard to cytogenetics and cytogenomics, the recently introduced genome theory calls upon a re-focusing of our attention on karyotype analyses of disease conditions. Karyotype heterogeneity has been demonstrated to be directly involved in the somatic cell evolution process which is the basis of many common and complex diseases such as cancer. To correctly use karyotype heterogeneity and apply it to monitor system instability, we need to include many seemingly unimportant non-specific chromosomal aberrations into our analysis. Traditionally, cytogenetic analysis has been focused on identifying recurrent types of abnormalities, particularly those that have been linked to specific diseases. In this perspective, drawing on the new framework of 4D-genomics, we will briefly review the importance of studying karyotype heterogeneity. We have also listed a number of overlooked chromosomal aberrations including defective mitotic figures, chromosome fragmentation as well as genome chaos. Finally, we call for the systematic discovery/characterization and classification of karyotype abnormalities in human diseases, as karyotype heterogeneity is the common factor that is essential for somatic cell evolution. PMID:23571381

Heng, H H Q; Liu, G; Stevens, J B; Abdallah, B Y; Horne, S D; Ye, K J; Bremer, S W; Chowdhury, S K; Ye, C J

2013-04-03

48

[Chromosomal abnormality diagnosis of male infertility by QF-PCR].  

PubMed

To assess the clinical practice of quantitative fluorescence PCR (QF-PCR) in genetic diagnosis of male infertility patients, 78 nonobstructive male infertility patients were pooled for semen routine screening and sexual hormone determination; QF-PCR was applied to detect the polymorphic short tandem repeat (STR) and specific sequence tagged site (STS) of sex chromosomes; routine chromosome G-band was used for karyotype analysis and PCR was used for the detection of AZF microdeletion. Routine screening of semen found 18 azoospermia and 20 oligospermia patients (48.72%). Three patients with 47, XXY, two with 46,XX(SRY+)and one with AZFc microdeletion were detected using QF-PCR technique which were verified by chromosome G-band and PCR. This study suggests that QF-PCR is a comprehensive, rapid and reliable method for detecting abnormal chromosomal regions and microstructures compared with traditional tests and provides a better candidate for diagnosis of male infertility caused by chromosomal anomalies and gene mutation. PMID:21831806

Qi, Man-Long; Zhang, Yuan-Yuan; Liu, Xiao-Liang; He, Rong; Zhao, Yan-Yan

2011-08-01

49

Sex chromosome Aneuploides among Men with Systemic Lupus Erythematosus  

PubMed Central

About 90% of patients with systemic lupus erythematosus (SLE) are female. We hypothesize that the number of X chromosomes, not sex, is a determinate of risk of SLE. Number of X chromosomes was determined by single nucleotide typing and then confirmed by karyotype or fluorescent in situ hybridization in a large group of men with SLE. Presence of an sry gene was assessed by rtPCR. We calculated 96% confidence intervals using the Adjusted Wald method, and used Bayes’ theorem to estimate the prevalence of SLE among 47,XXY and 46,XX men. Among 316 men with SLE, 7 had 47,XXY and 1 had 46,XX. The rate of Klinefelter’s syndrome (47,XXY) was statistically different from that found in control men and from the known prevalence in the population. The 46,XX man had an sry gene, which encodes the testes determining factor, on an X chromosome as a result of an abnormal crossover during meiosis. In the case of 46,XX, 1 of 316 was statistically different from the known population prevalence of 1 in 20,000 live male births. A previously reported 46,XX man with SLE had a different molecular mechanism in which there were no common gene copy number abnormalities with our patient. Thus, men with SLE are enriched for conditions with additional X chromosomes. Especially since 46,XX men are generally normal males, except for infertility, these data suggest the number of X chromosomes, not phenotypic sex, is responsible for the sex bias of SLE.

Dillon, Skyler P.; Kurien, Biji T.; Li, Shibo; Bruner, Gail R; Kaufman, Kenneth M.; Harley, John B; Gaffney, Patrick M.; Wallace, Daniel J.; Weisman, Michael H.; Scofield, R. Hal

2011-01-01

50

[Analysis of the chromosomal abnormality in 5774 patients with clinical reproductive abnormality and 32 new karyotypes].  

PubMed

To study the relationship between chromosomal abnormality and clinical ending events of reproductive abnormality, G-banding and karyotype analyses were carried out by using chromosome preparations from peripheral blood lymphocytes. Out of 5 774 cases with reproductive abnormality, 550 individuals had chromosomal abnormalities. Among them, 255 cases (46.36%) were trisomy, 91 cases (16.55%) were reciprocal translocation, 85 cases (15.45%) were chromosomal inversion, 81 cases (14.73%) were deletions, 21 cases (3.82%) were Robertsonian translocation, 7 cases (1.27%) were short arm increment, 6 cases (1.09%) were Y chromosome increment and 4 cases (0.73%) were abnormal satellites. Thirty-two cases with novel chromosomal abnormality karyotypes in them, being complicated by miscarriage, sterility, and congenital malformation, were firstly reported. The results suggested that chromosomal abnormality could be the one of main factors related to the bad reproductive ending events. PMID:19273421

Qin, Jing; Zheng, Chen-Guang; DU, Juan; Chen, Ke; Tian, Xiao-Xian; Xiang, Lei; Sun, Liang; Yang, Ze

2009-02-01

51

Meiosis and chromosome painting of sex chromosome systems in Ceboidea.  

PubMed

The identity of the chromosomes involved in the multiple sex system of Alouatta caraya (Aca) and the possible distribution of this system among other Ceboidea were investigated by chromosome painting of mitotic cells from five species and by analysis of meiosis at pachytene in two species. The identity of the autosome #7 (X2) involved in the multiple system of Aca and its breakage points were demonstrated by both meiosis and chromosome painting. These features are identical to those described by Consigliere et al. [1996] in Alouatta seniculus sara (Assa) and Alouatta seniculus arctoidea (Asar). This multiple system was absent in the other four Ceboidea species studied here. However, data from the literature strongly suggest the presence of this multiple in other members of this genus. The presence of this multiple system among several species and subspecies that show high levels of chromosome rearrangements may suggest a special selective value of this multiple. The meiotic features of the sex systems of Aca and Cebus apella paraguayanus (Cap) are strikingly different at pachytene, as the latter system is similar to the sex pair of man and other primates. The relatively large genetic distances between species presently showing this multiple system suggest that its origin is not recent. Other members of the same genus should be investigated at meiosis and by chromosome painting in order to know the extent and distribution of this complex sex-chromosome system. PMID:11376445

Mudry, M D; Rahn, I M; Solari, A J

2001-06-01

52

Sex chromosomes and speciation in Drosophila.  

PubMed

Two empirical rules suggest that sex chromosomes play a special role in speciation. The first is Haldane's rule - the preferential sterility and inviability of species hybrids of the heterogametic (XY) sex. The second is the disproportionately large effect of the X chromosome in genetic analyses of hybrid sterility. Whereas the causes of Haldane's rule are well established, the causes of the 'large X-effect' have remained controversial. New genetic analyses in Drosophila confirm that the X is a hotspot for hybrid male sterility factors, providing a proximate explanation for the large X-effect. Several other new findings -- on faster X evolution, X chromosome meiotic drive and the regulation of the X chromosome in the male-germline -- provide plausible evolutionary explanations for the large X-effect. PMID:18514967

Presgraves, Daven C

2008-07-01

53

Female meiotic sex chromosome inactivation in chicken.  

PubMed

During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW), whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs) may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis. PMID:19461881

Schoenmakers, Sam; Wassenaar, Evelyne; Hoogerbrugge, Jos W; Laven, Joop S E; Grootegoed, J Anton; Baarends, Willy M

2009-05-22

54

Female Meiotic Sex Chromosome Inactivation in Chicken  

PubMed Central

During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW), whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs) may contribute to silencing of Z. Surprisingly, ?H2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of ?H2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses ?H2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

Schoenmakers, Sam; Wassenaar, Evelyne; Hoogerbrugge, Jos W.; Laven, Joop S. E.; Grootegoed, J. Anton; Baarends, Willy M.

2009-01-01

55

Evolution and Survival on Eutherian Sex Chromosomes  

PubMed Central

Since the two eutherian sex chromosomes diverged from an ancestral autosomal pair, the X has remained relatively gene-rich, while the Y has lost most of its genes through the accumulation of deleterious mutations in nonrecombining regions. Presently, it is unclear what is distinctive about genes that remain on the Y chromosome, when the sex chromosomes acquired their unique evolutionary rates, and whether X-Y gene divergence paralleled that of paralogs located on autosomes. To tackle these questions, here we juxtaposed the evolution of X and Y homologous genes (gametologs) in eutherian mammals with their autosomal orthologs in marsupial and monotreme mammals. We discovered that genes on the X and Y acquired distinct evolutionary rates immediately following the suppression of recombination between the two sex chromosomes. The Y-linked genes evolved at higher rates, while the X-linked genes maintained the lower evolutionary rates of the ancestral autosomal genes. These distinct rates have been maintained throughout the evolution of X and Y. Specifically, in humans, most X gametologs and, curiously, also most Y gametologs evolved under stronger purifying selection than similarly aged autosomal paralogs. Finally, after evaluating the current experimental data from the literature, we concluded that unique mRNA/protein expression patterns and functions acquired by Y (versus X) gametologs likely contributed to their retention. Our results also suggest that either the boundary between sex chromosome strata 3 and 4 should be shifted or that stratum 3 should be divided into two strata.

Wilson, Melissa A.; Makova, Kateryna D.

2009-01-01

56

Fluorescence in situ hybridisation analysis of sex chromosome in non-obstructive azoospermic men.  

PubMed

The aim of this study was to compare results of karyotypes and fluorescence in situ hybridisation (FISH) technique among non-obstructive azoospermic men and to evaluate feasibility of using FISH to assess the types of major sex chromosome abnormalities. We compared results of karyotypes and FISH technique in those patients, and the association between genetic abnormality and clinical and hormonal parameters was evaluated. We studied 68 non-obstructive azoospermic men using conventional cytogenetics and FISH. Karyotyping revealed chromosomal abnormalities in 28 males (41%); the most common was Klinefelter syndrome (82%). FISH proved very effective in verifying low level of mosaisim in two cases with Klinefelter syndrome and complex chromosomal rearrangements in four cases with structural sex chromosome abnormalities. Our results indicate that genetic testing and screening is important in men with hypergonadotrophic azoospermia prior to the employment of assisted reproduction techniques. FISH analysis is recommended before discussing the risk of chromosomal aberrations in the offspring of infertile couples. PMID:23346943

Sadik, D I; Seifeldin, N S

2013-01-24

57

Incidental Prenatal Diagnosis of Sex Chromosome Aneuploidies: Health, Behavior, and Fertility  

PubMed Central

Objective. To assess the diagnostic relevance of incidental prenatal findings of sex chromosome aneuploidies. Methods. We searched with medical subject headings (MeSHs) and keywords in Medline and the Cochrane Library and systematically screened publications on postnatally diagnosed sex chromosomal aneuploidies from 2006 to 2011 as well as publications on incidentally prenatally diagnosed sex chromosomal aneuploidies from 1980 to 2011. Results. Postnatally diagnosed sex chromosomal aneuploidies demonstrated three clinical relevant domains of abnormality: physical (22–100%), behavior (0–56%), and reproductive health (47–100%), while incidentally prenatally diagnosed sex chromosomal aneuploidies demonstrated, respectively, 0–33%, 0–40%, and 0–36%. Conclusion. In the literature incidental prenatal diagnosis of sex chromosomal aneuploidies is associated with normal to mildly affected phenotypes. This contrasts sharply with those of postnatally diagnosed sex chromosomal aneuploidies and highlights the importance of this ascertainment bias towards the prognostic value of diagnosis of fetal sex chromosomal aneuploidies. This observation should be taken into account, especially when considering excluding the sex chromosomes in invasive prenatal testing using Rapid Aneuploidy Detection.

Pieters, J. J. P. M.; Kooper, A. J. A.; van Kessel, A. Geurts; Braat, D. D. M.; Smits, A. P. T.

2011-01-01

58

Incidental prenatal diagnosis of sex chromosome aneuploidies: health, behavior, and fertility.  

PubMed

Objective. To assess the diagnostic relevance of incidental prenatal findings of sex chromosome aneuploidies. Methods. We searched with medical subject headings (MeSHs) and keywords in Medline and the Cochrane Library and systematically screened publications on postnatally diagnosed sex chromosomal aneuploidies from 2006 to 2011 as well as publications on incidentally prenatally diagnosed sex chromosomal aneuploidies from 1980 to 2011. Results. Postnatally diagnosed sex chromosomal aneuploidies demonstrated three clinical relevant domains of abnormality: physical (22-100%), behavior (0-56%), and reproductive health (47-100%), while incidentally prenatally diagnosed sex chromosomal aneuploidies demonstrated, respectively, 0-33%, 0-40%, and 0-36%. Conclusion. In the literature incidental prenatal diagnosis of sex chromosomal aneuploidies is associated with normal to mildly affected phenotypes. This contrasts sharply with those of postnatally diagnosed sex chromosomal aneuploidies and highlights the importance of this ascertainment bias towards the prognostic value of diagnosis of fetal sex chromosomal aneuploidies. This observation should be taken into account, especially when considering excluding the sex chromosomes in invasive prenatal testing using Rapid Aneuploidy Detection. PMID:22191050

Pieters, J J P M; Kooper, A J A; van Kessel, A Geurts; Braat, D D M; Smits, A P T

2011-12-12

59

Sex differences in the human brain and the impact of sex chromosomes and sex hormones.  

PubMed

While there has been increasing support for the existence of cerebral sex differences, the mechanisms underlying these differences are unclear. Based on animal data, it has long been believed that sexual differentiation of the brain is primarily linked to organizational effects of fetal testosterone. This view is, however, in question as more recent data show the presence of sex differences before the onset of testosterone production. The present study focuses on the impact that sex chromosomes might have on these differences. Utilizing the inherent differences in sex and X-chromosome dosage among XXY males, XY males, and XX females, comparative voxel-based morphometry was conducted using sex hormones and sex chromosomes as covariates. Sex differences in the cerebellar and precentral gray matter volumes (GMV) were found to be related to X-chromosome dosage, whereas sex differences in the amygdala, the parahippocamus, and the occipital cortex were linked to testosterone levels. An increased number of sex chromosomes was associated with reduced GMV in the amygdala, caudate, and the temporal and insular cortices, with increased parietal GMV and reduced frontotemporal white matter volume. No selective, testosterone independent, effect of the Y-chromosome was detected. Based on these observations, it was hypothesized that programming of the motor cortex and parts of cerebellum is mediated by processes linked to X-escapee genes, which do not have Y-chromosome homologs, and that programming of certain limbic structures involves testosterone and X-chromosome escapee genes with Y-homologs. PMID:22891037

Lentini, E; Kasahara, M; Arver, S; Savic, I

2012-08-13

60

Psychoeducational Implications of Sex Chromosome Anomalies  

ERIC Educational Resources Information Center

Numerous anomalies involving the sex chromosomes (X or Y) have been documented and their impact on development, learning, and behavior studied. This article reviews three of these disorders, Turner syndrome, Klinefelter syndrome, and Lesch-Nyhan disease. Each of these three is associated with one or more selective impairments or behavioral…

Wodrich, David L.; Tarbox, Jennifer

2008-01-01

61

Psychoeducational Implications of Sex Chromosome Anomalies  

ERIC Educational Resources Information Center

|Numerous anomalies involving the sex chromosomes (X or Y) have been documented and their impact on development, learning, and behavior studied. This article reviews three of these disorders, Turner syndrome, Klinefelter syndrome, and Lesch-Nyhan disease. Each of these three is associated with one or more selective impairments or behavioral…

Wodrich, David L.; Tarbox, Jennifer

2008-01-01

62

Sex chromosome inactivation in the male.  

PubMed

Mammalian females have two X chromosomes, while males have only one X plus a Y chromosome. In order to balance X-linked gene dosage between the sexes, one X chromosome undergoes inactivation during development of female embryos. This process has been termed X-chromosome inactivation (XCI). Inactivation of the single X chromosome also occurs in the male, but is transient and is confined to the late stages of first meiotic prophase during spermatogenesis. This phenomenon has been termed meiotic sex chromosome inactivation (MSCI). A substantial portion ( approximately 15-25%) of X-linked mRNA-encoding genes escapes XCI in female somatic cells. While no mRNA genes are known to escape MSCI in males, approximately 80% of X-linked miRNA genes have been shown to escape this process. Recent results have led to the proposal that the RNA interference mechanism may be involved in regulating XCI in female cells. We suggest that some MSCI-escaping miRNAs may play a similar role in regulating MSCI in male germ cells. PMID:19838052

Yan, Wei; McCarrey, John R

2009-10-25

63

Sex Chromosome Inactivation in the Male  

PubMed Central

Mammalian females have two X chromosomes, while males have only one X plus a Y chromosome. In order to balance X-linked gene dosage between the sexes, one X chromosome undergoes inactivation during development of female embryos. This process has been termed X-chromosome inactivation (XCI). Inactivation of the single X chromosome also occurs in the male, but is transient and is confined to the late stages of first meiotic prophase during spermatogenesis. This phenomenon has been termed meiotic sex chromosome inactivation (MSCI). A substantial portion (~15–25%) of X-linked mRNA-encoding genes escapes XCI in female somatic cells. While no mRNA genes are known to escape MSCI in males, ~80% of X-linked miRNA genes have been shown to escape this process. Recent results have led to the proposal that the RNA interference mechanism may be involved in regulating XCI in female cells. We suggest that some MSCI-escaping miRNAs may play a similar role in regulating MSCI in male germ cells.

Yan, Wei; McCarrey, John R.

2011-01-01

64

Human male meiotic sex chromosome inactivation.  

PubMed

In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylated at S139 of H2AX leading to the repression of gonosomal genes, a process known as meiotic sex chromosome inactivation (MSCI), which has been studied best in mice. Post-meiotically this repression is largely maintained. Disturbance of MSCI in mice leads to harmful X,Y gene expression, eventuating in spermatocyte death and sperm heterogeneity. Sperm heterogeneity is a characteristic of the human male. For this reason we were interested in the efficiency of MSCI in human primary spermatocytes. We investigated MSCI in pachytene spermatocytes of seven probands: four infertile men and three fertile controls, using direct and indirect in situ methods. A considerable degree of variation in the degree of MSCI was detected, both between and within probands. Moreover, in post-meiotic stages this variation was observed as well, indicating survival of spermatocytes with incompletely inactivated sex chromosomes. Furthermore, we investigated the presence of H3K9me3 posttranslational modifications on the X and Y chromatin. Contrary to constitutive centromeric heterochromatin, this heterochromatin marker did not specifically accumulate on the XY body, with the exception of the heterochromatic part of the Y chromosome. This may reflect the lower degree of MSCI in man compared to mouse. These results point at relaxation of MSCI, which can be explained by genetic changes in sex chromosome composition during evolution and candidates as a mechanism behind human sperm heterogeneity. PMID:22355370

de Vries, Marieke; Vosters, Sanne; Merkx, Gerard; D'Hauwers, Kathleen; Wansink, Derick G; Ramos, Liliana; de Boer, Peter

2012-02-15

65

Sex chromosome aneuploidies among men with systemic lupus erythematosus.  

PubMed

About 90% of patients with systemic lupus erythematosus (SLE) are female. We hypothesize that the number of X chromosomes, not sex, is a determinate of risk of SLE. Number of X chromosomes was determined by single nucleotide typing and then confirmed by karyotype or fluorescent in situ hybridization in a large group of men with SLE. Presence of an sry gene was assessed by RT-PCR. We calculated 96% confidence intervals using the Adjusted Wald method, and used Bayes' theorem to estimate the prevalence of SLE among 47,XXY and 46,XX men. Among 316 men with SLE, 7 had 47,XXY and 1 had 46,XX. The rate of Klinefelter's syndrome (47,XXY) was statistically different from that found in control men and from the known prevalence in the population. The 46,XX man had an sry gene, which encodes the testes determining factor, on an X chromosome as a result of an abnormal crossover during meiosis. In the case of 46,XX, 1 of 316 was statistically different from the known population prevalence of 1 in 20,000 live male births. A previously reported 46,XX man with SLE had a different molecular mechanism in which there were no common gene copy number abnormalities with our patient. Thus, men with SLE are enriched for conditions with additional X chromosomes. Especially since 46,XX men are generally normal males, except for infertility, these data suggest the number of X chromosomes, not phenotypic sex, is responsible for the sex-bias of SLE. PMID:22154021

Dillon, Skyler P; Kurien, Biji T; Li, Shibo; Bruner, Gail R; Kaufman, Kenneth M; Harley, John B; Gaffney, Patrick M; Wallace, Daniel J; Weisman, Michael H; Scofield, R Hal

2011-12-06

66

An increased frequency of human sperm chromosomal abnormalities after radiotherapy.  

PubMed

13 cancer patients were studied before radiotherapy (RT) and at regular intervals after RT to determine the effect of RT on chromosomal abnormalities in sperm. The men were 19-47 years old and received testicular radiation doses of 0.4-5.0 Gray. Human pronuclear sperm chromosomes were analysed after penetration of zona-pellucida-free hamster eggs. Unfortunately the hamster egg penetration rates were exceedingly low, both before and after RT and this limited the number of sperm chromosome complements which could be analysed. Before RT, the frequency of abnormal sperm chromosome complements was 0% (0/9). After RT, the majority of men were azoospermic for 24 months but complements could be analysed from 4 men. In the first 12 months the frequency of abnormalities was 13% (1/8) and at 24 months it was 13% (7/55). By 36 months after RT, most men had recovered sperm production and the frequency of abnormalities in 8 men was 21% (18/86), which is significantly higher than the rate in control donors (8.5%). For individual men the range was 6-67%, and there was a significant correlation between testicular radiation dose and the frequency of sperm chromosomal abnormalities. The frequencies of both numerical and structural abnormalities were significantly increased after RT. This is the first evidence that radiation may increase the frequency of chromosomal abnormalities in human gametes. PMID:3724785

Martin, R H; Hildebrand, K; Yamamoto, J; Rademaker, A; Barnes, M; Douglas, G; Arthur, K; Ringrose, T; Brown, I S

1986-07-01

67

Chromosome 22 abnormalities in Ewing's sarcoma.  

PubMed Central

A child with disseminated Ewing's sarcoma underwent cytogenetic investigations which showed different structural rearrangements of chromosome 22 at diagnosis (?ring22), and at relapse [t(10;22)], but the classic translocation t(11;22) was not detectable. This case provides further evidence of the importance of chromosome 22 in this disease, while raising some questions about the central importance of the translocation between chromosomes 11 and 22. Images Figure

Davison, E V; Pearson, A D; Emslie, J; Reid, M M; Malcolm, A; Craft, A W

1989-01-01

68

Are all sex chromosomes created equal?  

PubMed

Three principal types of chromosomal sex determination are found in nature: male heterogamety (XY systems, as in mammals), female heterogamety (ZW systems, as in birds), and haploid phase determination (UV systems, as in some algae and bryophytes). Although these systems share many common features, there are important biological differences between them that have broad evolutionary and genomic implications. Here we combine theoretical predictions with empirical observations to discuss how differences in selection, genetic properties and transmission uniquely shape each system. We elucidate how the differences among these systems can be exploited to gain insights about general evolutionary processes, genome structure, and gene expression. We suggest directions for research that will greatly increase our general understanding of the forces driving sex-chromosome evolution in diverse organisms. PMID:21962970

Bachtrog, Doris; Kirkpatrick, Mark; Mank, Judith E; McDaniel, Stuart F; Pires, J Chris; Rice, William; Valenzuela, Nicole

2011-09-01

69

Recurrence risk of a serious, noninherited chromosomal abnormality  

Microsoft Academic Search

Objective: To investigate the recurrence risk of a serious, noninherited chromosomal abnormality.Design: Prospective and retrospective analysis.Setting: University-based prenatal diagnosis clinic.Patient(s): Data on 240 pregnancies in 165 couples after a pregnancy with a serious chromosomal abnormality.Result(s): Autosomic trisomic pregnancy had occurred in 133 families. In these families, there were 193 new pregnancies, 132 in women under 35 years and 61 in

Markku Ryynänen; Seppo Heinonen; Pertti Kirkinen

1997-01-01

70

The role of chromosomal rearrangements in the evolution of Silene latifolia sex chromosomes  

Microsoft Academic Search

Silene latifolia is a model plant for studies of the early steps of sex chromosome evolution. In comparison to mammalian sex chromosomes that\\u000a evolved 300 mya, sex chromosomes of S. latifolia appeared approximately 20 mya. Here, we combine results from physical mapping of sex-linked genes using polymerase chain\\u000a reaction on microdissected arms of the S. latifolia X chromosome, and fluorescence in situ

Roman Hobza; Eduard Kejnovsky; Boris Vyskot; Alex Widmer

2007-01-01

71

The key role of repeated DNAs in sex chromosome evolution in two fish species with ZW sex chromosome system  

PubMed Central

Despite substantial progress, there are still several gaps in our knowledge about the process of sex chromosome differentiation. The degeneration of sex-specific chromosome in some species is well documented, but it is not clear if all species follow the same evolutionary pathway. The accumulation of repetitive DNA sequences, however, is a common feature. To better understand this involvement, fish species emerge as excellent models because they exhibit a wide variety of sex chromosome and sex determining systems. Besides, they have much younger sex chromosomes compared to higher vertebrates, making it possible to follow early steps of differentiation. Here, we analyzed the arrangement of 9 repetitive DNA sequences in the W chromosomes of 2 fish species, namely Leporinus reinhardti and Triportheus auritus, which present well-differentiated ZZ/ZW sex system, but differ in respect to the size of the sex-specific chromosome. Both W chromosomes are almost fully heterochromatic, with accumulation of repeated DNAs in their heterochromatic regions. We found that microsatellites have strongly accumulated on the large W chromosome of L. reinhardti but not on the reduced-size W chromosome of T. auritus and are therefore important players of the W chromosome expansion. The present data highlight that the evolution of the sex chromosomes can diverge even in the same type of sex system, with and without the degeneration of the specific-sex chromosome, being more dynamic than traditionally appreciated.

2012-01-01

72

Detection of chromosomal abnormalities in human sperm  

SciTech Connect

A new technology developed by Rudak, et al. for examining the chromosomal constitution of human sperm through fusion with eggs from the Syrian hamster was used to obtain baseline data on the types and frequencies of aberrations in sperm of normal men. The frequency of structural aberrations in 2724 sperm chromosome karyotypes from the 13 healthy non-exposed donors ranged from 2 to 15.8%, demonstrating significant interindividual variability. The most frequently occurring aberrations were chromosome breaks, followed by acentric fragments, chromatid exchanges, chromatid breaks, dicentrics and translocations, chromosome deletions and duplications, inversions, and chromatid deletions. Two donors previously reported had one cell each with multiple chromatid exchanges and breaks. In addition, the oldest donor, AA, had 5 cells out of 124 examined with multiple breaks and rearrangements too extensive to completely identify. 17 refs., 2 tabs.

Brandriff, B.; Gordon, L.; Ashworth, A.K.; Watchmaker, G.; Carrano, A.V.

1985-06-19

73

Paternity uncertainty overrides sex chromosome selection for preferential grandparenting  

Microsoft Academic Search

With respect to autosomal genes, a grandparent is equally related to male and female grandchildren. Because males are heterozygous for sex chromosomes, however, grandparents are asymmetrically related to male and female grandchildren via the sex chromosomes. For example, the Y chromosome from the paternal grandfather passes directly down to grandsons. This asymmetry leads to a prediction that genes on the

Elizabeth R. Chrastil; Wayne M. Getz; Harald A. Euler; Philip T. Starks

2006-01-01

74

Gender in plants: sex chromosomes are emerging from the fog  

Microsoft Academic Search

Although most plants have flowers with both male and female sex organs, there are several thousands of plant species where male or female flowers form on different individuals. Surprisingly, the presence of well-established sex chromosomes in these dioecious plants is rare. The best-described example is white campion, for which large sex chromosomes have been identified and mapped partially. A recent

Boris Vyskot; Roman Hobza

2004-01-01

75

SEX CHROMOSOME TRANSLOCATIONS IN THE EVOLUTION OF REPRODUCTIVE ISOLATION  

Microsoft Academic Search

Haldane's rule states that in organisms with differentiated sex chromo- somes, hybrid sterility or inviability is generally expressed more frequently in the heterogametic sex. This observation has been variously explained as due to either genic or chromosomal imbalance. The fixation probabilities and mean times to fixation of sex-chromosome translocations of the type necessary to explain Haldane's rule on the basis

MARTIN L. TRACEY

1972-01-01

76

Detection of chromosomal abnormalities of chromosome 12 in uterine leiomyoma using fluorescence in situ hybridization.  

PubMed

Fifty uterine leiomyomas were examined using conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Of the 50 tumors, nine were examined using FISH on the non-cultured samples. Two (4.0%) of 50 tumor samples examined showed chromosomal abnormalities of chromosome 12 by the conventional cytogenetic analysis. For FISH, the whole-chromosome painting probe and D12Z3 probe specific for the centromeric region were used. Of the 50 cultured samples, 10 showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the nine non-cultured samples, four showed structural abnormalities of chromosome 12, all of which also showed structural abnormalities of chromosome 12 on the cultured samples. These results indicate that chromosomal abnormalities of chromosome 12 are important in the biology of at least some types of uterine leiomyoma, and that FISH is a useful complement to the conventional cytogenetic analysis in the study of solid tumors. PMID:8914635

Hayashi, S; Miharu, N; Okamoto, E; Samura, O; Hara, T; Ohama, K

1996-03-01

77

Immunoglobulin and Chromosome Abnormalities in Multiple Myeloma.  

National Technical Information Service (NTIS)

Protein abnormalities in 13 patients with multiple myeloma were studied by paper electrophoresis, immunoelectrophoresis, and immunoglobulin quantitation. Five patients had IgA myeloma, six had IgG myeloma, and two had hypoglobulinermic myeloma. These thre...

E. B. Rosenberg C. H. Liu S. L. Yang C. H. Wang T. S. Hwang

1970-01-01

78

Detection of Chromosomal Abnormalities in Human Sperm.  

National Technical Information Service (NTIS)

A new technology developed by Rudak, et al. for examining the chromosomal constitution of human sperm through fusion with eggs from the Syrian hamster was used to obtain baseline data on the types and frequencies of aberrations in sperm of normal men. The...

B. Brandriff L. Gordon A. K. Ashworth G. Watchmaker A. V. Carrano

1985-01-01

79

Human sex chromosomes in oral and craniofacial growth  

Microsoft Academic Search

Studies on tooth crown size and structure in families and in individuals with various sex chromosome anomalies have demonstrated differential direct effects of the human X and Y chromosome genes on growth. The Y chromosome promotes both tooth crown enamel and dentin growth, whereas the effect of the X chromosome on crown growth seems to be restricted to enamel formation.

Lassi Alvesalo

2009-01-01

80

Outcome of microdissection testicular sperm extraction in azoospermic patients with Klinefelter syndrome and other sex-chromosomal anomalies.  

PubMed

It has been indicated that approximately 20% of azoospermic patients have chromosomal anomalies, 90% of which are sex-chromosome abnormalities. Even azoospermic patients with sex-chromosomal anomalies might be able to father children using an advanced assisted reproductive technique such as microdissection testicular sperm extraction (micro-TESE) with intracytoplasmic sperm injection (ICSI). To evaluate the effect of micro-TESE in azoospermic patients with various sex-chromosomal anomalies, we reviewed their clinical results. A chromosomal survey using the G-banding technique was performed on males whose semen analysis demonstrated azoospermia at the Division of Male Infertilities at our institution between January 2004 and December 2009. Forty-two of these subjects demonstrated sex-chromosomal anomalies. The mean patient age was 34.4 ± 4.3 years. We classified them into two groups: Klinefelter syndrome (47,XXY) and other sex-chromosome abnormalities. Thirty-five patients showed Klinefelter syndrome and seven patients showed other sex-chromosome abnormalities. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) levels were 36.3 ± 14.0 IU/L, 15.8 ± 6.7 IU/L, and 3.2 ± 2.0 ng/ml in Klinefelter syndrome, and 20.8 ± 10.4 IU/L, 8.2 ± 5.2 IU/L and 4.1 ± 1.5 ng/ml in other sex-chromosome abnormalities, respectively. The mean testicular volume was 4.0 ± 2.1 ml in Klinefelter syndrome and 9.9 ± 4.6 ml in other sex-chromosome abnormalities. Serum FSH and LH in Klinefelter syndrome were significantly higher than those in other sex-chromosome abnormalities, and the mean testicular volume in Klinefelter syndrome was significantly smaller than that in other sex-chromosome abnormalities. The sperm retrieval rate (SRR) for micro-TESE showed no significant difference between the two groups (42.4% vs. 42.9%). In this study, the outcome of micro-TESE appeared not to differ between Klinefelter syndrome and other sex-chromosome abnormalities. PMID:23402654

Ando, Makoto; Yamaguchi, Kohei; Chiba, Koji; Miyake, Hideaki; Fujisawa, Masato

2013-02-12

81

Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes  

PubMed Central

Background The regular mammalian X and Y chromosomes diverged from each other at least 166 to 148 million years ago, leaving few traces of their early evolution, including degeneration of the Y chromosome and evolution of dosage compensation. Results We studied the intriguing case of black muntjac, in which a recent X-autosome fusion and a subsequent large autosomal inversion within just the past 0.5 million years have led to inheritance patterns identical to the traditional X-Y (neo-sex chromosomes). We compared patterns of genome evolution in 35-kilobase noncoding regions and 23 gene pairs on the homologous neo-sex chromosomes. We found that neo-Y alleles have accumulated more mutations, comprising a wide variety of mutation types, which indicates cessation of recombination and is consistent with an ongoing neo-Y degeneration process. Putative deleterious mutations were observed in coding regions of eight investigated genes as well as cis-regulatory regions of two housekeeping genes. In vivo assays characterized a neo-Y insertion in the promoter of the CLTC gene that causes a significant reduction in allelic expression. A neo-Y-linked deletion in the 3'-untranslated region of gene SNX22 abolished a microRNA target site. Finally, expression analyses revealed complex patterns of expression divergence between neo-Y and neo-X alleles. Conclusion The nascent neo-sex chromosome system of black muntjacs is a valuable model in which to study the evolution of sex chromosomes in mammals. Our results illustrate the degeneration scenarios in various genomic regions. Of particular importance, we report - for the first time - that regulatory mutations were probably able to accelerate the degeneration process of Y and contribute to further evolution of dosage compensation.

Zhou, Qi; Wang, Jun; Huang, Ling; Nie, Wenhui; Wang, Jinhuan; Liu, Yan; Zhao, Xiangyi; Yang, Fengtang; Wang, Wen

2008-01-01

82

Ever-Young Sex Chromosomes in European Tree Frogs  

PubMed Central

Non-recombining sex chromosomes are expected to undergo evolutionary decay, ending up genetically degenerated, as has happened in birds and mammals. Why are then sex chromosomes so often homomorphic in cold-blooded vertebrates? One possible explanation is a high rate of turnover events, replacing master sex-determining genes by new ones on other chromosomes. An alternative is that X-Y similarity is maintained by occasional recombination events, occurring in sex-reversed XY females. Based on mitochondrial and nuclear gene sequences, we estimated the divergence times between European tree frogs (Hyla arborea, H. intermedia, and H. molleri) to the upper Miocene, about 5.4–7.1 million years ago. Sibship analyses of microsatellite polymorphisms revealed that all three species have the same pair of sex chromosomes, with complete absence of X-Y recombination in males. Despite this, sequences of sex-linked loci show no divergence between the X and Y chromosomes. In the phylogeny, the X and Y alleles cluster according to species, not in groups of gametologs. We conclude that sex-chromosome homomorphy in these tree frogs does not result from a recent turnover but is maintained over evolutionary timescales by occasional X-Y recombination. Seemingly young sex chromosomes may thus carry old-established sex-determining genes, a result at odds with the view that sex chromosomes necessarily decay until they are replaced. This raises intriguing perspectives regarding the evolutionary dynamics of sexually antagonistic genes and the mechanisms that control X-Y recombination.

Lindtke, Dorothea; Sermier, Roberto; Betto-Colliard, Caroline; Dufresnes, Christophe; Bonjour, Emmanuel; Dumas, Zoe; Luquet, Emilien; Maddalena, Tiziano; Sousa, Helena Clavero; Martinez-Solano, Inigo; Perrin, Nicolas

2011-01-01

83

Comparative analysis of sex chromosomes in Leporinus species (Teleostei, Characiformes) using chromosome painting  

PubMed Central

Background The Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, particularly because of the presence of heteromorphic sex chromosomes only in some species of the genus. In this study we used W chromosome-derived probes in a series of cross species chromosome painting experiments to try to understand events of sex chromosome evolution in this family. Results W chromosome painting probes from Leporinus elongatus, L. macrocephalus and L. obtusidens were hybridized to each others chromosomes. The results showed signals along their W chromosomes and the use of L. elongatus W probe against L. macrocephalus and L. obtusidens also showed signals over the Z chromosome. No signals were observed when the later aforementioned probe was used in hybridization procedures against other four Anostomidae species without sex chromosomes. Conclusions Our results demonstrate a common origin of sex chromosomes in L. elongatus, L. macrocephalus and L. obtusidens but suggest that the L. elongatus chromosome system is at a different evolutionary stage. The absence of signals in the species without differentiated sex chromosomes does not exclude the possibility of cryptic sex chromosomes, but they must contain other Leporinus W sequences than those described here.

2013-01-01

84

10p- Syndrome associated with multiple chromosomal abnormalities  

Microsoft Academic Search

A karyotype with six de novo autosomal abnormalities in chromosomes 2, 4, 9, 10, 12, and 13 was identified in a 7-year-old boy with mental retardation and other minor malformations. The G-and C-banding techniques revealed an equilibrated translocation between autosomes 2 and 4 and between autosomes 9 and 13. One chromosome 10 has lost genetic material from its short arms,

F. Prieto; L. Badia; J. A. Moreno; P. Barbero; F. Asensi

1978-01-01

85

Chromosomal abnormalities in myelodysplastic syndromes and acute myeloid leukemia.  

PubMed

Clonal chromosome abnormalities are found in more than half the patients with hematologic malignancies. Karyotype is an independent prognostic factor in these patients. Cytogenetic findings correlate significantly with morphologic, immunologic, and clinical features as well as response to treatment, remission duration, and survival. The number of different cytogenetic abnormalities is enormous; however, many cytogenetic findings frequently occur in a given disease (e.g., abnormalities of 5 or 7 in 75% to 90% of patients with therapy-related AML). Some abnormalities are found only in myeloid malignancies, for example, the t(8;21)(q22;q22) and rearrangements of chromosome 16q22, both of which have a good prognosis. Other abnormalities usually are found in both myeloid and lymphoid malignancies, for example, the t(4;11)(q21;q23) and t(9;22)(q34;q11), both of which have a poor prognosis. The Human Gene Mapping Conferences have compiled much cytogenetic data and produced several interesting correlations in myeloid malignancies: rearrangements of 3q21-26 with myeloid proliferations associated with environmental exposure (similar to abnormalities of 5q, 7q, 12p, and 17q), aberrations of 12p, 11q13 and 11q23 with both myeloid and lymphoid disorders, and the lack of myeloid involvement and abnormalities of chromosomes 14 and 18. In conclusion, cytogenetic analysis of neoplastic cells at diagnosis for patients with MDS, AML, and SAML is required for appropriate diagnosis and treatment. The use of chromosome abnormalities to separate patients into high- and low-risk groups eventually may allow us to be more effective in selecting curative therapy. PMID:2272173

Machnicki, J L; Bloomfield, C D

1990-12-01

86

Pigmentary abnormalities in trisomy of chromosome 13.  

PubMed

This paper documents an unusual pigmentary mosaicism in a patient with translocation trisomy of chromosome 13. The dermatological lesions include: (1) broad hypopigmented bands following the typical description of Blaschko's lines on the dorsal aspect of both lower limbs; (2) horizontal linear streaks over the spine without the typical central V-shaped dip of Blaschko; and (3) a 'patchwork' hypopigmentation over the face, neck, chest, upper limbs and ventral surface of lower limbs. The lesions in (3) resemble the rare 'phylloid' or leaf-like pigmentary mosaicism type 3 of Happle, but differ in that the pattern shows no midline separation. A translocation trisomy 13 was uniformly detected on peripheral lymphocyte and skin fibroblast cultures from the hypopigmented and normal skin and there was no evidence of cytogenetic mosaicism or chimerism. These lesions resemble those of hypomelanosis of Ito on histopathological assessment. PMID:9689992

Pillay, T; Winship, W S; Ramdial, P K

1998-07-01

87

The evolution of chromosomal sex determination and dosage compensation  

Microsoft Academic Search

In many species, sex is determined by a system based on X and Y chromosomes, the latter having lost much of their genetic activity. Y chromosomes have evolved independently many times, and the associated change in gene dosage in the heterogametic (XY) sex is often compensated for by regulatory mechanisms which ensure equal amounts of gene products of X-linked loci

Brian Charlesworth

1996-01-01

88

How mammalian sex chromosomes acquired their peculiar gene content  

Microsoft Academic Search

Summary It has become increasingly evident that gene content of the sex chromosomes is markedly different from that of the autosomes. Both sex chromosomes appear enriched for genes related to sexual differentiation and reproduc- tion;butcuriously,thehumanXchromosomealsoseems to bear a preponderance of genes linked to brain and muscle functions. In this review, we will synthesize several evolutionary theories that may account for

Eric J. Vallender; Bruce T. Lahn

2004-01-01

89

Advanced age increases chromosome structural abnormalities in human spermatozoa  

PubMed Central

This study explores the relationship between sperm structural aberrations and age by using a multicolor multichromosome FISH strategy that provides information on the incidence of duplications and deletions on all the autosomes. ToTelvysion kit (Abbott Molecular, Abbott Park, IL, USA) with telomere-specific probes was used. We investigated the sperm of 10 male donors aged from 23 to 74 years old. The donors were divided into two groups according to age, a cohort of five individuals younger than 40 and a cohort of five individuals older than 60 years. The goal of this study was to determine (1) the relationship between donor age and frequency and type of chromosome structural abnormalities and (2) chromosomes more frequently involved in sperm structural aberrations. We found that the older patients had a higher rate of structural abnormalities (6.6%) compared with the younger cohort (4.9%). Although both duplications and deletions were seen more frequently in older men, our findings demonstrate the presence of an excess of duplications versus deletions in both groups at a ratio of 2 to 1. We demonstrate that the distribution of duplications and deletions was not linear along the chromosomes, although a trend toward a higher rate of abnormalities in larger chromosomes was observed. This work is the first study addressing the frequencies of sperm chromosome structural aberrations of all autosomes in a single assay thus making a contribution to the clarification of the amount and origin of damage present in human spermatozoa and in relation to age.

Templado, Cristina; Donate, Anna; Giraldo, Jesus; Bosch, Merce; Estop, Anna

2011-01-01

90

Prenatal diagnosis for chromosome abnormalities: past, present and future  

Microsoft Academic Search

Prenatal diagnosis for chromosome abnormalities has been available for over 30 years. The most common referral indication is a raised risk of Down’s syndrome, and diagnosis has, until recently, been carried out by culture of cells from invasive prenatal sampling, followed by full karyotype analysis, with a waiting time of around 2 weeks for results. More recent developments in fluorescence

Caroline Mackie Ogilvie

2003-01-01

91

Preimplantation genetic diagnosis of numerical and structural chromosome abnormalities  

Microsoft Academic Search

The causes of the decline in implantation rates observed with increasing maternal age are still a matter for debate. Data from oocyte donation strongly suggest that in women of advanced reproductive age, the ability to become pregnant is largely unaffected while oocyte quality is compromised. The incidence of chromosomal abnormalities in embryos is considerably higher than that reported in spontaneous

Santiago Munné

2002-01-01

92

Haldane's rule is extended to plants with sex chromosomes.  

PubMed

Haldane's rule is an empirical phenomenon that has been observed in animals with sex chromosomes. The rule states that the heterogametic sex (XY or ZW) will be “absent, rare, or sterile” following hybridization between two species. Despite the near ubiquity of Haldane's rule in animal hybridizations, it has not been documented in organisms other than animals. Here, we show evidence for both rarity and sterility in hybrid male but not female offspring in crosses between three dioecious plant species from the genus Silene with heteromorphic (XY) sex chromosomes. Our results are consistent with Haldane's rule, extending its applicability to plants with sex chromosomes. PMID:20681984

Brothers, Amanda N; Delph, Lynda F

2010-12-01

93

Evolution: From Autosomes to Sex Chromosomes - and Back.  

PubMed

Heteromorphic sex chromosomes are thought to represent a terminal evolutionary endpoint due to their specialized gene content and chromosome-specific regulation. New findings, however, show that an ancient X chromosome reverted to an autosome in the lineage leading to Drosophila. PMID:24070447

Landeen, Emily L; Presgraves, Daven C

2013-09-23

94

Chromosome abnormalities and their relationship to morphology and development of human embryos  

Microsoft Academic Search

This review covers the relationship between chromosome abnormalities, morphological abnormalities and embryonic development. The baseline of chromosome abnormalities in human embryos produced by assisted reproduction is higher than 50%, regardless of maternal age. While aneuploidy increases with maternal age, abnormalities arising post-meiotically, such as mosaicism, chaoticism, polyploidy and haploidy, have similar incidence in all age groups (about 33%). Post-meiotic abnormalities

Santiago Munné

2006-01-01

95

The genetics of sex chromosomes: evolution and implications for hybrid incompatibility.  

PubMed

Heteromorphic sex chromosomes, where one sex has two different types of sex chromosomes, face very different evolutionary consequences than do autosomes. Two important features of sex chromosomes arise from being present in only one copy in one of the sexes: dosage compensation and the meiotic silencing of sex chromosomes. Other differences arise because sex chromosomes spend unequal amounts of time in each sex. Thus, the impact of evolutionary processes (mutation, selection, genetic drift, and meiotic drive) differs substantially between each sex chromosome, and between the sex chromosomes and the autosomes. Sex chromosomes also play a disproportionate role in Haldane's rule and other important patterns related to hybrid incompatibility, and thus speciation. We review the consequences of sex chromosomes on hybrid incompatibility. A theme running through this review is that epigenetic processes, notably those related to chromatin, may be more important to the evolution of sex chromosomes and the evolution of hybrid incompatibility than previously recognized. PMID:23025408

Johnson, Norman A; Lachance, Joseph

2012-05-01

96

The genetics of sex chromosomes: evolution and implications for hybrid incompatibility  

PubMed Central

Heteromorphic sex chromosomes, where one sex has two different types of sex chromosomes, face very different evolutionary consequences than do the autosomes. Two important features of sex chromosomes arise from being present in only copy in one of the sexes: dosage compensation and the meiotic silencing of sex chromosomes. Other differences arise because sex chromosomes spend unequal amounts of time in each sex. Thus, the impact of evolutionary processes (mutation, selection, genetic drift, and meiotic drive) differs substantially between each sex chromosome, and between the sex chromosomes and the autosomes. Sex chromosomes also play a disproportionate role in Haldane’s rule and other important patterns related to hybrid incompatibility, and thus speciation. We review the consequences of sex chromosomes on hybrid incompatibility. A theme running through this review is that epigenetic processes, notably those related to chromatin, may be more important to the evolution of sex chromosomes and the evolution of hybrid incompatibility than previously recognized.

Johnson, Norman A.; Lachance, Joseph

2012-01-01

97

The unique sex chromosome system in platypus and echidna.  

PubMed

A striking example of the power of chromosome painting has been the resolution of the male platypus karyotype and the pairing relationships of the chain often sex chromosomes. We have extended our analysis to the nine sex chromosomes of the male echidna. Cross-species painting with platypus shows that the first five chromosomes in the chain are identical in both, but the order of the remainder are different and, in each species, a different autosome replaces one of the five X chromosomes. As the therian X is homologous mainly to platypus autosome 6 and echidna 16, and as SRY is absent in both, the sex determination mechanism in monotremes is currently unknown. Several of the X and Y chromosomes contain genes orthologous to those in the avian Z but the significance of this is also unknown. It seems likely that a novel testis determinant is carried by a Y chromosome common to platypus and echidna. We have searched for candidates for this determinant among the many genes known to be involved in vertebrate sex differentiation. So far fourteen such genes have been mapped, eleven are autosomal in platypus, two map to the differential regions of X chromosomes, and one maps to a pairing segment and is likewise excluded. Search for the platypus testis-determining gene continues, and the extension of comparative mapping between platypus and birds and reptiles may shed light on the ancestral origin of monotreme sex chromosomes. PMID:21250543

Ferguson-Smith, M A; Rens, W

2010-10-01

98

Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: oligozoospermia.  

PubMed

Recently, intracytoplasmic sperm injection (ICSI) has been extremely successful for the treatment of male infertility. However, transmission of cytogenetic defects to offspring is a great concern. There are two types of cytogenetic problems in patients seeking ICSI; one is the transmission of genetic defects from patients with constitutional chromosomal abnormalities and the second is the generation of de novo defects in infertile men. Generally about 5.1% of infertile men have chromosomal abnormalities. Among such infertile men, men with severe spermatogenesis defects, including oligozoospermia and azoospermia, are subjects for ICSI. Therefore it is very important to obtain cytogenetic information in these infertile patients. Furthermore, oligozoospermic men with a normal somatic karyotype also have increased frequencies of sperm chromosome abnormalities. Oligozoospermia is usually associated with other sperm alterations, for example oligoasthenozoospermia, oligoteratozoospemia and oligoasthenoteratozoospermia. In this review, the relationship between sperm concentration and sperm aneuploidy frequencies has been analyzed. The inverse correlation between the frequency of sperm aneuploidy and concentration has been reported in extensive studies. Especially in severe oligozoospermia, a significantly higher frequency of sex chromosome aneuploidy has been observed and this has been corroborated in recent clinical outcome data of ICSI. PMID:16192714

Miharu, N

2005-01-01

99

Fetal Facial Defects: Associated Malformations and Chromosomal Abnormalities  

Microsoft Academic Search

During an 8-year period, facial defects were observed in 146 (7%) of the 2,086 fetuses that underwent karyotyping in our unit because of fetal malformations and\\/or growth retardation. Chromosomal abnormalities were detected in 37 of 56 (66%) fetuses with micrognathia, in 10 of 13 (77%) with macroglossia, in 31 of 64 (48 %) with cleft lip and palate, in 5

K. H. Nicolaides; D. R. Salvesen; R. J. M. Snijders; C. M. Gosden

1993-01-01

100

Wide range of chromosome abnormalities in the embryos of young egg donors  

Microsoft Academic Search

Embryo chromosome studies show high rates of abnormalities, above 50%, but most embryos studied were from patients aged 35 and older. The objectives of this study were firstly, to evaluate the rate of chromosome abnormalities in embryos from young egg donors, and secondly, to compare the range of chromosome abnormality rates between donors and non-egg donor cycles, both undergoing preimplantation

S Munní; J Ary; C Zouves; T Escudero; F Barnes; C Cinioglu; B Ary; J Cohen

2006-01-01

101

Identification of embryonic chromosomal abnormality using FISH-based preimplantaion genetic diagnosis  

Microsoft Academic Search

Objective: Embryonic chromosomal abnormality is one of the main reasons for in vitro fertilization (IVF) failure. This study aimed at evaluating the value of Fluorescence in-situ Hybridization (FISH)-based Preimplantation Ge- netic Diagnosis (PGD) in screening for embryonic chromosomal abnormality to increase the successful rate of IVF. Method: Ten couples, four with high risk of chromosomal abnormality and six infertile couples,

YE Ying-hui; XU Chen-ming; QIAN Yu-li

102

Effects of sex chromosome aneuploidy on male sexual behavior  

PubMed Central

Incidence of sex chromosome aneuploidy in men is as high as 1:500. The predominant conditions are an additional Y chromosome (47,XYY) or an additional X chromosome (47,XXY). Behavioral studies using animal models of these conditions are rare. To assess the role of sex chromosome aneuploidy on sexual behavior, we used mice with a spontaneous mutation on the Y chromosome in which the testis-determining gene Sry is deleted (referred to as Y?) and insertion of a Sry transgene on an autosome. Dams were aneuploid (XXY?) and the sires had an inserted Sry transgene (XYSry). Litters contained six male genotypes, XY, XYY?, XXSry, XXY?Sry, XYSry and XYY?Sry. In order to eliminate possible differences in levels of testosterone, all of the subjects were castrated and received testosterone implants prior to tests for male sex behavior. Mice with an additional copy of the Y? chromosome (XYY?) had shorter latencies to intromit and achieve ejaculations than XY males. In a comparison of the four genotypes bearing the Sry transgene, males with two copies of the X chromosome (XXSry and XXY?Sry) had longer latencies to mount and thrust than males with only one copy of the X chromosome (XYSry and XYY?Sry) and decreased frequencies of mounts and intromissions as compared with XYSry males. The results implicate novel roles for sex chromosome genes in sexual behaviors.

Park, J. H.; Burns-Cusato, M.; Dominguez-Salazar, E.; Riggan, A.; Shetty, S.; Arnold, A. P.; Rissman, E. F.

2008-01-01

103

Mitotic chromosomes and the W-sex chromosome of the great horned owl (Bubo V. virginianus)  

Microsoft Academic Search

Mitotic chromosomes from the feather pulp and leucocyte cultures of the great horned owl (Bubo v. virginianus) were analyzed in both the sexes. The largest pair of chromosomes are acrocentrics while those of the second and the third pair have a short arm 1\\/6th the size of the large one. Chromosomes of the fourth and the fifth pairs have a

Awtar Krishan; G. J. Haiden; R. N. Shoffner

1965-01-01

104

Early Development of Children with Sex Chromosome Aberrations.  

ERIC Educational Resources Information Center

|Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue, Evanston, Illinois 60201. A prospective study was made of the early development of 42 children with sex chromosome aberrations. (Author)|

Haka-Ilse, Katerina; And Others

1978-01-01

105

Evolution of Genomic Structures on Mammalian Sex Chromosomes  

PubMed Central

Throughout mammalian evolution, recombination between the two sex chromosomes was suppressed in a stepwise manner. It is thought that the suppression of recombination led to an accumulation of deleterious mutations and frequent genomic rearrangements on the Y chromosome. In this article, we review three evolutionary aspects related to genomic rearrangements and structures, such as inverted repeats (IRs) and palindromes (PDs), on the mammalian sex chromosomes. First, we describe the stepwise manner in which recombination between the X and Y chromosomes was suppressed in placental mammals and discuss a genomic rearrangement that might have led to the formation of present pseudoautosomal boundaries (PAB). Second, we describe ectopic gene conversion between the X and Y chromosomes, and propose possible molecular causes. Third, we focus on the evolutionary mode and timing of PD formation on the X and Y chromosomes. The sequence of the chimpanzee Y chromosome was recently published by two groups. Both groups suggest that rapid evolution of genomic structure occurred on the Y chromosome. Our re-analysis of the sequences confirmed the species-specific mode of human and chimpanzee Y chromosomal evolution. Finally, we present a general outlook regarding the rapid evolution of mammalian sex chromosomes.

Katsura, Yukako; Iwase, Mineyo; Satta, Yoko

2012-01-01

106

Review: Sex Chromosome Evolution and the Expression of Sex-Specific Genes in the Placenta  

Microsoft Academic Search

Sex chromosomes have a disproportionate influence on health and disease. Both the X and Y are atypical in gene content and activity, as a result of their unique evolutionary trajectory. The X and Y chromosomes originated in a pair of autosomes, and differentiated as the Y chromosome degenerated progressively. The Y contains few active genes and is composed largely of

J. A. M. Graves

2010-01-01

107

Dosage compensation, the origin and the afterlife of sex chromosomes  

Microsoft Academic Search

Over the past 100 years Drosophila has been developed into an outstanding model system for the study of evolutionary processes. A fascinating aspect of evolution\\u000a is the differentiation of sex chromosomes. Organisms with highly differentiated sex chromosomes, such as the mammalian X and\\u000a Y, must compensate for the imbalance in gene dosage that this creates. The need to adjust the

Jan Larsson; Victoria H. Meller

2006-01-01

108

Chromosome painting of Z and W sex chromosomes in Characidium (Characiformes, Crenuchidae).  

PubMed

Some species of the genus Characidium have heteromorphic ZZ/ZW sex chromosomes with a totally heterochromatic W chromosome. Methods for chromosome microdissection associated with chromosome painting have become important tools for cytogenetic studies in Neotropical fish. In Characidium cf. fasciatum, the Z chromosome contains a pericentromeric heterochromatin block, whereas the W chromosome is completely heterochromatic. Therefore, a probe was produced from the W chromosome through microdissection and degenerate oligonucleotide-primed polymerase chain reaction amplification. FISH was performed using the W probe on the chromosomes of specimens of this species. This revealed expressive marks in the pericentromeric region of the Z chromosome as well as a completely painted W chromosome. When applying the same probe on chromosome preparations of C. cf. gomesi and Characidium sp., a pattern similar to C. cf. fasciatum was found, while C. cf. zebra, C. cf. lagosantense and Crenuchus spilurus species showed no hybridization signals. Structural changes in the chromosomes of an ancestral sexual system in the group that includes the species C. cf. gomesi, C. cf. fasciatum and Characidium sp., could have contributed to the process of speciation and could represent a causal mechanism of chromosomal diversification in this group. The heterochromatinization process possibly began in homomorphic and homologous chromosomes of an ancestral form, and this process could have given rise to the current patterns found in the species with sex chromosome heteromorphism. PMID:23344657

Pazian, Marlon F; Shimabukuro-Dias, Cristiane Kioko; Pansonato-Alves, José Carlos; Oliveira, Claudio; Foresti, Fausto

2013-01-24

109

The pseudoautosomal regions of the human sex chromosomes  

Microsoft Academic Search

In human females, both X chromosomes are equivalent in size and genetic content, and pairing and recombination can theoretically occur anywhere along their entire length. In human males, however, only small regions of sequence identity exist between the sex chromosomes. Recombination and genetic exchange is restricted to these regions of identity, which cover 2.6 and 0.4 Mbp, respectively, and are

Gudrun A. Rappold

1993-01-01

110

Dosage compensation, the origin and the afterlife of sex chromosomes.  

PubMed

Over the past 100 years Drosophila has been developed into an outstanding model system for the study of evolutionary processes. A fascinating aspect of evolution is the differentiation of sex chromosomes. Organisms with highly differentiated sex chromosomes, such as the mammalian X and Y, must compensate for the imbalance in gene dosage that this creates. The need to adjust the expression of sex-linked genes is a potent force driving the rise of regulatory mechanisms that act on an entire chromosome. This review will contrast the process of dosage compensation in Drosophila with the divergent strategies adopted by other model organisms. While the machinery of sex chromosome compensation is different in each instance, all share the ability to direct chromatin modifications to an entire chromosome. This review will also explore the idea that chromosome-targeting systems are sometimes adapted for other purposes. This appears the likely source of a chromosome-wide targeting system displayed by the Drosophila fourth chromosome. PMID:16821137

Larsson, Jan; Meller, Victoria H

2006-01-01

111

The association between sperm sex chromosome disomy and semen concentration, motility and morphology  

PubMed Central

STUDY QUESTION Is there an association between sex chromosome disomy and semen concentration, motility and morphology? SUMMARY ANSWER Higher rates of XY disomy were associated with a significant increase in abnormal semen parameters, particularly low semen concentration. WHAT IS KNOWN ALREADY Although some prior studies have shown associations between sperm chromosomal abnormalities and reduced semen quality, results of others are inconsistent. Definitive findings have been limited by small sample sizes and lack of adjustment for potential confounders. STUDY DESIGN, SIZE AND DURATION Cross-sectional study of men from subfertile couples presenting at the Massachusetts General Hospital Fertility Clinic from January 2000 to May 2003. PARTICIPANTS/MATERIALS, SETTING, METHODS With a sample of 192 men, multiprobe fluorescence in situ hybridization for chromosomes X, Y and 18 was used to determine XX, YY, XY and total sex chromosome disomy in sperm nuclei. Sperm concentration and motility were measured using computer-assisted sperm analysis; morphology was scored using strict criteria. Logistic regression models were used to evaluate the odds of abnormal semen parameters [as defined by World Health Organization (WHO)] as a function of sperm sex chromosome disomy. MAIN RESULTS AND THE ROLE OF CHANCE The median percentage disomy was 0.3 for XX and YY, 0.9 for XY and 1.6 for total sex chromosome disomy. Men who had abnormalities in all three semen parameters had significantly higher median rates of XX, XY and total sex chromosome disomy than controls with normal semen parameters (0.43 versus 0.25%, 1.36 versus 0.87% and 2.37 versus 1.52%, respectively, all P< 0.05). In logistic regression models, each 0.1% increase in XY disomy was associated with a 7% increase (odds ratio: 1.07, 95% confidence interval: 1.02–1.13) in the odds of having below normal semen concentration (<20 million/ml) after adjustment for age, smoking status and abstinence time. Increases in XX, YY and total sex chromosome disomy were not associated with an increase in the odds of a man having abnormal semen parameters. In addition, autosomal chromosome disomy (1818) was not associated with abnormal semen parameters. LIMITATIONS, REASONS FOR CAUTION A potential limitation of this study, as well as those currently in the published literature, is that it is cross-sectional. Cross-sectional analyses by nature do not lend themselves to inference about directionality for any observed associations; therefore, we cannot determine which variable is the cause and which one is the effect. Additionally, the use of WHO cutoff criteria for dichotomizing semen parameters may not fully define fertility status; however, in this study, fertility status was not an outcome we were attempting to assess. WIDER IMPLICATIONS OF THE FINDINGS This is the largest study to date seeking to understand the association between sperm sex chromosome disomy and semen parameters, and the first to use multivariate modeling to understand this relationship. The findings are similar to those in the published literature and highlight the need for mechanistic studies to better characterize the interrelationships between sex chromosome disomy and standard indices of sperm health. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by grants from NIOSH (T42 OH008416) and NIEHS (R01 ES009718, P30 ES000002 and R01 ES017457). The authors declare no competing interests. At the time this work was conducted and the initial manuscript written, MEM was affiliated with the Environmental Health Department at the Harvard School of Public Health. Currently, MEM is employed by Millennium: The Takeda Oncology Company. TRIAL REGISTRATION NUMBER N/A.

McAuliffe, M.E.; Williams, P.L.; Korrick, S.A.; Dadd, R.; Perry, M.J.

2012-01-01

112

Haploinsufficiency and the sex chromosomes from yeasts to humans  

PubMed Central

Background Haploinsufficient (HI) genes are those for which a reduction in copy number in a diploid from two to one results in significantly reduced fitness. Haploinsufficiency is increasingly implicated in human disease, and so predicting this phenotype could provide insights into the genetic mechanisms behind many human diseases, including some cancers. Results In the present work we show that orthologues of Saccharomyces cerevisiae HI genes are preferentially retained across the kingdom Fungi, and that the HI genes of S. cerevisiae can be used to predict haploinsufficiency in humans. Our HI gene predictions confirm known associations between haploinsufficiency and genetic disease, and predict several further disorders in which the phenotype may be relevant. Haploinsufficiency is also clearly relevant to the gene-dosage imbalances inherent in eukaryotic sex-determination systems. In S. cerevisiae, HI genes are over-represented on chromosome III, the chromosome that determines yeast's mating type. This may be a device to select against the loss of one copy of chromosome III from a diploid. We found that orthologues of S. cerevisiae HI genes are also over-represented on the mating-type chromosomes of other yeasts and filamentous fungi. In animals with heterogametic sex determination, accumulation of HI genes on the sex chromosomes would compromise fitness in both sexes, given X chromosome inactivation in females. We found that orthologues of S. cerevisiae HI genes are significantly under-represented on the X chromosomes of mammals and of Caenorhabditis elegans. There is no X inactivation in Drosophila melanogaster (increased expression of X in the male is used instead) and, in this species, we found no depletion of orthologues to yeast HI genes on the sex chromosomes. Conclusion A special relationship between HI genes and the sex/mating-type chromosome extends from S. cerevisiae to Homo sapiens, with the microbe being a useful model for species throughout the evolutionary range. Furthermore, haploinsufficiency in yeast can predict the phenotype in higher organisms.

2011-01-01

113

Meiotic sex chromosome inactivation in the marsupial Monodelphis domestica.  

PubMed

In eutherian mammals, the X and Y chromosomes undergo meiotic sex chromosome inactivation (MSCI) during spermatogenesis in males. However, following fertilization, both the paternally (Xp) and maternally (Xm) inherited X chromosomes are active in the inner cell mass of the female blastocyst, and then random inactivation of one X chromosome occurs in each cell, leading to a mosaic pattern of X-chromosome activity in adult female tissues. In contrast, marsupial females show a nonrandom pattern of X chromosome activity, with repression of the Xp in all somatic tissues. Here, we show that MSCI also occurs during spermatogenesis in marsupials in a manner similar to, but more stable than that in eutherians. These findings support the suggestion that MSCI may have provided the basis for an early dosage compensation mechanism in mammals based solely on gametogenic events, and that random X-chromosome inactivation during embryogenesis may have evolved subsequently in eutherian mammals. PMID:17987663

Hornecker, Jacey L; Samollow, Paul B; Robinson, Edward S; Vandeberg, John L; McCarrey, John R

2007-11-01

114

ETOPOSIDE INDUCES CHROMOSOMAL ABNORMALITIES IN SPERMATOCYTES AND SPERMATOGONIAL STEM CELLS  

SciTech Connect

Etoposide (ET) is a chemotherapeutic agent widely used in the treatment of leukemia, lymphomas and many solid tumors, such as testicular and ovarian cancers, that affect patients in their reproductive years. The purpose of the study was to use sperm FISH analyses to characterize the long-term effects of ET on male germ cells. We used a mouse model to characterize the induction of chromosomal aberrations (partial duplications and deletions) and whole chromosomal aneuploidies in sperm of mice treated with a clinical dose of ET. Semen samples were collected at 25 and 49 days after dosing to investigate the effects of ET on meiotic pachytene cells and spermatogonial stem-cells, respectively. ET treatment resulted in major increases in the frequencies of sperm carrying chromosomal aberrations in both meiotic pachytene (27- to 578-fold) and spermatogonial stem-cells (8- to 16-fold), but aneuploid sperm were induced only after treatment of meiotic cells (27-fold) with no persistent effects in stem cells. These results demonstrate that male meiotic germ cells are considerably more sensitive to ET than spermatogonial stem-cell and that increased frequencies of sperm with structural aberrations persist after spermatogonial stem-cell treatment. These findings predict that patients who undergo chemotherapy with ET may have transient elevations in the frequencies of aneuploid sperm, but more importantly, may have persistent elevations in the frequencies of sperm with chromosomal aberrations, placing them at higher risk for abnormal reproductive outcomes long after the end of their chemotherapy.

Marchetti, F; Pearson, F S; Bishop, J B; Wyrobek, A J

2005-07-15

115

Sex chromosome effects unmasked in angiotensin II-induced hypertension  

PubMed Central

Sex differences in mean arterial pressure (MAP) are reported in many experimental models of hypertension and are ascribed to gonadal sex based of studies showing gonadectomy and gonadal hormone replacement affect MAP. The interpretation of these studies, however, has been confounded by differences in the sex chromosome complement (XX vs. XY). To investigate the sex chromosome complement independently of gonadal sex, we used the four core genotype (FCG) mouse model in which gonadal sex is separated from the sex chromosome complement enabling comparisons among XX and XY females and XX and XY males. We found that in the gonadectomized (GDX) FCG, MAP after 2 weeks of angiotensin II (Ang II) infusion (200 ng/kg/min) was greater in XX than XY [MAP (mm Hg): GDX-XX-Female, 148±4.5; GDX-XY-Female, 133±4.4; GDX-XX-Male, 149±9.4; GDX-XY-Male, 138±5.5; p<0.03, XX vs XY; n=8-9/grp]. In contrast, no sex chromosome effects (SCE) were found on heart rate (HR) body weight (BW) or plasma Ang II 2 weeks after Ang II infusion. This study suggests that in addition to effects of gonadal hormones on blood pressure, X- or Y-linked genes, parental imprinting or X mosaicism contribute to sex differences in hypertension. Furthermore, the finding that MAP was greater in XX mice compared to XY mice in the GDX state suggests adverse SCE encoded within the XX sex chromosome complement could contribute to hypertension in women with ovarian hormone deficiency such as postmenopausal women and women with premature ovarian failure.

Ji, Hong; Zheng, Wei; Wu, Xie; Liu, Jun; Ecelbarger, Carolyn M.; Watkins, Rebecca; Arnold, Arthur P.; Sandberg, Kathryn

2010-01-01

116

Prenatal diagnosis for chromosome abnormalities: past, present and future.  

PubMed

Prenatal diagnosis for chromosome abnormalities has been available for over 30 years. The most common referral indication is a raised risk of Down's syndrome, and diagnosis has, until recently, been carried out by culture of cells from invasive prenatal sampling, followed by full karyotype analysis, with a waiting time of around 2 weeks for results. More recent developments in fluorescence in situ hybridisation (FISH) and quantitative fluorescence-PCR techniques have led to rapid 1-2 d reporting for Down's syndrome, opening the way to the possibility of targeted testing based on referral indication, thus reducing the incidence of difficult counselling issues and potentially unnecessary pregnancy terminations following the unexpected discovery of anomalies such as balanced chromosome rearrangements. The future of prenatal diagnosis must lie in the non-invasive diagnosis of Down's syndrome using fetal cells from maternal circulation. PMID:12781797

Ogilvie, Caroline Mackie

2003-04-01

117

Counseling parents before prenatal diagnosis: Do we need to say more about the sex chromosome aneuploidies?  

PubMed

Sex chromosome trisomies (SCT), an extra X chromosome in females (triple X, XXX), males with an extra X chromosome (Klinefelter syndrome, XXY) or an extra Y chromosome (XYY) occur because of errors during meiosis and are relatively frequent in humans. Their identification has never been the goal of prenatal diagnosis (PD) but they almost never escape detection by any of the methods commonly in use. Despite recommendations and guide-lines which emphasize the importance of structured counseling before and after PD, most women remain unaware that testing for serious genetic abnormalities is more likely to uncover these trisomies. With the increasing use of PD more and more prospective parents receive a diagnosis of sex chromosome trisomies and are faced with the dilemma of whether to terminate the pregnancy or to carry it to term. Despite the dramatic and emotionally devastating consequences of having to make such a decision, they have little opportunity to consider in advance the possible outcomes of such a pregnancy and, rather than relying on their own feelings and judgements, are forced to depend on the advice of counseling professionals who may or may not themselves be fully aware of what having an extra sex chromosome can mean to the development of a child. We address here the principles of reproductive autonomy together with an analysis of the major issues that ought to be discussed with the parents before a PD is carried out in order to minimize detrimental effects caused by this unexpected finding. © 2013 Wiley Periodicals, Inc. PMID:24115600

Lalatta, Faustina; Tint, G Stephen

2013-09-24

118

Aplasia cutis congenita with chromosome 12q abnormality.  

PubMed Central

A 32 week, small for dates baby with aplasia cutis congenita had an unbalanced translocation, being monosomic for distal 12q and trisomic for distal 1q. As far as is known, the association between extensive skin defects and a chromosomal abnormality has not been reported before. Keratin genes have been located in a different area of 12q, but this case may indicate other candidate areas to explore. Karyotyping should be undertaken in all babies with aplasia cutis. Images pF205-a

Khan, J. Y.; Moss, C.; Roper, H. P.

1995-01-01

119

Diagnosis of four chromosome abnormalities of unknown origin by chromosome microdissection and subsequent reverse and forward painting  

SciTech Connect

A molecular cytogenetic method consisting of chromosome microdissection and subsequent reverse/forward chromosome painting is a powerful tool to identify chromosome abnormalities of unknown origin. We present 4 cases of chromosome structural abnormalities whose origins were ascertained by this method. In one MCA/MR patient with an add(5q)chromosome, fluorescence in situ hybridization (FISH), using probes generated from a microdissected additional segment of the add(5q) chromosome and then from a distal region of normal chromosome 5, confirmed that the patient had a tandem duplication for a 5q35-qter segment. Similarly, we ascertained that an additional segment of an add(3p) chromosome in another MCA/MR patient had been derived from a 7q32-qter segment. In a woman with a history of successive spontaneous abortions and with a minute marker chromosome, painting using microdissected probes from the whole marker chromosome revealed that it was i(15)(p10) or psu dic(15;15)(q11;q11). Likewise, a marker observed in a fetus was a ring chromosome derived from the paracentromeric region of chromosome 19. We emphasize the value of the microdissection-based chromosome painting method in the identification of unknown chromosomes, especially for marker chromosomes. The method may contribute to a collection of data among patients with similar or identical chromosome abnormalities, which may lead to a better clinical syndrome delineation. 15 refs., 2 figs.

Coelho, K.E.F.A. de; Egashira, M.; Kato, R. [Nagasaki Univ. School of Medicine (Japan)] [and others

1996-06-14

120

Mouse models for evaluating sex chromosome effects that cause sex differences in non-gonadal tissues  

PubMed Central

XX and XY cells have a different number of X and Y genes. These differences in their genomes cause sex differences in the functions of cells, both in the gonads and in non-gonadal tissues. This review discusses mouse models that have shed light on these direct genetic effects of sex chromosomes that cause sex differences in physiology. Because many sex differences in tissues are caused by different effects of male and female gonadal hormones, it is important to attempt to discriminate between direct genetic and hormonal effects. Numerous mouse models exist in which the number of X or Y genes is manipulated, to observe the effects on phenotype. In two models, the Afour core genotypes@ model and SF1 knockout gonadless mice, it has been possible to detect sex chromosome effects that are not explained by group differences in gonadal hormones. Moreover, mouse models are available to determine whether the sex chromosome effects are caused by X or Y genes.

Arnold, Arthur P.

2009-01-01

121

Cross-species chromosome painting tracks the independent origin of multiple sex chromosomes in two cofamiliar Erythrinidae fishes  

PubMed Central

Background The Erythrinidae fish family is characterized by a large variation with respect to diploid chromosome numbers and sex-determining systems among its species, including two multiple X1X2Y sex systems in Hoplias malabaricus and Erythrinus erythrinus. At first, the occurrence of a same sex chromosome system within a family suggests that the sex chromosomes are correlated and originated from ancestral XY chromosomes that were either homomorphic or at an early stage of differentiation. To identify the origin and evolution of these X1X2Y sex chromosomes, we performed reciprocal cross-species FISH experiments with two sex-chromosome-specific probes designed from microdissected X1 and Y chromosomes of H. malabaricus and E. erythrinus, respectively. Results Our results yield valuable information regarding the origin and evolution of these sex chromosome systems. Our data indicate that these sex chromosomes evolved independently in these two closed related Erythrinidae species. Different autosomes were first converted into a poorly differentiated XY sex pair in each species, and additional chromosomal rearrangements produced both X1X2Y sex systems that are currently present. Conclusions Our data provide new insights into the origin and evolution of sex chromosomes, which increases our knowledge about fish sex chromosome evolution.

2011-01-01

122

An XX\\/XY heteromorphic sex chromosome system in the Australian chelid turtle Emydura macquarii : A new piece in the puzzle of sex chromosome evolution in turtles  

Microsoft Academic Search

Chromosomal sex determination is the prevalent system found in animals but is rare among turtles. In fact, heteromorphic sex\\u000a chromosomes are known in only seven of the turtles possessing genotypic sex determination (GSD), two of which correspond to\\u000a cryptic sex microchromosomes detectable only with high-resolution cytogenetic techniques. Sex chromosomes were undetected\\u000a in previous studies of Emydura macquarii, a GSD side-necked

Pedro Alonzo Martinez; Tariq Ezaz; Nicole Valenzuela; Arthur Georges; Jennifer A. Marshall Graves

2008-01-01

123

Sex Determination Diversity and Sex Chromosome Evolution in Poeciliid Fish  

Microsoft Academic Search

Poeciliids, a family of live-bearing freshwater fish, including among others platyfish, swordtails and guppies, fully illustrate the diversity of genetic sex determination mechanisms observed in teleosts. Besides unisexuality, a variety of sex-determining systems has been described in this group of fish, including male and female heterogamety with or without autosomal influence, as well as more complicated situations such as multichromosomal

C. Schultheis; A. Böhne; M. Schartl; J. N. Volff; D. Galiana-Arnoux

2009-01-01

124

The effects of Down syndrome and other chromosomal abnormalities on survival and management in oesophageal atresia  

Microsoft Academic Search

Recognisable chromosomal abnormalities occur in over 5% of patients with oesophageal atresia (OA). In a review of 670 patients with OA chromosomal abnormalities were identified in 35 (5.2%), of whom 16 had trisomy 18 and 12 had trisomy 21. In patients with trisomy 18, the diagnosis should be suspected on clinical grounds and confirmed on analysis of chromosomes; no active

S. W. Beasley; M. Allen; N. Myers

1997-01-01

125

The effects of Down syndrome and other chromosomal abnormalities on survival and management in oesophageal atresia  

Microsoft Academic Search

Recognisable chromosomal abnormalities occur in over 5% of patients with oesophageal atresia (OA). In a review of 670 patients with OA chromosomal abnormalities were identified in 35 (5.2%); of whom 16 had trisomy 18 and 12 had trisomy 21. In patients with trisomy 18, the diagnosis should be suspected on clinical grounds and confirmed on analysis of chromosomes; no active

S. W. Beasley; M. AllenN; N. Myers

1997-01-01

126

Organelle DNA accumulation in the recently evolved papaya sex chromosomes.  

PubMed

Sex chromosomes are a pair of specialized chromosomes containing a sex determination region that is suppressed for recombination. Without recombination, Y chromosomes are thought to accumulate repetitive DNA sequences which contribute to their degeneration. A pair of primitive sex chromosomes controls sex type in papaya with male and hermaphrodite determined by the slightly different male-specific region of the Y (MSY) and hermaphrodite-specific region of Y(h) (HSY) chromosomes, respectively. Here, we show that the papaya HSY and MSY in the absence of recombination have accumulated nearly 12 times the amount of chloroplast-derived DNA than the corresponding region of the X chromosome and 4 times the papaya genome-wide average. Furthermore, a chloroplast genome fragment containing the rsp15 gene has been amplified 23 times in the HSY, evidence of retrotransposon-mediated duplication. Surprisingly, mitochondria-derived sequences are less abundant in the X and HSY compared to the whole genome. Shared organelle integrations are sparse between X and HSY, with only 11 % of chloroplast and 12 % of mitochondria fragments conserved, respectively, suggesting that the accelerated accumulation of organelle DNA occurred after the HSY was suppressed for recombination. Most of the organelle-derived sequences have divergence times of <7 MYA, reinforcing this notion. The accumulated chloroplast DNA is evidence of the slow degeneration of the HSY. PMID:23636354

VanBuren, Robert; Ming, Ray

2013-05-01

127

Spermatogenic failure in male mice with four sex chromosomes.  

PubMed

There is accumulating evidence that meiosis, like mitosis, is monitored by a number of checkpoints. In mammals, the presence of asynapsed chromosomes at pachytene triggers a checkpoint (the pachytene or synapsis checkpoint) that removes cells via a p53-independent apoptotic pathway. In the special case of the sex bivalent in males, it is pseudoautosomal region (PAR) asynapsis that triggers the checkpoint. In male mice with three sex chromosomes (XYY or XYY(*X)) some pachytene spermatocytes achieve full (trivalent) PAR synapsis, but in many cells one sex chromosome remains as a univalent, thus triggering the checkpoint. Sperm counts in these males have been shown to be positively correlated with trivalent frequencies. In the present study sperm production and levels of sex chromosome synapsis were studied in mice with four sex chromosomes (XYYY(*X)) and XYY(*X)Y(*X)). These mice proved to be more severely affected than XYY or XYY(*X) mice. Nevertheless, pachytene synaptonemal complex analysis revealed that full PAR synapsis was achieved through the formation of radial quadrivalents or through the formation of two sex bivalents in 21%-49% of cells analysed. Given these levels of full PAR synapsis, the sperm counts were consistently lower than would have been predicted from the relationship between levels of PAR synapsis and sperm counts in mice with three sex chromosomes. It has been suggested that the inactivation of the asynapsed non-PAR X and Y axes of the XY bivalent of normal males (MSCI), which occurs during meiotic prophase, may be driven by Xist transcripts originating from the X. If this is the case, the non-PAR Y axes of YY and YY(*X) bivalents would fail to undergo MSCI. This could be cell lethal, either because of 'inappropriate' Y gene expression, or because the non-PAR Y axis may now trigger the synapsis checkpoint. PMID:11453555

Rodriguez, T A; Burgoyne, P S

2001-05-01

128

Sex-specific adaptation drives early sex chromosome evolution in Drosophila.  

PubMed

Most species' sex chromosomes are derived from ancient autosomes and show few signatures of their origins. We studied the sex chromosomes of Drosophila miranda, where a neo-Y chromosome originated only approximately 1 million years ago. Whole-genome and transcriptome analysis reveals massive degeneration of the neo-Y, that male-beneficial genes on the neo-Y are more likely to undergo accelerated protein evolution, and that neo-Y genes evolve biased expression toward male-specific tissues--the shrinking gene content of the neo-Y becomes masculinized. In contrast, although older X chromosomes show a paucity of genes expressed in male tissues, neo-X genes highly expressed in male-specific tissues undergo increased rates of protein evolution if haploid in males. Thus, the response to sex-specific selection can shift at different stages of X differentiation, resulting in masculinization or demasculinization of the X-chromosomal gene content. PMID:22822149

Zhou, Qi; Bachtrog, Doris

2012-07-20

129

Genetic aspects of human male infertility: the frequency of chromosomal abnormalities and Y chromosome microdeletions in severe male factor infertility  

Microsoft Academic Search

Objective: The main purpose of this study is to detect the frequency and type of both chromosomal abnormalities and Y chromosome microdeletions in patients with severe male factor infertility and fertile control subjects. The association between the genetic abnormality and clinical parameters was also evaluated. Methods: This study was carried out in 208 infertile and 20 fertile men. Results of

Arzu Vicdan; Kubilay Vicdan; Serdar Günalp; Aykut Kence; Cem Akarsu; Ahmet Zeki I??k; Eran Sözen

2004-01-01

130

The molecular basis of chromosome orthologies and sex chromosomal differentiation in palaeognathous birds.  

PubMed

Palaeognathous birds (Struthioniformes and Tinamiformes) have morphologically conserved karyotypes and less differentiated ZW sex chromosomes. To delineate interspecific chromosome orthologies in palaeognathous birds we conducted comparative chromosome painting with chicken (Gallus gallus, GGA) chromosome 1-9 and Z chromosome paints (GGA1-9 and GGAZ) for emu, double-wattled cassowary, ostrich, greater rhea, lesser rhea and elegant crested tinamou. All six species showed the same painting patterns: each probe was hybridized to a single pair of chromosomes with the exception that the GGA4 was hybridized to the fourth largest chromosome and a single pair of microchromosomes. The GGAZ was also hybridized to the entire region of the W chromosome, indicating that extensive homology remains between the Z and W chromosomes on the molecular level. Comparative FISH mapping of four Z- and/or W-linked markers, the ACO1/IREBP, ZOV3 and CHD1 genes and the EE0.6 sequence, revealed the presence of a small deletion in the proximal region of the long arm of the W chromosome in greater rhea and lesser rhea. These results suggest that the karyotypes and sex chromosomes of palaeognathous birds are highly conserved not only morphologically, but also at the molecular level; moreover, palaeognathous birds appear to retain the ancestral lineage of avian karyotypes. PMID:17605112

Nishida-Umehara, Chizuko; Tsuda, Yayoi; Ishijima, Junko; Ando, Junko; Fujiwara, Atushi; Matsuda, Yoichi; Griffin, Darren K

2007-07-03

131

Neo-sex chromosomes and adaptive potential in tortricid pests.  

PubMed

Changes in genome architecture often have a significant effect on ecological specialization and speciation. This effect may be further enhanced by involvement of sex chromosomes playing a disproportionate role in reproductive isolation. We have physically mapped the Z chromosome of the major pome fruit pest, the codling moth, Cydia pomonella (Tortricidae), and show that it arose by fusion between an ancestral Z chromosome and an autosome corresponding to chromosome 15 in the Bombyx mori reference genome. We further show that the fusion originated in a common ancestor of the main tortricid subfamilies, Olethreutinae and Tortricinae, comprising almost 700 pest species worldwide. The Z-autosome fusion brought two major genes conferring insecticide resistance and clusters of genes involved in detoxification of plant secondary metabolites under sex-linked inheritance. We suggest that this fusion significantly increased the adaptive potential of tortricid moths and thus contributed to their radiation and subsequent speciation. PMID:23569222

Nguyen, Petr; Sýkorová, Miroslava; Šíchová, Jindra; K?ta, Václav; Dalíková, Martina; ?apková Frydrychová, Radmila; Neven, Lisa G; Sahara, Ken; Marec, František

2013-04-08

132

Neo-sex chromosomes and adaptive potential in tortricid pests  

PubMed Central

Changes in genome architecture often have a significant effect on ecological specialization and speciation. This effect may be further enhanced by involvement of sex chromosomes playing a disproportionate role in reproductive isolation. We have physically mapped the Z chromosome of the major pome fruit pest, the codling moth, Cydia pomonella (Tortricidae), and show that it arose by fusion between an ancestral Z chromosome and an autosome corresponding to chromosome 15 in the Bombyx mori reference genome. We further show that the fusion originated in a common ancestor of the main tortricid subfamilies, Olethreutinae and Tortricinae, comprising almost 700 pest species worldwide. The Z–autosome fusion brought two major genes conferring insecticide resistance and clusters of genes involved in detoxification of plant secondary metabolites under sex-linked inheritance. We suggest that this fusion significantly increased the adaptive potential of tortricid moths and thus contributed to their radiation and subsequent speciation.

Nguyen, Petr; Sykorova, Miroslava; Sichova, Jindra; Kuta, Vaclav; Dalikova, Martina; Capkova Frydrychova, Radmila; Neven, Lisa G.; Sahara, Ken; Marec, Frantisek

2013-01-01

133

In the platypus a meiotic chain of ten sex chromosomes shares genes with the bird Z and mammal X chromosomes  

Microsoft Academic Search

Two centuries after the duck-billed platypus was discovered, monotreme chromosome systems remain deeply puzzling. Karyotypes of males, or of both sexes, were claimed to contain several unpaired chromosomes (including the X chromosome) that form a multi-chromosomal chain at meiosis. Such meiotic chains exist in plants and insects but are rare in vertebrates. How the platypus chromosome system works to determine

Frank Grützner; Willem Rens; Enkhjargal Tsend-Ayush; Nisrine El-Mogharbel; Patricia C. M. O'Brien; Russell C. Jones; Malcolm A. Ferguson-Smith; Jennifer A. Marshall Graves

2004-01-01

134

Identification of embryonic chromosomal abnormality using FISH-based preimplantaion genetic diagnosis  

Microsoft Academic Search

Objective: Embryonic chromosomal abnormality is one of the main reasons for in vitro fertilization (IVF) failure. This study\\u000a aimed at evaluating the value of Fluorescence in-situ Hybridization (FISH)-based Preimplantation Genetic Diagnosis (PGD) in\\u000a screening for embryonic chromosomal abnormality to increase the successful rate of IVF. Method: Ten couples, four with high\\u000a risk of chromosomal abnormality and six infertile couples, underwent

Ying-hui Ye; Chen-ming Xu; Fan Jin; Yu-li Qian

2004-01-01

135

Sex chromosome evolution and Haldane's rule.  

PubMed

Haldane observed that where interspecies hybrids show sex differences in sex ratio or fertility, it is always heterogametic sex which is affected. Many hypotheses have been advanced to explain Haldane's rule, but it is difficult to find a unifying explanation that will accommodate male and female heterogamety, and explains why fertility, especially, is affected. Here we propose that asymmetry can be accounted for by interactions involved in determining male dimorphisms or fertility between genes which diverged from allele pairs on the X and Y. Failure of one or more heterospecific interactions will render the male sterile. Similar arguments may be made for other groups with male or female heterogamety, and the argument can be extended to account for Y- (or W-) autosome interactions. PMID:9378909

Graves, J A; O'Neill, R J

136

MDC1 directs chromosome-wide silencing of the sex chromosomes in male germ cells.  

PubMed

Chromosome-wide inactivation is an epigenetic signature of sex chromosomes. The mechanism by which the chromosome-wide domain is recognized and gene silencing is induced remains unclear. Here we identify an essential mechanism underlying the recognition of the chromosome-wide domain in the male germline. We show that mediator of DNA damage checkpoint 1 (MDC1), a binding partner of phosphorylated histone H2AX (?H2AX), defines the chromosome-wide domain, initiates meiotic sex chromosome inactivation (MSCI), and leads to XY body formation. Importantly, MSCI consists of two genetically separable steps. The first step is the MDC1-independent recognition of the unsynapsed axis by DNA damage response (DDR) factors such as ataxia telangiectasia and Rad3-related (ATR), TOPBP1, and ?H2AX. The second step is the MDC1-dependent chromosome-wide spreading of DDR factors to the entire chromatin. Furthermore, we demonstrate that, in somatic cells, MDC1-dependent amplification of the ?H2AX signal occurs following replicative stress and is associated with transcriptional silencing. We propose that a common DDR pathway underlies both MSCI and the response of somatic cells to replicative stress. These results establish that the DDR pathway centered on MDC1 triggers epigenetic silencing of sex chromosomes in germ cells. PMID:21536735

Ichijima, Yosuke; Ichijima, Misako; Lou, Zhenkun; Nussenzweig, André; Camerini-Otero, R Daniel; Chen, Junjie; Andreassen, Paul R; Namekawa, Satoshi H

2011-05-01

137

Evidence for different origin of sex chromosomes in snakes, birds, and mammals and step-wise differentiation of snake sex chromosomes  

PubMed Central

All snake species exhibit genetic sex determination with the ZZ/ZW type of sex chromosomes. To investigate the origin and evolution of snake sex chromosomes, we constructed, by FISH, a cytogenetic map of the Japanese four-striped rat snake (Elaphe quadrivirgata) with 109 cDNA clones. Eleven of the 109 clones were localized to the Z chromosome. All human and chicken homologues of the snake Z-linked genes were located on autosomes, suggesting that the sex chromosomes of snakes, mammals, and birds were all derived from different autosomal pairs of the common ancestor. We mapped the 11 Z-linked genes of E. quadrivirgata to chromosomes of two other species, the Burmese python (Python molurus bivittatus) and the habu (Trimeresurus flavoviridis), to investigate the process of W chromosome differentiation. All and 3 of the 11 clones were localized to both the Z and W chromosomes in P. molurus and E. quadrivirgata, respectively, whereas no cDNA clones were mapped to the W chromosome in T. flavoviridis. Comparative mapping revealed that the sex chromosomes are only slightly differentiated in P. molurus, whereas they are fully differentiated in T. flavoviridis, and E. quadrivirgata is at a transitional stage of sex-chromosome differentiation. The differentiation of sex chromosomes was probably initiated from the distal region on the short arm of the protosex chromosome of the common ancestor, and then deletion and heterochromatization progressed on the sex-specific chromosome from the phylogenetically primitive boids to the more advanced viperids.

Matsubara, Kazumi; Tarui, Hiroshi; Toriba, Michihisa; Yamada, Kazuhiko; Nishida-Umehara, Chizuko; Agata, Kiyokazu; Matsuda, Yoichi

2006-01-01

138

Trisomy 7 and sex chromosome loss in human brain tissue  

Microsoft Academic Search

Short-term cultures of nonneoplastic brain tissue from 11 patients, seven of whom had a malignant brain tumor, were cytogenetically examined. In only a single case was a wholly normal chromosome complement detected; the remaining ten cases exhibited mosaicism with clonal numerical aberrations found alongside cells carrying a normal karyotype. The abnormal clones were characterized by trisomy 7, the loss of

S. Heim; N. Mandahl; Y. Jin; S. Strömblad; E. Lindström; L. G. Salford; F. Mitelman

1989-01-01

139

THE CONTRIBUTION OF FEMALE MEIOTIC DRIVE TO THE EVOLUTION OF NEO-SEX CHROMOSOMES  

PubMed Central

Sex chromosomes undergo rapid turnover in certain taxonomic groups. One of the mechanisms of sex chromosome turnover involves fusions between sex chromosomes and autosomes. Sexual antagonism, heterozygote advantage, and genetic drift have been proposed as the drivers for the fixation of this evolutionary event. However, all empirical patterns of the prevalence of multiple sex chromosome systems across different taxa cannot be simply explained by these three mechanisms. In this study, we propose that female meiotic drive may contribute to the evolution of neo-sex chromosomes. The results of this study showed that in mammals, the XY1Y2 sex chromosome system is more prevalent in species with karyotypes of more biarmed chromosomes, whereas the X1X2Y sex chromosome system is more prevalent in species with predominantly acrocentric chromosomes. In species where biarmed chromosomes are favored by female meiotic drive, X-autosome fusions (XY1Y2 sex chromosome system) will be also favored by female meiotic drive. In contrast, in species with more acrocentric chromosomes, Y-autosome fusions (X1X2Y sex chromosome system) will be favored just because of the biased mutation rate toward chromosomal fusions. Further consideration should be given to female meiotic drive as a mechanism in the fixation of neo-sex chromosomes.

Yoshida, Kohta; Kitano, Jun

2012-01-01

140

The role of repetitive DNA in structure and evolution of sex chromosomes in plants  

Microsoft Academic Search

Eukaryotic genomes contain a large proportion of repetitive DNA sequences, mostly transposable elements (TEs) and tandem repeats. These repetitive sequences often colonize specific chromosomal (Y or W chromosomes, B chromosomes) or subchromosomal (telomeres, centromeres) niches. Sex chromosomes, especially non-recombining regions of the Y chromosome, are subject to different evolutionary forces compared with autosomes. In non-recombining regions of the Y chromosome

E Kejnovsky; R Hobza; T Cermak; Z Kubat; B Vyskot

2009-01-01

141

An accumulation of tandem DNA repeats on the Y chromosome in Silene latifolia during early stages of sex chromosome evolution  

Microsoft Academic Search

Sex chromosomes in mammals are about 300 million years old and typically have a highly degenerated Y chromosome. The sex chromosomes in the dioecious plant Silene latifolia in contrast, represent an early stage of evolution in which functional X–Y gene pairs are still frequent. In this study, we characterize a novel tandem repeat called TRAYC, which has accumulated on the

Roman Hobza; Martina Lengerova; Julia Svoboda; Hana Kubekova; Eduard Kejnovsky; Boris Vyskot

2006-01-01

142

Identification of cryptic sex chromosomes and isolation of X- and Y-borne genes.  

PubMed

Comparative molecular cytogenetics provides a powerful tool for deciphering the evolutionary history of vertebrate sex chromosomes. We have adapted cell culture and molecular cytogenetic techniques to study the sex chromosomes of many exotic mammals, birds, and reptiles. Here we describe differential chromosome banding and staining techniques that distinguish sex chromosomes in species with no morphologically distinct XY or ZW chromosome pairs. We describe a method to isolate, identify, and map genomic BAC clones from the Y chromosome, and we also identify strategies for isolating candidate sex chromosome genes. PMID:18629671

Waters, Paul D; Marshall Graves, Jennifer A; Thompson, Katherine; Sankovic, Natasha; Ezaz, Tariq

2008-01-01

143

Nucleolar precursor body distribution in pronuclei is correlated to chromosomal abnormalities in embryos.  

PubMed

In-vitro generated human embryos have low implantation rates and high chromosomal abnormalities. Embryos are mostly selected on the basis of microscopic morphological examination. The relationship between pronuclear morphology and chromosomal abnormalities was investigated in this study. Zygotes were scored according to pronuclear morphology on day 1. Excess embryos that were not transferred or cryopreserved on day 3 were fixed. Chromosomes 13, 18, 21, X and Y were analysed by fluorescence in-situ hybridization (FISH). A total of 125 embryos were analysed; 58 (46%) were abnormal, 32 (26%) were mosaic and 35 (28%) were normal. Results were analysed according to different pronuclear morphology. Zygotes with polarized pattern had a significantly lower incidence of chromosome abnormality than those with a non-polarized pattern. The presence of cytoplasmic halo, the size of each pronucleus and the number of nucleolar precursor body had no significant effect on chromosomal abnormalities. In conclusion, embryos generated from zygotes with polarized pattern have fewer chromosomal abnormalities compared with other patterns. A simple microscopic examination during fertilization confirmation would be useful to select embryos with fewer chromosomal abnormalities, preferably in combination with other observations shown to correlate with chromosomal abnormalities. PMID:12930583

Coskun, Serdar; Hellani, Ali; Jaroudi, Kamal; Al-Mayman, Hend; Al-Kabra, Maya; Qeba, Meshal

144

Evaluation of routine prenatal ultrasound examination in detecting fetal chromosomal abnormalities in a low risk population  

Microsoft Academic Search

Prenatal diagnosis performed by fetal ultrasound scan is now a routine part of antenatal care in many countries. We have used our registry of congenital malformations to determine how many fetal anomalies and consequently how many chromosomal abnormalities are detected by this procedure. In our region, evaluation of prenatal diagnosis of chromosomal abnormalities in women of 38 years and younger

Claude Stoll; Béatrice Dott; Yves Alembik; Marie-Paule Roth

1993-01-01

145

DNA methylation of sex chromosomes in a dioecious plant, Melandrium album  

Microsoft Academic Search

Melandrium album, a dioecious plant species, has two heteromorphic sex chromosomes with the XY constitution typical for male and the XX for female plants. This plant represents an experimental model system of sex determination in which the Y chromosome plays a strongly dominant male role. We present data on the overall transcriptional activities of M. album sex chromosomes. DNA methylation

Boris Vyskot; Alejandro Araya; Jacky Veuskens; Ioan Negrutiu; Armand Mouras

1993-01-01

146

Investigation of the frequencies of prenatally diagnosed fetal chromosomal abnormalities at a single institution.  

PubMed

The objective of this study was to investigate, retrospectively, the frequencies of fetal chromosomal abnormalities identified in 4176 prenatal cytogenetic examinations at the Xiamen Maternity and Child Health Care Hospital over the 5-year period from October 2005 to September 2010. The frequency of abnormal fetal karyotypes was 4.6%. Numerical chromosome abnormalities were identified in 150 cases. The frequency of trisomy 21 was by far the highest, followed by trisomy 18. Structural aberrations of chromosomes were identified in 43 cases, including 21 cases with balanced and 22 cases with unbalanced chromosomal aberrations. In addition, 16 cases of apparently de novo chromosomal aberrations and 27 cases of familial inheritances were observed. Increased awareness of the frequencies of fetal chromosome abnormalities is important for the improvement of prenatal care and providing the options of termination or continuation of the pregnancy. Data obtained in this study provide the basis of a database for genetic counseling. PMID:22607389

Wu, Qichang; Wang, Wenbo; Kong, Hui; Sun, Li; Ge, Yunsheng; Xu, Yasong; Zhou, Yulin

2012-05-18

147

Chromosome mapping of repetitive sequences in Anostomidae species: implications for genomic and sex chromosome evolution  

PubMed Central

Background Members of the Anostomidae family provide an interesting model system for the study of the influence of repetitive elements on genome composition, mainly because they possess numerous heterochromatic segments and a peculiar system of female heterogamety that is restricted to a few species of the Leporinus genus. The aim of this study was to isolate and identify important new repetitive DNA elements in Anostomidae through restriction enzyme digestion, followed by cloning, characterisation and chromosome mapping of this fragment. To identify repetitive elements in other Leporinus species and expand on studies of repetitive elements in Anostomidae, hybridisation experiments were also performed using previously described probes of LeSpeI repetitive elements. Results The 628-base pair (bp) LeSpeII fragment was hybridised to metaphase cells of L. elongatus individuals as well as those of L. macrocephalus, L. obtusidens, L. striatus, L. lacustris, L. friderici, Schizodon borellii and S. isognathus. In L. elongatus, both male and female cells contained small clusters of LeSpeII repetitive elements dispersed on all of the chromosomes, with enrichment near most of the terminal portions of the chromosomes. In the female sex chromosomes of L. elongatus (Z2,Z2/W1W2), however, this repeated element was absent. In the remaining species, a dispersed pattern of hybridisation was observed on all chromosomes irrespective of whether or not they were sex chromosomes. The repetitive element LeSpeI produced positive hybridisations signals only in L. elongatus, L. macrocephalus and L. obtusidens, i.e., species with differentiated sex chromosomes. In the remaining species, the LeSpeI element did not produce hybridisation signals. Conclusions Results are discussed in terms of the effects of repetitive sequences on the differentiation of the Anostomidae genome, especially with respect to sex chromosome evolution. LeSpeII showed hybridisation patterns typical of Long Interspersed Elements (LINEs). The differential distribution of this element may be linked to sex chromosome differentiation in L. elongatus species. The relationship between sex chromosome specificity and the LeSpeI element is confirmed in the species L. elongatus, L. macrocephalus and L. obtusidens.

2012-01-01

148

Enigma of Y chromosome degeneration: Neo-Y and Neo-X chromosomes of Drosophila miranda a model for sex chromosome evolution  

Microsoft Academic Search

Y chromosome degeneration is characterized by structural changes in the chromosome architecture and expansion of genetic inertness\\u000a along the Y chromosome. It is generally assumed that the heteromorphic sex chromosome pair has developed from a pair of homologues.\\u000a Several models have been suggested. We use the unique situation of the secondary sex chromosome pair, neo-Y and neo-X (X2),\\u000a in Drosophila

Manfred Steinemann; Sigrid Steinemann

1998-01-01

149

Mechanisms leading to the formation of micronuclei containing sex chromosomes differ with age.  

PubMed

The frequency of spontaneously occurring micronuclei (MN) increases with age, with many of these MN containing sex chromatin. However, it is not known if this MN frequency increase is attributable to a higher number of the same cellular events that occur in younger people, or if a different sex chromosomal instability mechanism(s) arises with age. To gain insight regarding this question, the total number of signals present in MN and their corresponding binucleates, was scored in older (ages 40-80+ y.o.; n=40) compared to younger (7-39 y.o.; n=19) individuals using probes specific for the X and Y chromosomes. In 19.9% of the cells scored at least one sex chromatin positive micronucleus was present. A significant decrease in cells having a "corrective" loss pattern (i.e. trisomy rescue, leading to euploid binucleates following sex chromatin exclusion into the MN) was observed with increasing age for the Y chromosome in males (p=0.022) and the X chromosome in females (p=0.004). In addition, a significant increase (p<0.001) in cells having multiple signals beyond those expected from a single cellular error was observed in the older compared to younger study participants, with these imbalances resulting from cells having either a single micronucleus with multiple signals, or cells having multiple MN. Collectively, these findings suggest that age-related increases in MN frequencies reflect both gains in the occurrence of similar cellular errors, as well as changes in the types of chromosomal findings that occur. Importantly, these results also illustrate that while MN frequencies reflect acquired abnormalities, they may also reflect cellular responses to "correct" an error, particularly when evaluated in young individuals. Therefore, when analyzing MN frequencies, one may also wish to evaluate the imbalances present in both the binucleates and MN to facilitate the recognition of varying cellular responses to environmental or genotoxic exposures. PMID:22613870

Jones, Kimberly H; York, Timothy P; Jackson-Cook, Colleen

2012-05-18

150

Progressive Recombination Suppression and Differentiation in Recently Evolved Neo-sex Chromosomes  

PubMed Central

Recombination suppression leads to the structural and functional differentiation of sex chromosomes and is thus a crucial step in the process of sex chromosome evolution. Despite extensive theoretical work, the exact processes and mechanisms of recombination suppression and differentiation are not well understood. In threespine sticklebacks (Gasterosteus aculeatus), a different sex chromosome system has recently evolved by a fusion between the Y chromosome and an autosome in the Japan Sea lineage, which diverged from the ancestor of other lineages approximately 2 Ma. We investigated the evolutionary dynamics and differentiation processes of sex chromosomes based on comparative analyses of these divergent lineages using 63 microsatellite loci. Both chromosome-wide differentiation patterns and phylogenetic inferences with X and Y alleles indicated that the ancestral sex chromosomes were extensively differentiated before the divergence of these lineages. In contrast, genetic differentiation appeared to have proceeded only in a small region of the neo-sex chromosomes. The recombination maps constructed for the Japan Sea lineage indicated that recombination has been suppressed or reduced over a large region spanning the ancestral and neo-sex chromosomes. Chromosomal regions exhibiting genetic differentiation and suppressed or reduced recombination were detected continuously and sequentially in the neo-sex chromosomes, suggesting that differentiation has gradually spread from the fusion point following the extension of recombination suppression. Our study illustrates an ongoing process of sex chromosome differentiation, providing empirical support for the theoretical model postulating that recombination suppression and differentiation proceed in a gradual manner in the very early stage of sex chromosome evolution.

Natri, Heini M.; Shikano, Takahito; Merila, Juha

2013-01-01

151

The Master Sex-Determination Locus in Threespine Sticklebacks Is on a Nascent Y Chromosome  

Microsoft Academic Search

Background: Many different environmental and genetic sex-determination mechanisms are found in nature. Closely related species can use different master sex-determination switches, suggesting that these developmental pathways can evolve very rapidly. Previous cytological studies suggest that recently diverged species of stickleback fish have different sex chromosome complements. Here, we investigate the genetic and chromosomal mechanisms that underlie sex determination in the

Catherine L. Peichel; Joseph A. Ross; Clinton K. Matson; Mark Dickson; Jane Grimwood; Jeremy Schmutz; Richard M. Myers; Seiichi Mori; Dolph Schluter; David M. Kingsley

2004-01-01

152

Sexually Antagonistic "Zygotic Drive" of the Sex Chromosomes  

PubMed Central

Genomic conflict is perplexing because it causes the fitness of a species to decline rather than improve. Many diverse forms of genomic conflict have been identified, but this extant tally may be incomplete. Here, we show that the unusual characteristics of the sex chromosomes can, in principle, lead to a previously unappreciated form of sexual genomic conflict. The phenomenon occurs because there is selection in the heterogametic sex for sex-linked mutations that harm the sex of offspring that does not carry them, whenever there is competition among siblings. This harmful phenotype can be expressed as an antagonistic green-beard effect that is mediated by epigenetic parental effects, parental investment, and/or interactions among siblings. We call this form of genomic conflict sexually antagonistic “zygotic drive”, because it is functionally equivalent to meiotic drive, except that it operates during the zygotic and postzygotic stages of the life cycle rather than the meiotic and gametic stages. A combination of mathematical modeling and a survey of empirical studies is used to show that sexually antagonistic zygotic drive is feasible, likely to be widespread in nature, and that it can promote a genetic “arms race” between the homo- and heteromorphic sex chromosomes. This new category of genomic conflict has the potential to strongly influence other fundamental evolutionary processes, such as speciation and the degeneration of the Y and W sex chromosomes. It also fosters a new genetic hypothesis for the evolution of enigmatic fitness-reducing traits like the high frequency of spontaneous abortion, sterility, and homosexuality observed in humans.

Rice, William R.; Gavrilets, Sergey; Friberg, Urban

2008-01-01

153

Microarray-based prenatal diagnosis for the identification of fetal chromosome abnormalities.  

PubMed

The goal of prenatal cytogenetic testing is to provide reassurance to the couple seeking testing for their pregnancy, identify chromosome abnormalities in the fetus, if present, and provide treatments and medical management for affected babies. Cytogenetic analysis of banded chromosomes has been the standard for identifying chromosome abnormalities in the fetus for over 40 years. With chromosome analysis, whole chromosome aneuploidies and large structural rearrangements can be identified. The sequencing of the human genome has provided the resources to develop molecular tools that allow higher resolution observations of human chromosomes. The future holds the promise of sequencing that may identify chromosomal imbalances and deleterious single nucleotide variants. This review will focus on the use of genomic microarrays for the testing and identification of chromosome anomalies in prenatal diagnosis and will discuss the future directions of fetal testing. PMID:23895129

Shaffer, Lisa G; Rosenfeld, Jill A

2013-07-01

154

Increased number of sex chromosomes affects height in a nonlinear fashion: a study of 305 patients with sex chromosome aneuploidy.  

PubMed

Tall stature and eunuchoid body proportions characterize patients with 47,XXY Klinefelter syndrome, whereas patients with 45,X Turner syndrome are characterized by impaired growth. Growth is relatively well characterized in these two syndromes, while few studies describe the growth of patients with higher grade sex chromosome aneuploidies. It has been proposed that tall stature in sex chromosome aneuploidy is related to an overexpression of SHOX, although the copy number of SHOX has not been evaluated in previous studies. Our aims were therefore: (1) to assess stature in 305 patients with sex chromosome aneuploidy and (2) to determine the number of SHOX copies in a subgroup of these patients (n = 255) these patients and 74 healthy controls. Median height standard deviation scores in 46,XX males (n = 6) were -1.2 (-2.8 to 0.3), +0.9 (-2.2 to +4.6) in 47,XXY (n = 129), +1.3 (-1.8 to +4.9) in 47,XYY (n = 44), +1.1 (-1.9 to +3.4) in 48,XXYY (n = 45), +1.8 (-2.0 to +3.2) in 48,XXXY (n = 9), and -1.8 (-4.2 to -0.1) in 49,XXXXY (n = 10). Median height standard deviation scores in patients with 45,X (n = 6) were -2.6 (-4.1 to -1.6), +0.7 (-0.9 to +3.2) in 47,XXX (n = 40), -0.6 (-1.9 to +2.1) in 48,XXXX (n = 13), and -1.0 (-3.5 to -0.8) in 49,XXXXX (n = 3). Height increased with an increasing number of extra X or Y chromosomes, except in males with five, and in females with four or five sex chromosomes, consistent with a nonlinear effect on height. PMID:20425825

Ottesen, Anne Marie; Aksglaede, Lise; Garn, Inger; Tartaglia, Nicole; Tassone, Flora; Gravholt, Claus H; Bojesen, Anders; Sørensen, Kaspar; Jørgensen, Niels; Rajpert-De Meyts, Ewa; Gerdes, Tommy; Lind, Anne-Marie; Kjaergaard, Susanne; Juul, Anders

2010-05-01

155

Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes  

Microsoft Academic Search

BACKGROUND: The regular mammalian X and Y chromosomes diverged from each other at least 166 to 148 million years ago, leaving few traces of their early evolution, including degeneration of the Y chromosome and evolution of dosage compensation. RESULTS: We studied the intriguing case of black muntjac, in which a recent X-autosome fusion and a subsequent large autosomal inversion within

Qi Zhou; Jun Wang; Ling Huang; Wen-hui Nie; Jin-huan Wang; Yan Liu; Xiang-yi Zhao; Feng-tang Yang; Wen Wang

2008-01-01

156

Frequency of Drumsticks in Normal Women and in Patients with Chromosomal Abnormalities  

Microsoft Academic Search

THE demonstration of sex chromatin has become an important aspect of human genetics, both for practical reasons, and for the purpose of establishing the theoretical relationship between sex chromatin and the X-chromosome. The term `sex chromatin' comprises two superficially dissimilar structures : (1) the Barr body, present in epithelial and other tissue cells ; (2) the drumstick of the polymorphonuclear

Ursula Mittwoch

1964-01-01

157

Comparative sex chromosome genomics in snakes: differentiation, evolutionary strata, and lack of global dosage compensation.  

PubMed

Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females). Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae), but completely heteromorphic sex chromosomes in both garter snakes (Colubridae) and pygmy rattlesnake (Viperidae). Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases). This demonstrates that mutation rates are male-biased in snakes (male-driven evolution), but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex chromosomes evolution. PMID:24015111

Vicoso, Beatriz; Emerson, J J; Zektser, Yulia; Mahajan, Shivani; Bachtrog, Doris

2013-08-27

158

Spectral karyotyping refines cytogenetic diagnostics of constitutional chromosomal abnormalities  

Microsoft Academic Search

Karyotype analysis by chromosome banding is the standard method for identifying numerical and structural chromosomal aberrations\\u000a in pre- and postnatal cytogenetics laboratories. However, the chromosomal origins of markers, subtle translocations, or complex\\u000a chromosomal rearrangements are often difficult to identify with certainty. We have developed a novel karyotyping technique,\\u000a termed spectral karyotyping (SKY), which is based on the simultaneous hybridization of

Evelin Schröck; Tim Veldman; Hesed Padilla-Nash; Yi Ning; Jack Spurbeck; Syed Jalal; Lisa G. Shaffer; Peter Papenhausen; Chahira Kozma; Mary C. Phelan; Eigil Kjeldsen; Stephen A. Schonberg; Patricia O’Brien; Les Biesecker; Stan du Manoir; Thomas Ried

1997-01-01

159

Sex chromosome silencing in the marsupial male germ line.  

PubMed

In marsupials, dosage compensation involves silencing of the father's X-chromosome. Because no XIST orthologue has been found, how imprinted X-inactivation occurs is unknown. In eutherians, the X is subject to meiotic sex chromosome inactivation (MSCI) in the paternal germ line and persists thereafter as postmeiotic sex chromatin (PMSC). One hypothesis proposes that the paternal X is inherited by the eutherian zygote as a preinactive X and raises the possibility of a similar process in the marsupial germ line. Here we demonstrate that MSCI and PMSC occur in the opossum. Surprisingly, silencing occurs before X-Y association. After MSCI, the X and Y fuse through a dense plate without obvious synapsis. Significantly, sex chromosome silencing continues after meiosis, with the opossum PMSC sharing features of eutherian PMSC. These results reveal a common gametogenic program in two diverse clades of mammals and support the idea that male germ-line silencing may have provided an ancestral form of mammalian dosage compensation. PMID:17535928

Namekawa, Satoshi H; VandeBerg, John L; McCarrey, John R; Lee, Jeannie T

2007-05-29

160

Chromosomal abnormalities and hormonal disorders of primary amenorrhea patients in Egypt  

PubMed Central

BACKGROUND: Primary amenorrhea is defined as the absence of menstruation and secondary sexual characteristics in phenotypic women aged 14 years or older. Hormonal disorders are main causes of primary amenorrhea. Common hormonal cause of primary amenorrhea includes pituitary dysfunction and absent ovarian function. The aim of this study was to estimate the incidence and types of chromosomal abnormalities in patients with primary amenorrhea in Egypt. MATERIALS AND METHODS: Chromosomal analysis and hormonal assay were carried out on 223 patients with primary amenorrhea that were referred from different parts of Egypt to Cytogenetic laboratory of Genetic Unit, Children Hospital Mansoura University, from July 2008 to December 2010. FISH technique was carried out in some of cases to more evaluation. RESULTS: The frequency of chromosomal abnormalities was 46 (20.63%) in primary amenorrhea patients. The chromosomal abnormalities can be classified into four main types. (1) The numerical abnormalities of the X?chromosome were detected in 23 (50 %). (2) Structural abnormalities of the X chromosome were detected in 11 (23.91%). (3) Mosaicism of X chromosome was found in 10 (21.74%). (4) Male karyotype 46, XY was presented in 2 (4.35%). CONCLUSION: The present study showed that karyotype and FISH are necessary to detect the causes of primary amenorrhea. This study also revealed the incidence of chromosomal abnormalities in women with primary amenorrhea in Egypt is similar to that reported in previous literatures.

El-Dahtory, Faeza

2012-01-01

161

Genomic organization of the sex-determining and adjacent regions of the sex chromosomes of medaka  

PubMed Central

Sequencing of the human Y chromosome has uncovered the peculiarities of the genomic organization of a heterogametic sex chromosome of old evolutionary age, and has led to many insights into the evolutionary changes that occurred during its long history. We have studied the genomic organization of the medaka fish Y chromosome, which is one of the youngest heterogametic sex chromosomes on which molecular data are available. The Y specific and adjacent regions were sequenced and compared to the X. The male sex-determining gene, dmrt1bY, appears to be the only functional gene in the Y-specific region. The Y-specific region itself is derived from the duplication of a 43-kb fragment from linkage group 9. All other coduplicated genes except dmrt1bY degenerated. The Y-specific region has accumulated large stretches of repetitive sequences and duplicated pieces of DNA from elsewhere in the genome, thereby growing to 258 kb. Interestingly the non-recombining part of the Y did not spread out considerably from the original duplicated fragment, possibly because of a large sequence duplication bordering the Y-specific fragment. This may have conserved the more ancestral structure of the medaka Y and provides insights into some of the initial processes of Y chromosome evolution.

Kondo, Mariko; Hornung, Ute; Nanda, Indrajit; Imai, Shuichiro; Sasaki, Takashi; Shimizu, Atsushi; Asakawa, Shuichi; Hori, Hiroshi; Schmid, Michael; Shimizu, Nobuyoshi; Schartl, Manfred

2006-01-01

162

Extinct and Extant Reptiles: A Model System for the Study of Sex Chromosome Evolution  

Microsoft Academic Search

\\u000a The evolution and functional dynamics of sex chromosomes are focuses of current biological research. Although common organismal\\u000a morphologies and functions of males and females are found among amniotes, underlying sex chromosome organizations and sex-determining\\u000a mechanisms are widely variable. This chapter investigates the role that reptiles play in the study of sex chromosome evolution.\\u000a Reptile studies have described the coevolution of

Daniel E. Janes

163

Male only progeny in Anastrepha suspensa by RNAi-induced sex reversion of chromosomal females.  

PubMed

In Tephritidae sex determination is established by orthologs to the Drosophila melanogaster transformer and transformer-2 genes, though the primary signals for sex determination differ. The presence of the Y chromosome in the tephritid species is critical for male differentiation, while the ratio of X chromosomes to autosome ploidy is critical in drosophilids. Here the isolation, expression and function of tra and tra-2 orthologs are described for the agriculturally important tephritid, Anastrepha suspensa, and their possible use in genetically modified organisms for biologically-based pest management. The Astra and Astra-2 genes are highly conserved in structure, regulation and function with respect to those known from other tephritid species. Sex-specific transcripts for Astra were detected, one in females and three in males, whereas Astra-2 had a single common transcript found in both sexes. To test the function of these genes, Astra and Astra-2 dsRNA was injected into A. suspensa embryos from a transgenic strain having a Y-linked DsRed marker integration, allowing XY males to be distinguished from XX phenotypic males. Nearly all XX embryos developed into fully masculinized phenotypic male adults with no apparent female morphology. Upon dissection abnormal hypertrophic gonads were revealed in XX pseudomales but not in the XY males. Our findings suggest that Astra and Astra-2 are both necessary for female development, and that the potential exists for producing a male-only population when either gene alone, or both genes simultaneously, are knocked-down. PMID:22079281

Schetelig, Marc F; Milano, Andreina; Saccone, Giuseppe; Handler, Alfred M

2011-11-04

164

Reversal of an ancient sex chromosome to an autosome in Drosophila.  

PubMed

Although transitions of sex-determination mechanisms are frequent in species with homomorphic sex chromosomes, heteromorphic sex chromosomes are thought to represent a terminal evolutionary stage owing to chromosome-specific adaptations such as dosage compensation or an accumulation of sex-specific mutations. Here we show that an autosome of Drosophila, the dot chromosome, was ancestrally a differentiated X chromosome. We analyse the whole genome of true fruitflies (Tephritidae), flesh flies (Sarcophagidae) and soldier flies (Stratiomyidae) to show that genes located on the dot chromosome of Drosophila are X-linked in outgroup species, whereas Drosophila X-linked genes are autosomal. We date this chromosomal transition to early drosophilid evolution by sequencing the genome of other Drosophilidae. Our results reveal several puzzling aspects of Drosophila dot chromosome biology to be possible remnants of its former life as a sex chromosome, such as its minor feminizing role in sex determination or its targeting by a chromosome-specific regulatory mechanism. We also show that patterns of biased gene expression of the dot chromosome during early embryogenesis, oogenesis and spermatogenesis resemble that of the current X chromosome. Thus, although sex chromosomes are not necessarily evolutionary end points and can revert back to an autosomal inheritance, the highly specialized genome architecture of this former X chromosome suggests that severe fitness costs must be overcome for such a turnover to occur. PMID:23792562

Vicoso, Beatriz; Bachtrog, Doris

2013-06-23

165

On the maintenance of sex chromosome polymorphism by sex-antagonistic selection.  

PubMed

Complex sex determination systems are a priori unstable and require specific selective forces for their maintenance. Analytical derivations suggest that sex antagonistic selection may play such a role, but this assumes absence of recombination between the sex-determining and sex-antagonistic genes. Using individual-based simulations and focusing on the sex chromosome and coloration polymorphisms of platy fishes as a case study, we show that the conditions for polymorphism maintenance induce female biases in primary sex ratios, so that sex ratio selection makes the system collapse toward male or female heterogamety as soon as recombinant genotypes appear. However, a polymorphism can still be maintained under scenarios comprising strong sexual selection against dull males, mild natural selection against bright females, and low recombination rates. Though such conditions are plausibly met in natural populations of fishes harboring such polymorphisms, quantitative empirical evaluations are required to properly test whether sex antagonistic selection is a causal agent or whether other selective processes are required (such as local mate competition favoring female-biased sex ratios). PMID:21956029

Blaser, Olivier; Neuenschwander, Samuel; Perrin, Nicolas

2011-08-17

166

Risk of Chromosomal Abnormalities in Early Spontaneous Abortion after Assisted Reproductive Technology: A Meta-Analysis  

PubMed Central

Background Studies on the risk of chromosomal abnormalities in early spontaneous abortion after assisted reproductive technology (ART) are relatively controversial and insufficient. Thus, to obtain a more precise evaluation of the risk of embryonic chromosomal abnormalities in first-trimester miscarriage after ART, we performed a meta-analysis of all available case–control studies relating to the cytogenetic analysis of chromosomal abnormalities in first-trimester miscarriage after ART. Methods Literature search in the electronic databases MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) based on the established strategy. Meta-regression, subgroup analysis, and Galbraith plots were conducted to explore the sources of heterogeneity. Results A total of 15 studies with 1,896 cases and 1,186 controls relevant to the risk of chromosomal abnormalities in first- trimester miscarriage after ART, and 8 studies with 601 cases and 602 controls evaluating frequency of chromosome anomaly for maternal age?35 versus <35 were eligible for the meta-analysis. No statistical difference was found in risk of chromosomally abnormal miscarriage compared to natural conception and the different types of ART utilized, whereas the risk of fetal aneuploidy significantly increased with maternal age?35 (OR 2.88, 95% CI: 1.74–4.77). Conclusions ART treatment does not present an increased risk for chromosomal abnormalities occurring in a first trimester miscarriage, but incidence of fetal aneuploidy could increase significantly with advancing maternal age.

Qin, Jun-Zhen; Pang, Li-Hong; Li, Min-Qing; Xu, Jing; Zhou, Xing

2013-01-01

167

Recent gene-capture on the uv sex chromosomes of the moss ceratodon purpureus.  

PubMed

Sex chromosomes evolve from ordinary autosomes through the expansion and subsequent degeneration of a region of suppressed recombination that is inherited through one sex. Here we investigate the relative timing of these processes in the UV sex chromosomes of the moss Ceratodon purpureus using molecular population genetic analyses of eight newly discovered sex-linked loci. In this system, recombination is suppressed on both the female-transmitted (U) sex chromosome and the male-transmitted (V) chromosome. Genes on both chromosomes therefore should show the deleterious effects of suppressed recombination and sex-limited transmission, while purifying selection should maintain homologs of genes essential for both sexes on both sex chromosomes. Based on analyses of eight sex-linked loci, we show that the nonrecombining portions of the U and V chromosomes expanded in at least two events (?0.6-1.3 MYA and ?2.8-3.5 MYA), after the divergence of C. purpureus from its dioecious sister species, Trichodon cylindricus and Cheilothela chloropus. Both U- and V-linked copies showed reduced nucleotide diversity and limited population structure, compared to autosomal loci, suggesting that the sex chromosomes experienced more recent selective sweeps that the autosomes. Collectively these results highlight the dynamic nature of gene composition and molecular evolution on nonrecombining portions of the U and V sex chromosomes. PMID:24094335

McDaniel, Stuart F; Neubig, Kurt M; Payton, Adam C; Quatrano, Ralph S; Cove, David J

2013-06-07

168

Independent Origin of Sex Chromosomes in Two Species of the Genus Silene  

Microsoft Academic Search

Here we introduce a new model species, Silene colpophylla, that could facilitate research of sex chromosome evolution and sex-determining systems. This species is related to the well-established dioecious plant model Silene latifolia. Our results show that S. colpophylla is, similarly to S. latifolia, a male heterogametic species, but its sex chromosomes have evolved from a different pair of autosomes than

Martina Mrackova; Michael Nicolas; Roman Hobza; Ioan Negrutiu; F. Moneger; A. Widmer; B. Vyskot; B. Janousek

2008-01-01

169

A cytogenetic survey of consecutive liveborn infants-incidence and type of chromosome abnormalities  

Microsoft Academic Search

Summary Cytogenetic investigations have been carried out with particular concern to the frequency of chromosome abnormalities in newborn infants, and this is a preliminary report of data derived from 2,626 consecutive liveborns (1,393 males and 1,233 females) which were collected in one hospital. Of these, 18 infants (0.69%) were found to have a major chromosome abnormality. Eight infants (0.30%) showed

Tohru Maeda; Michiko Ohno; Masumi Takada; Yoshikatsu Kato; Masato Nishida; Toshiko Jobo; Hideo Adachi; Akira Taguchi

1978-01-01

170

Genetic and Functional Analysis of DD44, a Sex-Linked Gene From the Dioecious Plant Silene latifolia, Provides Clues to Early Events in Sex Chromosome Evolution  

Microsoft Academic Search

Silene latifolia is a dioecious plant with heteromorphic sex chromosomes. The sex chromosomes of S. latifolia provide an opportunity to study the early events in sex chromosome evolution because of their relatively recent emergence. In this article, we present the genetic and physical mapping, expression analysis, and molecular evolutionary analysis of a sex-linked gene from S. latifolia, DD44 (Differential Display

Richard C. Moore; Olga Kozyreva; Sabine Lebel-Hardenack; Jiri Siroky; Roman Hobza; Boris Vyskot; Sarah R. Grant

171

MMPI Profiles of Males with Abnormal Sex Chromosome Complements  

ERIC Educational Resources Information Center

|Nine males with Klinefelter's syndrome (XXY) and seven XYY males, located primarily in prisons and psychiatric hospitals, were administered the Minnesota Multiphasic Personality Inventory. (Author/KW)|

Rosen, M.; And Others

1971-01-01

172

Sex chromosome complement contributes to sex differences in bradycardic baroreflex response.  

PubMed

To investigate whether sex chromosome complement modulates bradycardic baroreflex response and contributes to the angiotensin II-bradycardic baroreflex sex differences, we used the four core genotype mouse model in which the effect of gonadal sex and sex chromosome complement is dissociated, allowing comparisons of sexually dimorphic traits among XX and XY females, as well as in XX and XY males. In conscious gonadectomized (GDX) MF1 transgenic mice we evaluated baroreflex regulation of heart rate in response to changes in blood pressure evoked by phenylephrine (1 mg/mL), angiotensin II (100 ?g/mL), and sodium nitroprusside (1 mg/mL). The administration of phenylephrine in GDX-XY females resulted in a significantly lower baroreflex response when compared with the other genotypes (in beats · min(-1) · mm Hg(-1) [slopes of regression lines for GDX-XY females -3.56±0.37 versus -6.06±0.38, -6.37±0.54 and -6.70±0.34 for GDX-XY male, GDX-XX female, and GDX-XX male mice, respectively]) {F(1,19)=9.63; P<0.01}. In addition, in both GDX-XY males and females, the angiotensin II-bradycardic baroreflex response was attenuated when compared with heart rate changes in GDX-XX male and female mice (in beats · min(-1) · mm Hg(-1) [slopes of regression lines: -2.83±0.28 versus -5.76±0.26 in GDX-XY and GDX-XX mice, respectively]) {F(1,19)=13.91; P<0.005}. In contrast, reflex tachycardic responses to sodium nitroprusside were comparable in all of the genotypes. These data support the hypothesis that sex chromosome complement modulates reflex inhibition of heart rate to phenylephrine and angiotensin II. Elucidating the foundational sources of sexually dimorphic traits in the regulation of baroreceptor reflex may enable the design of more appropriate sex-tailored therapeutic treatments in the future. PMID:21810650

Caeiro, Ximena E; Mir, Franco R; Vivas, Laura M; Carrer, Hugo F; Cambiasso, María J

2011-08-01

173

Spectral Karyotyping for identification of constitutional chromosomal abnormalities at a national reference laboratory  

PubMed Central

Spectral karyotyping is a diagnostic tool that allows visualization of chromosomes in different colors using the FISH technology and a spectral imaging system. To assess the value of spectral karyotyping analysis for identifying constitutional supernumerary marker chromosomes or derivative chromosomes at a national reference laboratory, we reviewed the results of 179 consecutive clinical samples (31 prenatal and 148 postnatal) submitted for spectral karyotyping. Over 90% of the cases were requested to identify either small supernumerary marker chromosomes (sSMCs) or chromosomal exchange material detected by G-banded chromosome analysis. We also reviewed clinical indications of those cases with marker chromosomes in which chromosomal origin was identified by spectral karyotyping. Our results showed that spectral karyotyping identified the chromosomal origin of marker chromosomes or the source of derivative chromosomal material in 158 (88%) of the 179 clinical cases; the identification rate was slightly higher for postnatal (89%) compared to prenatal (84%) cases. Cases in which the origin could not be identified had either a small marker chromosome present at a very low level of mosaicism (< 10%), or contained very little euchromatic material. Supplemental FISH analysis confirmed the spectral karyotyping results in all 158 cases. Clinical indications for prenatal cases were mainly for marker identification after amniocentesis. For postnatal cases, the primary indications were developmental delay and multiple congenital anomalies (MCA). The most frequently encountered markers were of chromosome 15 origin for satellited chromosomes, and chromosomes 2 and 16 for non-satellited chromosomes. We were able to obtain pertinent clinical information for 47% (41/88) of cases with an identified abnormal chromosome. We conclude that spectral karyotyping is sufficiently reliable for use and provides a valuable diagnostic tool for establishing the origin of supernumerary marker chromosomes or derivative chromosomal material that cannot be identified with standard cytogenetic techniques.

2012-01-01

174

Abnormal development in the mouse caused by chromosome unbalance  

Microsoft Academic Search

Summary  A line of mice, designated as the T1 stock, which has been derived from a single male whose father was X-rayed, is characterised by the production of about 4·6\\u000a per cent. of abnormal embryos, and of a somewhat smaller percentage of abnormal young at term.\\u000a \\u000a The abnormality consists of a failure of the neural groove to close throughout a portion

George D. Snell; Dorothea Isabel Picken

1935-01-01

175

Spectral karyotyping refines cytogenetic diagnostics of constitutional chromosomal abnormalities.  

PubMed

Karyotype analysis by chromosome banding is the standard method for identifying numerical and structural chromosomal aberrations in pre- and postnatal cytogenetics laboratories. However, the chromosomal origins of markers, subtle translocations, or complex chromosomal rearrangements are often difficult to identify with certainty. We have developed a novel karyotyping technique, termed spectral karyotyping (SKY), which is based on the simultaneous hybridization of 24 chromosome-specific painting probes labeled with different fluorochromes or fluorochrome combinations. The measurement of defined emission spectra by means of interferometer-based spectral imaging allows for the definitive discernment of all human chromosomes in different colors. Here, we report the comprehensive karyotype analysis of 16 samples from different cytogenetic laboratories by merging conventional cytogenetic methodology and spectral karyotyping. This approach could become a powerful tool for the cytogeneticists, because it results in a considerable improvement of karyotype analysis by identifying chromosomal aberrations not previously detected by G-banding alone. Advantages, limitations, and future directions of spectral karyotyping are discussed. PMID:9439652

Schröck, E; Veldman, T; Padilla-Nash, H; Ning, Y; Spurbeck, J; Jalal, S; Shaffer, L G; Papenhausen, P; Kozma, C; Phelan, M C; Kjeldsen, E; Schonberg, S A; O'Brien, P; Biesecker, L; du Manoir, S; Ried, T

1997-12-01

176

A major locus on mouse chromosome 18 controls XX sex reversal in Odd Sex (Ods) mice.  

PubMed

We have previously reported a dominant mouse mutant, Odd sex (Ods), in which XX Ods/+ mice on the FVB/N background show complete sex reversal, associated with expression of Sox9 in the fetal gonads. Remarkably, when crossed to the A/J strain approximately 95% of the (AXFVB) F(1) XX Ods/+ mice developed as fully fertile, phenotypic females, the remainder developing as males or hermaphrodites. Using a (AXFVB) F(2) population, we conducted a genome-wide linkage scan to identify the number and chromosomal location of potential Ods modifier genes. A single major locus termed Odsm1 was mapped to chromosome 18, tightly linked to D18Mit189 and D18Mit210. Segregation at this locus could account for the presence of sex reversal in 100% of XX Ods/+ mice which develop as males, for the absence of sex reversal in approximately 92% of XX Ods/+ mice which develop as females, and for the mixed sexual phenotype in approximately 72% of XX Ods/+ mice that develop with ambiguous genitalia. We propose that homozygosity for the FVB-derived allele strongly favors Ods sex reversal, whereas homozygosity for the A/J-derived allele inhibits it. In mice heterozygous at Odsm1, the phenotypic outcome, male, female or hermaphrodite, is determined by a complex interaction of several minor modifying loci. The close proximity of Smad2, Smad7 and Smad4 to D18Mit189/210 provides a potential mechanism through which Odsm1 might act. PMID:12588798

Qin, Yangjun; Poirier, Christophe; Truong, Cavatina; Schumacher, Armin; Agoulnik, Alexander I; Bishop, Colin E

2003-03-01

177

Ultraviolet radiation--induced chromosomal abnormalities in fetal fibroblasts from New Zealand black mice.  

PubMed

Fibroblasts from New Zealand Black mouse fetuses manifest increased frequency of chromosomal breaks and interchanges after exposure to ultraviolet radiation when compared with cells from BABL/c fetuses. This chromosomal instability is similar to what has been reported in cells from patients with xeroderma pigmentosum and may be related to the chromosomally abnormal clones and malignancy previously reported in adult New Zealand Black mice. PMID:684417

Reddy, A L; Fialkow, P G; Salo, A

1978-09-01

178

Chromosomal gene movements reflect the recent origin and biology of therian sex chromosomes.  

PubMed

Mammalian sex chromosomes stem from ancestral autosomes and have substantially differentiated. It was shown that X-linked genes have generated duplicate intronless gene copies (retrogenes) on autosomes due to this differentiation. However, the precise driving forces for this out-of-X gene "movement" and its evolutionary onset are not known. Based on expression analyses of male germ-cell populations, we here substantiate and extend the hypothesis that autosomal retrogenes functionally compensate for the silencing of their X-linked housekeeping parental genes during, but also after, male meiotic sex chromosome inactivation (MSCI). Thus, sexually antagonistic forces have not played a major role for the selective fixation of X-derived gene copies in mammals. Our dating analyses reveal that although retrogenes were produced ever since the common mammalian ancestor, selectively driven retrogene export from the X only started later, on the placental mammal (eutherian) and marsupial (metatherian) lineages, respectively. Together, these observations suggest that chromosome-wide MSCI emerged close to the eutherian-marsupial split approximately 180 million years ago. Given that MSCI probably reflects the spread of the recombination barrier between the X and Y, crucial for their differentiation, our data imply that these chromosomes became more widely differentiated only late in the therian ancestor, well after the divergence of the monotreme lineage. Thus, our study also provides strong independent support for the recent notion that our sex chromosomes emerged, not in the common ancestor of all mammals, but rather in the therian ancestor, and therefore are much younger than previously thought. PMID:18384235

Potrzebowski, Lukasz; Vinckenbosch, Nicolas; Marques, Ana Claudia; Chalmel, Frédéric; Jégou, Bernard; Kaessmann, Henrik

2008-04-01

179

Lack of Dosage Compensation Accompanies the Arrested Stage of Sex Chromosome Evolution in Ostriches  

PubMed Central

Sex chromosome evolution is usually seen as a process that, once initiated, will inevitably progress toward an advanced stage of degeneration of the nonrecombining chromosome. However, despite evidence that avian sex chromosome evolution was initiated >100 Ma, ratite birds have been trapped in an arrested stage of sex chromosome divergence. We performed RNA sequencing of several tissues from male and female ostriches and assembled the transcriptome de novo. A total of 315 Z-linked genes fell into two categories: those that have equal expression level in the two sexes (for which Z–W recombination still occurs) and those that have a 2-fold excess of male expression (for which Z–W recombination has ceased). We suggest that failure to evolve dosage compensation has constrained sex chromosome divergence in this basal avian lineage. Our results indicate that dosage compensation is a prerequisite for, not only a consequence of, sex chromosome evolution.

Adolfsson, Sofia; Ellegren, Hans

2013-01-01

180

Transmission and expression of the parasitic paternal sex ratio (PSR) chromosome  

Microsoft Academic Search

B-chromosomes are often considered genomic parasites. They are extra to the normal chromosomal complement, are unnecessary for survival of an individual, and are often inherited at higher than Mendelian rates. Paternal Sex Ratio (PSR) is an extreme example of a parasitic B-chromosome in the wasp Nasonia vitripennis. It is transmitted via sperm but then destroys the other paternal chromosomes in

Leo W Beukeboom; John H Werren

1993-01-01

181

Abnormal sex ratios in human populations: Causes and consequences  

Microsoft Academic Search

In the absence of manipulation, both the sex ratio at birth and the population sex ratio are remarkably constant in human populations. Small alterations do occur naturally; for example, a small excess of male births has been reported to occur during and after war. The tradition of son preference, however, has distorted these natural sex ratios in large parts of

Therese Hesketh; Zhu Wei Xing

2006-01-01

182

Should Y stay or should Y go: The evolution of non-recombining sex chromosomes  

PubMed Central

Gradual degradation seems inevitable for non-recombining sex chromosomes. This has been supported by the observation of degenerated non-recombining sex chromosomes in a variety of species. The human Y chromosome has also degenerated significantly during its evolution, and theories have been advanced that the Y chromosome could disappear within the next ~5 million years, if the degeneration rate it has experienced continues. However, recent studies suggest that this is unlikely. Conservative evolutionary forces such as strong purifying selection and intrachromosomal repair through gene conversion balance the degeneration tendency of the Y chromosome and maintain its integrity after an initial period of faster degeneration. We discuss the evidence both for and against the extinction of the Y chromosome. We also discuss potential insights gained on the evolution of sex-determining chromosomes by studying simpler sex-determining chromosomal regions of unicellular and multicellular microorganisms.

Sun, Sheng; Heitman, Joseph

2013-01-01

183

Ring X and other structural X chromosome abnormalities: X inactivation and phenotype.  

PubMed

Patients who carry a structural abnormality of the X chromosome are a fascinating group who have provided opportunities to evaluate genotype/phenotype correlation in relation to X chromosome content and inactivation. Turner syndrome (TS) is most commonly associated with a 45,X karyotype and presents with an array of phenotypes, the main ones being poor viability in utero, ovarian failure and infertility, short stature, lymphedema, and other congenital malformations but usually not mental retardation. In some TS patients the karyotype shows both a normal X and a structurally rearranged X chromosome. These structural abnormalities, which include deletions, duplications, inversions, translocations, and rings, are associated with chromosome breaks and significant imbalance of gene content of the X chromosome. However, such abnormalities are generally well tolerated because of the preferential inactivation of the abnormal X, which can restore, at least in part, a balanced genetic makeup. This beneficial effect of X inactivation results in a mild phenotype in most patients with structural abnormalities of the X, similar to that found in TS patients with a 45,X karyotype. However, in cases of ring X chromosomes and of X/autosome translocations the incidence of mental retardation and other congenital abnormalities can be significantly higher than in TS. These abnormal phenotypes can be ascribed to failed or partial X inactivation and/or incomplete selection in favor of cells with normal balance of gene expression. In this article, we present phenotype/genotype correlation in female patients with structural abnormalities of the X and address the role of X inactivation and cell selection in the phenotypic findings. Our review emphasizes a subset of rare patients with ring X chromosomes who have provided evidence of a direct role for X inactivation in determining phenotypes. PMID:11480912

Leppig, K A; Disteche, C M

2001-06-01

184

The Importance of Screening and Prenatal Diagnosis in the Identification of the Numerical Chromosomal Abnormalities  

PubMed Central

ABSTRACT Background and aims: The obstetric care of a pregnancy, as it is practiced today, includes non-invasive screening approaches as well as invasive procedures for the definitive prenatal diagnosis of fetal disorders correlations between indications for prenatal cytogenetic diagnosis and results of the chromosomal analysis made upon fetal cells. The aim of our study was to evaluate the correlations between the screening test results and results of chromosomal analysis on fetal cells. Methods: Amniotic fluid samples from 1159 pregnant women were studied with the rapid FISH method and the cytogenetic analysis (karyotype). The results from both methods were compared. Results: The indications to perform prenatal cytogenetic diagnosis for numerical chromosomal abnormalities were: abnormal results of double or triple test, advanced maternal age, fetal abnormality detected through ultrasound examination, and positive family history for chromosomal anomalies. In our study we identified 30 cases with abnormal numeric chromosomes (18 cases of trisomy 21, 4 cases of trisomy 18, 3 cases of trisomy X, 1 case of monosomy, 2 cases of trisomy XYY, 1 case of trisomy XXY and 1 case of triploidy). Conclusions: This report confirms the importance of screening and the cytogenetic diagnosis in the identification of the numerical chromosomal abnormalities.

NEAGOS, Daniela; CRETU, Ruxandra; SFETEA, Roxana Corina; BOHILTEA, Laurentiu Camil

2011-01-01

185

Prognosis of prenatally diagnosed children with sex chromosome aneuploidy.  

PubMed

Sex chromosome aneuploidy (SCA) occurs in about 1/250 amniocenteses, and the significance of the long-term prognosis of fetuses with SCA is of concern to prospective parents and health care providers. Longitudinal studies in an unselected group of newborn infants with SCA diagnosed postnatally have refuted allegations of mental retardation but have documented an increased risk for developmental problems. Of the 530 phone consultations with parents faced with a prenatal diagnosis of SCA, 68% continued the pregnancy. Twenty of the oldest subsequently born children (now 7-14 years old) were available for follow-up. In this small sample and age group, the propositi are progressing developmentally at a rate comparable to their sibs and are doing better at school and in peer relations than the SCA group diagnosed postnatally. Only 2 have documented IQs as low as 90. The documented IQs of the remainder, none of whom are sex chromosome mosaics, are all over 110. The parent population in this prenatally diagnosed group is unique and different from that of the postnatally diagnosed group in that over 85% of them are college graduates, often professionals, and upper socioeconomic individuals. The developmental competence of this SCA sample may be attributable to the supportive environment provided by these families, all of whom made a conscious decision to continue the pregnancy. PMID:1488987

Robinson, A; Bender, B G; Linden, M G

1992-10-01

186

[Effect of chromosomal constitution with respect to the sex chromosomes on the proliferative activity of human lymphocytes].  

PubMed

Rate division of human lymphocytes was studied in 85 healthy siblings and 142 normal non-related individuals using sister chromatid differential staining in standard conditions of cell culturing. It was shown that proliferation of male lymphocytes exceeds that of female cells. This sexual dimorphism does not depend on the time of fixation of cell cultures and probably is conditioned by differential chromosomal constitution of the two sexes. The study of sex chromosome mosaics revealed rate modification of cell proliferation in the line: 45,X greater than 46,XY greater than 46,XX. The possibility of influence of heterochromatin and sex chromosomal genes on control of cell division is discussed. PMID:3250909

Nazarenko, S A; Burmakina, Iu E; Viktorov, V V

1988-12-01

187

Meiotic Pairing and Segregation of Achiasmate Sex Chromosomes in Eutherian Mammals: The Role of SYCP3 Protein  

Microsoft Academic Search

In most eutherian mammals, sex chromosomes synapse and recombine during male meiosis in a small region called pseudoautosomal region. However in some species sex chromosomes do not synapse, and how these chromosomes manage to ensure their proper segregation is under discussion. Here we present a study of the meiotic structure and behavior of sex chromosomes in one of these species,

Roberto de la Fuente; María Teresa Parra; Alberto Viera; Adela Calvente; Rocío Gómez; José Ángel Suja; Julio S Rufas; Jesús Page

2007-01-01

188

Novel sex-determining genes in fish and sex chromosome evolution.  

PubMed

Although the molecular mechanisms underlying many developmental events are conserved across vertebrate taxa, the lability at the top of the sex-determining (SD) cascade has been evident from the fact that four master SD genes have been identified: mammalian Sry; chicken DMRT1; medaka Dmy; and Xenopus laevis DM-W. This diversity is thought to be associated with the turnover of sex chromosomes, which is likely to be more frequent in fishes and other poikilotherms than in therian mammals and birds. Recently, four novel candidates for vertebrate SD genes were reported, all of them in fishes. These include amhy in the Patagonian pejerrey, Gsdf in Oryzias luzonensis, Amhr2 in fugu and sdY in rainbow trout. These studies provide a good opportunity to infer patterns from the seemingly chaotic picture of sex determination systems. Here, we review recent advances in our understanding of the master SD genes in fishes. PMID:23335327

Kikuchi, Kiyoshi; Hamaguchi, Satoshi

2013-03-01

189

The dragon lizard Pogona vitticeps has ZZ\\/ZW micro-sex chromosomes  

Microsoft Academic Search

The bearded dragon, Pogona vitticeps (Agamidae: Reptilia) is an agamid lizard endemic to Australia. Like crocodilians and many turtles, temperature-dependent sex determination (TSD) is common in agamid lizards, although many species have genotypic sex determination (GSD). P. vitticeps is reported to have GSD, but no detectable sex chromosomes. Here we used molecular cytogenetic and differential banding techniques to reveal sex

Tariq Ezaz; Alexander E. Quinn; Ikuo Miura; Stephen D. Sarre; Arthur Georges; Jennifer A. Marshall Graves

2005-01-01

190

Sex chromosome variation and cytotaxonomy of the onchocerciasis vector Simulium squamosum in Cameroon and Nigeria.  

PubMed

On the basis of sex chromosome variation, three cytotypes of Simulium squamosum (Enderlein) (Diptera: Simuliidae) are described from Cameroon and Nigeria. Simulium squamosum A is the typical form as originally described by Vajime & Dunbar (1975) with chromosome I as the sex chromosome. It occurs throughout most of Cameroon and south-east Nigeria. A second cytotype, S. squamosum B, is described from the river Sanaga (Cameroon). It also has chromosome I as the sex chromosome, but the nature of the sex differential region is different. Simulium squamosum C has no sex-linked chromosomal rearrangements. It is widespread in Nigeria and occurs near Mount Cameroon, where it seems to hybridize with S. squamosum A. PMID:11434559

Traore-Lamizana, M; Somiari, S; Mafuyai, H B; Vajime, C G; Post, R J

2001-06-01

191

Identification of chromosome abnormalities in the horse using a panel of chromosome-specific painting probes generated by microdissection.  

PubMed

Fluorescent in situ hybridisation (FISH) using a panel of molecular probes for all chromosome pairs obtained by chromosome microdissection of the domestic horse ( Equus caballus ) was used to diagnose karyotype abnormalities in 35 horses (32 mares, 2 stallions and 1 intersex), which were selected for the study due to infertility (23 horses), reduced fertility (10 horses) and developmental anomalies (2 horses). The use of the FISH technique with probes for each horse chromosome pair enabled the diagnosis of many different chromosome aberrations in this population. Among the horses analysed, 21 animals had normal karyotype - 64,XX (19 mares) and 64,XY (2 stallions). Fourteen animals, constituting 40% of the population studied, showed the following chromosome abnormalities: 63,X (1 mare); 63,X/64,XX (6 mares); 63,X/64,XX/65,XXX (3 mares); 63,X/65,XXX (1 mare); 64,XX/65,XX+Xp (1 mare); 63,X/64,XX/65,XX+Xq (1 mare), and 63,X/64,XX/65,XX+delY (1 intersex). When only the mares studied because of complete infertility were taken into consideration, this proportion exceeded 56%. Due to the increased frequency of the above-mentioned aberrations in the mosaic form of two or more lines, it was necessary to analyse a large number (100-300) of metaphase spreads. The use of specific molecular probes obtained by chromosome microdissection made these diagnoses much easier. PMID:19635709

Bugno, Monika; S?ota, Ewa; Pie?kowska-Schelling, Aldona; Schelling, Claude

2009-09-01

192

Sex Differences in the Cerebellum and Frontal Cortex: Roles of Estrogen Receptor Alpha and Sex Chromosome Genes  

PubMed Central

Most neurobehavioral diseases are sexually dimorphic in their incidence, and sex differences in the brain may be key for understanding and treating these diseases. Calbindin (Calb) D28K is used as a biomarker for the well-studied sexually dimorphic nucleus, a hypothalamic structure that is larger in males than in females. In the current study weanling C56BL/6J mice were used to examine sex differences in the Calb protein and message focusing on regions outside of the hypothalamus. A robust sex difference was found in Calb in the frontal cortex (FC) and cerebellum (CB; specifically in Purkinje cells); mRNA and protein were higher in females than in males. Using 2 mouse lines, i.e. one with a complete deletion of estrogen receptor alpha (ER?) and the other with uncoupled gonads and sex chromosomes, we probed the mechanisms that underlie sexual dimorphisms. In the FC, deletion of ER? reduced Calb1 mRNA in females compared to males. In addition, females with XY sex chromosomes had levels of Calb1 equal to those of males. Thus, both ER? and the sex chromosome complement regulate Calb1 in the FC. In the CB, ER? knockout mice of both sexes had reduced Calb1 mRNA, yet sex differences were retained. However, the sex chromosome complement, regardless of gonadal sex, dictated Calb1 mRNA levels. Mice with XX chromosomes had significantly greater Calb1 than did XY mice. This is the first study demonstrating that sex chromosome genes are a driving force producing sex differences in the CB and FC, which are neuoranatomical regions involved in many normal functions and in neurobehavioral diseases.

Abel, Jean M.; Witt, Diane M.; Rissman, Emilie F.

2011-01-01

193

A large pseudoautosomal region on the sex chromosomes of the frog Silurana tropicalis.  

PubMed

Sex chromosome divergence has been documented across phylogenetically diverse species, with amphibians typically having cytologically nondiverged ("homomorphic") sex chromosomes. With an aim of further characterizing sex chromosome divergence of an amphibian, we used "RAD-tags" and Sanger sequencing to examine sex specificity and heterozygosity in the Western clawed frog Silurana tropicalis (also known as Xenopus tropicalis). Our findings based on approximately 20 million genotype calls and approximately 200 polymerase chain reaction-amplified regions across multiple male and female genomes failed to identify a substantially sized genomic region with genotypic hallmarks of sex chromosome divergence, including in regions known to be tightly linked to the sex-determining region. We also found that expression and molecular evolution of genes linked to the sex-determining region did not differ substantially from genes in other parts of the genome. This suggests that the pseudoautosomal region, where recombination occurs, comprises a large portion of the sex chromosomes of S. tropicalis. These results may in part explain why African clawed frogs have such a high incidence of polyploidization, shed light on why amphibians have a high rate of sex chromosome turnover, and raise questions about why homomorphic sex chromosomes are so prevalent in amphibians. PMID:23666865

Bewick, Adam J; Chain, Frédéric J J; Zimmerman, Lyle B; Sesay, Abdul; Gilchrist, Michael J; Owens, Nick D L; Seifertova, Eva; Krylov, Vladimir; Macha, Jaroslav; Tlapakova, Tereza; Kubickova, Svatava; Cernohorska, Halina; Zarsky, Vojtech; Evans, Ben J

2013-01-01

194

A Large Pseudoautosomal Region on the Sex Chromosomes of the Frog Silurana tropicalis  

PubMed Central

Sex chromosome divergence has been documented across phylogenetically diverse species, with amphibians typically having cytologically nondiverged (“homomorphic”) sex chromosomes. With an aim of further characterizing sex chromosome divergence of an amphibian, we used “RAD-tags” and Sanger sequencing to examine sex specificity and heterozygosity in the Western clawed frog Silurana tropicalis (also known as Xenopus tropicalis). Our findings based on approximately 20 million genotype calls and approximately 200 polymerase chain reaction-amplified regions across multiple male and female genomes failed to identify a substantially sized genomic region with genotypic hallmarks of sex chromosome divergence, including in regions known to be tightly linked to the sex-determining region. We also found that expression and molecular evolution of genes linked to the sex-determining region did not differ substantially from genes in other parts of the genome. This suggests that the pseudoautosomal region, where recombination occurs, comprises a large portion of the sex chromosomes of S. tropicalis. These results may in part explain why African clawed frogs have such a high incidence of polyploidization, shed light on why amphibians have a high rate of sex chromosome turnover, and raise questions about why homomorphic sex chromosomes are so prevalent in amphibians.

Bewick, Adam J.; Chain, Frederic J.J.; Zimmerman, Lyle B.; Sesay, Abdul; Gilchrist, Michael J.; Owens, Nick D.L.; Seifertova, Eva; Krylov, Vladimir; Macha, Jaroslav; Tlapakova, Tereza; Kubickova, Svatava; Cernohorska, Halina; Zarsky, Vojtech; Evans, Ben J.

2013-01-01

195

Rapid De Novo Evolution of X Chromosome Dosage Compensation in Silene latifolia, a Plant with Young Sex Chromosomes  

Microsoft Academic Search

Evidence for dosage compensation in Silene latifolia, a plant with 10-million-year-old sex chromosomes, reveals that dosage compensation can evolve rapidly in young XY systems and is not an animal-specific phenomenon.

Aline Muyle; Niklaus Zemp; Clothilde Deschamps; Sylvain Mousset; Alex Widmer; Gabriel A. B. Marais

2012-01-01

196

Effects of Sex Chromosome Aneuploidies on Brain Development: Evidence from Neuroimaging Studies  

ERIC Educational Resources Information Center

|Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the…

Lenroot, Rhoshel K.; Lee, Nancy Raitano; Giedd, Jay N.

2009-01-01

197

Genetic architecture of sexual dimorphism in a subdioecious plant with a proto-sex chromosome  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sexual dimorphism is thought to arise once sexually antagonistic genes accumulate on sex chromosomes early in their evolution. Yet because the earliest stages of sex chromosome evolution are elusive, we lack empirical evidence supporting this theory. In this study, we shed first light on the genetic...

198

Male only progeny in Anastrepha suspensa by RNAi-induced sex reversion of chromosomal females  

Microsoft Academic Search

In Tephritidae sex determination is established by orthologs to the Drosophila melanogaster transformer and transformer-2 genes, though the primary signals for sex determination differ. The presence of the Y chromosome in the tephritid species is critical for male differentiation, while the ratio of X chromosomes to autosome ploidy is critical in drosophilids. Here the isolation, expression and function of tra

Marc F. Schetelig; Andreina Milano; Giuseppe Saccone; Alfred M. Handler

199

Alterations and Abnormal Mitosis of Wheat Chromosomes Induced by Wheat-Rye Monosomic Addition Lines  

PubMed Central

Background Wheat-rye addition lines are an old topic. However, the alterations and abnormal mitotic behaviours of wheat chromosomes caused by wheat-rye monosomic addition lines are seldom reported. Methodology/Principal Findings Octoploid triticale was derived from common wheat T. aestivum L. ‘Mianyang11’×rye S. cereale L. ‘Kustro’ and some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ followed by self-fertilization. Genomic in situ hybridization (GISH) using rye genomic DNA and fluorescence in situ hybridization (FISH) using repetitive sequences pAs1 and pSc119.2 as probes were used to analyze the mitotic chromosomes of these progeny. Strong pSc119.2 FISH signals could be observed at the telomeric regions of 3DS arms in ‘Mianyang11’. However, the pSc119.2 FISH signals were disappeared from the selfed progeny of 4R monosomic addition line and the changed 3D chromosomes could be transmitted to next generation stably. In one of the selfed progeny of 7R monosomic addition line, one 2D chromosome was broken and three 4A chromosomes were observed. In the selfed progeny of 6R monosomic addition line, structural variation and abnormal mitotic behaviour of 3D chromosome were detected. Additionally, 1A and 4B chromosomes were eliminated from some of the progeny of 6R monosomic addition line. Conclusions/Significance These results indicated that single rye chromosome added to wheat might cause alterations and abnormal mitotic behaviours of wheat chromosomes and it is possible that the stress caused by single alien chromosome might be one of the factors that induced karyotype alteration of wheat.

Fu, Shulan; Yang, Manyu; Fei, Yunyan; Tan, Feiquan; Ren, Zhenglong; Yan, Benju; Zhang, Huaiyu; Tang, Zongxiang

2013-01-01

200

A time stamp comparative analysis of frequent chromosomal abnormalities in Romanian patients.  

PubMed

Abstract Chromosome abnormalities represent the leading cause in many human genetic disorders. Gain or loss of genetic material can disrupt the normal expression of genes important in fetal development and result in abnormal phenotypes. Approximately 60% of first-trimester spontaneous abortions exhibit karyotype abnormalities. The majority of these abnormalities consist of numerical chromosomal changes, such as autosomal trisomy, monosomy X and polyploidy. In our current study, 411 cases were analyzed over a period of 5 years, which reflected the incidence of cytogenetic abnormalities in Romania. Down syndrome showed the highest frequency at 79%. At 2.6% structural chromosome abnormality syndromes and Turner syndrome followed suit. Next were the Edwards and Patau syndromes with an incidence of 1.2%. Klinefelter, Cri du chat and Wolf-Hirschhorn syndromes all had an incidence of 0.7%. Finally, the lowest frequencies were shown by Williams at 0.4% and only one case of Beckwith-Wiedemann syndrome with abnormal karyotype. The average maternal age at childbirth was 31.15 years (SD?=?6.96) and the average paternal age was 33.41 years (SD?=?7.17). PMID:23570267

Suciu, Nicolae; Plaiasu, Vasilica

2013-06-01

201

Chromosomal abnormalities determined by comparative genomic hybridization are helpful in the diagnosis of atypical hepatocellular neoplasms  

PubMed Central

Aims To explore the utility of cytogenetic abnormalities in the distinction of hepatic adenoma (HA) and well-differentiated hepatocellular carcinoma (HCC). Methods and results Array-based comparative genomic hybridization (CGH) was used to determine chromosomal abnormalities in 39 hepatocellular neoplasms: 12 HA, 15 atypical hepatocellular neoplasms (AHN) and 12 well-differentiated HCC. The designation of AHN was used in two situations: (i) adenoma-like neoplasms (n = 8) in male patients (any age) and women >50 years and <15 years old; (ii) adenoma-like neoplasms with focal atypical features (n = 7). CGH abnormalities were seen in none of the HAs (0/12), eight (53%) AHNs and 11 (92%) HCCs. The number and nature of abnormalities in AHN was similar to HCC with gains in 1q, 8q and 7q being the most common. Although follow-up information was limited, recurrence and/or metastasis were observed in three AHNs (two with abnormal, one with normal CGH). Conclusions Adenoma-like neoplasms with focal atypical morphological features or unusual clinical settings such as male gender or women outside the 15–50 year age group can show chromosomal abnormalities similar to well-differentiated HCC. Even though these tumours morphologically mimic adenoma, they can recur and metastasize. Determination of chromosomal abnormalities can be useful in the diagnosis of AHN.

Kakar, Sanjay; Chen, Xin; Ho, Coral; Burgart, Lawrence J; Adeyi, Oyedele; Jain, Dhanpat; Sahai, Viabhav; Ferrell, Linda D

2013-01-01

202

Multiple Sex-Associated Regions and a Putative Sex Chromosome in Zebrafish Revealed by RAD Mapping and Population Genomics  

PubMed Central

Within vertebrates, major sex determining genes can differ among taxa and even within species. In zebrafish (Danio rerio), neither heteromorphic sex chromosomes nor single sex determination genes of large effect, like Sry in mammals, have yet been identified. Furthermore, environmental factors can influence zebrafish sex determination. Although progress has been made in understanding zebrafish gonad differentiation (e.g. the influence of germ cells on gonad fate), the primary genetic basis of zebrafish sex determination remains poorly understood. To identify genetic loci associated with sex, we analyzed F2 offspring of reciprocal crosses between Oregon *AB and Nadia (NA) wild-type zebrafish stocks. Genome-wide linkage analysis, using more than 5,000 sequence-based polymorphic restriction site associated (RAD-tag) markers and population genomic analysis of more than 30,000 single nucleotide polymorphisms in our *ABxNA crosses revealed a sex-associated locus on the end of the long arm of chr-4 for both cross families, and an additional locus in the middle of chr-3 in one cross family. Additional sequencing showed that two SNPs in dmrt1 previously suggested to be functional candidates for sex determination in a cross of ABxIndia wild-type zebrafish, are not associated with sex in our AB fish. Our data show that sex determination in zebrafish is polygenic and that different genes may influence sex determination in different strains or that different genes become more important under different environmental conditions. The association of the end of chr-4 with sex is remarkable because, unique in the karyotype, this chromosome arm shares features with known sex chromosomes: it is highly heterochromatic, repetitive, late replicating, and has reduced recombination. Our results reveal that chr-4 has functional and structural properties expected of a sex chromosome.

Anderson, Jennifer L.; Rodriguez Mari, Adriana; Braasch, Ingo; Amores, Angel; Hohenlohe, Paul; Batzel, Peter; Postlethwait, John H.

2012-01-01

203

Frequent Nonrandom Chromosome Abnormalities in 27 Patients with Untreated Large Cell Lymphoma and Immunoblastic Lymphoma1  

Microsoft Academic Search

Fresh tumor samples from 27 patients with large cell lymphoma, either previously untreated (26 patients) or minimally treated (one patient), were processed for cytogenetic studies. Cytogenetic abnormalities were observed in all patients, most commonly in chromosomes 1, 3, 7, 12, 14, 17, and 18. Nine chromosomal breakpoints appeared frequently: 14q32 in 14 instances; 18q21 in seven; 9pl3-21, 17pll-13, and 3q21-23

Fernando Cabanillas; Sen Pathak; Jose Trujillo; John Manning; Ruth Katz; Peter McLaughlin; William S. Velasquez; Fredrick B. Hagemeister; Angela Goodacre; Ann Cork; James J. Butler; J Freireich

204

Detection of Chromosome Abnormalities by Quantitative Fluorescent PCR in Ectopic Pregnancies  

Microsoft Academic Search

Objective: To evaluate the potential value of quantitative fluorescent polymerase chain reaction (QF-PCR) in the detection of chromosome abnormalities in ectopic pregnancies. Methods: Seventy chorionic villi samples of ectopic pregnancies were studied by QF-PCR. Primers for chromosomes 16, 21, X and Y in chorionic villi were evaluated. Fluorescence in situ hybridization (FISH) was performed when results of QF-PCR showed aneuploidy,

Mariette Goddijn; Marja van Stralen; Heleen Schuring-Blom; Bert Redeker; Liesbeth van Leeuwen; Sjoerd Repping; Nico Leschot; Fulco van der Veen

2005-01-01

205

Chromosome Abnormalities in Malignant Lymphoma in Patients from Kurashiki: Histological and ImmunophenotypicCorrelations1  

Microsoft Academic Search

Clonal chromosomal abnormalities were found in tumor tissue of 43 (84%) of 51 patients with non-Hodgkin's lymphoma (B-cell, 32; T-cell, 15) from an adult T-cell leukemia\\/I) mphoma-nonendemicarea in western mainland Japan. Four tumors were tetraploid, and the other 39 had a chromosome number in the diploid range. Trisomies 3, 5, 7, 18, and \\\\. monosomy 13, and loss of an

Hiroshi Konishi; Masaharu Sakurai; Hatsue Nakao; Nobuo Maseki; Yasuhiko Kaneko; Yoshio Yagiri; Kenji Notohara

206

Chromosome 2 (2p16) abnormalities in Carney complex tumours  

PubMed Central

Carney complex (CNC) is an autosomal dominant multiple endocrine neoplasia and lentiginosis syndrome characterised by spotty skin pigmentation, cardiac, skin, and breast myxomas, and a variety of endocrine and other tumours. The disease is genetically heterogeneous; two loci have been mapped to chromosomes 17q22–24 (the CNC1 locus) and 2p16 (CNC2). Mutations in the PRKAR1A tumour suppressor gene were recently found in CNC1 mapping kindreds, while the CNC2 and perhaps other genes remain unidentified. Analysis of tumour chromosome rearrangements is a useful tool for uncovering genes with a role in tumorigenesis and/or tumour progression. CGH analysis showed a low level 2p amplification recurrently in four of eight CNC tumours; one tumour showed specific amplification of the 2p16-p23 region only. To define more precisely the 2p amplicon in these and other tumours, we completed the genomic mapping of the CNC2 region, and analysed 46 tumour samples from CNC patients with and without PRKAR1A mutations by fluorescence in situ hybridisation (FISH) using bacterial artificial chromosomes (BACs). Consistent cytogenetic changes of the region were detected in 40 (87%) of the samples analysed. Twenty-four samples (60%) showed amplification of the region represented as homogeneously stained regions (HSRs). The size of the amplicon varied from case to case, and frequently from cell to cell in the same tumour. Three tumours (8%) showed both amplification and deletion of the region in their cells. Thirteen tumours (32%) showed deletions only. These molecular cytogenetic changes included the region that is covered by BACs 400-P-14 and 514-O-11 and, in the genetic map, corresponds to an area flanked by polymorphic markers D2S2251 and D2S2292; other BACs on the centromeric and telomeric end of this region were included in varying degrees. We conclude that cytogenetic changes of the 2p16 chromosomal region that harbours the CNC2 locus are frequently observed in tumours from CNC patients, including those with germline, inactivating PRKAR1A mutations. These changes are mostly amplifications of the 2p16 region, that overlap with a previously identified amplicon in sporadic thyroid cancer, and an area often deleted in sporadic adrenal tumours. Both thyroid and adrenal tumours constitute part of CNC indicating that the responsible gene(s) in this area may indeed be involved in both inherited and sporadic endocrine tumour pathogenesis and/or progression.

Matyakhina, L; Pack, S; Kirschner, L; Pak, E; Mannan, P; Jaikumar, J; Taymans, S; Sandrini, F; Carney, J; Stratakis, C

2003-01-01

207

Nonrandom Representation of Sex-Biased Genes on Chicken Z Chromosome  

Microsoft Academic Search

Several lines of evidence suggest that the X chromosome of various animal species has an unusual complement of genes with\\u000a sex-biased or sex-specific expression. However, the study of the X chromosome gene content in different organisms provided\\u000a conflicting results. The most striking contrast concerns the male-biased genes, which were reported to be almost depleted\\u000a from the X chromosome in Drosophila

R. Storchová; P. Divina

2006-01-01

208

Analysis and Evolution of Two Functional Y-Linked Loci in a Plant Sex Chromosome System  

Microsoft Academic Search

White campion (Silene latifolia) is one of the few examples of plants with separate sexes and with X and Y sex chromosomes. The presence or absence of the Y chromosome determines which type of reproductive organs—male or female—will develop. Recently, we characterized the first active gene located on a plant Y chromosome, SlY1, and its X-linked homolog, SlX1. These genes

Ivan Atanassov; Catherine Delichere; Dmitry A. Filatov; Deborah Charlesworth; Ioan Negrutiu; Francoise Moneger

209

Abnormal chromosome complement resulting from a familial inversion of chromosome 2.  

PubMed Central

It has been suggested that pericentric inversions of chromosome 2 increase the risk for spontaneous abortion but do not increase the risk for unbalanced recombinant offspring. We report our experience of a familial pericentric inversion of chromosome 2 resulting in two unbalanced recombinant offspring. Both subjects have 46,XX,rec(2),dup q,inv(2)(p25q35). Images

Richter, S; Lockwood, B; Lockwood, D; Allanson, J

1989-01-01

210

All dosage compensation is local: Gene-by-gene regulation of sex-biased expression on the chicken Z chromosome  

Microsoft Academic Search

Recent reports have suggested that birds lack a mechanism of wholesale dosage compensation for the Z sex chromosome. This discovery was rather unexpected, as all other animals investigated with chromosomal mechanisms of sex determination have some method to counteract the effects of gene dosage of the dominant sex chromosome in males and females. Despite the lack of a global mechanism

J E Mank; H Ellegren

2009-01-01

211

The Amylase Gene Cluster on the Evolving Sex Chromosomes of Drosophila miranda  

Microsoft Academic Search

On the basis of chromosomal homology, the Amylase gene cluster in Drosophila miranda must be located on the secondary sex chromosome pair, neo-X (X2) and neo-Y, but is autosomally inherited in all other Drosophila species. Genetic evidence indicates no active amylase on the neo-Y chromosome and the X2- chromosomal locus already shows dosage compensation. Several lines of evidence strongly suggest

Sigrid Steinemann; Manfred Steinemann

212

Pachytene asynapsis drives meiotic sex chromosome inactivation and leads to substantial postmeiotic repression in spermatids.  

PubMed

Transcriptional silencing of the sex chromosomes during male meiosis (MSCI) is conserved among organisms with limited sex chromosome synapsis, including mammals. Since the 1990s the prevailing view has been that MSCI in mammals is transient, with sex chromosome reactivation occurring as cells exit meiosis. Recently, we found that any chromosome region unsynapsed during pachytene of male and female mouse meiosis is subject to transcriptional silencing (MSUC), and we hypothesized that MSCI is an inevitable consequence of this more general meiotic silencing mechanism. Here, we provide direct evidence that asynapsis does indeed drive MSCI. We also show that a substantial degree of transcriptional repression of the sex chromosomes is retained postmeiotically, and we provide evidence that this postmeiotic repression is a downstream consequence of MSCI/MSUC. While this postmeiotic repression occurs after the loss of MSUC-related proteins at the end of prophase, other histone modifications associated with transcriptional repression have by then become established. PMID:16580996

Turner, James M A; Mahadevaiah, Shantha K; Ellis, Peter J I; Mitchell, Michael J; Burgoyne, Paul S

2006-04-01

213

Chromosomal Abnormalities in Dupuytren’s Contracture and Carpal Tunnel Syndrome  

Microsoft Academic Search

The cytogenetics of cell cultures derived from Dupuytren’s tissue, adjacent palmar fascia and palmar skin from patients undergoing fasciectomy have been examined and the results compared to cell cultures established from palmar fascia, flexor retinaculum and palmar skin of patients undergoing carpal tunnel decompression. Chromosomal abnormalities were detected in cell cultures from Dupuytren’s tissue in eight of the nine patients

A. V. BONNICI; F. BIRJANDI; J. D. SPENCER; S. P. FOX; A. C. BERRY

1992-01-01

214

Overview of Epidemiology, Genetics, Birth Defects, and Chromosome Abnormalities Associated With CDH  

PubMed Central

Congenital diaphragmatic hernia (CDH) is a common and well-studied birth defect. The etiology of most cases remains unknown but increasing evidence points to genetic causation. The data supporting genetic etiologies which are detailed below include the association of CDH with recurring chromosome abnormalities, the existence of CDH-multiplex families, and the co-occurrence of CDH with additional congenital malformations.

Pober, Barbara R.

2010-01-01

215

The psychological impact of cryptic chromosomal abnormalities diagnosis announcement.  

PubMed

This qualitative study aims to describe the psychological impact of the diagnosis announcement of pathogenic Copy Number Variations (pCNVs). We performed semi-structured interviews of 60 parents of 41 affected children and 5 geneticists who announced the diagnoses. The diagnosis of the best characterized microdeletion syndromes, often defined by patronymic names (e.g. Williams syndrome), is generally made on a clinical basis by geneticists and confirmed by fluorescence in situ hybridization analysis. Chromosomal microarray, on the contrary, can allow the disclosure of rare pCNVs named after cytogenetic formulas, with poorly known clinical consequences: this makes doctors feel less confident with these diagnosis announcements. The disclosure of pCNVs named after cytogenetic formulas does not facilitate the parental mental representation of the disease, leading some parents to call into question the genotype-phenotype correlation or the very notion of a diagnosis. The announcement of inherited pCNVs can increase the feeling of parental guilt; the disclosure of de novo pCNVs can induce a feeling of "breakage" in the mental representation of the parent-child vertical transmission. In conclusion, our study shows that the disclosure of pCNVs has a significant psychological impact: a multidisciplinary approach to the diagnosis announcement, including a psychological support, should be systematically warranted. PMID:24055527

Houdayer, Françoise; Gargiulo, Marcela; Frischmann, Martine; Labalme, Audrey; Decullier, Evelyne; Cordier, Marie-Pierre; Dupuis-Girod, Sophie; Lesca, Gaetan; Till, Marianne; Sanlaville, Damien; Edery, Patrick; Rossi, Massimiliano

2013-09-17

216

The Genomic Distribution of Sex-Biased Genes in Drosophila serrata: X Chromosome Demasculinization, Feminization, and Hyperexpression in Both Sexes  

PubMed Central

The chromosomal distribution of genes with sex-biased expression is often nonrandom, and in species with XY sex chromosome systems, it is common to observe a deficit of X-linked male-biased genes and an excess of X-linked female-biased genes. One explanation for this pattern is that sex-specific selection has shaped the gene content of the X. Alternatively, the deficit of male-biased and excess of female-biased genes could be an artifact of differences between the sexes in the global expression level of their X chromosome(s), perhaps brought about by a lack of dosage compensation in males and hyperexpression in females. In the montium fruit fly, Drosophila serrata, both these explanations can account for a deficit of male-biased and excess of female-biased X-linked genes. Using genome-wide expression data from multiple male and female tissues (n = 176 hybridizations), we found that testis- and accessory gland-specific genes are underrepresented whereas female ovary-specific genes are overrepresented on the X chromosome, suggesting that X-linkage is disfavored for male function genes but favored for female function genes. However, genes with such sex-specific functions did not fully account for the deficit of male-biased and excess of female-biased X-linked genes. We did, however, observe sex differences in the global expression level of the X chromosome and autosomes. Surprisingly, and in contrast to other species where a lack of dosage compensation in males is responsible, we found that hyperexpression of X-linked genes in both sexes leads to this imbalance in D. serrata. Our results highlight how common genomic distributions of sex-biased genes, even among closely related species, may arise via quite different evolutionary processes.

Allen, Scott L.; Bonduriansky, Russell; Chenoweth, Stephen F.

2013-01-01

217

Sex chromosome-specific regulation in the Drosophila male germline but little evidence for chromosomal dosage compensation or meiotic inactivation.  

PubMed

The evolution of heteromorphic sex chromosomes (e.g., XY in males or ZW in females) has repeatedly elicited the evolution of two kinds of chromosome-specific regulation: dosage compensation--the equalization of X chromosome gene expression in males and females--and meiotic sex chromosome inactivation (MSCI)--the transcriptional silencing and heterochromatinization of the X during meiosis in the male (or Z in the female) germline. How the X chromosome is regulated in the Drosophila melanogaster male germline is unclear. Here we report three new findings concerning gene expression from the X in Drosophila testes. First, X chromosome-wide dosage compensation appears to be absent from most of the Drosophila male germline. Second, microarray analysis provides no evidence for X chromosome-specific inactivation during meiosis. Third, we confirm the previous discovery that the expression of transgene reporters driven by autosomal spermatogenesis-specific promoters is strongly reduced when inserted on the X chromosome versus the autosomes; but we show that this chromosomal difference in expression is established in premeiotic cells and persists in meiotic cells. The magnitude of the X-autosome difference in transgene expression cannot be explained by the absence of dosage compensation, suggesting that a previously unrecognized mechanism limits expression from the X during spermatogenesis in Drosophila. These findings help to resolve several previously conflicting reports and have implications for patterns of genome evolution and speciation in Drosophila. PMID:21857805

Meiklejohn, Colin D; Landeen, Emily L; Cook, Jodi M; Kingan, Sarah B; Presgraves, Daven C

2011-08-16

218

Sex Chromosome-Specific Regulation in the Drosophila Male Germline But Little Evidence for Chromosomal Dosage Compensation or Meiotic Inactivation  

PubMed Central

The evolution of heteromorphic sex chromosomes (e.g., XY in males or ZW in females) has repeatedly elicited the evolution of two kinds of chromosome-specific regulation: dosage compensation—the equalization of X chromosome gene expression in males and females— and meiotic sex chromosome inactivation (MSCI)—the transcriptional silencing and heterochromatinization of the X during meiosis in the male (or Z in the female) germline. How the X chromosome is regulated in the Drosophila melanogaster male germline is unclear. Here we report three new findings concerning gene expression from the X in Drosophila testes. First, X chromosome-wide dosage compensation appears to be absent from most of the Drosophila male germline. Second, microarray analysis provides no evidence for X chromosome-specific inactivation during meiosis. Third, we confirm the previous discovery that the expression of transgene reporters driven by autosomal spermatogenesis-specific promoters is strongly reduced when inserted on the X chromosome versus the autosomes; but we show that this chromosomal difference in expression is established in premeiotic cells and persists in meiotic cells. The magnitude of the X-autosome difference in transgene expression cannot be explained by the absence of dosage compensation, suggesting that a previously unrecognized mechanism limits expression from the X during spermatogenesis in Drosophila. These findings help to resolve several previously conflicting reports and have implications for patterns of genome evolution and speciation in Drosophila.

Meiklejohn, Colin D.; Landeen, Emily L.; Cook, Jodi M.; Kingan, Sarah B.; Presgraves, Daven C.

2011-01-01

219

Dysplastic cells in cytological cervical samples show a high incidence of chromosomal abnormalities.  

PubMed

Chromosomal abnormalities are frequent in most cervical cancers. Amplifications of both the 3q26 (TERC) and 8q24 (MYC) loci have been shown to be prevalent in both high-grade lesions and invasive cervical carcinoma. Most of these studies have looked at either the histological sample or at the entire cytological population of cells. We have developed a Papanicolaou (Pap) destaining method that allows for the accurate analysis of individual cells that were previously identified by cytopathology as dysplastic. The application of fluorescence in situ hybridization (FISH) was then implemented to determine the chromosomal status of the dysplastic cells in the samples and correlate the two events. Chromosomal abnormality is over a thousand times more frequent in dysplastic cells compared with their morphologically normal counterparts. PMID:19626623

Song, Minghao; Ruth, Adam; Policht, Frank A; Bubendorf, Lukas; Feichter, Georg; Kipp, Benjamin R; Halling, Kevin C; Sokolova, Irina A

2010-01-01

220

[Correlations between karyotype and phenotype in structural and numerical abnormalities of chromosome 18].  

PubMed

Five cases with different abnormalities of chromosome 18 are described: one case with trisomy 18, two cases with ring 18, one case with partial trisomy 18q and one case with a mosaic 18p-/iso 18q. The karyotypes of the parents were normal. Cytogenetic analysis was performed on PHA stimulated blood lymphocytes. GTG, QFQ, MTX banding techniques were used. Karyotype-phenotype correlations are made. All patients present mental retardation, hypotonia and facial dismorphisms. The different degree of mental retardation and the clinical signs are in relation to the different size of deletions or trisomies of the short or long arm of chromosome 18. In the case with mosaicism 18p-/iso18q the phenotype is determined from the chromosomal abnormality more frequent in the cells (18p-). PMID:1463601

Vivarelli, R; Paolieri, M; Anichini, C; Scarinci, R; Berardi, R; Rosaia, L; Pucci, L

1992-04-01

221

Massively parallel sequencing for chromosomal abnormality testing in trophectoderm cells of human blastocysts.  

PubMed

Preimplantation genetic diagnosis and screening are widely accepted for chromosomal abnormality identification to avoid transferring embryos with genetic defects. Massively parallel sequencing (MPS) is a rapidly developing approach for genome analysis with increasing application in clinical practice. The purpose of this study was to use MPS for identification of aneuploidies and unbalanced chromosomal rearrangements after blastocyst biopsy. Trophectoderm (TE) samples of 38 blastocysts from 16 in vitro fertilization cycles were subjected to analysis. Low-coverage whole genome sequencing was performed using the Illumina HiSeq2000 platform with a novel algorithm purposely created for chromosomal analysis. The efficiency of this MPS approach was estimated by comparing results obtained by an Affymetrix single-nucleotide polymorphism (SNP) array. Whole genome amplification (WGA) products of TE cells were detected by MPS, with an average of 0.07× depth and 5.5% coverage of the human genome. Twenty-six embryos (68.4%) were detected as euploid, while six embryos (15.8%) contained uniform aneuploidies. Four of these (10.5%) were with solely unbalanced chromosomal rearrangements, whereas the remaining two embryos (5.3%) showed both aneuploidies and unbalanced rearrangements. Almost all these results were confirmed by the SNP array, with the exception of one sample, where different sizes of unbalanced rearrangements were detected, possibly due to chromosomal GC bias in array analysis. Our study demonstrated MPS could be applied to accurately detect embryonic chromosomal abnormality with a flexible and cost-effective strategy and higher potential accuracy. PMID:23349234

Yin, XuYang; Tan, Ke; Vajta, Gábor; Jiang, Hui; Tan, YueQiu; Zhang, ChunLei; Chen, Fang; Chen, ShengPei; Zhang, ChunSheng; Pan, XiaoYu; Gong, Chun; Li, XuChao; Lin, ChuYu; Gao, Ya; Liang, Yu; Yi, Xin; Mu, Feng; Zhao, LiJian; Peng, HuanHuan; Xiong, Bo; Zhang, ShuoPing; Cheng, DeHua; Lu, GuangXiu; Zhang, XiuQing; Lin, Ge; Wang, Wei

2013-03-21

222

Somatic Chromosome Abnormalities in the Lungs of Patients with Pulmonary Arterial Hypertension  

PubMed Central

Rationale: Vascular remodeling in pulmonary arterial hypertension (PAH) involves proliferation and migration of endothelial and smooth muscle cells, leading to obliterative vascular lesions. Previous studies have indicated that the endothelial cell proliferation is quasineoplastic, with evidence of monoclonality and instability of short DNA microsatellite sequences. Objectives: To assess whether there is larger-scale genomic instability. Methods: We performed genome-wide microarray copy number analysis on pulmonary artery endothelial cells and smooth muscle cells isolated from the lungs of patients with PAH. Measurements and Main Results: Mosaic chromosomal abnormalities were detected in PAEC cultures from five of nine PAH lungs but not in normal (n = 8) or disease control subjects (n = 5). Fluorescent in situ hybridization analysis confirmed the presence of these abnormalities in vivo in two of three cases. One patient harbored a germline mutation of BMPR2, the primary genetic cause of PAH, and somatic loss of chromosome-13, which constitutes a second hit in the same pathway by deleting Smad-8. In two female subjects with mosaic loss of the X chromosome, methylation analysis showed that the active X was deleted. One subject also showed completely skewed X-inactivation in the nondeleted cells, suggesting the pulmonary artery endothelial cell population was clonal before the acquisition of the chromosome abnormality. Conclusions: Our data indicate a high frequency of genetically abnormal subclones within PAH lung vessels and provide the first definitive evidence of a second genetic hit in a patient with a germline BMPR2 mutation. We propose that these chromosome abnormalities may confer a growth advantage and thus contribute to the progression of PAH.

Aldred, Micheala A.; Comhair, Suzy A.; Varella-Garcia, Marileila; Asosingh, Kewal; Xu, Weiling; Noon, George P.; Thistlethwaite, Patricia A.; Tuder, Rubin M.; Erzurum, Serpil C.; Geraci, Mark W.; Coldren, Christopher D.

2010-01-01

223

Caenorhabditis elegans histone methyltransferase MET-2 shields the male X chromosome from checkpoint machinery and mediates meiotic sex chromosome inactivation.  

PubMed

Meiosis is a specialized form of cellular division that results in the precise halving of the genome to produce gametes for sexual reproduction. Checkpoints function during meiosis to detect errors and subsequently to activate a signaling cascade that prevents the formation of aneuploid gametes. Indeed, asynapsis of a homologous chromosome pair elicits a checkpoint response that can in turn trigger germline apoptosis. In a heterogametic germ line, however, sex chromosomes proceed through meiosis with unsynapsed regions and are not recognized by checkpoint machinery. We conducted a directed RNAi screen in Caenorhabditis elegans to identify regulatory factors that prevent recognition of heteromorphic sex chromosomes as unpaired and uncovered a role for the SET domain histone H3 lysine 9 histone methyltransferase (HMTase) MET-2 and two additional HMTases in shielding the male X from checkpoint machinery. We found that MET-2 also mediates the transcriptional silencing program of meiotic sex chromosome inactivation (MSCI) but not meiotic silencing of unsynapsed chromatin (MSUC), suggesting that these processes are distinct. Further, MSCI and checkpoint shielding can be uncoupled, as double-strand breaks targeted to an unpaired, transcriptionally silenced extra-chromosomal array induce checkpoint activation in germ lines depleted for met-2. In summary, our data uncover a mechanism by which repressive chromatin architecture enables checkpoint proteins to distinguish between the partnerless male X chromosome and asynapsed chromosomes thereby shielding the lone X from inappropriate activation of an apoptotic program. PMID:21909284

Checchi, Paula M; Engebrecht, JoAnne

2011-09-01

224

Limb malformations and abnormal sex hormone concentrations in frogs.  

PubMed Central

Declines in amphibian populations, and amphibians with gross malformations, have prompted concern regarding the biological status of many anuran species. A survey of bullfrogs, Rana catesbeiana, and green frogs, Rana clamitans, conducted in central and southern New Hampshire showed malformed frogs at 81% of the sites sampled (13 of 16 sites). Brain gonadotropin-releasing hormone (GnRH) and the synthesis of androgens and estradiol, hormones essential to reproductive processes, were measured from limb-malformed and normal (no limb malformation) frogs. Normal frogs had significantly higher concentrations (nearly 3-fold) of in vitro produced androgens and of brain GnRH than malformed frogs. Because most malformations are thought to occur during development, we propose that environmental factors or endocrine-disrupting chemicals that may cause developmental abnormalities also act during early development to ultimately cause abnormally reduced GnRH and androgen production in adult frogs. The consequences of reduced GnRH and androgens on anuran reproductive behavior and population dynamics are unknown but certainly may be profound and warrant further research.

Sower, S A; Reed, K L; Babbitt, K J

2000-01-01

225

The behaviour and structure of the sex chromosomes in spermatocytes of Microtus oeconomus  

Microsoft Academic Search

The meiotic behaviour and structure of the sex chromosomes of Microtus oeconomus (2n=30) in Giemsa stained preparations are described. The X-Y pair appears as a sex vesicle at late zygotene. At late pachytene an unfolded sex vesicle is visible. A condensed sex vesicle appears during pre-diffuse diplotene and starts to unfold again during post-diffuse diplotene. At diakinesis and metaphase I

A. J. J. Dietrich; R. J. P. Mulder; A. D. Tates

1983-01-01

226

Reliability of comparative genomic hybridization to detect chromosome abnormalities in first polar bodies and metaphase II oocytes  

Microsoft Academic Search

BACKGROUND: Preimplantation Genetic Diagnosis (PGD) using FISH to analyze up to nine chromosomes to dis- card chromosomally abnormal embryos has resulted in an increase of pregnancy rates in certain groups of patients. However, the number of chromosomes that can be analyzed is a clear limitation. We evaluate the reliability of using comparative genomic hybridization (CGH) to detect the whole set

Cristina Gutierrez-Mateo; Dagan Wells; Jordi Benet; Jorge F. Sanchez-Garcia; Mercedes G. Bermudez; Itziar Belil; Josep Egozcue; Santiago Munne

2004-01-01

227

Effects of Sex Chromosome Aneuploidies on Brain Development: Evidence From Neuroimaging Studies  

PubMed Central

Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the effects of different dosages of sex chromosome genes on brain development may help to understand the basis for functional differences in affected individuals. It may also be informative regarding how sex chromosomes contribute to typical sexual differentiation. Studies of 47,XXY males make up the bulk of the current literature of neuroimaging studies in individuals with supernumerary sex chromosomes, with a few small studies or case reports of the other SCAs. Findings in 47,XXY males typically include decreased gray and white matter volumes, with most pronounced effects in the frontal and temporal lobes. Functional studies have shown evidence of decreased lateralization. Although the hypogonadism typically found in 47,XXY males may contribute to the decreased brain volume, the observation that 47,XXX females also show decreased brain volume in the presence of normal pubertal maturation suggests a possible direct dosage effect of X chromosome genes. Additional X chromosomes, such as in 49,XXXXY males, are associated with more markedly decreased brain volume and increased incidence of white matter hyperintensities. The limited data regarding effects of having two Y chromosomes (47,XYY) do not find significant differences in brain volume, although there are some reports of increased head size.

Lenroot, Rhoshel K.; Lee, Nancy Raitano; Giedd, Jay N.

2010-01-01

228

Contrasting patterns of X/Y polymorphism distinguish Carica papaya from other sex chromosome systems.  

PubMed

The sex chromosomes of the tropical crop papaya (Carica papaya) are evolutionarily young and consequently allow for the examination of evolutionary mechanisms that drive early sex chromosome divergence. We conducted a molecular population genetic analysis of four X/Y gene pairs from a collection of 45 wild papaya accessions. These population genetic analyses reveal striking differences in the patterns of polymorphism between the X and Y chromosomes that distinguish them from other sex chromosome systems. In most sex chromosome systems, the Y chromosome displays significantly reduced polymorphism levels, whereas the X chromosome maintains a level of polymorphism that is comparable to autosomal loci. However, the four papaya sex-linked loci that we examined display diversity patterns that are opposite this trend: the papaya X alleles exhibit significantly reduced polymorphism levels, whereas the papaya Y alleles maintain greater than expected levels of diversity. Our analyses suggest that selective sweeps in the regions of the X have contributed to this pattern while also revealing geographically restricted haplogroups on the Y. We discuss the possible role sexual selection and/or genomic conflict have played in shaping the contrasting patterns of polymorphism found for the papaya X and Y chromosomes. PMID:22855536

Weingartner, Laura A; Moore, Richard C

2012-08-01

229

Analysis of non-clonal chromosome abnormalities observed in hematologic malignancies among Southwest Oncology Group patients  

SciTech Connect

From 1987-1994, the Southwest Oncology Group Cytogenetics Committee reviewed 1571 studies in 590 adult patient cases with ALL, AML, CML or CLL. These were analyzed for the presence of clinically important non-clonal abnormalities (NCA). Abnormalities were defined as non-clonal if one metaphase had a structural abnormality or an extra chromosome. Chromosome loss was not analyzed due to the possibility of random loss. In 72 cases (12%) comprising 136 studies, at least one NCA was observed. In 21 of these cases (29%), NCAs consisted of obvious clonal evolution or instability, and thus were not included in the analysis. At least one structural NCA was observed in which the abnormality differed from the mainline in 36 (50%) patients. Seventeen of the 36 cases had a normal mode. Nineteen of the 36 patients had an abnormal or normal/abnormal mode. At least one numerical NCA was found in 15 cases (21%). Fifteen cases (21%) contained at least one marker chromosome. Several cases involved NCA in more than one of the above divisions. NCAs could be classified into several categories: (1){open_quotes}the clone to come{close_quotes}, (2) evolving clones which then disappeared, (3) NCAs with putative clinical importance that never became clonal, (4) NCAs during remission identical to the preceding clonal abnormality, (5) NCAs which indicated clonal evolution or instability. Examples include one metaphase with t(9;22) or del(20q) or inv(16) or +8 which either preceded or followed clonal findings of the same aberration. Such findings should be communicated to the clinician.

McConnell, T.S. [Univ. of New Mexico, Albuquerque, NM (United States); Dobin, S.M. [Oregon Health Sciences Univ., Portland, OR (United States)

1994-09-01

230

DNA methylation of sex chromosomes in a dioecious plant, Melandrium album.  

PubMed

Melandrium album, a dioecious plant species, has two heteromorphic sex chromosomes with the XY constitution typical for male and the XX for female plants. This plant represents an experimental model system of sex determination in which the Y chromosome plays a strongly dominant male role. We present data on the overall transcriptional activities of M. album sex chromosomes. DNA methylation patterns were analysed directly at the level of chromosomes using in situ nick-translation of fixed root mitotic chromosomes after nuclease digestion and in vivo labelling with S-adenosyl-L-[methyl-3H] methionine as donor of methyl groups. Both techniques revealed that the two X chromosomes of female plants had different levels of DNA methylation. Cell treatment with a DNA hypomethylating drug, 5-azacytidine, significantly influenced the labelling densities. These results imply that in female M. album plants, one of the two X chromosomes may be hypermethylated and inactive as described for mammalian cells (Lyon hypothesis). A similar analysis made on male cells displayed a similar relative levels of methylation in autosomes and sex chromosomes, thus indicating the transcriptional activity of both Y and X male chromosomes. PMID:8510648

Vyskot, B; Araya, A; Veuskens, J; Negrutiu, I; Mouras, A

1993-05-01

231

Uniparental isodisomy of chromosome 14 in two cases: An abnormal child and a normal adult  

SciTech Connect

Uniparental disomy (UPD) of a number of different chromosomes has been found in association with abnormal phenotypes. A growing body of evidence for an imprinting effect involving chromosome 14 has been accumulating. We report on a case of paternal UPD of chromosome 14 studied in late gestation due to polyhydramnios and a ventral wall hernia. A prenatal karyotype documented a balanced Robertsonian 14:14 translocation. The baby was born prematurely with hairy forehead, retrognathia, mild puckering of the lips and finger contractures. Hypotonia has persisted since birth and at age one year, a tracheostomy for laryngomalacia and gastrostomy for feeding remain necessary. Absence of maternal VNTR polymorphisms and homozygosity of paternal polymorphisms using chromosome 14 specific probes at D14S22 and D14S13 loci indicated paternal uniparental isodisomy (pUPID). Parental chromosomes were normal. We also report on a case of maternal LTPD in a normal patient with a balanced Robertsonian 14:14 translocation and a history of multiple miscarriages. Five previous reports of chromosome 14 UPD suggest that an adverse developmental effect may be more severe whenever the UPD is paternal in origin. This is the second reported patient with paternal UPD and the fifth reported with maternal UPD, and only few phenotypic similarities are apparent. Examination of these chromosome 14 UPD cases of maternal and paternal origin suggests that there are syndromic imprinting effects. 30 refs., 3 figs.

Papenhausen, P.R.; Mueller, O.T.; Sutcliffe, M.; Diamond, T.M.; Kousseff, B.G. [Univ. of South Florida College of Medicine, Tampa, FL (United States); Johnson, V.P. [Univ. of South Dakota, Sioux Falls, SD (United States)

1995-11-20

232

Clinical and molecular cytogenetic studies in ring chromosome 5: report of a child with congenital abnormalities.  

PubMed

We report here a child with a ring chromosome 5 (r(5)) associated with facial dysmorphology and multiple congenital abnormalities. Fluorescent in situ hybridization (FISH) using bacterial artificial chromosome (BAC) clones was performed to determine the breakpoints involved in the r(5). The 5p deletion extended from 5p13.2-3 to 5pter and measured 34.61 Mb (range: 33.7-35.52 Mb) while the 5q deletion extended from 5q35.3 to 5qter and measured 2.44 Mb (range: 2.31-2.57 Mb). The patient presented signs such as microcephaly, hypertelorism, micrognathia and epicanthal folds, partially recalling those of a deletion of the short arm of chromosome 5 and the "cri-du-chat" syndrome. The most striking phenotypic features were the congenital heart abnormalities which have been frequently reported in deletions of the distal part of the long arm of chromosome 5 and in rings leading to a 5q35-5qter deletion. However, the NKX2-5 gene, which has been related to congenital heart defects, was not deleted in our patient, nor presumably to some other patients with 5q35.3-5qter deletion. We propose that VEGFR3, deleted in our patient, could be a candidate gene for the congenital heart abnormalities observed. PMID:22193390

Basinko, Audrey; Giovannucci Uzielli, Maria Luisa; Scarselli, Gloria; Priolo, Manuela; Timpani, Giuseppina; De Braekeleer, Marc

2011-12-02

233

[Heterogeneity of chromosomal abnormalities in acute myeloid leukemia in different age groups children].  

PubMed

Characteristic of chromosomal abnormalities in bone marrow cells among 123 children with acute myeloid leukemia were presented according five aging groups: I - up to 2 years, II - 2-5 years, III - 5-10 years, IV - 10-15 years, V - 15-18 years. Normal karyotype wasn't found in group up to 2 years and in low presented in another groups (5, 9-10,3%). The highest frequency of chromosomal abnormality evolution in group up to 2 years was established (69,2%). The highest frequency of hyperdiploidy (47-50 chromosomes) in group 15-18 years (31%) was found. More often near-tetraploidy and pseudodiploidy clones were met in group 2-5 years (47% and 58,8%, respectively). Between structural types in all groups were predominated translocations and deletions. In group up to 2 years was prevalented translocations (61,5%), 2-18 years - deletions (64,7; 34,5; 45,7 and 41,4 % respectively). In group up to 2 years more often were met abnormalities chromosomes (Chr) 9, 11, 16 (in 30,8%), 2-5 years - Chr 16, 21 (in 29,4%), 5-10 years - Chr 11 (24,1%), 8, 15, 17 (in 17,2%), 10-15 years - Chr 16 (40%) and 15-18 years - Chr 8, 9, 15, 17 (in 17,2%). PMID:23534279

Andreieva, S V; Drozdova, V D; Kavardakova, N V

234

How did the platypus get its sex chromosome chain? A comparison of meiotic multiples and sex chromosomes in plants and animals  

Microsoft Academic Search

The duck-billed platypus is an extraordinary mammal. Its chromosome complement is no less extraordinary, for it includes a\\u000a system in which ten sex chromosomes form an extensive meiotic chain in males. Such meiotic multiples are unprecedented in\\u000a vertebrates but occur sporadically in plant and invertebrate species. In this paper, we review the evolution and formation\\u000a of meiotic multiples in plants

Frank Gruetzner; Terry Ashley; David M. Rowell; Jennifer A. Marshall Graves

2006-01-01

235

Additional chromosome abnormalities in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy  

PubMed Central

Background Acute promyelocytic leukemia is a subtype of acute myeloid leukemia characterized by the t(15;17). The incidence and prognostic significance of additional chromosomal abnormalities in acute promyelocytic leukemia is still a controversial matter. Design and Methods Based on cytogenetic data available for 495 patients with acute promyelocytic leukemia enrolled in two consecutive PETHEMA trials (LPA96 and LPA99), we analyzed the incidence, characteristics, and outcome of patients with acute promyelocytic leukemia with and without additional chromosomal abnormalities who had been treated with all-trans retinoic acid plus anthracycline monochemotherapy for induction and consolidation. Results Additional chromosomal abnormalities were observed in 140 patients (28%). Trisomy 8 was the most frequent abnormality (36%), followed by abn(7q) (5%). Patients with additional chromosomal abnormalities more frequently had coagulopathy (P=0.03), lower platelet counts (P=0.02), and higher relapse-risk scores (P=0.02) than their counterparts without additional abnormalities. No significant association with FLT3/ITD or other clinicopathological characteristics was demonstrated. Patients with and without additional chromosomal abnormalities had similar complete remission rates (90% and 91%, respectively). Univariate analysis showed that additional chromosomal abnormalities were associated with a lower relapse-free survival in the LPA99 trial (P=0.04), but not in the LPA96 trial. However, neither additional chromosomal abnormalities overall nor any specific abnormality was identified as an independent risk factor for relapse in multivariate analysis. Conclusions The lack of independent prognostic value of additional chromosomal abnormalities in acute promyelocytic leukemia does not support the use of alternative therapeutic strategies when such abnormalities are found.

Cervera, Jose; Montesinos, Pau; Hernandez-Rivas, Jesus M.; Calasanz, Maria J.; Aventin, Anna; Ferro, Maria T.; Luno, Elisa; Sanchez, Javier; Vellenga, Edo; Rayon, Chelo; Milone, Gustavo; de la Serna, Javier; Rivas, Concha; Gonzalez, Jose D.; Tormo, Mar; Amutio, Elena; Gonzalez, Marcos; Brunet, Salut; Lowenberg, Bob; Sanz, Miguel A.

2010-01-01

236

X and Y chromosome behavior in brain tumors: Pieces in a puzzle  

Microsoft Academic Search

Sex chromosome behavior in selected somatic cells is baffling. We serendipitously encountered this sex chromosome shuffle while studying malignant gliomas. Tumor specimens from 3\\/10 (30%) females and 15\\/27 (56%) males had sex chromosome abnormalities. Specimens from females showed X loss in 2 cases and possible X gain in 1 case. In 2 cases with autosomal abnormalities, only XX cells were

B. K. Hecht; M Chatel; J. Gioanni

1994-01-01

237

Detection of chromosomal abnormalities in uterine leiomyoma using conventional cytogenetic method and interphase fluorescence in situ hybridization.  

PubMed

Seventy-nine uterine leiomyomas were examined using a conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Nine (17.6%) of 51 tumor samples examined showed chromosomal abnormalities by conventional cytogenetic analysis. Rearrangements of chromosome 12 were detected in two tumors. Other tumors showed abnormalities affecting chromosomes 1, 4, 6, 7, 10, 13, 14, and 22. For FISH, the whole-chromosome painting probe and the D12Z3 probe specific for the centromeric region were used to detect structural and numerical abnormalities of chromosome 12. Of forty-one tumor samples, six showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the tumors with structural aberrations identified by FISH, two had normal karyotypes, two showed structural rearrangements of chromosome 12 cytogenetically, and two could not be analyzed because of an insufficient number of metaphases. There were no correlations between the cytogenetic data and clinical parameters. The results indicate that chromosomal abnormalities are important in the biology of at least some types of uterine leiomyomas, and that FISH is a useful complement to conventional cytogenetic analysis in the study of solid tumors. PMID:8697434

Hayashi, S; Miharu, N; Okamoto, E; Samura, O; Hara, T; Ohama, K

1996-07-15

238

Lack of global meiotic sex chromosome inactivation, and paucity of tissue-specific gene expression on the Drosophila X chromosome  

Microsoft Academic Search

Background  Paucity of male-biased genes on the Drosophila X chromosome is a well-established phenomenon, thought to be specifically linked to the role of these genes in reproduction\\u000a and\\/or their expression in the meiotic male germline. In particular, meiotic sex chromosome inactivation (MSCI) has been widely\\u000a considered a driving force behind depletion of spermatocyte-biased X-linked genes in Drosophila by analogy with mammals,

Lyudmila M Mikhaylova; Dmitry I Nurminsky

2011-01-01

239

[Analysis of sex chromosome homologies in representatives of the family Calliphoridae].  

PubMed

The distribution of sequences homologous to the Calliphora erythrocephala Mg. sex chromosome was studied in Protophormia terranovae R-D and Lucilia sp. The chromatin structure was found to be similar in regions containing homologous DNA sequences. PMID:21254545

Vedernikov, A E; Anan'ina, T V; Kokhanenko, A A; Stegni?, V N

2010-10-01

240

Persistent Mosaicism for 12p Duplication/Triplication Chromosome Structural Abnormality in Peripheral Blood  

PubMed Central

We present a rare case of mosaicism for a structural abnormality of chromosome 12 in a patient with phenotypic features of Pallister-Killian syndrome. A six-month-old child with dysmorphic features, exotropia, hypotonia, and developmental delay was mosaic for both a normal karyotype and a cell line with 12p duplication/triplication in 25 percent of metaphase cells. Utilization of fluorescence in situ hybridization (FISH) identified three copies of probes from the end of the short arm of chromosome 12 (TEL(12p13) locus and the subtelomere (12p terminal)) on the structurally abnormal chromosome 12. Genome-wide SNP array analysis revealed that the regions of duplication and triplication were of maternal origin. The abnormal cell line in our patient was present at 25 percent at six months and 19 months of age in both metaphase and interphase cells from peripheral blood, where typically the isochromosome 12p is absent in the newborn. This may suggest that the gene(s) resulting in a growth disadvantage of abnormal cells in peripheral blood of patients with tetrasomy 12p may not have the same influence when present in only three copies.

Shackelford, Amy L.; Conlin, Laura K.; Spinner, Nancy B.; Wenger, Sharon L.

2013-01-01

241

Parental origin and mechanism of formation of X chromosome structural abnormalities: four cases determined with RFLPs.  

PubMed

Parental origin and mechanism of formation of X chromosome structural abnormalities were studied in one each case of dup(X)(pter----p11.4::p22.1----qter), del(X)(qter----p11:), i(X)(qter----cen----qter), and inv dup(X) (pter----q22::q22----pter) using various X-linked RFLPs as genetic markers. Segregation and densitometric analyses on polymorphic DNAs revealed that the dup(Xp) and the del(Xp) are both of paternal origin and the i(Xq) and i dic(X) are of maternal origin. The dup(Xp) had arisen by an unequal sister chromatid exchange and the del(Xp) had occurred through an intrachromosomal breakage-reunion mechanism, both in the paternal X chromosome. The i(Xq) had arisen either through centromere fission of a maternal X chromosome, followed by duplication of its long-arm, or through a translocation between two maternal X chromosomes after meiotic crossing-over. The inv dup(X) arose through sister chromatid breakage and reunion in a maternal X chromosome. These results, together with those of previous studies, suggest that the de novo abnormalities due to events involving centromere disruption arise predominantly during oogenesis, while those due to simple breakage-reunion events occur preferentially during spermatogenesis. PMID:1979996

Deng, H X; Xia, J H; Ishikawa, M; Niikawa, N

1990-09-01

242

Robertsonian translocation in a sex reversal dog (XX, SRY negative) may indicate that the causative mutation for this intersexuality syndrome resides on canine chromosome 23 (CFA23).  

PubMed

A Bernese mountain dog was subjected for clinical evaluation due to the presence of ambiguous external genitalia (enlarged clitoris). Anatomical and histological studies revealed the presence of one testicle, one ovotestis and a uterus. This dog was classified as a female-to-male sex reversal, with 2 normal X chromosomes and a lack of the Y chromosome-linked genes SRY and ZFY. It is the first case of this syndrome in this breed. Apparently a Robertsonian translocation, rob(5;23), was also identified in this dog and it is again the first case of this type of chromosome abnormality in this breed, as well as the first case of co-occurrence of the sex reversal syndrome along with a centric fusion in the dog. Since on the canine chromosome 23 (CFA23) 3 genes (FOXL2,PISRT1 and CTNNB1) involved in the sex determination process are present, further cytogenetic FISH studies were carried out with the use of BAC probes specific for this chromosome. It was found that a pericentromeric fragment of CFA23 was deleted as a result of the centric fusion. We hypothesize that a cis regulatory sequence for the sex determination genes on CFA23 (e.g. proximally located CTNNB1) is present in the deleted fragment. Thus, a causative mutation responsible for this sex reversal syndrome may reside on CFA23. PMID:21430365

Switonski, M; Szczerbal, I; Nizanski, W; Kociucka, B; Bartz, M; Dzimira, S; Mikolajewska, N

2011-03-23

243

Chromosomal Disorders and Autism.  

ERIC Educational Resources Information Center

|This paper reviews the literature on chromosomal aberrations in autism, especially possible gene markers. It notes that Chromosome 15 and numerical and structural abnormalities of the sex chromosomes have been most frequently reported as related to the genesis of autism. (Author/DB)|

Gillberg, Christopher

1998-01-01

244

Volumetric magnetic resonance imaging study of the brain in subjects with sex chromosome aneuploidies  

Microsoft Academic Search

OBJECTIVESCognitive impairment has been reported in people with sex chromosome aneuploides (SCAs) and it has been proposed that the presence of an extra sex chromosome may have an adverse effect on neurodevelopment. This study examines the hypothesis with structural MRI of the brain.METHODSThirty two subjects with SCA (XXX (n=12), XYY (n=10), and XXY (n=10)) from a birth cohort study were

Michael M Warwick; Gillian A Doody; Stephen M Lawrie; Julia N Kestelman; Jonathan J K Best; Eve C Johnstone

1999-01-01

245

The role of repetitive DNA in structure and evolution of sex chromosomes in plants.  

PubMed

Eukaryotic genomes contain a large proportion of repetitive DNA sequences, mostly transposable elements (TEs) and tandem repeats. These repetitive sequences often colonize specific chromosomal (Y or W chromosomes, B chromosomes) or subchromosomal (telomeres, centromeres) niches. Sex chromosomes, especially non-recombining regions of the Y chromosome, are subject to different evolutionary forces compared with autosomes. In non-recombining regions of the Y chromosome repetitive DNA sequences are accumulated, representing a dominant and early process forming the Y chromosome, probably before genes start to degenerate. Here we review the occurrence and role of repetitive DNA in Y chromosome evolution in various species with a focus on dioecious plants. We also discuss the potential link between recombination and transposition in shaping genomes. PMID:19277056

Kejnovsky, E; Hobza, R; Cermak, T; Kubat, Z; Vyskot, B

2009-03-11

246

Independent Origin of Sex Chromosomes in Two Species of the Genus Silene  

PubMed Central

Here we introduce a new model species, Silene colpophylla, that could facilitate research of sex chromosome evolution and sex-determining systems. This species is related to the well-established dioecious plant model Silene latifolia. Our results show that S. colpophylla is, similarly to S. latifolia, a male heterogametic species, but its sex chromosomes have evolved from a different pair of autosomes than in S. latifolia. The results of our phylogenetic study and mapping of homologs of S. latifolia X-linked genes indicate that the sex determination system in S. colpophylla evolved independently from that in S. latifolia. We assert that this model species pair will make it possible to study two independent patterns of sex chromosome evolution in related species.

Mrackova, Martina; Nicolas, Michael; Hobza, Roman; Negrutiu, Ioan; Moneger, Francoise; Widmer, Alexander; Vyskot, Boris; Janousek, Bohuslav

2008-01-01

247

Independent origin of sex chromosomes in two species of the genus Silene.  

PubMed

Here we introduce a new model species, Silene colpophylla, that could facilitate research of sex chromosome evolution and sex-determining systems. This species is related to the well-established dioecious plant model Silene latifolia. Our results show that S. colpophylla is, similarly to S. latifolia, a male heterogametic species, but its sex chromosomes have evolved from a different pair of autosomes than in S. latifolia. The results of our phylogenetic study and mapping of homologs of S. latifolia X-linked genes indicate that the sex determination system in S. colpophylla evolved independently from that in S. latifolia. We assert that this model species pair will make it possible to study two independent patterns of sex chromosome evolution in related species. PMID:18558658

Mrackova, Martina; Nicolas, Michael; Hobza, Roman; Negrutiu, Ioan; Monéger, Françoise; Widmer, Alexander; Vyskot, Boris; Janousek, Bohuslav

2008-06-01

248

Small but mighty: the evolutionary dynamics of W and Y sex chromosomes  

PubMed Central

Although sex chromosomes have been the focus of a great deal of scientific scrutiny, most interest has centred on understanding the evolution and relative importance of X and Z chromosomes. By contrast, the sex-limited W and Y chromosomes have received far less attention, both because of their generally degenerate nature and the difficulty in studying non-recombining and often highly heterochromatic genomic regions. However, recent theory and empirical evidence suggest that the W and Y chromosomes play a far more important role in sex-specific fitness traits than would be expected based on their size alone, and this importance may explain the persistence of some Y and W chromosomes in the face of powerful degradative forces. In addition to their role in fertility and fecundity, the sex-limited nature of these genomic regions results in unique evolutionary forces acting on Y and W chromosomes, implicating them as potentially major contributors to sexual selection and speciation. Recent empirical studies have borne out these predictions and revealed that some W and Y chromosomes play a vital role in key sex-specific evolutionary processes.

2012-01-01

249

Comparative genetic mapping points to different sex chromosomes in sibling species of wild strawberry (Fragaria).  

PubMed

Separate sexes have evolved repeatedly from hermaphroditic ancestors in flowering plants, and thus select taxa can provide unparalleled insight into the evolutionary dynamics of sex chromosomes that are thought to be shared by plants and animals alike. Here we ask whether two octoploid sibling species of wild strawberry--one almost exclusively dioecious (males and females), Fragaria chiloensis, and one subdioecious (males, females, and hermaphrodites), F. virginiana--share the same sex-determining chromosome. We created a genetic map of the sex chromosome and its homeologs in F. chiloensis and assessed macrosynteny between it and published maps of the proto-sex chromosome of F. virginiana and the homeologous autosome of hermaphroditic diploid species. Segregation of male and female function in our F. chiloensis mapping population confirmed that linkage and dominance relations are similar to those in F. virginiana. However, identification of the molecular markers most tightly linked to the sex-determining locus in the two octoploid species shows that, in both, this region maps to homeologues of chromosome 6 in diploid congeners, but is located at opposite ends of their respective chromosomes. PMID:20923978

Goldberg, Margot T; Spigler, Rachel B; Ashman, Tia-Lynn

2010-10-05

250

Comparative Genetic Mapping Points to Different Sex Chromosomes in Sibling Species of Wild Strawberry (Fragaria)  

PubMed Central

Separate sexes have evolved repeatedly from hermaphroditic ancestors in flowering plants, and thus select taxa can provide unparalleled insight into the evolutionary dynamics of sex chromosomes that are thought to be shared by plants and animals alike. Here we ask whether two octoploid sibling species of wild strawberry—one almost exclusively dioecious (males and females), Fragaria chiloensis, and one subdioecious (males, females, and hermaphrodites), F. virginiana—share the same sex-determining chromosome. We created a genetic map of the sex chromosome and its homeologs in F. chiloensis and assessed macrosynteny between it and published maps of the proto-sex chromosome of F. virginiana and the homeologous autosome of hermaphroditic diploid species. Segregation of male and female function in our F. chiloensis mapping population confirmed that linkage and dominance relations are similar to those in F. virginiana. However, identification of the molecular markers most tightly linked to the sex-determining locus in the two octoploid species shows that, in both, this region maps to homeologues of chromosome 6 in diploid congeners, but is located at opposite ends of their respective chromosomes.

Goldberg, Margot T.; Spigler, Rachel B.; Ashman, Tia-Lynn

2010-01-01

251

Postzygotic isolation involves strong mitochondrial and sex-specific effects in Tigriopus californicus, a species lacking heteromorphic sex chromosomes.  

PubMed

Detailed studies of the genetics of speciation have focused on a few model systems, particularly Drosophila. The copepod Tigriopus californicus offers an alternative that differs from standard animal models in that it lacks heteromorphic chromosomes (instead, sex determination is polygenic) and has reduced opportunities for sexual conflict, because females mate only once. Quantitative trait loci (QTL) mapping was conducted on reciprocal F2 hybrids between two strongly differentiated populations, using a saturated linkage map spanning all 12 autosomes and the mitochondrion. By comparing sexes, a possible sex ratio distorter was found but no sex chromosomes. Although studies of standard models often find an excess of hybrid male sterility factors, we found no QTL for sterility and multiple QTL for hybrid viability (indicated by non-Mendelian adult ratios) and other characters. Viability problems were found to be stronger in males, but the usual explanations for weaker hybrid males (sex chromosomes, sensitivity of spermatogenesis, sexual selection) cannot fully account for these male viability problems. Instead, higher metabolic rates may amplify deleterious effects in males. Although many studies of standard speciation models find the strongest genetic incompatibilities to be nuclear-nuclear (specifically X chromosome-autosome), we found the strongest deleterious interaction in this system was mito-nuclear. Consistent with the snowball theory of incompatibility accumulation, we found that trigenic interactions in this highly divergent cross were substantially more frequent (>6 × ) than digenic interactions. This alternative system thus allows important comparisons to studies of the genetics of reproductive isolation in more standard model systems. PMID:23860232

Foley, B R; Rose, C G; Rundle, D E; Leong, W; Edmands, S

2013-07-17

252

Role of testis-specific gene expression in sex-chromosome evolution of Anopheles gambiae.  

PubMed

Gene expression in Anopheles gambiae shows a deficiency of testis-expressed genes on the X chromosome associated with an excessive movement of retrogene duplication. We suggest that the degeneration of sex chromosomes in this monandrous species is likely the result of pressures from X inactivation, dosage compensation, and sexual antagonism. PMID:21890740

Baker, Dean A; Russell, Steven

2011-09-02

253

Genome structure and emerging evidence of an incipient sex chromosome in Populus  

Microsoft Academic Search

The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this

Tongming Yin; Stephen P DiFazio; Lee E Gunter; Xinye Zhang; Mitchell Sewell; Scott Woolbright; Gery Allan; Colin Kelleher; Carl Douglas; Mingxiu Wang; Gerald A Tuskan

2008-01-01

254

Solar activity cycle and the incidence of foetal chromosome abnormalities detected at prenatal diagnosis  

NASA Astrophysics Data System (ADS)

We studied 2001 foetuses during the period of minimal solar activity of solar cycle 21 and 2265 foetuses during the period of maximal solar activity of solar cycle 22, in all women aged 37 years and over who underwent free prenatal diagnosis in four hospitals in the greater Tel Aviv area. There were no significant differences in the total incidence of chromosomal abnormalities or of trisomy between the two periods (2.15% and 1.8% versus 2.34% and 2.12%, respectively). However, the trend of excessive incidence of chromosomal abnormalities in the period of maximal solar activity suggests that a prospective study in a large population would be required to rule out any possible effect of extreme solar activity.

Halpern, Gabrielle J.; Stoupel, Eliahu G.; Barkai, Gad; Chaki, Rina; Legum, Cyril; Fejgin, Moshe D.; Shohat, Mordechai

1995-06-01

255

Strong biases in the transmission of sex chromosomes in the aphid Rhopalosiphum padi.  

PubMed

The typical life cycle of aphids involves several parthenogenetic generations followed by a single sexual one in autumn, i.e. cyclical parthenogenesis. Sexual females are genetically identical to their parthenogenetic mothers and carry two sex chromosomes (XX). Male production involves the elimination of one sex chromosome (to produce X0) that could give rise to genetic conflicts between X-chromosomes. In addition, deleterious recessive mutations could accumulate on sex chromosomes during the parthenogenetic phase and affect males differentially depending on the X-chromosome they inherit. Genetic conflicts and deleterious mutations thus may induce transmission bias that could be exaggerated in males. Here, the transmission of X-chromosomes has been studied in the laboratory in two cyclically parthenogenetic lineages of the bird cherry-oat aphid Rhopalosiphum padi . X-chromosome transmission was followed, using X-linked microsatellite loci, at male production in the two lineages and in their hybrids deriving from reciprocal crosses. Genetic analyses revealed non-Mendelian inheritance of X-chromosomes in both parental and hybrid lineages at different steps of male function. Putative mechanisms and evolutionary consequences of non-Mendelian transmission of X-chromosomes to males are discussed. PMID:16174329

Frantz, Adrien; Plantegenest, Manuel; Bonhomme, Joël; Prunier-Leterme, Nathalie; Simon, Jean-Christophe

2005-04-01

256

Molecular evolution of the avian CHD1 genes on the Z and W sex chromosomes.  

PubMed Central

Genes shared between the nonrecombining parts of the two types of sex chromosomes offer a potential means to study the molecular evolution of the same gene exposed to different genomic environments. We have analyzed the molecular evolution of the coding sequence of the first pair of genes found to be shared by the avian Z (present in both sexes) and W (female-specific) sex chromosomes, CHD1Z and CHD1W. We show here that these two genes evolve independently but are highly conserved at nucleotide as well as amino acid levels, thus not indicating a female-specific role of the CHD1W gene. From comparisons of sequence data from three avian lineages, the frequency of nonsynonymous substitutions (K(a)) was found to be higher for CHD1W (1.55 per 100 sites) than for CHD1Z (0.81), while the opposite was found for synonymous substitutions (K(s), 13.5 vs. 22.7). We argue that the lower effective population size and the absence of recombination on the W chromosome will generally imply that nonsynonymous substitutions accumulate faster on this chromosome than on the Z chromosome. The same should be true for the Y chromosome relative to the X chromosome in XY systems. Our data are compatible with a male-biased mutation rate, manifested by the faster rate of neutral evolution (synonymous substitutions) on the Z chromosome than on the female-specific W chromosome.

Fridolfsson, A K; Ellegren, H

2000-01-01

257

Independent evolution of transcriptional inactivation on sex chromosomes in birds and mammals.  

PubMed

X chromosome inactivation in eutherian mammals has been thought to be tightly controlled, as expected from a mechanism that compensates for the different dosage of X-borne genes in XX females and XY males. However, many X genes escape inactivation in humans, inactivation of the X in marsupials is partial, and the unrelated sex chromosomes of monotreme mammals have incomplete and gene-specific inactivation of X-linked genes. The bird ZW sex chromosome system represents a third independently evolved amniote sex chromosome system with dosage compensation, albeit partial and gene-specific, via an unknown mechanism (i.e. upregulation of the single Z in females, down regulation of one or both Zs in males, or a combination). We used RNA-fluorescent in situ hybridization (RNA-FISH) to demonstrate, on individual fibroblast cells, inactivation of 11 genes on the chicken Z and 28 genes on the X chromosomes of platypus. Each gene displayed a reproducible frequency of 1Z/1X-active and 2Z/2X-active cells in the homogametic sex. Our results indicate that the probability of inactivation is controlled on a gene-by-gene basis (or small domains) on the chicken Z and platypus X chromosomes. This regulatory mechanism must have been exapted independently to the non-homologous sex chromosomes in birds and mammals in response to an over-expressed Z or X in the homogametic sex, highlighting the universal importance that (at least partial) silencing plays in the evolution on amniote dosage compensation and, therefore, the differentiation of sex chromosomes. PMID:23874231

Livernois, Alexandra M; Waters, Shafagh A; Deakin, Janine E; Marshall Graves, Jennifer A; Waters, Paul D

2013-07-18

258

Scientists find that chromosomal abnormalities are associated with aging and cancer  

Cancer.gov

Two new studies have found that large structural abnormalities in chromosomes, some of which have been associated with increased risk of cancer, can be detected in a small fraction of people without a prior history of cancer. These studies were conducted by two consortia, one led by scientists at the National Cancer Institute, and one by Gene Environment Association Studies (GENEVA) which is sponsored by the National Human Genome Research Institute.

259

Colchicine-induced abnormal meiotic chromosomal segregation in primary oocytes of the Chinese hamster  

Microsoft Academic Search

Summary A single dose of 3 ?g\\/g b.w. colchicine was intraperitoneally injected to female Chinese hamsters with a normal estrous cycle at the onset of the formation of the first meiotic spindle. Morphologically abnormal secondary oocytes having one or two extremely large first polar bodies occurred frequently,i.e., 47 (11.3%) out of 416 oocytes. In 30 of them, chromosome analysis was

Kazuya Mikamo; Shigeki Sugawara

1980-01-01

260

Nuchal translucency and other first-trimester sonographic markers of chromosomal abnormalities  

Microsoft Academic Search

There is extensive evidence that effective screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Prospective studies in a total of 200,868 pregnancies, including 871 fetuses with trisomy 21, have demonstrated that increased nuchal translucency can identify 76.8% of fetuses with trisomy 21, which represents a false-positive rate of 4.2%. When fetal nuchal translucency was

Kypros H. Nicolaides

2004-01-01

261

Features of chromosomal abnormalities in spontaneous abortion cell culture failures detected by interphase FISH analysis  

Microsoft Academic Search

Cytogenetic analysis of reproductive wastage is an important stage in understanding the genetic background of early embryogenesis. The results of conventional cytogenetic studies of spontaneous abortions depend on tissue culturing and are associated with a significant cell culture failure rate. We performed interphase dual-colour FISH analysis to detect chromosomal abnormalities in noncultured cells from two different tissues–cytotrophoblast and extraembryonic mesoderm–of

Igor N Lebedev; Nadezhda V Ostroverkhova; Tatyana V Nikitina; Natalia N Sukhanova; Sergey A Nazarenko

2004-01-01

262

Brain Organization in a Reptile Lacking Sex Chromosomes: Effects of Gonadectomy and Exogenous Testosterone  

Microsoft Academic Search

In mammals, males and females differ both genetically and hormonally, making it difficult to assess the relative contributions of genetic constitution and fetal environment in the process of sexual differentiation. Many reptiles lack sex chromosomes, relying instead on the temperature of incubation to determine sex. In the leopard gecko (Eublepharis macularius), an incubation temperature of 26°C produces all females, whereas

David Crews; Patricia Coomber; Ryan Baldwin; Nilofer Azad; Francisco Gonzalez-Lima

1996-01-01

263

IDENTIFICATION OF SEX CHROMOSOME MOLECULAR MARKERS USING RAPDS AND FLUORESCENT IN SITU HYBRIDIZATION IN RAINBOW TROUT  

EPA Science Inventory

The goal of this work is to identify molecular markers associated with the sex chromosomes in rainbow trout to study the mode of sex determination mechanisms in this species. Using the RAPD assay and bulked segregant analysis, two markers were identified that generated polymorphi...

264

The Number of X Chromosomes Causes Sex Differences in Adiposity in Mice  

Microsoft Academic Search

Sexual dimorphism in body weight, fat distribution, and metabolic disease has been attributed largely to differential effects of male and female gonadal hormones. Here, we report that the number of X chromosomes within cells also contributes to these sex differences. We employed a unique mouse model, known as the “four core genotypes,” to distinguish between effects of gonadal sex (testes

Xuqi Chen; Rebecca McClusky; Jenny Chen; Simon W. Beaven; Peter Tontonoz; Arthur P. Arnold; Karen Reue

2012-01-01

265

Deciphering neo-sex and B chromosome evolution by the draft genome of Drosophila albomicans  

PubMed Central

Background Drosophila albomicans is a unique model organism for studying both sex chromosome and B chromosome evolution. A pair of its autosomes comprising roughly 40% of the whole genome has fused to the ancient X and Y chromosomes only about 0.12 million years ago, thereby creating the youngest and most gene-rich neo-sex system reported to date. This species also possesses recently derived B chromosomes that show non-Mendelian inheritance and significantly influence fertility. Methods We sequenced male flies with B chromosomes at 124.5-fold genome coverage using next-generation sequencing. To characterize neo-Y specific changes and B chromosome sequences, we also sequenced inbred female flies derived from the same strain but without B's at 28.5-fold. Results We assembled a female genome and placed 53% of the sequence and 85% of the annotated proteins into specific chromosomes, by comparison with the 12 Drosophila genomes. Despite its very recent origin, the non-recombining neo-Y chromosome shows various signs of degeneration, including a significant enrichment of non-functional genes compared to the neo-X, and an excess of tandem duplications relative to other chromosomes. We also characterized a B-chromosome linked scaffold that contains an actively transcribed unit and shows sequence similarity to the subcentromeric regions of both the ancient X and the neo-X chromosome. Conclusions Our results provide novel insights into the very early stages of sex chromosome evolution and B chromosome origination, and suggest an unprecedented connection between the births of these two systems in D. albomicans.

2012-01-01

266

Neoplastic behavior of chromosomally abnormal clones in New Zealand Black mice.  

PubMed

Old New Zealand Black (NZB) mice frequently develop reticulum-cell sarcoma and clones of aneuploid cells in their spleens. In order to define the relationship between neoplasms and chromosomal abnormalities, the pattern of distribution of aneuploid cells was studied to see if it corresponds to that expected of the malignancy, and chromosomally aberrant or normal spleen cells were transplanted into syngeneic newborn recipients. The results indicate that aneuploid cells arise focally but may disseminate widely in an affected mouse. A strong association was found between spleen-cell aneuploidy in a transplantation donor and both aneuploidy and histological evidence of reticulum-cell sarcoma in young recipients. Chromosomal aberrations in young recipients were always of donor origin. On the basis of these data, it seems likely that aneuploid clones which arise in the spleens of old NZB mice usually are at least potentially neoplastic. PMID:359489

Friedman, J M; Fialkow, P J; Bryant, J; Reddy, A L; Salo, A C

1978-10-15

267

Trisomy 19 as the sole chromosomal abnormality in proliferative chronic myelomonocytic leukemia.  

PubMed

Distinct morphologic and clinical features associated with specific chromosomal abnormalities have been described in subgroups of myelodysplastic syndromes (MDS), which often are losses or gains and only rarely translocations. Among 103 consecutive MDS patients diagnosed and karyotyped at the Albert-Ludwigs University of Freiburg (ALU) between 1993 and 1999, two chronic myelomonocytic leukemias (CMMoL) displayed trisomy 19 (+19) as the sole chromosomal abnormality. Three further CMMoL cases with +19 as the single abnormality, two of which previously reported, were collected from other centers. Four of the five patients presented with leukocytosis and splenomegaly, and an increased number of ringed sideroblasts was observed in two cases. Treatment was low-dose Decitabine (cases 1 and 2), oral steroids (case 3), hydroxyurea (case 4), and daunorubicin/Ara-C (case 5). Transformation to acute myeloid leukemias (AML) occurred in three/five patients (cases 1, 2, and 4) 26, 12, and 22 months after diagnosis of CMMoL, respectively. We conclude that +19 as the sole anomaly is a rare but recurrent change in CMMoL, in particular of the proliferative type. It is at present unclear which gene(s) located on chromosome 19 might have a functional role for the development of this phenotype. PMID:16464494

Daskalakis, M; Mauritzson, N; Johansson, B; Bouabdallah, K; Onida, F; Kunzmann, R; Müller-Berndorff, H; Schmitt-Gräff, A; Lübbert, M

2006-02-07

268

Sex chromosomes of the Asian black pond turtle, Siebenrockiella crassicollis (Testudines: Emydidae).  

PubMed

A heteromorphism in a pair of macrochromosomes in male Siebenrockiella crassicollis is interpreted as an XX/XY sex determining system. The heteromorphism involves a difference in centromere position and amount and distribution of heterochromatin. The only other sex chromosome system known in turtles is found in the kinosternid genus Staurotypus and is also an XX/XY system, but it involves a different chromosome pair and different chromosomal rearrangements. These two systems have independently arisen within the suborder Cryptodira and share no common ancestry. The sex chromosome system in Siebenrockiella represents a relatively early stage of differentiation. It differs from the hypothesized steps of differentiation in having a heterochromatically derived X. PMID:7326996

Carr, J L; Bickham, J W

1981-01-01

269

Triploid plover female provides support for a role of the W chromosome in avian sex determination  

PubMed Central

Two models, Z Dosage and Dominant W, have been proposed to explain sex determination in birds, in which males are characterized by the presence of two Z chromosomes, and females are hemizygous with a Z and a W chromosome. According to the Z Dosage model, high dosage of a Z-linked gene triggers male development, whereas the Dominant W model postulates that a still unknown W-linked gene triggers female development. Using 33 polymorphic microsatellite markers, we describe a female triploid Kentish plover Charadrius alexandrinus identified by characteristic triallelic genotypes at 14 autosomal markers that produced viable diploid offspring. Chromatogram analysis showed that the sex chromosome composition of this female was ZZW. Together with two previously described ZZW female birds, our results suggest a prominent role for a female determining gene on the W chromosome. These results imply that avian sex determination is more dynamic and complex than currently envisioned.

Kupper, Clemens; Augustin, Jakob; Edwards, Scott; Szekely, Tamas; Kosztolanyi, Andras; Burke, Terry; Janes, Daniel E.

2012-01-01

270

Dosage Compensation Regulatory Proteins and the Evolution of Sex Chromosomes in Drosophila  

PubMed Central

In the fruitfly Drosophila melanogaster, the four male-specific lethal (msl) genes are required to achieve dosage compensation of the male X chromosome. The MSL proteins are thought to interact with cis-acting sites that confer dosage compensation to nearby genes, as they are detected at hundreds of discrete sites along the length of the polytene X chromosome in males but not in females. The histone H4 acetylated isoform, H4Ac16, colocalizes with the MSL proteins at a majority of sites on the D. melanogaster X chromosome. Using polytene chromosome immunostaining of other species from the genus Drosophila, we found that X chromosome association of MSL proteins and H4Ac16 is conserved despite differences in the sex chromosome karyotype between species. Our results support a model in which cis-acting regulatory sites for dosage compensation evolve on a neo-X chromosome arm in response to the degeneration of its former homologue.

Bone, J. R.; Kuroda, M. I.

1996-01-01

271

Incidence of chromosome aberrations among 11 148 newborn children  

Microsoft Academic Search

Chromosome analysis has been made of 11 148 children; 29 had sex chromosome abnormalities (2.60 per 1000) and 64 autosomal abnormalities (5.74 per 1000). The total incidence of major chromosome abnormalities was 8.34 per 1000.

Johannes Nielsen; Ingelise Sillesen

1975-01-01

272

Parental decisions regarding a prenatally detected fetal chromosomal abnormality and the impact of genetic counseling: an analysis of 38 cases with aneuploidy in Southeast Turkey.  

PubMed

This study investigated parental decision-making to terminate or continue a pregnancy after prenatal diagnosis of a chromosomal abnormality among a sample of patients in Southeast Turkey. Between 2004 and 2007, 1068 amniocentesis tests were performed in the Medical Biology and Genetic Department Laboratory at Dicle University. Aneuploidy was found in 38 cases (3.56%). Genetic counseling was provided for the couples that received abnormal results, and they were later interviewed and asked if they had continued or interrupted the pregnancy after the diagnosis. When confronted with autosomal aneuploidy in which a severe prognosis was expected, 85% of cases decided to terminate the pregnancy. When confronted with sex chromosome aneuploidy with a low risk of an abnormal clinical phenotype 60% of cases decided to continue the pregnancy. Among the diagnoses with aneuploidy, pregnancy was continued in 21.1% of cases due to religious beliefs regardless of whether there was a low or severe risk of an abnormal clinical phenotype. These findings indicate that both severity of abnormality and religiosity play an important role in genetic counseling patients' decision-making processes and outcomes in Turkey. In addition, the findings suggest the need for legislation that reduces the differences in approaches between the physicians and institutions regarding parental decision-making to terminate or continue a pregnancy in our country. PMID:20119701

Balkan, Mahmut; Kalkanli, Sevgi; Akbas, Halit; Yalinkaya, Ahmet; Alp, M Nail; Budak, Turgay

2010-01-30

273

First evidence of sex chromosome pre-reduction in male meiosis in the Miridae bugs (Heteroptera).  

PubMed

The karyotype and male meiosis of Macrolophus costalis Fieber (Insecta, Heteroptera, Miridae) were studied using C-banding, AgNOR-banding and DNA sequence specific fluorochrome staining. The chromosome formula of the species is 2n = 28(24+X1X2X3Y). Male meiotic prophase is characterized by a prominent condensation stage. At this stage, two sex chromosomes, "X" and Y are positively heteropycnotic and always appeared together, while in autosomal bivalents homologous chromosomes were aligned side by side along their entire length, that is, meiosis is achiasmatic. At metaphase I, "X" and Y form a pseudobivalent and orient to the opposite poles. At early anaphase I, the "X" chromosome disintegrates into three separate small chromosomes, X1, X2, and X3. Hence both the autosomes and sex chromosomes segregate reductionally in the first anaphase, and separate equationally in the second anaphase. This is the first evidence of sex chromosome pre-reduction in the family Miridae. Data on C-heterochromatin distribution and its composition in the chromosomes of this species are discussed. PMID:17044253

Grozeva, Snejana; Nokkala, Seppo; Simov, Nikolay

2006-01-01

274

Molecular detection of chromosomal abnormalities in germ and somatic cells of aged male mice  

SciTech Connect

Three cytogenetic methods were applied to eight B6C3F1 male mice aged 22.5 - 30.5mo to determine if advanced age was associated with an elevated risk of producing chromosomally defective germinal and somatic cells; sperm aneuploidy analysis by multi-color fluorescence in situ hybridization for three chromosomes, spermatid micronucleus analysis with anti-kinetochore antibodies, and translocation analysis of somatic metaphases by {open_quotes}painting{close_quotes} for two chromosomes. Eight mice aged 2.4mo served as controls. Sperm aneuploidy was measured by multi-color fluorescence in situ co-hybridization with DNA probes specific for chromosomes X, Y and 8, scoring 10,000 cells per animal. The aged group showed significant 1.5 - 2.0 fold increases in the hyperhaploidy phenotypes X-X-8, Y-Y-8, 8-8-Y, and 8-8-X with the greater effects appearing in animals aged >29mo. The aged group also showed significantly increased frequencies of micronucleated spermatids (2.0 vs 0.4 per 1000; all were kinetochore negative). Analysis of metaphase chromosomes from blood by {open_quotes}painting{close_quotes} of chromosomes 2 and 8 yielded 4 translocation per 858 cell-equivalents in the aged group which was a non-significant elevation over 0/202 in controls. Although interpretation must be cautious due to the small number of animals analyzed, these findings suggest that advanced paternal age may be a risk factor for chromosomal abnormalities of reproductive and somatic importance.

Lowe, X.; Baulch, J.; Quintana, L.; Ramsey, M.; Breneman, J.; Tucker, J.; Wyrobek, A. [Lawrence Livermore National Laboratory, CA (United States); Collins, B.; Allen, J. [EPA, Research Triangle Park, NC (United States); Holland, N. [Univ. of California, Berkeley, CA (United States)

1994-12-31

275

High-resolution identification of chromosomal abnormalities using oligonucleotide arrays containing 116,204 SNPs.  

PubMed

Mutation of the human genome ranges from single base-pair changes to whole-chromosome aneuploidy. Karyotyping, fluorescence in situ hybridization, and comparative genome hybridization are currently used to detect chromosome abnormalities of clinical significance. These methods, although powerful, suffer from limitations in speed, ease of use, and resolution, and they do not detect copy-neutral chromosomal aberrations--for example, uniparental disomy (UPD). We have developed a high-throughput approach for assessment of DNA copy-number changes, through use of high-density synthetic oligonucleotide arrays containing 116,204 single-nucleotide polymorphisms, spaced at an average distance of 23.6 kb across the genome. Using this approach, we analyzed samples that failed conventional karyotypic analysis, and we detected amplifications and deletions across a wide range of sizes (1.3-145.9 Mb), identified chromosomes containing anonymous chromatin, and used genotype data to determine the molecular origin of two cases of UPD. Furthermore, our data provided independent confirmation for a case that had been misinterpreted by karyotype analysis. The high resolution of our approach provides more-precise breakpoint mapping, which allows subtle phenotypic heterogeneity to be distinguished at a molecular level. The accurate genotype information provided on these arrays enables the identification of copy-neutral loss-of-heterozygosity events, and the minimal requirement of DNA (250 ng per array) allows rapid analysis of samples without the need for cell culture. This technology overcomes many limitations currently encountered in routine clinical diagnostic laboratories tasked with accurate and rapid diagnosis of chromosomal abnormalities. PMID:16252233

Slater, Howard R; Bailey, Dione K; Ren, Hua; Cao, Manqiu; Bell, Katrina; Nasioulas, Steven; Henke, Robert; Choo, K H Andy; Kennedy, Giulia C

2005-09-16

276

Flow sorting of the Y sex chromosome in the dioecious plant Melandrium album.  

PubMed

The preparation of stable chromosome suspensions and flow cytometric sorting of both the Y sex chromosome of the white campion, Melandrium album, and the deleted Y chromosome of an asexual mutant, 5K63, is described. The principle has been to maintain transformed roots in vitro, synchronise and block mitosis, reduce cells to protoplasts, and lyse these to release chromosomes. Such in vitro material, unlike many cell suspensions, showed a stable karyotype. Factors critical to producing high-quality chromosome suspensions from protoplasts include osmolality of isolation solutions and choice of spindle toxin and of lysis buffer. Agrobacterium rhizogenes transformed young growing root cultures were synchronised at G1/S with 50 microM aphidicolin for 24 h and released to a mitotic block with 30 microM oryzalin for 11 h. Protoplast preparations from such tissue routinely had metaphase indices reaching 15%. Suspensions of intact metaphase chromosomes, with few chromatids, were obtained by lysing swollen mitotic protoplasts in a citric acid/disodium phosphate buffer. Except for the presence of clumps of autosomal chromosomes near the X and Y chromosome zones, monoparametric histograms of fluorescence intensities of suspensions stained with 4',6-diamino-2-phenylindole showed profiles similar to theoretical flow karyotypes. Two types of Y chromosomes, one full-length and one partially deleted (from the asexual mutant), could be sorted at 90% purity (21-fold enrichment of Y). These results are discussed in the context of sex determination and differentiation in higher plants. PMID:8608734

Veuskens, J; Marie, D; Brown, S C; Jacobs, M; Negrutiu, I

1995-12-01

277

The sex chromosomes of Silene latifolia revisited and revised.  

PubMed Central

Classical studies have established that, during meiosis, the X and Y chromosomes of the model dioecious plant Silene latifolia pair over a region at the ends of their q arms. We used fluorescence in situ hybridization of two molecular markers to demonstrate that this widely accepted model is incorrect. From these data we conclude that the homologous arm of the X chromosome is the p arm and that of the Y chromosome is the q arm. The establishment of the proper orientation of the pseudoautosomal region is essential for mapping and evolutionary studies.

Lengerova, Martina; Moore, Richard C; Grant, Sarah R; Vyskot, Boris

2003-01-01

278

Chromatin structural changes around satellite repeats on the female sex chromosome in Schistosoma mansoni and their possible role in sex chromosome emergence  

PubMed Central

Background In the leuphotrochozoan parasitic platyhelminth Schistosoma mansoni, male individuals are homogametic (ZZ) whereas females are heterogametic (ZW). To elucidate the mechanisms that led to the emergence of sex chromosomes, we compared the genomic sequence and the chromatin structure of male and female individuals. As for many eukaryotes, the lower estimate for the repeat content is 40%, with an unknown proportion of domesticated repeats. We used massive sequencing to de novo assemble all repeats, and identify unambiguously Z-specific, W-specific and pseudoautosomal regions of the S. mansoni sex chromosomes. Results We show that 70 to 90% of S. mansoni W and Z are pseudoautosomal. No female-specific gene could be identified. Instead, the W-specific region is composed almost entirely of 36 satellite repeat families, of which 33 were previously unknown. Transcription and chromatin status of female-specific repeats are stage-specific: for those repeats that are transcribed, transcription is restricted to the larval stages lacking sexual dimorphism. In contrast, in the sexually dimorphic adult stage of the life cycle, no transcription occurs. In addition, the euchromatic character of histone modifications around the W-specific repeats decreases during the life cycle. Recombination repression occurs in this region even if homologous sequences are present on both the Z and W chromosomes. Conclusion Our study provides for the first time evidence for the hypothesis that, at least in organisms with a ZW type of sex chromosomes, repeat-induced chromatin structure changes could indeed be the initial event in sex chromosome emergence.

2012-01-01

279

The genomic signature of sexual selection in the genetic diversity of the sex chromosomes and autosomes.  

PubMed

Genomic levels of variation can help reveal the selective and demographic forces that have affected a species during its history. The relative amount of genetic diversity observed on the sex chromosomes as compared to the autosomes is predicted to differ among monogamous and polygynous species. Many species show departures from the expectation for monogamy, but it can be difficult to conclude that this pattern results from variation in mating system because forces other than sexual selection can act upon sex chromosome genetic diversity. As a critical test of the role of mating system, we compared levels of genetic diversity on the Z chromosome and autosomes of phylogenetically independent pairs of shorebirds that differed in their mating systems. We found general support for sexual selection shaping sex chromosome diversity because most polygynous species showed relatively reduced genetic variation on their Z chromosomes as compared to monogamous species. Differences in levels of genetic diversity between the sex chromosomes and autosomes may therefore contribute to understanding the long-term history of sexual selection experienced by a species. PMID:22759291

Corl, Ammon; Ellegren, Hans

2012-02-23

280

Analysis and evolution of two functional Y-linked loci in a plant sex chromosome system.  

PubMed

White campion (Silene latifolia) is one of the few examples of plants with separate sexes and with X and Y sex chromosomes. The presence or absence of the Y chromosome determines which type of reproductive organs--male or female--will develop. Recently, we characterized the first active gene located on a plant Y chromosome, SlY1, and its X-linked homolog, SlX1. These genes encode WD-repeat proteins likely to be involved in cell proliferation. Here, we report the characterization of a novel Y-linked gene, SlY4, which also has a homolog on the X chromosome, SlX4. Both SlY4 and SlX4 potentially encode fructose-2,6-bisphosphatases. A comparative molecular analysis of the two sex-linked loci (SlY1/SlX1 and SlY4/SlX4) suggests selective constraint on both X- and Y-linked genes and thus that both X- and Y-linked copies are functional. Divergence between SlY4 and SlX4 is much greater than that between the SlY1 and SlX1 genes. These results suggest that, as for human XY-linked genes, the sex-linked plant loci ceased recombining at different times and reveal distinct events in the evolutionary history of the sex chromosomes. PMID:11719565

Atanassov, I; Delichère, C; Filatov, D A; Charlesworth, D; Negrutiu, I; Monéger, F

2001-12-01

281

An apparent excess of sex- and reproduction-related genes on the human X chromosome.  

PubMed Central

We describe here the results of a search of Mendelian inheritance in man, GENDIAG and other sources which suggest that, in comparison with autosomes 1, 2, 3, 4 and 11, the X chromosome may contain a significantly higher number of sex- and reproduction-related (SRR) genes. A similar comparison between X-linked entries and a subset of randomly chosen entries from the remaining autosomes also indicates an excess of genes on the X chromosome with one or more mutations affecting sex determination (e.g. DAX1), sexual differentiation (e.g. androgen receptor) or reproduction (e.g. POF1). A possible reason for disproportionate occurrence of such genes on the X chromosome could be that, during evolution, the 'choice' of a particular pair of homomorphic chromosomes for specialization as sex chromosomes may be related to the number of such genes initially present in it or, since sex determination and sexual dimorphism are often gene dose-dependent processes, the number of such genes necessary to be regulated in a dose-dependent manner. Further analysis of these data shows that XAR, the region which has been added on to the short arm of the X chromosome subsequent to eutherian-marsupial divergence, has nearly as high a proportion of SRR genes as XCR, the conserved region of the X chromosome. These observations are consistent with current hypotheses on the evolution of sexually antagonistic traits on sex chromosomes and suggest that both XCR and XAR may have accumulated SRR traits relatively rapidly because of X linkage.

Saifi, G M; Chandra, H S

1999-01-01

282

Prenatal diagnosis of genomic disorders and chromosome abnormalities using array-based comparative genomic hybridization.  

PubMed

Cytogenetic analysis is a crucial tool of prenatal diagnosis. The ability to rapidly detect aneuploidy and identify small structural abnormalities of foetal chromosomes has been greatly improved by the use of molecular cytogenetic technologies. Microarray-based Comparative Genomic Hybridization (aCGH) has been recently employed in postnatal diagnosis of cryptic chromosomal aberrations, but use in prenatal diagnosis is still limited.We set-up a diagnostic protocol which uses aCGH technology on genomic DNA isolated from uncultured chorionic villus sampled at 11-12 week's gestation. We used a commercially targeted microarray (MDTelArray, Technogenetics Srl - Bouty Group, Sesto S. Giovanni, Milan, Italy) constituted by 167 genomic clones corresponding to 34 critical regions frequently involved in microdeletions and microduplications and 126 subtelomeric clones. Array validation has been carried-out via retrospective analysis of DNA isolated from a series of cytogenetically normal chorionic villus samples (CVS) and of DNA isolated from cytogenetically abnormal cultured amniocytes, CVS or peripheral blood. A pilot prospective study was undertaken analyzing 25 CVS obtained from foetuses at risk for chromosomal aberrations. aCGH results both for retrospective and prospective studies were in agreement with data obtained using "classical" cytogenetic analysis, and/or FISH analysis or DNA testing. Although these preliminary data support the usefulness of aCGH in prenatal diagnosis, further prospective studies are required to verify the feasibility of introducing this technique as part of the diagnostic armamentarium for identify affected foetuses. PMID:22470819

Gullotta, Francesca; Biancolella, Michela; Costa, Elena; Colapietro, Isabella; Nardone, Anna Maria; Molinaro, Paolo; Pietropolli, Adalgisa; Narcisi, Marianovella; Di Rosa, Cristiana; Novelli, Giuseppe

2007-01-01

283

Inflammatory cytokines in maternal circulation and placenta of chromosomally abnormal first trimester miscarriages.  

PubMed

The impact of abnormal placental karyotype on the inflammatory response within the villous tissue and peripheral circulation of women with miscarriage was evaluated. Villous (n = 38) and venous blood samples (n = 26) were obtained from women with missed miscarriage. Tissue chromosome analysis indicated 23 abnormal and 15 normal karyotypes. Concentration of tumour necrosis factor alpha (TNF?), TNF-R1 and TNF-R2, and interleukin (IL)-10 were measured using flowcytometric bead array in fresh villous homogenate, cultured villous extracts, culture medium, maternal whole blood, and plasma. Plasma TNF?/IL-10 ratios were significantly (P < 0.05) lower in miscarriages with abnormal karyotype. In the abnormal karyotype group, there were significantly higher levels of TNF? (P < 0.01), IL-10 (P < 0.01), TNF-R1 (P < 0.001), and TNF-R2 (P < 0.001) in the villous extracts and culture-conditioned medium compared to normal karyotype group. In miscarriage with abnormal karyotype, there is an exacerbated placental inflammatory response, in contrast to miscarriage of normal karyotype where maternal systemic response is increased. PMID:21977049

Calleja-Agius, Jean; Jauniaux, Eric; Muttukrishna, Shanthi

2011-09-29

284

Inflammatory Cytokines in Maternal Circulation and Placenta of Chromosomally Abnormal First Trimester Miscarriages  

PubMed Central

The impact of abnormal placental karyotype on the inflammatory response within the villous tissue and peripheral circulation of women with miscarriage was evaluated. Villous (n = 38) and venous blood samples (n = 26) were obtained from women with missed miscarriage. Tissue chromosome analysis indicated 23 abnormal and 15 normal karyotypes. Concentration of tumour necrosis factor alpha (TNF?), TNF-R1 and TNF-R2, and interleukin (IL)-10 were measured using flowcytometric bead array in fresh villous homogenate, cultured villous extracts, culture medium, maternal whole blood, and plasma. Plasma TNF?/IL-10 ratios were significantly (P < 0.05) lower in miscarriages with abnormal karyotype. In the abnormal karyotype group, there were significantly higher levels of TNF? (P < 0.01), IL-10 (P < 0.01), TNF-R1 (P < 0.001), and TNF-R2 (P < 0.001) in the villous extracts and culture-conditioned medium compared to normal karyotype group. In miscarriage with abnormal karyotype, there is an exacerbated placental inflammatory response, in contrast to miscarriage of normal karyotype where maternal systemic response is increased.

Calleja-Agius, Jean; Jauniaux, Eric; Muttukrishna, Shanthi

2012-01-01

285

Accelerated evolution of sex chromosomes in aphids, an x0 system.  

PubMed

Sex chromosomes play a role in many important biological processes, including sex determination, genomic conflicts, imprinting, and speciation. In particular, they exhibit several unusual properties such as inheritance pattern, hemizygosity, and reduced recombination, which influence their response to evolutionary factors (e.g., drift, selection, and demography). Here, we examine the evolutionary forces driving X chromosome evolution in aphids, an XO system where females are homozygous (XX) and males are hemizygous (X0) at sex chromosomes. We show by simulations that the unusual mode of transmission of the X chromosome in aphids, coupled with cyclical parthenogenesis, results in similar effective population sizes and predicted levels of genetic diversity for X chromosomes and autosomes under neutral evolution. These results contrast with expectations from standard XX/XY or XX/X0 systems (where the effective population size of the X is three-fourths that of autosomes) and have deep consequences for aphid X chromosome evolution. We then localized 52 microsatellite markers on the X and 351 on autosomes. We genotyped 167 individuals with 356 of these loci and found similar levels of allelic richness on the X and on the autosomes, as predicted by our simulations. In contrast, we detected higher dN and dN/dS ratio for X-linked genes compared with autosomal genes, a pattern compatible with either positive or relaxed selection. Given that both types of chromosomes have similar effective population sizes and that the single copy of the X chromosome of male aphids exposes its recessive genes to selection, some degree of positive selection seems to best explain the higher rates of evolution of X-linked genes. Overall, this study highlights the particular relevance of aphids to study the evolutionary factors driving sex chromosomes and genome evolution. PMID:21998277

Jaquiéry, Julie; Stoeckel, Solenn; Rispe, Claude; Mieuzet, Lucie; Legeai, Fabrice; Simon, Jean-Christophe

2011-10-13

286

Chromosome aberrations, micronucleus and sperm head abnormalities in mice treated with natamycin, [corrected] a food preservative.  

PubMed

Natamycin [corrected] is used as preservative in foods. The genotoxic effects of the food preservative natamycin [corrected] were evaluated using chromosome aberrations and micronucleus test in bone marrow cells and sperm head abnormality assays in mice. Blood samples were taken from mice and levels of total testosterone in serum were also determined. Natamycin [corrected] was intraperitoneally (ip) injected at 200, 400 and 800 mg/kg. Natamycin [corrected] did not induce chromosome aberrations but significantly increased the number of micronucleated polychromatic erythrocytes in bone marrow and sperm head abnormalities at all concentrations and treatment periods. It also decreased MI at all concentrations for 6, 12 and 24h treatment periods. Natamycin [corrected] decreased PCE/NCE ratio at all concentrations for 48h in female mice, for 24 and 48h treatment periods in male mice. At the 800 mg/kg concentration, natamycin [corrected] decreased PCE/NCE ratio for 24 and 72h in female mice. A dose dependent increase was observed in the percentage of sperm head abnormalities. The levels of serum testosterone decreased dose-dependently. The obtained results indicate that natamycin [corrected] is not clastogenic, but it is aneugenic in mice bone marrow and it is a potential germ cell mutagen in sperm cells. PMID:20026162

Rasgele, Pinar Goc; Kaymak, Fisun

2009-12-21

287

Interphase cytogenetics reveals somatic pairing of chromosome 17 centromeres in normal human brain tissue, but no trisomy 7 or sex-chromosome loss  

Microsoft Academic Search

Nuclei isolated from normal human brain tissue, collected from six autopsies, were hybridized with a panel of nine satellite DNA probes specific for the centromeric regions of chromosomes 1, 6, 7, 10, 11, 17, 18, and the X and Y chromosomes. The results did not confirm the recently reported trisomy 7 and loss of sex chromosomes observed in metaphases obtained

E. P. J. Arnoldus; I. A. Noordermeer; A. C. B. Peters; A. K. Raap; M. Van der Ploeg

1991-01-01

288

Step-by-step evolution of neo-sex chromosomes in geographical populations of wild silkmoths, Samia cynthia ssp.  

PubMed Central

Geographical subspecies of wild silkmoths, Samia cynthia ssp. (Lepidoptera: Saturniidae), differ considerably in sex chromosome constitution owing to sex chromosome fusions with autosomes, which leads to variation in chromosome numbers. We cloned S. cynthia orthologues of 16 Bombyx mori genes and mapped them to chromosome spreads of S. cynthia subspecies by fluorescence in situ hybridization (FISH) to determine the origin of S. cynthia neo-sex chromosomes. FISH mapping revealed that the Z chromosome and chromosome 12 of B. mori correspond to the Z chromosome and an autosome (A1) of S. c. ricini (Vietnam population, 2n=27, Z0 in female moths), respectively. B. mori chromosome 11 corresponds partly to another autosome (A2) and partly to a chromosome carrying nucleolar organizer region (NOR) of this subspecies. The NOR chromosome of S. c. ricini is also partly homologous to B. mori chromosome 24. Furthermore, our results revealed that two A1 homologues each fused with the W and Z chromosomes in a common ancestor of both Japanese subspecies S. c. walkeri (Sapporo population, 2n=26, neo-Wneo-Z) and S. cynthia subsp. indet. (Nagano population, 2n=25, neo-WZ1Z2). One homologue, corresponding to the A2 autosome in S. c. ricini and S. c. walkeri, fused with the W chromosome in S. cynthia subsp. indet. Consequently, the other homologue became a Z2 chromosome. These results clearly showed a step-by-step evolution of the neo-sex chromosomes by repeated autosome–sex chromosome fusions. We suggest that the rearrangements of sex chromosomes may facilitate divergence of S. cynthia subspecies towards speciation.

Yoshido, A; Sahara, K; Marec, F; Matsuda, Y

2011-01-01

289

Abnormal tissue-dependent polytenization of a block of chromosome 3 pericentric heterochromatin in Drosophila melanogaster.  

PubMed

Heterochromatic DNA sequences in the polytene chromosomes of Drosophila melanogaster salivary glands are under-replicated in wild-type strains. In salivary glands of SuUR and in the nurse cells of otu mutants, under-replication is partly suppressed and a banded structure appears within the centric heterochromatin of chromosome 3. This novel banded structure in salivary gland chromosomes was called Plato Atlantis. In order to characterize the heterochromatic component of Plato Atlantis, we constructed a fine-scale cytogenetic map of deletions with break points within centric heterochromatin (Df(3L)1-16, Df(3L)2-66, Df(3R)10-65, Df(3R)4-75 and Df(3L)6B-29 + Df(3R)6B-29). Salivary gland chromosomes show that Df(3L)1-16 removes the complete Plato Atlantis, while Df(3L)2-66 deletes the most proximal 3L regions. These deletions therefore show a substantial cytological overlap. However, in the chromosomes of nurse cells, the same deficiencies remove distinct heterochromatic blocks, with the region of overlap being almost invisible. Satellite (AATAACATAG, AAGAG) and dodecasatellite DNAs mapped in a narrow interval in salivary glands but were found in three clearly distinguishable blocks in nurse cells. The 1.688 satellite was found at a single site in salivary glands but at two sites in nurse cells. We show that newly polytenized heterochromatic structures include blocks h47-h50d of mitotic heterochromatin in salivary glands, but the additional blocks h50p, h53 and h57 are also included in nurse cell chromosomes. Tissue specificity of the patterns of abnormal heterochromatic polytenization implies differential control of DNA replication in somatic and germline cells. PMID:12584247

Koryakov, Dmitry E; Domanitskaya, Elena V; Belyakin, Stepan N; Zhimulev, Igor F

2003-03-15

290

Prenatal diagnosis of chromosome 15 abnormalities in the Prader-Willi/Angelman syndrome region by traditional and molecular cytogenetics  

SciTech Connect

With improvements in culturing and banding techniques, amniotic fluid studies now achieve a level of resolution at which the Prader-Willi syndrome (PWS) and Angelman syndrome (AS) region may be questioned. Chromosome 15 heteromorphisms, detected with Q- and R-banding and used in conjunction with PWS/AS region-specific probes, can confirm a chromosome deletion and establish origin to predict the clinical outcome. We report four de novo cases of an abnormal-appearing chromosome 15 in amniotic fluid samples referred for advanced maternal age or a history of a previous chromosomally abnormal child. The chromosomes were characterized using G-, Q-, and R-banding, as well as isotopic and fluorescent in situ hybridization of DNA probes specific for the proximal chromosome 15 long arm. In two cases, one chromosome 15 homolog showed a consistent deletion of the ONCOR PWS/AS region A and B. In the other two cases, one of which involved an inversion with one breakpoint in the PWS/AS region, all of the proximal chromosome 15 long arm DNA probes used in the in situ hybridization were present on both homologs. Clinical follow-up was not available on these samples, as in all cases the parents chose to terminate the pregnancies. These cases demonstrate the ability to prenatally diagnose chromosome 15 abnormalities associated with PWS/AS. In addition, they highlight the need for a better understanding of this region for accurate prenatal diagnosis. 41 refs., 5 figs.

Toth-Fejel, S.; Magenis, R.E.; Leff, S. [Oregon Health Sciences Univ., Portland, OR (United States)] [and others

1995-02-13

291

Sex chromosome loss and aging: In situ hybridization studies on human interphase nuclei  

SciTech Connect

A total of 1,000 lymphocyte interphase nuclei per proband from 90 females and 138 males age 1 wk to 93 years were analyzed by in situ hybridization for loss of the X and Y chromosomes, respectively. Both sex chromosomes showed an age-dependent loss. In males, Y hypoploidy was very low up to age 15 years (0.05%) but continuously increased to a frequency of 1.34% in men age 76-80 years. In females, the baseline level for X chromosome loss is much higher than that seen for the Y chromosome in males. Even prepubertal females show a rate of X chromosome loss on the order of 1.5%-2.5%, rising to {approximately}4.5%-5% in women older than 75 years. Dividing the female probands into three biological age groups on the basis of sex hormone function (<13 years, 13-51 years, and >51 years), a significant correlation of X chromosome loss versus age could clearly be demonstrated in women beyond age 51 years. Females age 51-91 years showed monosomy X at a rate from 3.2% to 5.1%. In contrast to sex chromosomal loss, the frequency of autosomal monosomies does not change during the course of aging: chromosome 1 and chromosome 17 monosomic cells were found with a constant incidence of 1.2% and 1%, respectively. These data also indicate that autosome loss in interphase nuclei is not a function of chromosome size. 34 refs., 5 figs., 6 tabs.

Guttenbach, M.; Koschorz, B.; Bernthaler, U. [and others

1995-11-01

292

Chromosome banding in Amphibia. XXVI. Coexistence of homomorphic XY sex chromosomes and a derived Y-autosome translocation in Eleutherodactylus maussi (Anura, Leptodactylidae).  

PubMed

A 15-year cytogenetic survey on one population of the leaf litter frog Eleutherodactylus maussi in northern Venezuela confirmed the existence of multiple XXAA male symbol /XAA(Y) female symbol sex chromosomes which originated by a centric (Robertsonian) fusion between the original Y chromosome and an autosome. 95% of the male individuals in this population are carriers of this Y-autosome fusion. In male meiosis the XAA(Y) sex chromosomes pair in the expected trivalent configuration. In the same population, 5% of the male animals still possess the original, free XY sex chromosomes. In a second population of E. maussi analyzed, all male specimens are characterized by these ancestral XY chromosomes which form normal bivalents in meiosis. E. maussi apparently represents the first vertebrate species discovered in which a derived Y-autosome fusion still coexists with the ancestral free XY sex chromosomes. The free XY sex chromosomes, as well as the multiple XA(Y) sex chromosomes are still in a very primitive (homomorphic) stage of differentiation. With no banding technique applied it is possible to distinguish the Y from the X. DNA flow cytometric measurements show that the genome of E. maussi is among the largest in the anuran family Leptodactylidae. The present study also supplies further data on differential chromosome banding and fluorescence in situ hybridization experiments in this amphibian species. PMID:12900583

Schmid, M; Feichtinger, W; Steinlein, C; Haaf, T; Schartl, M; Visbal García, R; Manzanilla Pupo, J; Fernández Badillo, A

2002-01-01

293

46,XX sex reversal with partial duplication of chromosome arm 22q.  

PubMed

We present a case of 46,XX sex reversal in the absence of SRY but with partial duplication of chromosome 22q. The subject had multiple congenital anomalies but nearly complete masculinization of the external genitalia. Our case along with a previous case supports the existence of a gene on chromosome 22q that can trigger testis determination in the absence of SRY. We proposed that overexpression of the SOX10 gene at 22q13 might be the cause of sex reversal. We investigated 13 additional subjects with SRY-negative 46,XX sex reversal for microduplication of chromosome arm 22q in the region of SOX10 gene, but could not find evidence for it. PMID:15108202

Seeherunvong, Tossaporn; Perera, Erasmo M; Bao, Yong; Benke, Paul J; Benigno, Adelaida; Donahue, Roger P; Berkovitz, Gary D

2004-06-01

294

Investigation of chromosome abnormalities and early embryonic mortality in goose lines.  

PubMed

Early embryonic mortality and chromosome abnormalities were studied in three goose lines: Grey Landes (line 7), White Polish (line 4) and their synthetic line (line 9). Eggs laid at the beginning, in the middle and at the end of the laying season were set. At candling at 5th day after egg set, all eggs (2847) were examined and those showing no normal embryonic development were opened 2847. Dead embryos were classified phenotypically and karyotyped. The mean ratio of embryonic mortality (EM) among fertile eggs was 9.4%, 5.2%, 7.3% in the lines 4, 7 and 9, respectively. The mean ratio of embryos with chromosomal abnormalities (CA) among the dead embryos was 8.0%, 14.8% and 13.1% in the lines 4, 7 and 9, respectively. Gander effect and layer within gander effect on embryo mortality were significant, indicating genetic factors. Father and mother of the layer effects were also significant, showing family effects. Animals producing dead embryos and embryos with chromosome abnormalities in high proportion were selected. In the selected groups the mean EM was 17.7-22.9%, and the mean CA was 11.7-34.7% among the three lines. The repetition of CA was not observed in the reproductive season of following year, while animals repeated the high EM (repeatability coefficient of 0.54). This shows that some part of EM may be resulted from other genetic factors. Ganders and layers progeny of these selected animals showed also high EM. It was concluded that culling pairs giving high EM value in their embryos could increase the average level of embryo viability and that the study of genetic determinism of that trait should be continued in geese. PMID:15813214

Liptói, Krisztina; Hidas, A; Rouvier, R

2005-01-01

295

Recurrent chromosomal abnormalities in lymphomas in fine needle aspirates of lymph node.  

PubMed

The detection of specific chromosomal abnormalities is important in the diagnostic workup of aggressive lymphomas, giving its impact on the treatment strategies and prognosis. This has been accomplished by using the fluorescent in situ hybridisation method (FISH) performed on fine needle aspiration (FNA) specimens what is attractive in the diagnosis of lymphoma in the comparation with other methods for collecting samples. The cytogenetic analyses were performed in series of 80 patients with lymphoma (43 women and 37 men, median age 48, range 3-90 years). In our series 89.0% (71) of the specimens yield sufficient numbers of analysable metaphases, comprising 63 non-Hodgkin lymphomas (NHL) and 8 examples of Hodgkin disease (HD). Among 71 successful karyotyped specimens 58 (82.0%) showed clonal karyotypic abnormalities. Numerical changes in 4, structural changes in 20 and both and numerical with structural changes in 30 of 54 NHL cases. Trisomies 3, 7, 8, 12, 18, X and monosomies 1 were most common numerical abnormalities. The NHL cases were typically characterised by structural rather than numerical aberrations with chromosome arms 1p/q, 3p/q, 6q, 11q, 17p and 14q most frequently involved. The expected translocation (14;18) (q32;q21) in 8 and t(8;14) (q24;q34) in 6 cases, both translocations at the same time in three cases, complex rearrangement with chromosome 8, 14, and 18, namely t(8;14;18) (q24;q32;q21) in one case, t(11;14) (q13;q32) in three and one case with translocation 14q32 with chromosome 3q27, 6q and 14q32 were found. In 28 of 54 (52%) NHL cases t(14;v) was present. Four abnormal clones detected in Hodgkin disease were typically consisted of a small percentage of metaphases. The use of FISH method enable the detection of loss or gain of genetic material and reveal rearrangements unsuspected by conventional cytogenetics in 34 (48.0%) cases. PMID:20698107

Trci?, Ruzica Lasan; Susterci?, Dunja; Kuspili?, Maja; Jeli?-Puskari?, Biljana; Fabijani?, Iris; Kardum-Skelin, Ika

2010-06-01

296

Sex chromosomes and associated rDNA form a heterochromatic network in the polytene nuclei of Bactrocera oleae (Diptera: Tephritidae).  

PubMed

The olive fruit fly, Bactrocera oleae, has a diploid set of 2n = 12 chromosomes including a pair of sex chromosomes, XX in females and XY in males, but polytene nuclei show only five polytene chromosomes, obviously formed by five autosome pairs. Here we examined the fate of the sex chromosomes in the polytene complements of this species using fluorescence in situ hybridization (FISH) with the X and Y chromosome-derived probes, prepared by laser microdissection of the respective chromosomes from mitotic metaphases. Specificity of the probes was verified by FISH in preparations of mitotic chromosomes. In polytene nuclei, both probes hybridized strongly to a granular heterochromatic network, indicating thus underreplication of the sex chromosomes. The X chromosome probe (in both female and male nuclei) highlighted most of the granular mass, whereas the Y chromosome probe (in male nuclei) identified a small compact body of this heterochromatic network. Additional hybridization signals of the X probe were observed in the centromeric region of polytene chromosome II and in the telomeres of six polytene arms. We also examined distribution of the major ribosomal DNA (rDNA) using FISH with an 18S rDNA probe in both mitotic and polytene chromosome complements of B. oleae. In mitotic metaphases, the probe hybridized exclusively to the sex chromosomes. The probe signals localized a discrete rDNA site at the end of the short arm of the X chromosome, whereas they appeared dispersed over the entire dot-like Y chromosome. In polytene nuclei, the rDNA was found associated with the heterochromatic network representing the sex chromosomes. Only in nuclei with preserved nucleolar structure, the probe signals were scattered in the restricted area of the nucleolus. Thus, our study clearly shows that the granular heterochromatic network of polytene nuclei in B. oleae is formed by the underreplicated sex chromosomes and associated rDNA. PMID:22825842

Drosopoulou, Elena; Nakou, Ifigeneia; Síchová, Jindra; Kubí?ková, Svatava; Marec, František; Mavragani-Tsipidou, Penelope

2012-07-24

297

Longitudinal studies of chromosomal abnormalities and reticulum cell proliferation in New Zealand Black mice.  

PubMed

A longitudinal study of 40 New Zealand Black (NZB) mice and 20 BALB/c control animals was performed. A significant association was observed between the presence of acquired spleen-cell aneuploidy at some time during life and development of histological evidence of reticulum-cell neoplasia in individual animals. This finding is compatible with the hypothesis that aneuploid clones which arise in the spleens of aging NZBs are at least potentially neoplastic. However, no relationship between histologically neoplastic reticulum cell proliferation and aneuploidy was apparent in single splenic specimens obtained from NZB mice of various ages. This lack of association indicates that failure to detect chromosomal abnormalities on direct study of cells from a tumor cannot be taken as evidence that the neoplastic cells themselves lack such abnormalities. PMID:359488

Friedman, J M; Fialkow, P J; East, J; Bryant, J I; Salo, A C

1978-10-15

298

Absence of sperm sex chromosome aneuploidies in an X0\\/XYY man  

Microsoft Academic Search

Objective: To determine appropriate genetic counseling of patients with a mosaic karyotype who wished to undergo assisted reproduction technology.Design: Case report.Setting: A tertiary center for assisted reproduction technology.Patient(s): A male with a mosaic karyotype X0\\/XYY.Intervention(s): Analysis of ejaculated spermatozoa by using fluorescence in situ hybridisation with probes directed against chromosomes X, Y, and 18.Main Outcome Measure(s): Degree of sex chromosome

Brian Dale; Martin Wilding; Loredana De Matteo; Fulvio Zullo

2002-01-01

299

Genomic imprinting as a probable explanation for variable intrafamilial phenotypic expression of an unusual chromosome 3 abnormality  

Microsoft Academic Search

We present a 4 generation family in which an abnormal chromosome 3 with dup(3)(q25) segregated from great-grandmother to grandmother to son without phenotypic effect. The son`s 2 daughters have dysmorphic features, mild developmental delays and congenital heart disease. Both girls have the abnormal chr. 3 but are the only family members with the abnormality to have phenotypic effects. An unaffected

J. S. Fryburg; V. Shashi; T. E. Kelly

1994-01-01

300

Assessment of sex chromosome ratio and aneuploidy rate in motile spermatozoa selected by three different methods.  

PubMed

Using three-colour fluorescence in-situ hybridization, sex chromosome ratios and frequencies of diploidy and disomy for chromosomes X, Y and 18 were compared in spermatozoa of good and poor motility after separation by swim-up, glass-wool and two-layer discontinuous Percoll methods. Semen samples were collected from seven normal males aged 26-31 years. A minimum of 6000 sperm nuclei per sample were evaluated for each chromosome for a total of 308,432 sperm nuclei. Hybridization efficiency was 99.8%. A slight change in the ratio of X- to Y-bearing spermatozoa was noted after Percoll separation (from 49.3:49.5 to 50.0:48.9; P = 0.036 and P = 0.046), but not after separation by the other two methods. We did not observe significant differences in the disomy rates for sex chromosomes or chromosome 18 or in the diploidy rate between spermatozoa with good and poor motility after separation by any of the three methods. Our data indicate that separation of motile spermatozoa does not alter the ratio of X- to Y-bearing spermatozoa to a degree that represents sex chromosome selection. PMID:9436680

Samura, O; Miharu, N; He, H; Okamoto, E; Ohama, K

1997-11-01

301

DNA is organized into 46 chromosomes including sex chromosomes, 3D animation with no audioSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

The millions of bases, which make up the human genome are organized into structures called chromosomes. These are arranged into 22 matching pairs plus 1 pair of sex chromosomes consisting of 2 X's in women and an X and a Y in men. So humans have a total of 46 chromosomes in each cell, known collectively as a karyotype. This set of chromosomes has a Y, so it must belong to a male.

2008-10-06

302

Cognition and the Sex Chromosomes: Studies in Turner Syndrome  

Microsoft Academic Search

Turner syndrome (TS) is a human genetic disorder involving females who lack all or part of one X chromosome. The complex phenotype includes ovarian failure, a characteristic neurocognitive profile and typical physical features. TS features are associated not only with complete monosomy X but also with partial deletions of either the short (Xp) or long (Xq) arm (partial monosomy X).

Judith Ross; David Roeltgen; Andrew Zinn

2006-01-01

303

Sex-dependent selection differentially shapes genetic variation on and off the guppy Y chromosome.  

PubMed

Because selection is often sex-dependent, alleles can have positive effects on fitness in one sex and negative effects in the other, resulting in intralocus sexual conflict. Evolutionary theory predicts that intralocus sexual conflict can drive the evolution of sex limitation, sex-linkage, and sex chromosome differentiation. However, evidence that sex-dependent selection results in sex-linkage is limited. Here, we formally partition the contribution of Y-linked and non-Y-linked quantitative genetic variation in coloration, tail, and body size of male guppies (Poecilia reticulata)-traits previously implicated as sexually antagonistic. We show that these traits are strongly genetically correlated, both on and off the Y chromosome, but that these correlations differ in sign and magnitude between both parts of the genome. As predicted, variation in attractiveness was found to be associated with the Y-linked, rather than with the non-Y-linked component of genetic variation in male ornamentation. These findings show how the evolution of Y-linkage may be able to resolve sexual conflict. More generally, they provide unique insight into how sex-specific selection has the potential to differentially shape the genetic architecture of fitness traits across different parts of the genome. PMID:21790565

Postma, Erik; Spyrou, Nicolle; Rollins, Lee Ann; Brooks, Robert C

2011-05-03

304

Meiotic sex chromosome inactivation in male mice with targeted disruptions of Xist.  

PubMed

X chromosome inactivation occurs twice during the life cycle of placental mammals. In normal females, one X chromosome in each cell is inactivated early in embryogenesis, while in the male, the X chromosome is inactivated together with the Y chromosome in spermatogenic cells shortly before or during early meiotic prophase. Inactivation of one X chromosome in somatic cells of females serves to equalise X-linked gene dosage between males and females, but the role of male meiotic sex chromosome inactivation (MSCI) is unknown. The inactive X-chromosome of somatic cells and male meiotic cells share similar properties such as late replication and enrichment for histone macroH2A1.2, suggesting a common mechanism of inactivation. This possibility is supported by the fact that Xist RNA that mediates somatic X-inactivation is expressed in the testis of male mice and humans. In the present study we show that both Xist RNA and Tsix RNA, an antisense RNA that controls Xist function in the soma, are expressed in the testis in a germ-cell-dependent manner. However, our finding that MSCI and sex-body formation are unaltered in mice with targeted mutations of Xist that prevent somatic X inactivation suggests that somatic X-inactivation and MSCI occur by fundamentally different mechanisms. PMID:12356914

Turner, James M A; Mahadevaiah, Shantha K; Elliott, David J; Garchon, Henri-Jean; Pehrson, John R; Jaenisch, Rudolf; Burgoyne, Paul S

2002-11-01

305

Sex chromosome aberrations and stature: deduction of the principal factors involved in the determination of adult height  

Microsoft Academic Search

Although sex chromosome aberrations are frequently associated with statural changes, the underlying factors have not been clarified. To define the factors leading to the statural changes, we took the following three steps: (1) determination of the mean adult height in non-mosaic Caucasian patients with sex chromosome aberrations reported in the literature (assessment of genetic height potential); (2) assessment of the

Tsutomu Ogata; Nobutake Matsuo

1993-01-01

306

Autosomal location of genes from the conserved mammalian X in the platypus ( Ornithorhynchus anatinus ): implications for mammalian sex chromosome evolution  

Microsoft Academic Search

Mammalian sex chromosomes evolved from an ancient autosomal pair. Mapping of human X- and Y-borne genes in distantly related mammals and non-mammalian vertebrates has proved valuable to help deduce the evolution of this unique part of the genome. The platypus, a monotreme mammal distantly related to eutherians and marsupials, has an extraordinary sex chromosome system comprising five X and five

Paul D. Waters; Margaret L. Delbridge; Janine E. Deakin; Nisrine El-Mogharbel; Patrick J. Kirby; Denise R. Carvalho-Silva; Jennifer A. Marshall Graves

2005-01-01

307

Four loci on abnormal chromosome 10 contribute to meiotic drive in maize.  

PubMed Central

We provide a genetic analysis of the meiotic drive system on maize abnormal chromosome 10 (Ab10) that causes preferential segregation of specific chromosomal regions to the reproductive megaspore. The data indicate that at least four chromosomal regions contribute to meiotic drive, each providing distinct functions that can be differentiated from each other genetically and/or phenotypically. Previous reports established that meiotic drive requires neocentromere activity at specific tandem repeat arrays (knobs) and that two regions on Ab10 are involved in trans-activating neocentromeres. Here we confirm and extend data suggesting that only one of the neocentromere-activating regions is sufficient to move many knobs. We also confirm the localization of a locus/loci on Ab10, thought to be a prerequisite for meiotic drive, which promotes recombination in structural heterozygotes. In addition, we identified two new and independent functions required for meiotic drive. One was identified through the characterization of a deletion derivative of Ab10 [Df(L)] and another as a newly identified meiotic drive mutation (suppressor of meiotic drive 3). In the absence of either function, meiotic drive is abolished but neocentromere activity and the recombination effect typical of Ab10 are unaffected. These results demonstrate that neocentromere activity and increased recombination are not the only events required for meiotic drive.

Hiatt, Evelyn N; Dawe, R Kelly

2003-01-01

308

Array-Based Comparative Genomic Hybridization for the Genomewide Detection of Submicroscopic Chromosomal Abnormalities  

PubMed Central

Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using ?3,500 flourescent in situ hybridization–verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome.

Vissers, Lisenka E. L. M.; de Vries, Bert B. A.; Osoegawa, Kazutoyo; Janssen, Irene M.; Feuth, Ton; Choy, Chik On; Straatman, Huub; van der Vliet, Walter; Huys, Erik H. L. P. G.; van Rijk, Anke; Smeets, Dominique; van Ravenswaaij-Arts, Conny M. A.; Knoers, Nine V.; van der Burgt, Ineke; de Jong, Pieter J.; Brunner, Han G.; van Kessel, Ad Geurts; Schoenmakers, Eric F. P. M.; Veltman, Joris A.

2003-01-01

309

Embryo sexing and sex chromosomal chimerism analysis by loop-mediated isothermal amplification in cattle and water buffaloes.  

PubMed

In domestic animals of the family Bovidae, sex preselection of offspring has been demanded for convenience of milk/beef production and animal breeding. Development of the nonsurgical embryo transfer technique and sexing methods of preimplantation embryos made it possible. Sexing based on detection of Y chromosome-specific DNA sequences is considered the most reliable method to date. PCR enables amplification of a target sequence from a small number of blastomeres. However, it requires technical skill and is time consuming. Furthermore, PCR has the risk of false positives because of DNA contamination during handling of the PCR products in duplicate PCR procedures and/or electrophoresis. Therefore, for embryo sexing to become widely used in the cattle embryo transfer industry, a simple, rapid and precise sexing method needs to be developed. Loop-mediated isothermal amplification (LAMP) is a novel DNA amplification method, and the reaction is carried out under isothermal conditions (range, 60 to 65 C) using DNA polymerase with strand displacement activity. When the target DNA is amplified by LAMP, a white precipitate derived from magnesium pyrophosphate (a by-product of the LAMP reaction) is observed. It is noteworthy that LAMP does not need special reagents or electrophoresis to detect the amplified DNA. This review describes the development and application of an embryo sexing method using LAMP in cattle and water buffaloes. PMID:23965599

Hirayama, Hiroki; Kageyama, Soichi; Moriyasu, Satoru; Sawai, Ken; Minamihashi, Akira

2013-01-01

310

Gender-Specific Gene Expression in Post-Mortem Human Brain: Localization to Sex Chromosomes  

Microsoft Academic Search

Gender differences in brain development and in the prevalence of neuropsychiatric disorders such as depression have been reported. Gender differences in human brain might be related to patterns of gene expression. Microarray technology is one useful method for investigation of gene expression in brain. We investigated gene expression, cell types, and regional expression patterns of differentially expressed sex chromosome genes

Marquis P Vawter; Simon Evans; Prabhakara Choudary; Hiroaki Tomita; Jim Meador-Woodruff; Margherita Molnar; Jun Li; Juan F Lopez; Rick Myers; David Cox; Stanley J Watson; Huda Akil; Edward G Jones; William E Bunney

2004-01-01

311

Imprinted chromosomal regions of the human genome display sex-specific meiotic recombination frequencies  

Microsoft Academic Search

Background: Meiotic recombination events do not occur randomly along a chromosome, but appear to be restricted to specific regions. In addition, some regions in the genome undergo recombination more frequently in the germ cells of one sex than the other. Genomic imprinting, the process by which the two parental alleles of a gene are differentially marked, is another genetic phenomenon

Andràs Pàldi; Gàbor Gyapay; Jacques Jami

1995-01-01

312

Convergent Evolution of Chromosomal Sex-Determining Regions in the Animal and Fungal Kingdoms  

Microsoft Academic Search

Sexual identity is governed by sex chromosomes in plants and animals, and by mating type (MAT) loci in fungi. Comparative analysis of the MAT locus from a species cluster of the human fungal pathogen Cryptococcus revealed sequential evolutionary events that fashioned this large, highly unusual region. We hypothesize that MAT evolved via four main steps, beginning with acquisition of genes

James A Fraser; Stephanie Diezmann; Ryan L Subaran; Andria Allen; Klaus B Lengeler; Fred S Dietrich; Joseph Heitman

2004-01-01

313

Self-correction of chromosomal abnormalities in human preimplantation embryos and embryonic stem cells.  

PubMed

Aneuploidy is commonly seen in human preimplantation embryos, most particularly at the cleavage stage because of genome activation by third cell division. Aneuploid embryos have been used for the derivation of normal embryonic stem cell (ESC) lines and developmental modeling. This review addresses aneuploidies in human preimplantation embryos and human ESCs and the potential of self-correction of these aberrations. Diploid-aneuploid mosaicism is the most frequent abnormality observed; hence, embryos selected by preimplantation genetic diagnosis at the cleavage or blastocyst stage could be partly abnormal. Differentiation is known as the barrier for eliminating mosaic embryos by death and/or decreased division of abnormal cells. However, some mosaicisms, such as copy number variations could be compatible with live birth. Several reasons have been proposed for self-correction of aneuploidies during later stages of development, including primary misdiagnosis, allocation of the aneuploidy in the trophectoderm, cell growth advantage of diploid cells in mosaic embryos, lagging of aneuploid cell division, extrusion or duplication of an aneuploid chromosome, and the abundance of DNA repair gene products. Although more studies are needed to understand the mechanisms of self-correction as a rare phenomenon, most likely, it is related to overcoming mosaicism. PMID:23557100

Bazrgar, Masood; Gourabi, Hamid; Valojerdi, Mojtaba Rezazadeh; Yazdi, Poopak Eftekhari; Baharvand, Hossein

2013-05-14

314

X chromosome dosage by quantitative fluorescent PCR and rapid prenatal diagnosis of sex chromosome aneuploidies  

Microsoft Academic Search

During the past few years, rapid prenatal diagnosis of chromosome aneuploidies has been successfully achieved by quantitative fluorescent PCR (QF-PCR) amplification of chromosome-specific small tandem repeats (STR). This approach has proven to be very useful in clinical settings, since it allows the detection of major numerical disorders in a few hours after sampling. For the detection of Turner's syndrome (45,X),

Vincenzo Cirigliano; Maijo Ejarque; Carme Fuster; Matteo Adinolfi

2002-01-01

315

Genome structure and emerging evidence of an incipient sex chromosome in Populus  

PubMed Central

The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F1 interspecific cross involving the female genotype that was used for genome sequencing. This region shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane’s rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender.

Yin, Tongming; DiFazio, Stephen P.; Gunter, Lee E.; Zhang, Xinye; Sewell, Michell M.; Woolbright, Scott A.; Allan, Gery J.; Kelleher, Collin T.; Douglas, Carl J.; Wang, Mingxiu; Tuskan, Gerald A.

2008-01-01

316

Genome structure and emerging evidence of an incipient sex chromosome in Populus.  

PubMed

The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F(1) interspecific cross involving the female genotype that was used for genome sequencing. This region shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane's rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender. PMID:18256239

Yin, Tongming; Difazio, Stephen P; Gunter, Lee E; Zhang, Xinye; Sewell, Michell M; Woolbright, Scott A; Allan, Gery J; Kelleher, Collin T; Douglas, Carl J; Wang, Mingxiu; Tuskan, Gerald A

2008-02-06

317

Genome structure and emerging evidence of an incipient sex chromosome in Populus  

SciTech Connect

The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F1 interspecific cross involving the female genotype that was used for genome sequencing. This region shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane's rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender.

Yin, Tongming [ORNL; DiFazio, Stephen P [West Virginia University; Gunter, Lee E [ORNL; Zhang, Xinye [ORNL; Sewell, Mitchell [ORNL; Woolbright, Dr. Scott [North Arizona University; Allan, Dr. Gery [North Arizona University; Kelleher, Colin [University of British Columbia, Vancouver; Douglas, Carl [University of British Columbia, Vancouver; Wang, Prof. Mingxiu [Nanjing Forestry University, China; Tuskan, Gerald A [ORNL

2008-01-01

318

Anterior positioning of sex chromosomes on the head of human sperm sorted using visible wavelengths.  

PubMed

The human ejaculate contains subpopulations of sperm with distinct properties. Human X- and Y-bearing sperm were separated with fluorescence activated cell sorting. To avoid the use of UV light the quantitative DNA dyes DRAQ5® and Dyecycle™ Vybrant® Violet were used. Sorting efficiency was similar for both dyes, but lower than what is usually obtained with the classical method involving Hoechst 33342 and UV light (60-70% enrichment, versus 80-90%). A total of 2,739 spermatozoa were evaluated, from seven distinct samples using fluorescence in situ hybridization (FISH) chromosomal probes. No differences were found in sorted and unsorted populations in terms of chromosome positioning, and numeric chromosomal anomalies were not more evident following cell sorting. Furthermore in both sorted and unsorted populations the sex chromosomes were clearly located in the anterior portion of the sperm head, while a control autosome (chromosome 18) showed no such tendency, confirming previous findings. These results suggest that other quantitative DNA dyes may be used for sex chromosome-based human sperm sorting, but with lower efficiency than the standard UV-Hoechst based assay. PMID:23631693

Alçada-Morais, Sofia; Sousa, Ana Paula; Paiva, Artur; Almeida-Santos, Teresa; Ramalho-Santos, João

2013-05-01

319

The Chromosome 11 Region From Strain 129 Provides Protection From Sex Reversal in XYPOS Mice  

PubMed Central

C57BL/6J (B6) mice containing the Mus domesticus poschiavinus Y chromosome, YPOS, develop ovarian tissue, whereas testicular tissue develops in DBA/2J or 129S1/SvImJ (129) mice containing the YPOS chromosome. To identify genes involved in sex determination, we used a congenic strain approach to determine which chromosomal regions from 129Sl/SvImJ provide protection against sex reversal in XYPOS mice of the C57BL/6J.129-YPOS strain. Genome scans using microsatellite and SNP markers identified a chromosome 11 region of 129 origin in C57BL/6J.129-YPOS mice. To determine if this region influenced testis development in XYPOS mice, two strains of C57BL/6J-YPOS mice were produced and used in genetic experiments. XYPOS adults homozygous for the 129 region had a lower incidence of sex reversal than XYPOS adults homozygous for the B6 region. In addition, many homozygous 129 XYPOS fetuses developed normal-appearing testes, an occurrence never observed in XYPOS mice of the C57BL/6J-YPOS strain. Finally, the amount of testicular tissue observed in ovotestes of heterozygous 129/B6 XYPOS fetuses was greater than the amount observed in ovotestes of homozygous B6 XYPOS fetuses. We conclude that a chromosome 11 locus derived from 129Sl/SvImJ essentially protects against sex reversal in XYPOS mice. A number of genes located in this chromosome 11 region are discussed as potential candidates.

Nikolova, Ganka; Sinsheimer, Janet S.; Eicher, Eva M.; Vilain, Eric

2008-01-01

320

Chromosome-wide nucleosome replacement and H3.3 incorporation during mammalian meiotic sex chromosome inactivation.  

PubMed

In mammalian males, the first meiotic prophase is characterized by formation of a separate chromatin domain called the sex body. In this domain, the X and Y chromosomes are partially synapsed and transcriptionally silenced, a process termed meiotic sex-chromosome inactivation (MSCI). Likewise, unsynapsed autosomal chromatin present during pachytene is also silenced (meiotic silencing of unsynapsed chromatin, MSUC). Although it is known that MSCI and MSUC are both dependent on histone H2A.X phosphorylation mediated by the kinase ATR, and cause repressive H3 Lys9 dimethylation, the mechanisms underlying silencing are largely unidentified. Here, we demonstrate an extensive replacement of nucleosomes within unsynapsed chromatin, depending on and initiated shortly after induction of MSCI and MSUC. Nucleosomal eviction results in the exclusive incorporation of the H3.3 variant, which to date has primarily been associated with transcriptional activity. Nucleosomal exchange causes loss and subsequent selective reacquisition of specific histone modifications. This process therefore provides a means for epigenetic reprogramming of sex chromatin presumably required for gene silencing in the male mammalian germ line. PMID:17237782

van der Heijden, Godfried W; Derijck, Alwin A H A; Pósfai, Eszter; Giele, Maud; Pelczar, Pawel; Ramos, Liliana; Wansink, Derick G; van der Vlag, Johan; Peters, Antoine H F M; de Boer, Peter

2007-01-21

321

Allelic interaction of F1 pollen sterility loci and abnormal chromosome behaviour caused pollen sterility in intersubspecific autotetraploid rice hybrids  

PubMed Central

The intersubspecific hybrids of autotetraploid rice has many features that increase rice yield, but lower seed set is a major hindrance in its utilization. Pollen sterility is one of the most important factors which cause intersubspecific hybrid sterility. The hybrids with greater variation in seed set were used to study how the F1 pollen sterile loci (S-a, S-b, and S-c) interact with each other and how abnormal chromosome behaviour and allelic interaction of F1 sterility loci affect pollen fertility and seed set of intersubspecific autotetraploid rice hybrids. The results showed that interaction between pollen sterility loci have significant effects on the pollen fertility of autotetraploid hybrids, and pollen fertility further decreased with an increase in the allelic interaction of F1 pollen sterility loci. Abnormal ultra-structure and microtubule distribution patterns during pollen mother cell (PMC) meiosis were found in the hybrids with low pollen fertility in interphase and leptotene, suggesting that the effect-time of pollen sterility loci interaction was very early. There were highly significant differences in the number of quadrivalents and bivalents, and in chromosome configuration among all the hybrids, and quadrivalents decreased with an increase in the seed set of autotetraploid hybrids. Many different kinds of chromosomal abnormalities, such as chromosome straggling, chromosome lagging, asynchrony of chromosome disjunction, and tri-fission were found during the various developmental stages of PMC meiosis. All these abnormalities were significantly higher in sterile hybrids than in fertile hybrids, suggesting that pollen sterility gene interactions tend to increase the chromosomal abnormalities which cause the partial abortion of male gametes and leads to the decline in the seed set of the autotetraploid rice hybrids.

He, J. H.; Shahid, M. Q.; Guo, H. B.; Cheng, X. A.; Liu, X. D.; Lu, Y. G.

2011-01-01

322

Chromosomal microarray analysis as a first-line test in pregnancies with a priori low risk for the detection of submicroscopic chromosomal abnormalities.  

PubMed

In this study, we aimed to explore the utility of chromosomal microarray analysis (CMA) in groups of pregnancies with a priori low risk for detection of submicroscopic chromosome abnormalities, usually not considered an indication for testing, in order to assess whether CMA improves the detection rate of prenatal chromosomal aberrations. A total of 3000 prenatal samples were processed in parallel using both whole-genome CMA and conventional karyotyping. The indications for prenatal testing included: advanced maternal age, maternal serum screening test abnormality, abnormal ultrasound findings, known abnormal fetal karyotype, parental anxiety, family history of a genetic condition and cell culture failure. The use of CMA resulted in an increased detection rate regardless of the indication for analysis. This was evident in high risk groups (abnormal ultrasound findings and abnormal fetal karyotype), in which the percentage of detection was 5.8% (7/120), and also in low risk groups, such as advanced maternal age (6/1118, 0.5%), and parental anxiety (11/1674, 0.7%). A total of 24 (0.8%) fetal conditions would have remained undiagnosed if only a standard karyotype had been performed. Importantly, 17 (0.6%) of such findings would have otherwise been overlooked if CMA was offered only to high risk pregnancies.The results of this study suggest that more widespread CMA testing of fetuses would result in a higher detection of clinically relevant chromosome abnormalities, even in low risk pregnancies. Our findings provide substantial evidence for the introduction of CMA as a first-line diagnostic test for all pregnant women undergoing invasive prenatal testing, regardless of risk factors. PMID:23211699

Fiorentino, Francesco; Napoletano, Stefania; Caiazzo, Fiorina; Sessa, Mariateresa; Bono, Sara; Spizzichino, Letizia; Gordon, Anthony; Nuccitelli, Andrea; Rizzo, Giuseppe; Baldi, Marina

2012-12-05

323

Preimplantation genetic diagnosis increases the implantation rate in human in vitro fertilization by avoiding the transfer of chromosomally abnormal embryos  

Microsoft Academic Search

Objective: To verify the percentage of chromosomally abnormal preimplantation embryos in patients with a poor prognosis and possibly to increase the chance of implantation by selecting chromosomally normal embryos.Design: A prospective, randomized, controlled study.Setting: In vitro fertilization program at the Reproductive Medicine Unit of the Societá Italiana Studi Medicina della Riproduzione, Bologna, Italy.Patient(s): In a total of 28 stimulated cycles,

Luca Gianaroli; M. Cristina Magli; Anna Pia Ferraretti; Agnese Fiorentino; John Garrisi; Santiago Munné

1997-01-01

324

BrdU33258 Hoechst analysis of DNA replication in human lymphocytes with supernumerary or structurally abnormal X chromosomes  

Microsoft Academic Search

BrdU-33258 Hoechst techniques have been used to characterize DNA replication patterns in lymphocytes from human females with supernumerary or structurally abnormal X chromosomes. Fluorescence analysis permits identification of late replicating X chromosomes in a very high proportion of cells and affords a high resolution method for determining the interchange points of X-X and X-autosome translocations. Asynchrony among terminal replication patterns

Samuel A. Latt; Huntington F. Willard; Park S. Gerald

1976-01-01

325

Triple structural mosaicism of chromosome 18 in a child with MR\\/MCA syndrome and abnormal skin pigmentation  

Microsoft Academic Search

A case of triple mosaicism involving chromosome 18 is described in a girl with abnormal skin pigmentation similar to hypomelanosis of Ito. The karyotype is 46,XX, -18, + del(18)(p11.23-->pter)\\/46,XX, -18, + idic(18)(p11.23)\\/46,XX, -18, + r(18). The patient displays some clinical features of monosomy 18p and a few signs of trisomy 18q. Our case illustrates a non-random association of chromosomal mosaicism

E Bocian; T Mazurczak; E Bu?awa; H Sta?czak; G Rowicka

1993-01-01

326

A pseudoautosomal random amplified polymorphic DNA marker for the sex chromosomes of Silene dioica.  

PubMed Central

The segregation pattern of an 810-bp random amplified polymorphic DNA (RAPD) band in the F1 and backcross generations of a Silene dioica (L.) Clairv. family provides evidence that this molecular marker is located in the pseudoautosomal region (PAR) of the X and Y chromosomes. The marker was found through a combination of bulked segregant analysis (BSA) and RAPD techniques. Recombination rates between this pseudoautosomal marker and the differentiating portion of the Y chromosome are 15% in both generations. Alternative explanations involving nondisjunction or autosomal inheritance are presented and discussed. Chromosome counts provide evidence against the nondisjunction hypothesis, and probability calculations argue against the possibility of autosomal inheritance. This constitutes the first report of a pseudoautosomal DNA marker for plant sex chromosomes.

Di Stilio, V S; Kesseli, R V; Mulcahy, D L

1998-01-01

327

Correlations of chromosome abnormalities with histologic and immunologic characteristics in 49 patients from Akita, Japan with non-hodgkin lymphoma  

Microsoft Academic Search

We have analyzed the chromosomes of 49 non-Hodgkin lymphoma patients from an area of Japan that is nonendemic for adult T -cell leukemia\\/lymphoma. Clonal chromosome abnormalities were found in the majority (88%) of the specimens examined. The most characteristic structural abnormalities were: t(14;18)(q32;q21), t(3;22)(q27;q11), t(11;14)(q13;q32), idic(18)(p11.2), and the combination del(1)(p13) and del(i)(q11). The t(14;18) were found in four of five

Keiko Hashimoto; Ikuo Miura; Akihiko Chyubachi; Masahiro Saito; Akira B. Miura

1995-01-01

328

Triple structural mosaicism of chromosome 18 in a child with MR/MCA syndrome and abnormal skin pigmentation.  

PubMed

A case of triple mosaicism involving chromosome 18 is described in a girl with abnormal skin pigmentation similar to hypomelanosis of Ito. The karyotype is 46,XX, -18, + del(18)(p11.23-->pter)/46,XX, -18, + idic(18)(p11.23)/46,XX, -18, + r(18). The patient displays some clinical features of monosomy 18p and a few signs of trisomy 18q. Our case illustrates a non-random association of chromosomal mosaicism with abnormal skin pigmentation. PMID:8411041

Bocian, E; Mazurczak, T; Bu?awa, E; Sta?czak, H; Rowicka, G

1993-07-01

329

Using BAC clones to characterize unbalanced chromosome abnormalities in interphase cells.  

PubMed

Carriers of balanced translocations usually carry alterations in gene sequences, which lead to dysfunction during early and late embryogenesis. Related spatial rearrangement causes either cumulative delay in cell cycles and/or anomalies in transcription and translation. This has also an important impact at the time of genomic activation, the longest cell cycle of preimplantation development. Carrier patients may be affected either with primary infertility or by repeated miscarriages [Hum. Reprod. 12 (1997) 2019.]. Assuming that a fraction of the germ cells is karyotypically normal, these patients would greatly benefit from efficient procedures for generation and use of breakpoint-specific DNA hybridisation probes in preconception and preimplantation genetic diagnosis (PGD) after polar body or blastomere biopsy of the embryos. The objective of this research was to design an approach of patient-specific probes for preimplantation diagnosis of chromosome translocations and which could be used eventually to select chromosomally normal embryos from balanced or unbalanced interphase cells prior to their transfer to the mother's womb. This approach was used for a couple, where the female partner was a carrier of a balanced translocation 46,XX,t(4;12)(p16.1;q24.31). First, BAC/PAC clones were chosen from specific chromosome bands from the genome sequence that hybridise adjacent to the chromosomal breakpoints or span them. Then, the probes and hybridisation conditions were optimised using unrelated normal amniocytes, lymphoblastoid cells and lymphocytes from the carrier to increase hybridisation signal intensity and decrease background. Finally, the probes were tested on target cells before they were used for mimicking preconception or preimplantation genetic diagnosis. Three slides were analysed blindly from a normal karyotype, an unbalanced and a balanced translocation. A total of 78 cells were analysed of which in the slide A 19/22 (86%) were found to be unbalanced, in slide B 25/31 (81%) were normal and in slide C 21/25 (84%) were balanced. Thus, it was demonstrated that cells with known structural abnormalities could be detected, based on hybridisation of breakpoint spanning bacterial artificial chromosome (BAC) DNA probes in interphase cells. PMID:16762825

Plastira, Konstantina; Maher, Eddy; Fantes, Judith; Ramsay, Jacqueline; Angelopoulou, Roxani

2005-02-01

330

The Sex Chromosome Trisomy mouse model of XXY and XYY: metabolism and motor performance  

PubMed Central

Background Klinefelter syndrome (KS), caused by XXY karyotype, is characterized by low testosterone, infertility, cognitive deficits, and increased prevalence of health problems including obesity and diabetes. It has been difficult to separate direct genetic effects from hormonal effects in human studies or in mouse models of KS because low testosterone levels are confounded with sex chromosome complement. Methods In this study, we present the Sex Chromosome Trisomy (SCT) mouse model that produces XXY, XYY, XY, and XX mice in the same litters, each genotype with either testes or ovaries. The independence of sex chromosome complement and gonadal type allows for improved recognition of sex chromosome effects that are not dependent on levels of gonadal hormones. All mice were gonadectomized and treated with testosterone for 3 weeks. Body weight, body composition, and motor function were measured. Results Before hormonal manipulation, XXY mice of both sexes had significantly greater body weight and relative fat mass compared to XY mice. After gonadectomy and testosterone replacement, XXY mice (both sexes) still had significantly greater body weight and relative fat mass, but less relative lean mass compared to XY mice. Liver, gonadal fat pad, and inguinal fat pad weights were also higher in XXY mice, independent of gonadal sex. In several of these measures, XX mice also differed from XY mice, and gonadal males and females differed significantly on almost every metabolic measure. The sex chromosome effects (except for testis size) were also seen in gonadally female mice before and after ovariectomy and testosterone treatment, indicating that they do not reflect group differences in levels of testicular secretions. XYY mice were similar to XY mice on body weight and metabolic variables but performed worse on motor tasks compared to other groups. Conclusions We find that the new SCT mouse model for XXY and XYY recapitulates features found in humans with these aneuploidies. We illustrate that this model has significant promise for unveiling the role of genetic effects compared to hormonal effects in these syndromes, because many phenotypes are different in XXY vs. XY gonadal female mice which have never been exposed to testicular secretions.

2013-01-01

331

Comparative cytogenetic analysis of sex chromosomes in several Canidae species using zoo-FISH.  

PubMed

Sex chromosome differentiation began early during mammalian evolution. The karyotype of almost all placental mammals living today includes a pair of heterosomes: XX in females and XY in males. The genomes of different species may contain homologous synteny blocks indicating that they share a common ancestry. One of the tools used for their identification is the Zoo-FISH technique. The aim of the study was to determine whether sex chromosomes of some members of the Canidae family (the domestic dog, the red fox, the arctic fox, an interspecific hybrid: arctic fox x red fox and the Chinese raccoon dog) are evolutionarily conservative. Comparative cytogenetic analysis by Zoo-FISH using painting probes specific to domestic dog heterosomes was performed. The results show the presence of homologous synteny covering the entire structures of the X and the Y chromosomes. This suggests that sex chromosomes are conserved in the Canidae family. The data obtained through Zoo-FISH karyotype analysis append information obtained using other comparative genomics methods, giving a more complete depiction of genome evolution. PMID:22428301

Bugno-Poniewierska, Monika; Sojecka, Agnieszka; Pawlina, Klaudia; Jakubczak, Andrzej; Jezewska-Witkowska, Grazyna

2012-01-01

332

Sex-ratio drive in Drosophila simulans: variation in segregation ratio of X chromosomes from a natural population.  

PubMed Central

The sex-ratio trait that exists in a dozen Drosophila species is a case of naturally occurring X chromosome drive that causes males to produce female-biased progeny. Autosomal and Y polymorphism for suppressors are known to cause variation in drive expression, but the X chromosome polymorphism has never been thoroughly investigated. We characterized 41 X chromosomes from a natural population of Drosophila simulans that had been transferred to a suppressor-free genetic background. We found two clear-cut groups of chromosomes, sex-ratio and standard. The sex-ratio X chromosomes differed in their segregation ratio (81-96% females in the progeny), the less powerful drivers being less stable in their expression. A sib analysis, using a moderate driver, indicated that within-X variation in drive expression depended on genetic (autosomal) or epigenetic factors and that the age of the males also affected the trait. The other X chromosomes produced equal or roughly equal sex ratios, but again with significant variation. The continuous pattern of variation observed within both groups suggested that, in addition to a major sex-ratio gene, many X-linked loci of small effect modify the segregation ratio of this chromosome and are maintained in a polymorphic state. This was also supported by the frequency distribution of sex ratios produced by recombinant X chromosomes.

Montchamp-Moreau, Catherine; Cazemajor, Michel

2002-01-01

333

Fetal nuchal translucency scan and early prenatal diagnosis of chromosomal abnormalities by rapid aneuploidy screening: observational study  

PubMed Central

Objective To investigate an approach for the analysis of samples obtained in screening for trisomy 21 that retains the advantages of quantitative fluorescent polymerase chain reaction (qf-PCR) over full karyotyping and maximises the detection of clinically significant abnormalities. Design Observational study. Setting Tertiary referral centre. Subjects 17 446 pregnancies, from which chorionic villous samples had been taken after assessment of risk for trisomy 21 by measurement of fetal nuchal translucency (NT) thickness at 11 to 13+6 weeks of gestation. Interventions Analysis of chorionic villous samples by full karyotyping and by qf-PCR for chromosomes 13, 18, 21, X, and Y. Main outcome measure Detection of clinically significant chromosomal abnormalities. Results The fetal karyotype was normal in 15 548 (89.1%) cases and abnormal in 1898 (10.9%) cases, including 1722 with a likely clinically significant adverse outcome. Karyotyping all cases would lead to the diagnosis of all clinically significant abnormalities, and a policy of relying entirely on qf-PCR would lead to the diagnosis of 97.9% of abnormalities. An alternative strategy whereby qf-PCR is the main method of analysis and full karyotyping is reserved for those cases with a minimum fetal NT thickness of 4 mm would require full karyotyping in 10.1% of the cases, would identify 99.0% of the significant abnormalities, and would cost 60% less than full karyotyping for all. Conclusions In the diagnosis of chromosomal abnormalities after first trimester screening for trisomy 21, a policy of qf-PCR for all samples and karyotyping only if the fetal NT thickness is increased would reduce the economic costs, provide rapid delivery of results, and identify 99% of the clinically significant chromosomal abnormalities.

Chitty, Lyn S; Kagan, Karl O; Molina, Francisca S; Waters, Jonathan J; Nicolaides, Kypros H

2006-01-01

334

Simultaneous Occurrence of Inflammatory Bowel Disease and Myelodysplastic Syndrome due to Chromosomal Abnormalities in Bone Marrow Cells  

Microsoft Academic Search

Background\\/Aims: Although chromosomal abnormalities in bone marrow (BM) cells, such as trisomy 8, are risk factors for the development of inflammatory bowel diseases (IBD) as well as myelodysplastic syndrome (MDS), the mechanisms of how these cytogenetic abnormalities cause intestinal inflammation are poorly understood. Methods and Results: A 55-year-old man with a 3-month history of watery diarrhea, fever and abdominal pain

Fumiyasu Nakamura; Tomohiro Watanabe; Kimiko Hori; Yoshiaki Ohara; Kouhei Yamashita; Yoshihisa Tsuji; Yoshihide Ueda; Sakae Mikami; Hiroshi Nakase; Tsutomu Chiba

2009-01-01

335

Investigation with Tritiated Thymidine of the Relationship Between the Sex Chromosomes, Sex Chromatin, and the Drumstick in the Cells of the Female Nine-Banded Armadillo, Dasypus novemcinctus  

Microsoft Academic Search

The functional analogies between the sex chromosomes, sex chromatin, and the drumstick in the cells of the female nine-banded armadillo (Dasypus no&ypsilon;emcinctus) were investigated utilizing tritium labelled thymidine both in vitro and in vivo. Tissue culture studies demonstrated that one of the female X chromosomes is asynchronous and synthesizes DNA later than the other X and most of the autosomal

M. A. Grinberg; M. M. Sullivan; K. Benirschke

1966-01-01

336

Dosage Effects of X and Y Chromosomes on Language and Social Functioning in Children with Supernumerary Sex Chromosome Aneuploidies: Implications for Idiopathic Language Impairment and Autism Spectrum Disorders  

ERIC Educational Resources Information Center

|Background: Supernumerary sex chromosome aneuploidies (X/Y-aneuploidies), the presence of extra X and/or Y chromosomes, are associated with heightened rates of language impairments and social difficulties. However, no single study has examined different language domains and social functioning in the same sample of children with tri-, tetra-, and…

Lee, Nancy Raitano; Wallace, Gregory L.; Adeyemi, Elizabeth I.; Lopez, Katherine C.; Blumenthal, Jonathan D.; Clasen, Liv S.; Giedd, Jay N.

2012-01-01

337

Platypus chain reaction: directional and ordered meiotic pairing of the multiple sex chromosome chain in Ornithorhynchus anatinus.  

PubMed

Monotremes are phylogenetically and phenotypically unique animals with an unusually complex sex chromosome system that is composed of ten chromosomes in platypus and nine in echidna. These chromosomes are alternately linked (X1Y1, X2Y2, ...) at meiosis via pseudoautosomal regions and segregate to form spermatozoa containing either X or Y chromosomes. The physical and epigenetic mechanisms involved in pairing and assembly of the complex sex chromosome chain in early meiotic prophase I are completely unknown. We have analysed the pairing dynamics of specific sex chromosome pseudoautosomal regions in platypus spermatocytes during prophase of meiosis I. Our data show a highly coordinated pairing process that begins at the terminal Y5 chromosome and completes with the union of sex chromosomes X1Y1. The consistency of this ordered assembly of the chain is remarkable and raises questions about the mechanisms and factors that regulate the differential pairing of sex chromosomes and how this relates to potential meiotic silencing mechanisms and alternate segregation. PMID:19874721

Daish, Tasman; Casey, Aaron; Grützner, Frank

2009-01-01

338

Effect of separating bull semen into X and Y chromosome-bearing fractions on the sex ratio of resulting embryos.  

PubMed Central

Seventy-six, day 12 to day 15 bovine embryos, collected from 14 donors which had been inseminated with either X or Y chromosome-bearing spermatozoa fractions of semen separated by a thermal convection counterstreaming sedimentation and forced convection galvanization process, were processed for sexing by chromosomal analysis. Fifty-seven embryos were sexed; 20 from Y chromosome-bearing and 37 from X chromosome-bearing fractions of semen. Statistical analysis of the sexing data indicated that there was no significant difference in the male: female ratio for donors receiving male fractions compared to those receiving female fractions. The Y chromosome-bearing fractions produced a male: female ratio that was indistinguishable from the expected 1:1 ratio. However, the X chromosome-bearing fractions of semen produced a highly significant deviation from the expected 1:1 ratio towards the male.

Hagele, W C; Hare, W C; Singh, E L; Grylls, J L; Abt, D A

1984-01-01

339

Sex Chromosome Mosaicism and Hybrid Speciation among Tiger Swallowtail Butterflies  

PubMed Central

Hybrid speciation, or the formation of a daughter species due to interbreeding between two parental species, is a potentially important means of diversification, because it generates new forms from existing variation. However, factors responsible for the origin and maintenance of hybrid species are largely unknown. Here we show that the North American butterfly Papilio appalachiensis is a hybrid species, with genomic admixture from Papilio glaucus and Papilio canadensis. Papilio appalachiensis has a mosaic phenotype, which is hypothesized to be the result of combining sex-linked traits from P. glaucus and P. canadensis. We show that P. appalachiensis' Z-linked genes associated with a cooler thermal habitat were inherited from P. canadensis, whereas its W-linked mimicry and mitochondrial DNA were inherited from P. glaucus. Furthermore, genome-wide AFLP markers showed nearly equal contributions from each parental species in the origin of P. appalachiensis, indicating that it formed from a burst of hybridization between the parental species, with little subsequent backcrossing. However, analyses of genetic differentiation, clustering, and polymorphism based on molecular data also showed that P. appalachiensis is genetically distinct from both parental species. Population genetic simulations revealed P. appalachiensis to be much younger than the parental species, with unidirectional gene flow from P. glaucus and P. canadensis into P. appalachiensis. Finally, phylogenetic analyses, combined with ancestral state reconstruction, showed that the two traits that define P. appalachiensis' mosaic phenotype, obligatory pupal diapause and mimicry, evolved uniquely in P. canadensis and P. glaucus, respectively, and were then recombined through hybridization to form P. appalachiensis. These results suggest that natural selection and sex-linked traits may have played an important role in the origin and maintenance of P. appalachiensis as a hybrid species. In particular, ecological barriers associated with a steep thermal cline appear to maintain the distinct, mosaic genome of P. appalachiensis despite contact and occasional hybridization with both parental species.

Kunte, Krushnamegh; Shea, Cristina; Aardema, Matthew L.; Scriber, J. Mark; Juenger, Thomas E.; Gilbert, Lawrence E.; Kronforst, Marcus R.

2011-01-01

340

No Evidence for a Second Evolutionary Stratum during the Early Evolution of Mammalian Sex Chromosomes  

PubMed Central

Mammalian sex chromosomes originated from a pair of autosomes, and homologous genes on the sex chromosomes (gametologs) differentiated through recombination arrest between the chromosomes. It was hypothesized that this differentiation in eutherians took place in a stepwise fashion and left a footprint on the X chromosome termed “evolutionary strata.” The evolutionary stratum hypothesis claims that strata 1 and 2 (which correspond to the first two steps of chromosomal differentiation) were generated in the stem lineage of Theria or before the divergence between eutherians and marsupials. However, this prediction relied solely on the molecular clock hypothesis between pairs of human gametologs, and molecular evolution of marsupial sex chromosomal genes has not yet been investigated. In this study, we analyzed the following 7 pairs of marsupial gametologs, together with their eutherian orthologs that reside in stratum 1 or 2: SOX3/SRY, RBMX/Y, RPS4X/Y, HSFX/Y, XKRX/Y, SMCX/Y (KDM5C/D, JARID1C/D), and UBE1X/Y (UBA1/UBA1Y). Phylogenetic analyses and estimated divergence time of these gametologs reveal that they all differentiated at the same time in the therian ancestor. We have also provided strong evidence for gene conversion that occurred in the 3? region of the eutherian stratum 2 genes (SMCX/Y and UBE1X/Y). The results of the present study show that (1) there is no compelling evidence for the second stratum in the stem lineage of Theria; (2) gene conversion, which may have occurred between SMCX/Y and UBE1X/Y in the eutherian lineage, potentially accounts for their apparently lower degree of overall divergence.

Katsura, Yukako; Satta, Yoko

2012-01-01

341

Sequencing chromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries.  

PubMed

Balanced chromosomal abnormalities (BCAs) represent a relatively untapped reservoir of single-gene disruptions in neurodevelopmental disorders (NDDs). We sequenced BCAs in patients with autism or related NDDs, revealing disruption of 33 loci in four general categories: (1) genes previously associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, and CDKL5), (2) single-gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, and SNURF-SNRPN), (3) novel risk loci (e.g., CHD8, KIRREL3, and ZNF507), and (4) genes associated with later-onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, and ANK3). We also discovered among neurodevelopmental cases a profoundly increased burden of copy-number variants from these 33 loci and a significant enrichment of polygenic risk alleles from genome-wide association studies of autism and schizophrenia. Our findings suggest a polygenic risk model of autism and reveal that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages. PMID:22521361

Talkowski, Michael E; Rosenfeld, Jill A; Blumenthal, Ian; Pillalamarri, Vamsee; Chiang, Colby; Heilbut, Adrian; Ernst, Carl; Hanscom, Carrie; Rossin, Elizabeth; Lindgren, Amelia M; Pereira, Shahrin; Ruderfer, Douglas; Kirby, Andrew; Ripke, Stephan; Harris, David J; Lee, Ji-Hyun; Ha, Kyungsoo; Kim, Hyung-Goo; Solomon, Benjamin D; Gropman, Andrea L; Lucente, Diane; Sims, Katherine; Ohsumi, Toshiro K; Borowsky, Mark L; Loranger, Stephanie; Quade, Bradley; Lage, Kasper; Miles, Judith; Wu, Bai-Lin; Shen, Yiping; Neale, Benjamin; Shaffer, Lisa G; Daly, Mark J; Morton, Cynthia C; Gusella, James F

2012-04-19

342

Aberrant subclavian artery origin in tetralogy of Fallot with pulmonary stenosis is associated with chromosomal or genetic abnormality.  

PubMed

We determined the relationship between aortic arch anatomy in tetralogy of Fallot with pulmonary stenosis and chromosomal or genetic abnormality, by performing analysis of 257 consecutive patients undergoing surgical repair from January, 2003 to March, 2011. Chromosomal or genetic abnormality was identified in 49 of the 257 (19%) patients. These included trisomy 21 (n = 14); chromosome 22q11.2 deletion (n = 16); other chromosomal abnormalities (n = 9); CHARGE (n = 2); Pierre Robin (n = 2); and Kabuki, Alagille, Holt-Oram, Kaufman McKusick, Goldenhar, and PHACE (n = 1 each). Aortic anatomy was classified as left arch with normal branching, right arch with mirror image branching, left arch with aberrant right subclavian artery, or right arch with aberrant left subclavian artery. Associated syndromes occurred in 33 of 203 (16%) patients with left arch and normal branching (odds ratio 1); three of 36 (8%) patients with right arch and mirror image branching (odds ratio 0.4, 95% confidence interval 0.1-1.6); seven of eight (88%) patients with left arch and aberrant right subclavian artery (odds ratio 36, 95% confidence interval 4-302); and six of 10 (60%) patients with right arch and aberrant left subclavian artery (odds ratio 8, 95% confidence interval 2-26). Syndromes were present in 13 of 18 (72%) patients with either right or left aberrant subclavian artery (odds ratio 15, 95% confidence interval 4-45). Syndromes in patients with an aberrant subclavian artery included trisomy 21 (n = 4); chromosome 22q11.2 deletion (n = 5); and Holt-Oram, PHACE, CHARGE, and chromosome 18p deletion (n = 1 each). Aberrant right or left subclavian artery in tetralogy of Fallot with pulmonary stenosis is associated with an increased incidence of chromosomal or genetic abnormality, whereas right aortic arch with mirror image branching is not. The assessment of aortic arch anatomy at prenatal diagnosis can assist counselling. PMID:23732114

Oswal, Nilesh; Christov, Georgi; Sridharan, Shankar; Khambadkone, Sachin; Bull, Catherine; Sullivan, Ian

2013-06-01

343

Chromosome banding in Amphibia. XXVIII. Homomorphic XY sex chromosomes and a derived Y-autosome translocation in Eleutherodactylus riveroi (Anura, Leptodactylidae).  

PubMed

Extensive cytogenetic analyses on a population of the leptodactylid frog Eleutherodactylus riveroi in northern Venezuela revealed the existence of multiple XXAA male/XYAA female/XAA(Y) female sex chromosomes. The XAA(Y) karyotype originated by a centric (Robertsonian) fusion between the original, free Y chromosome and an autosome. 46.2% of the male individuals in this population are carriers of this Y-autosome fusion. In male meiosis the XAA(Y) sex chromosomes pair in the expected trivalent configuration. In the same population 53.8% of the male animals still possess the original, free XY sex chromosomes. E. riveroi is only the second vertebrate species discovered in which a derived Y-autosome fusion coexists with the ancestral free XY sex chromosomes. The free XY sex chromosomes, as well as the multiple XA(Y) sex chromosomes are still in a very primitive (homomorphic) stage of differentiation. With no banding technique applied it is possible to distinguish the Y from the X. Various banding techniques and in situ hybridizations have been carried out to characterize the karyotypes. DNA flow cytometric measurements show that the genome size of E. riveroi resembles that of other Eleutherodactylus species. The cytogenetic data obtained in E. riveroi are compared with those of the sole other vertebrate known to possess the extremely rare, multiple XXAA male/XYAA female/XAA(Y) female sex chromosomes. Surprisingly enough, this vertebrate again is a frog belonging to the genus Eleutherodactylus [E. ((maussi) biporcatus] which lives exactly in the same habitat in northern Venezuela as does E. riveroi. PMID:14571139

Schmid, M; Feichtinger, W; Steinlein, C; Visbal García, R; Fernández Badillo, A

2003-01-01

344

Prevalence of sex chromosome loss in benign and malignant brain neoplasms  

SciTech Connect

Loss of gonosomes in a variety of benign and malignant neoplasms is well-documented, but the clinical and/or biological significance of such loss remains obscure. Loss of the Y chromosome from the leukocytes of elderly men is also well-known. In an attempt to elucidate the significance of the loss of gonosomes, we have determined the incidence of such loss in human brain tumors ranging from benign to highly malignant. Loss of the X or Y chromosomes were evaluated by karyotyping short-term cultures and by fluorescence in situ hybridization (FISH) on uncultured samples of 129 tumors. Loss of gonosomes was also evaluated in leukocytes from these patients. In glioblastoma multiforme (GM), the Y chromosome was lost from 64% and the X from 41% of 42 tumors. The Y chromosome was lost from 36% of 55 meningiomas (MA) and from 33% of other less malignant gliomas. Loss of the X chromosome was negligible in both MAs and the pre- or less malignant gliomas. Loss of the X or the Y in GM was the most common nonrandom abnormality and loss of the Y was the most nonrandom abnormality in all brain tumors, other than MA in which loss of chromosome 22 is the most common. There was insignificant difference in the detection of gonosomes loss by karyotyping or by FISH of interphase cells. There was no loss of gonosomes in the leukocytes of the studied patients. Although the significance of the X or Y loss is not clear, it appears that gonosomes play a role in the development of brain tumors. The gonosomes may carry genes involved in growth regulation. Although loss of the X or Y is nonrandom, loss of the X was limited to the malignant brain neoplasms whereas loss of the Y was noted in both benign and malignant tumors, which may suggest different functions in growth regulation of the two chromosomes.

Al Saadi, A. [William Beaumont Hospital, Royal Oak, MI (United States)

1994-09-01

345

RNF8 regulates active epigenetic modifications and escape gene activation from inactive sex chromosomes in post-meiotic spermatids  

PubMed Central

Sex chromosomes are uniquely subject to chromosome-wide silencing during male meiosis, and silencing persists into post-meiotic spermatids. Against this background, a select set of sex chromosome-linked genes escapes silencing and is activated in post-meiotic spermatids. Here, we identify a novel mechanism that regulates escape gene activation in an environment of chromosome-wide silencing in murine germ cells. We show that RNF8-dependent ubiquitination of histone H2A during meiosis establishes active epigenetic modifications, including dimethylation of H3K4 on the sex chromosomes. RNF8-dependent active epigenetic memory, defined by dimethylation of H3K4, persists throughout meiotic division. Various active epigenetic modifications are subsequently established on the sex chromosomes in post-meiotic spermatids. These RNF8-dependent modifications include trimethylation of H3K4, histone lysine crotonylation (Kcr), and incorporation of the histone variant H2AFZ. RNF8-dependent epigenetic programming regulates escape gene activation from inactive sex chromosomes in post-meiotic spermatids. Kcr accumulates at transcriptional start sites of sex-linked genes activated in an RNF8-dependent manner, and a chromatin conformational change is associated with RNF8-dependent epigenetic programming. Furthermore, we demonstrate that this RNF8-dependent pathway is distinct from that which recognizes DNA double-strand breaks. Our results establish a novel connection between a DNA damage response factor (RNF8) and epigenetic programming, specifically in establishing active epigenetic modifications and gene activation.

Sin, Ho-Su; Barski, Artem; Zhang, Fan; Kartashov, Andrey V.; Nussenzweig, Andre; Chen, Junjie; Andreassen, Paul R.; Namekawa, Satoshi H.

2012-01-01

346

RNF8 regulates active epigenetic modifications and escape gene activation from inactive sex chromosomes in post-meiotic spermatids.  

PubMed

Sex chromosomes are uniquely subject to chromosome-wide silencing during male meiosis, and silencing persists into post-meiotic spermatids. Against this background, a select set of sex chromosome-linked genes escapes silencing and is activated in post-meiotic spermatids. Here, we identify a novel mechanism that regulates escape gene activation in an environment of chromosome-wide silencing in murine germ cells. We show that RNF8-dependent ubiquitination of histone H2A during meiosis establishes active epigenetic modifications, including dimethylation of H3K4 on the sex chromosomes. RNF8-dependent active epigenetic memory, defined by dimethylation of H3K4, persists throughout meiotic division. Various active epigenetic modifications are subsequently established on the sex chromosomes in post-meiotic spermatids. These RNF8-dependent modifications include trimethylation of H3K4, histone lysine crotonylation (Kcr), and incorporation of the histone variant H2AFZ. RNF8-dependent epigenetic programming regulates escape gene activation from inactive sex chromosomes in post-meiotic spermatids. Kcr accumulates at transcriptional start sites of sex-linked genes activated in an RNF8-dependent manner, and a chromatin conformational change is associated with RNF8-dependent epigenetic programming. Furthermore, we demonstrate that this RNF8-dependent pathway is distinct from that which recognizes DNA double-strand breaks. Our results establish a novel connection between a DNA damage response factor (RNF8) and epigenetic programming, specifically in establishing active epigenetic modifications and gene activation. PMID:23249736

Sin, Ho-Su; Barski, Artem; Zhang, Fan; Kartashov, Andrey V; Nussenzweig, Andre; Chen, Junjie; Andreassen, Paul R; Namekawa, Satoshi H

2012-12-15

347

A Key Transcription Cofactor on the Nascent Sex Chromosomes of European Tree Frogs (Hyla arborea)  

PubMed Central

We show that MED15, a key component of the transcription complex Mediator, lies within the nonrecombining segment of nascent sex chromosomes in the male-heterogametic Hyla arborea. Both X and Y alleles are expressed during embryonic development and differ by three frame-preserving indels (eight amino acids in total) within their glutamine-rich central part. These changes have the potential to affect the conformation of the Mediator complex and to activate genes in a sex-specific way and might thus represent the first steps toward the acquisition of a male-specific function. Alternatively, they might result from an ancestral neutral polymorphism, with different alleles picked by chance on the X and Y chromosomes when MED15 was trapped in the nonrecombining segment.

Niculita-Hirzel, H.; Stock, M.; Perrin, N.

2008-01-01

348

Survey of repetitive sequences in Silene latifolia with respect to their distribution on sex chromosomes  

Microsoft Academic Search

We carried out a global survey of all major types of transposable elements in Silene latifolia, a model species with sex chromosomes that are in the early stages of their evolution. A shotgun genomic library was screened\\u000a with genomic DNA to isolate and characterize the most abundant elements. We found that the most common types of elements were\\u000a the subtelomeric

Tomas Cermak; Zdenek Kubat; Roman Hobza; Andrea Koblizkova; Alex Widmer; Jiri Macas; Boris Vyskot; Eduard Kejnovsky

2008-01-01

349

Recent evolution of NOR-bearing and sex chromosomes of the North African rodent Lemniscomys barbarus  

Microsoft Academic Search

The karyotype and meiotic phases of Lemniscomys barbarus from Morocco were extensively studied with G- and C-banding, Ag-NOR and fluorochrome staining, in situ hybridization with an rDNA probe, and synaptonemal complex analysis. Comparison of the data with those previously published for an Algerian specimen revealed in the Moroccan specimens the presence of large heterochromatic segments in the sex chromosomes, a

S. Stitou; M. Burgos; F. Zurita; R. Jimenez; A. Sanchez; R. Diaz de la Guardia

1997-01-01

350

Probing the W chromosome of the codling moth, Cydia pomonella , with sequences from microdissected sex chromatin  

Microsoft Academic Search

The W chromosome of the codling moth, Cydia pomonella, like that of most Lepidoptera species, is heterochromatic and forms a female-specific sex chromatin body in somatic cells.\\u000a We collected chromatin samples by laser microdissection from euchromatin and W-chromatin bodies. DNA from the samples was\\u000a amplified by degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR) and used to prepare painting probes and\\u000a start

Iva Fuková; Walther Traut; Magda Vítková; Petr Nguyen; Svatava Kubí?ková; František Marec

2007-01-01

351

Chromatin configuration and epigenetic landscape at the sex chromosome bivalent during equine spermatogenesis  

PubMed Central

Pairing of the sex chromosomes during mammalian meiosis is characterized by the formation of a unique heterochromatin structure at the XY body. The mechanisms underlying the formation of this nuclear domain are reportedly highly conserved from marsupials to mammals. In this study, we demonstrate that in contrast to all eutherian species studied to date, partial synapsis of the heterologous sex chromosomes during pachytene stage in the horse is not associated with the formation of a typical macrochromatin domain at the XY body. While phosphorylated histone H2AX (?H2AX) and macroH2A1.2 are present as a diffuse signal over the entire macrochromatin domain in mouse pachytene spermatocytes, ?H2AX, macroH2A1.2, and the cohesin subunit SMC3 are preferentially enriched at meiotic sex chromosome cores in equine spermatocytes. Moreover, although several histone modifications associated with this nuclear domain in the mouse such as H3K4me2 and ubH2A are conspicuously absent in the equine XY body, prominent RNA polymerase II foci persist at the sex chromosomes. Thus, the localization of key marker proteins and histone modifications associated with the XY body in the horse differs significantly from all other mammalian systems described. These results demonstrate that the epigenetic landscape and heterochromatinization of the equine XY body might be regulated by alternative mechanisms and that some features of XY body formation may be evolutionary divergent in the domestic horse. We propose equine spermatogenesis as a unique model system for the study of the regulatory networks leading to the epigenetic control of gene expression during XY body formation.

Baumann, Claudia; Daly, Christopher M.; McDonnell, Sue M.; Viveiros, Maria M.; De La Fuente, Rabindranath

2011-01-01

352

Serial study of the effect of radiotherapy on semen parameters, hamster egg penetration rates, and lymphocyte chromosome abnormalities  

SciTech Connect

This study was designed to assess the long-term effects of radiotherapy (RT) on male fertility and the induction of lymphocyte and sperm chromosome abnormalities. This preliminary report provides information on 11 cancer patients (mainly seminomas) treated by RT (testicular dose, 44 to 499 rads). All 11 men were studied pre-RT and at intervals post-RT. The pre-RT semen profile varied considerably, but, in general, the profile was poor with a mean sperm concentration of 19.4 x 10/sup 6/ ml and a mean hamster egg penetration rate of 5%. One month after RT, the sperm concentration decreased and hamster egg penetration was 0% in all men. At 3 and 12 months post-RT, all but two patients were azoospermic. By 24 months post-RT, 9 of 11 patients had regained sperm production and 5 had sperm capable of hamster egg penetration. The three men who have been studied 36 months post-RT had a mean sperm concentration of 45.3 x 10/sup 6/ ml, and all had positive hamster egg penetration tests, although two of the three men had very low penetration rates (2% and 4%). Lymphocyte chromosome analysis demonstrated a striking frequency of chromosome abnormalities post-RT which decreased with time (pre-RT, 0%; 1 month, 42.4%; 3 months, 24.7%; 12 months, 13.8%; 24 months, 11.2%; and 36 months, 10.0%). Thus, it appears that sperm production starts to recover 2 to 3 years after RT when the frequency of lymphocyte chromosome abnormalities has decreased, but the sperm may not be fully functional at this time, as evidenced by poor rates of hamster egg penetration. Future studies of sperm chromosome analysis in these men will determine whether this impairment of the sperm is associated with meiotic chromosome abnormalities.

Martin, R.H.; Barnes, M.; Arthur, K.; Ringrose, T.; Douglas, G.

1984-02-01

353

Fluorescence in situ hybridization on single cells. (Sex determination and chromosome rearrangements).  

PubMed

Fluorescence in situ hybridization (FISH) is the technique of choice for preimplantation genetic diagnosis (PGD) selection of female embryos in families with X-linked disease, for which there is no mutation-specific test. FISH with target-specific DNA probes is also the primary technique used for PGD detection of chromosome imbalance associated with Robertsonian translocations, reciprocal translocations, inversions, and other chromosome rearrangements, because the DNA probes, labeled with different fluorochromes or haptens, detect the copy number of their target loci. The methods described outline strategies for PGD for sex determination and chromosome rearrangements. These methods are assessment of reproductive risks, the selection of suitable probes for interphase FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring using directly labeled and indirectly labeled probes. PMID:17876073

Scriven, Paul N; Ogilvie, Caroline Mackie

2007-01-01

354

Sumoylation precedes accumulation of phosphorylated H2AX on sex chromosomes during their meiotic inactivation.  

PubMed

During meiosis in male mammals, X and Y chromosomes undergo the process of meiotic sex chromosome inactivation (MSCI). A crucial role in MSCI has recently been reported for BRCA1, ATR kinase, and phosphorylated histone H2AX, but the exact mechanism remains to be determined. Small ubiquitin-like modifier (SUMO) proteins have recently been shown to localize to the sex body in mouse meiotic spermatocytes, but the role they play during MSCI is unknown. In this study, in order to better understand the molecular events of MSCI, we followed dynamic changes in gammaH2AX and SUMO localization patterns during MSCI. Using confocal laser scanning microscopy (CLSM) as an analytical tool for visualizing numerous spermatocytes from the same development stage and for consecutively following the meiotic progression, we were able to demonstrate a very early appearance of SUMO-1, which preceded gammaH2AX accumulation on the sex chromosomes during their meiotic inactivation. In contrast to SUMO-1, SUMO-2/3 was undetectable in zygotene spermatocytes, suggesting a possible specific role for SUMO-1 in the initiation of MSCI. PMID:19156530

Vigodner, Margarita

2009-01-21

355

BRCA1, histone H2AX phosphorylation, and male meiotic sex chromosome inactivation.  

PubMed

In mammalian spermatogenesis, the X and Y chromosomes are transcriptionally silenced during the pachytene stage of meiotic prophase (meiotic sex chromosome inactivation, MSCI), forming a condensed chromatin domain termed the sex or XY body. The nucleosomal core histone H2AX is phosphorylated within the XY chromatin domain just prior to MSCI, and it has been hypothesized that this triggers the chromatin condensation and transcriptional repression. Here, we show that the kinase ATR localizes to XY chromatin at the onset of MSCI and that this localization is disrupted in mice with a mutant form of the tumor suppressor protein BRCA1. In the mutant pachytene cells, ATR is usually present at nonsex chromosomal sites, where it colocalizes with aberrant sites of H2AX phosphorylation; in these cells, there is MSCI failure. In rare pachytene cells, ATR does locate to XY chromatin, H2AX is then phosphorylated, a sex body forms, and MSCI ensues. These observations highlight an important role for BRCA1 in recruiting the kinase ATR to XY chromatin at the onset of MSCI and provide compelling evidence that it is ATR that phosphorylates H2AX and triggers MSCI. PMID:15589157

Turner, James M A; Aprelikova, Olga; Xu, Xiaoling; Wang, Ruihong; Kim, Sangsoo; Chandramouli, Gadisetti V R; Barrett, J Carl; Burgoyne, Paul S; Deng, Chu-Xia

2004-12-14

356

Chromosomal abnormalities and novel disease-related regions in progression from Barrett's esophagus to esophageal adenocarcinoma.  

PubMed

Barrett's esophagus (BE) is a metaplastic condition caused by chronic gastroesophageal reflux which represents an early step in the development of esophageal adenocarcinoma (EAC). Single-nucleotide polymorphism microarray (SNP-chip) analysis is a novel, precise, high-throughput approach to examine genomic alterations in neoplasia. Using 250K SNP-chips, we examined the neoplastic progression of BE to EAC, studying 11 matched sample sets: 6 sets of normal esophagus (NE), BE and EAC, 4 of NE and BE and 1 of NE and EAC. Six (60%) of 10 total BE samples and 4 (57%) of 7 total EAC samples exhibited 1 or more genomic abnormalities comprising deletions, duplications, amplifications and copy-number-neutral loss of heterozygosity (CNN-LOH). Several shared abnormalities were identified, including chromosome 9p CNN-LOH [2 BE samples (20%)], deletion of CDKN2A [4 BE samples (40%)] and amplification of 17q12-21.2 involving the ERBB2, RARA and TOP2A genes [3.1 Mb, 2 EAC (29%)]. Interestingly, 1 BE sample contained a homozygous deletion spanning 9p22.3-p22.2 (1.2 Mb): this region harbors only 1 known gene, basonuclin 2 (BNC2). Real-time PCR analysis confirmed the deletion of this gene and decreased the expression of BNC2 mRNA in the BE sample. Furthermore, transfection and stable expression of BNC2 caused growth arrest of OE33 EAC cells, suggesting that BNC2 functions as a tumor suppressor gene in the esophagus and that deletion of this gene occurs during the development of EAC. Thus, this SNP-chip analysis has identified several early cytogenetic events and novel candidate cancer-related genes that are potentially involved in the evolution of BE to EAC. PMID:19670330

Akagi, Tadayuki; Ito, Tetsuo; Kato, Motohiro; Jin, Zhe; Cheng, Yulan; Kan, Takatsugu; Yamamoto, Go; Olaru, Alexandru; Kawamata, Norihiko; Boult, Jessica; Soukiasian, Harmik J; Miller, Carl W; Ogawa, Seishi; Meltzer, Stephen J; Koeffler, H Phillip

2009-11-15

357

Chromosome banding in amphibia. XXIII. Giant W sex chromosomes and extremely small genomes in Eleutherodactylus euphronides and Eleutherodactylus shrevei (Anura, Leptodactylidae).  

PubMed

Highly differentiated, heteromorphic ZZ female symbol /ZW male symbol sex chromosomes were found in the karyotypes of the neotropical leptodactylid frogs Eleutherodactylus euphronides and E. shrevei. The W chromosomes are the largest heterochromatic, female-specific chromosomes so far discovered in the class Amphibia. The analyses of the banding patterns with AT- and GC base-pair specific fluorochromes show that the constitutive heterochromatin in the giant W chromosomes consists of various categories of repetitive DNA sequences. The W chromosomes of both species are similar in size, morphology and banding patterns, whereas their Z chromosomes exhibit conspicuous differences. In the cell nuclei of female animals, the W chromosomes form very prominent chromatin bodies (W chromatin). DNA flow cytometric measurements demonstrate clear differences in the DNA content of male and female erythrocytes caused by the giant W chromosome, and also shows that these Eleutherodactylus genomes are among the smallest of all amphibian genomes. The importance of the heteromorphic ZW sex chromosomes for the study of Z-linked genes, the similarities and differences of the two karyotypes, and the significance of the exceptionally small genomes are discussed. PMID:12438744

Schmid, M; Feichtinger, W; Steinlein, C; Rupprecht, A; Haaf, T; Kaiser, H

2002-01-01

358

Sex chromosome linked genetic variance and the evolution of sexual dimorphism of quantitative traits.  

PubMed

Theory predicts that sex chromsome linkage should reduce intersexual genetic correlations thereby allowing the evolution of sexual dimorphism. Empirical evidence for sex linkage has come largely from crosses and few studies have examined how sexual dimorphism and sex linkage are related within outbred populations. Here, we use data on an array of different traits measured on over 10,000 individuals from two pedigreed populations of birds (collared flycatcher and zebra finch) to estimate the amount of sex-linked genetic variance (h(2)z ). Of 17 traits examined, eight showed a nonzero h(2)Z estimate but only four were significantly different from zero (wing patch size and tarsus length in collared flycatchers, wing length and beak color in zebra finches). We further tested how sexual dimorphism and the mode of selection operating on the trait relate to the proportion of sex-linked genetic variance. Sexually selected traits did not show higher h(2)Z than morphological traits and there was only a weak positive relationship between h(2)Z and sexual dimorphism. However, given the relative scarcity of empirical studies, it is premature to make conclusions about the role of sex chromosome linkage in the evolution of sexual dimorphism. PMID:23461313

Husby, Arild; Schielzeth, Holger; Forstmeier, Wolfgang; Gustafsson, Lars; Qvarnström, Anna

2012-10-11

359

Non-Mendelian segregation of sex chromosomes in heterospecific Drosophila males.  

PubMed Central

Interspecific hybrids and backcrossed organisms generally suffer from reduced viability and/or fertility. To identify and genetically map these defects, we introgressed regions of the Drosophila sechellia genome into the D. simulans genome. A female-biased sex ratio was observed in 24 of the 221 recombinant inbred lines, and subsequent tests attributed the skew to failure of Y-bearing sperm to fertilize the eggs. Apparently these introgressed lines fail to suppress a normally silent meiotic drive system. Using molecular markers we mapped two regions of the Drosophila genome that appear to exhibit differences between D. simulans and D. sechellia in their regulation of sex chromosome segregation distortion. The data indicate that the sex ratio phenotype results from an epistatic interaction between at least two factors. We discuss whether this observation is relevant to the meiotic drive theory of hybrid male sterility.

Dermitzakis, E T; Masly, J P; Waldrip, H M; Clark, A G

2000-01-01

360

Bird and mammal sex-chromosome orthologs map to the same autosomal region in a salamander (ambystoma).  

PubMed

We tested hypotheses concerning the origin of bird and mammal sex chromosomes by mapping the location of amniote sex-chromosome loci in a salamander amphibian (Ambystoma). We found that ambystomatid orthologs of human X and chicken Z sex chromosomes map to neighboring regions of a common Ambystoma linkage group 2 (ALG2). We show statistically that the proportion of human X and chicken Z orthologs observed on ALG2 is significantly different from the proportion that would be expected by chance. We further show that conserved syntenies between ALG2 and amniote chromosomes are identified as overlapping conserved syntenies when all available chicken (N = 3120) and human (N = 14,922) RefSeq orthologs are reciprocally compared. In particular, the data suggest that chromosomal regions from chicken chromosomes (GGA) Z and 4 and from human chromosomes (HSA) 9, 4, X, 5, and 8 were linked ancestrally. A more distant outgroup comparison with the pufferfish Tetraodon nigroviridis reveals ALG2/GGAZ/HSAX syntenies among three pairs of ancestral chromosome duplicates. Overall, our results suggest that sex chromosomal regions of birds and mammals were recruited from a common ancestral chromosome, and thus our findings conflict with the currently accepted hypothesis of separate autosomal origins. We note that our results were obtained using the most immediate outgroup to the amniote clade (mammals, birds, and other reptiles) while the currently accepted hypothesis is primarily based upon conserved syntenies between in-group taxa (birds and mammals). Our study illustrates the importance of an amphibian outgroup perspective in identifying ancestral amniote gene orders and in reconstructing patterns of vertebrate sex-chromosome evolution. PMID:17660573

Smith, Jeramiah J; Voss, S Randal

2007-07-29

361

Placental contribution to the origins of sexual dimorphism in health and diseases: sex chromosomes and epigenetics  

PubMed Central

Sex differences occur in most non-communicable diseases, including metabolic diseases, hypertension, cardiovascular disease, psychiatric and neurological disorders and cancer. In many cases, the susceptibility to these diseases begins early in development. The observed differences between the sexes may result from genetic and hormonal differences and from differences in responses to and interactions with environmental factors, including infection, diet, drugs and stress. The placenta plays a key role in fetal growth and development and, as such, affects the fetal programming underlying subsequent adult health and accounts, in part for the developmental origin of health and disease (DOHaD). There is accumulating evidence to demonstrate the sex-specific relationships between diverse environmental influences on placental functions and the risk of disease later in life. As one of the few tissues easily collectable in humans, this organ may therefore be seen as an ideal system for studying how male and female placenta sense nutritional and other stresses, such as endocrine disruptors. Sex-specific regulatory pathways controlling sexually dimorphic characteristics in the various organs and the consequences of lifelong differences in sex hormone expression largely account for such responses. However, sex-specific changes in epigenetic marks are generated early after fertilization, thus before adrenal and gonad differentiation in the absence of sex hormones and in response to environmental conditions. Given the abundance of X-linked genes involved in placentogenesis, and the early unequal gene expression by the sex chromosomes between males and females, the role of X- and Y-chromosome-linked genes, and especially those involved in the peculiar placenta-specific epigenetics processes, giving rise to the unusual placenta epigenetic landscapes deserve particular attention. However, even with recent developments in this field, we still know little about the mechanisms underlying the early sex-specific epigenetic marks resulting in sex-biased gene expression of pathways and networks. As a critical messenger between the maternal environment and the fetus, the placenta may play a key role not only in buffering environmental effects transmitted by the mother but also in expressing and modulating effects due to preconceptional exposure of both the mother and the father to stressful conditions.

2013-01-01

362

Cytogenetic evaluation of human glial tumors: correlation of overexpression of epidermal growth factor receptor (EGFB) with abnormalities of chromosome 7  

SciTech Connect

Chromosome banding analysis of human glial tumors were performed using G- and Q-banding techniques in an attempt to establish recurring sites of chromosome change. Results revealed a nonrandom karyotypic profile including aneuploidy and considerable variation in chromosome number (range 40 ..-->.. 200). All tumors examined displayed numerical abnormalities, with the most common numeric change being a gain of chromosome 7. An attempt was then made to correlate the observed chromosome 7 changes with activation of the cellular proto-oncogene c-erb-B, whose produce is the epidermal growth factor receptor (EGFR). Six human glial tumors were analyzed for /sup 125/I-EGF binding, EGFR gene copy number, EGFR gene rearrangement, mRNA expression, and karyotypic profile. Saturation analysis at 4/sup 0/C revealed significant numbers of EGFR's in all 6 tumors. Southern blotting analysis utilizing cDNA probes for the EGFR failed to demonstrate significant amplification or structural rearrangement of the EFGR gene. The results suggest that overexpression of the EGFR may be related to an alternative mechanism, other than gene amplification and elevated mRNA levels, such as the regulation of receptor biosynthesis and degradation. In summary, findings indicate that alterations of chromosome 7 are the most prevalent chromosomal change in human glial tumors, and that these alterations may lead to overexpression of the protooncogene c-erb-B.

Bell, C.W.

1987-01-01

363

Deletion Analysis of the Selfish B Chromosome, Paternal Sex Ratio (Psr), in the Parasitic Wasp Nasonia Vitripennis  

PubMed Central

Paternal Sex Ratio (PSR) is a ``selfish'' B chromosome in the parasitoid wasp Nasonia vitripennis. It is transmitted via sperm, but causes supercondensation and destruction of the paternal chromosomes in early fertilized eggs. Because this wasp has haplodiploid sex determination, the effect of PSR is to convert diploid (female) eggs into haploid (male) eggs that carry PSR. Characterizing its genetic structure is a first step toward understanding mechanisms of PSR action. The chromosome is largely heterochromatic and contains several tandemly repeated DNA sequences that are not present on the autosomes. A deletion analysis of PSR was performed to investigate organization of repeats and location of functional domains causing paternal chromosome destruction. Deletion profiles using probes to PSR-specific repetitive DNA indicate that most repeats are organized in blocks on the chromosome. This study shows that the functional domains of PSR can be deleted, resulting in nonfunctional PSR chromosomes that are transmitted to daughters. A functional domain may be linked with the psr22 repeat, but function may also depend on abundance of PSR-specific repeats on the chromosome. It is hypothesized that the repeats act as a ``sink'' for a product required for proper paternal chromosome processing. Almost all deletion chromosomes remained either functional of nonfunctional in subsequent generations following their creation. One chromosome was exceptional in that it reverted from nonfunctionality to functionality in one lineage. Transmission rates of nonfunctional deletion chromosomes were high through haploid males, but low through diploid females.

Beukeboom, L. W.; Werren, J. H.

1993-01-01

364

FISH analysis for apparently simple terminal deletions of the X chromosome: identification of hidden structural abnormalities.  

PubMed

We report on fluorescence in situ hybridization (FISH) analysis in 30 mosaic or nonmosaic females diagnosed as having apparently simple terminal X deletions by standard G-banding analysis. FISH studies for DXZ1, the Xp and Xq telomere regions, and the whole X chromosome painting were carried out for the 30 females, indicating rearranged X chromosomes with signal patterns discordant with terminal deletions in 6 cases: one dic(X)(DXZ1++) chromosome, two der(X)(qtel++) chromosomes, one Xq- (qtel+) chromosome, and two der(X)(ptel++) chromosomes. Additional FISH studies were performed for the 6 cases using probes defining 12 loci on the X chromosome, showing large Xp deletion and small Xp duplication in the dic(X)(DXZ1++) chromosome, partial Xp deletions and partial Xq duplications in the two der(X)(qtel++) chromosomes, an interstitial Xq deletion in the Xq- (qtel+) chromosome, and partial Xq deletions and partial Xp duplications in the two der(X)(ptel++) chromosomes. Clinical assessment of the 6 cases revealed tall and normal stature in the two mosaic cases with the der(X)(ptel++) chromosomes that were shown to be associated with SHOX duplication. The results suggest that unusual X chromosome rearrangements are often misinterpreted as simple terminal X deletions, and that FISH analysis is useful for precise structural determination and better genotype-phenotype correlation of the X chromosome aberrations. PMID:11754066

Ogata, T; Matsuo, N; Fukushima, Y; Saito, M; Nose, O; Miharu, N; Uehara, S; Ishizuka, B

2001-12-15

365

Chromosomal abnormality limited to T4 lymphocytes in a patient with T-cell chronic lymphocytic leukaemia.  

PubMed

Cytogenetic, immunologic and DNA studies were performed on a patient with the T-cell type of chronic lymphocytic leukaemia. Standard G-banding karyotype analysis revealed clonal chromosome abnormalities with the karyotype 42-44,XY,-11,-12,-13,-16,-21,-22,i(8q),inv(14) (q11q32), t(15;?)(p11;?), +4-6mar/43-44,X,t(Y;14)(p11;q11),-11,-12, -13,-21,-22,i(6p),i(8q),inv(14)(q11q32),t(15;?)(q11;?), +1-3mar. MAC (morphology, antibody, chromosomes) methodology, which allows the immunophenotyping of mitotic cells, showed that the chromosome abnormalities were restricted to CD4-positive helper/inducer T lymphocytes and that CD8 suppressor/cytotoxic T cells and B lymphocytes possessed a normal karyotype. The results also indicate that the proportion of abnormal metaphases and the overall mitotic activity after 3.5 days of stimulation in vitro were highest when PHA and TPA were used as mitogens. When the culture period in the presence of PHA + IL-2 was extended, the proportion of the abnormal cell population decreased in direct relation to the length of the culture period, ranging from 100% at 3.5 d to 0% at 31 d after stimulation. Southern blotting analysis revealed rearrangements of both the immunoglobulin heavy chain gene and the beta T-cell receptor gene. PMID:1974208

Larramendy, M L; Peltomäki, P; Salonen, E; Knuutila, S

1990-07-01

366

Possible influences on the expression of X chromosome-linked dystrophin abnormalities by heterozygosity for autosomal recessive Fukuyama congenital muscular dystrophy  

SciTech Connect

Abnormalities of dystrophin, a cytoskeletal protein of muscle and nerve, are generally considered specific for Duchenne and Becker muscular dystrophy. However, several patients have recently been identified with dystrophin deficiency who, before dystrophin testing, were considered to have Fukuyama congenital muscular dystrophy (FCMD) on the basis of clinical findings. Epidemiologic data suggest that only 1/3,500 males with autosomal recessive FCMD should have abnormal dystrophin. To explain the observation of 3/23 FCMD males with abnormal dystrophin, the authors propose that dystrophin and the FCMD gene product interact and that the earlier onset and greater severity of these patients' phenotype (relative to Duchenne muscular dystrophy) are due to their being heterozygous for the FCMD mutation in addition to being hemizygous for Duchenne muscular dystrophy, a genotype that is predicted to occur in 1/175,000 Japanese males. This model may help explain the genetic basis for some of the clinical and pathological variability seen among patients with FCMD, and it has potential implications for understanding the inheritance of other autosomal recessive disorders in general. For example, sex ratios for rare autosomal recessive disorders caused by mutations in proteins that interact with X chromosome-linked gene products may display predictable deviation from 1:1.

Beggs, A.H.; Neumann, P.E.; Anderson, M.S.; Kunkel, L.M. (Harvard Medical School, Boston, MA (United States)); Arahata, Kiichi; Arikawa, Eri; Nonaka, Ikuya (National Inst. of Neuroscience, Tokyo (Japan))

1992-01-15

367

Partial Paternal Uniparental Disomy of Chromosome 6 in an Infant with Neonatal Diabetes, Macroglossia, and Craniofacial Abnormalities  

PubMed Central

Neonatal diabetes, which can be transient or permanent, is defined as hyperglycemia that presents within the first month of life and requires insulin therapy. Transient neonatal diabetes mellitus has been associated with abnormalities of the paternally inherited copy of chromosome 6, including duplications of a portion of the long arm of chromosome 6 and uniparental disomy, implicating overexpression of an imprinted gene in this disorder. To date, all patients with transient neonatal diabetes mellitus and uniparental disomy have had complete paternal isodisomy. We describe a patient with neonatal diabetes, macroglossia, and craniofacial abnormalities, with partial paternal uniparental disomy of chromosome 6 involving the distal portion of 6q, from 6q24-qter. This observation demonstrates that mitotic recombination of chromosome 6 can also give rise to uniparental disomy and neonatal diabetes, a situation similar to that observed in Beckwith-Wiedemann syndrome, another imprinted disorder. This finding has clinical implications, since somatic mosaicism for uniparental disomy of chromosome 6 should also be considered in patients with transient neonatal diabetes mellitus.

Das, S.; Lese, C. M.; Song, M.; Jensen, J. L.; Wells, L. A.; Barnoski, B. L.; Roseberry, J. A.; Camacho, J. M.; Ledbetter, D. H.; Schnur, R. E.

2000-01-01

368

Structural chromosomal abnormalities detected during CVS analysis and their role in the prenatal ascertainment of cryptic subtelomeric rearrangements.  

PubMed

Mosaic structural chromosomal abnormalities observed along the trophoblast-mesenchyme-fetal axis, although rare, pose a difficult problem for their prognostic interpretation in prenatal diagnosis. Additional issues are raised by the presence of mosaic imbalances of the same chromosome showing different sizes in the different tissues, that is, deletions and duplications in the cytotrophoblast and mesenchyme of chorionic villi (CV). Some of these cytogenetic rearrangements originate from the post-zygotic breakage of a dicentric chromosome or of the product of its first anaphasic breakage. Selection of the most viable cell line may result in confined placental mosaicism of the most severe imbalance, favoring the presence of the cell lines with the mildest duplications or deletions in the fetal tissues. We document three cases of ambiguous results in CV analysis due to the presence of different cell lines involving structural rearrangements of the same chromosome which were represented differently in the trophoblast and the mesenchyme. Observation by conventional karyotype of a grossly rearranged chromosome in one of the CV preparations (direct or culture) was crucial to call attention to the involved chromosomal region in other tissues (villi or amniotic fluid), allowing the prenatal diagnosis through molecular cytogenetic methods of subtelomeric rearrangements [del(7)(q36qter); del(11)(q25qter); del(20)(p13pter)]. This would have surely been undiagnosed with the routine banding technique. In conclusion, the possibility to diagnose complex abnormalities leading to cryptic subtelomeric rearrangements, together with a better knowledge of the initial/intermediate products leading to the final abnormal cryptic deletion should be added to the advantages of the CV sampling technique. © 2013 Wiley Periodicals, Inc. PMID:23922197

Pittalis, Maria Carla; Mattarozzi, Angela; Menozzi, Cristina; Malacarne, Michela; Baccolini, Ilaria; Farina, Antonio; Pompilii, Eva; Magini, Pamela; Percesepe, Antonio

2013-08-06

369

Getting a Full Dose? Reconsidering Sex Chromosome Dosage Compensation in the Silkworm, Bombyx mori  

PubMed Central

Dosage compensation—equalizing gene expression levels in response to differences in gene dose or copy number—is classically considered to play a critical role in the evolution of heteromorphic sex chromosomes. As the X and Y diverge through degradation and gene loss on the Y (or the W in female-heterogametic ZW taxa), it is expected that dosage compensation will evolve to correct for sex-specific differences in gene dose. Although this is observed in some organisms, recent genome-wide expression studies in other taxa have revealed striking exceptions. In particular, reports that both birds and the silkworm moth (Bombyx mori) lack dosage compensation have spurred speculation that this is the rule for all female-heterogametic taxa. Here, we revisit the issue of dosage compensation in silkworm by replicating and extending the previous analysis. Contrary to previous reports, our efforts reveal a pattern typically associated with dosage compensated taxa: the global male:female expression ratio does not differ between the Z and autosomes. We believe the previous report of unequal male:female ratios on the Z reflects artifacts of microarray normalization in conjunction with not testing a major assumption that the male:female global expression ratio was unbiased for autosomal loci. However, we also find that the global Z chromosome expression is significantly reduced relative to autosomes, a pattern not expected in dosage compensated taxa. This combination of male:female parity with an overall reduction in expression for sex-linked loci is not consistent with the prevailing evolutionary theory of sex chromosome evolution and dosage compensation.

Walters, James R.; Hardcastle, Thomas J.

2011-01-01

370

XX/XO, a rare sex chromosome system in Potamotrygon freshwater stingray from the Amazon Basin, Brazil.  

PubMed

Potamotrygonidae is a representative family of South American freshwater elasmobranchs. Cytogenetic studies were performed in a Potamotrygon species from the middle Negro River, Amazonas, Brazil, here named as Potamotrygon sp. C. Mitotic and meiotic chromosomes were analyzed using conventional staining techniques, C-banding, and detection of the nucleolus organizing regions (NOR) with Silver nitrate (Ag-NOR). The diploid number was distinct between sexes, with males having 2n = 67 chromosomes, karyotype formula 19m + 8sm + 10st + 30a, and fundamental number (FN) = 104, and females having 2n = 68 chromosomes, karyotype formula 20m + 8sm + 10st + 30a, and FN = 106. A large chromosome, corresponding to pair number two in the female karyotype, was missing in the male complement. Male meiotic cells had 33 bivalents plus a large univalent chromosome in metaphase I, and n = 33 and n = 34 chromosomes in metaphase II. These characteristics are consistent with a sex chromosome system of the XX/XO type. Several Ag-NOR sites were identified in both male and female karyotypes. Positive C-banding was located only in the centromeric regions of the chromosomes. This sex chromosome system, which rarely occurs in fish, is now being described for the first time among the freshwater rays of the Amazon basin. PMID:24068425

de Souza Valentim, Francisco Carlos; Porto, Jorge Ivan Rebelo; Bertollo, Luiz Antonio Carlos; Gross, Maria Claudia; Feldberg, Eliana

2013-09-26

371

Survey of repetitive sequences in Silene latifolia with respect to their distribution on sex chromosomes.  

PubMed

We carried out a global survey of all major types of transposable elements in Silene latifolia, a model species with sex chromosomes that are in the early stages of their evolution. A shotgun genomic library was screened with genomic DNA to isolate and characterize the most abundant elements. We found that the most common types of elements were the subtelomeric tandem repeat X-43.1 and Gypsy retrotransposons, followed by Copia retrotransposons and LINE non-LTR elements. SINE elements and DNA transposons were less abundant. We also amplified transposable elements with degenerate primers and used them to screen the library. The localization of elements by FISH revealed that most of the Copia elements were accumulated on the Y chromosome. Surprisingly, one type of Gypsy element, which was similar to Ogre elements known from legumes, was almost absent on the Y chromosome but otherwise uniformly distributed on all chromosomes. Other types of elements were ubiquitous on all chromosomes. Moreover, we isolated and characterized two new tandem repeats. One of them, STAR-C, was localized at the centromeres of all chromosomes except the Y chromosome, where it was present on the p-arm. Its variant, STAR-Y, carrying a small deletion, was specifically localized on the q-arm of the Y chromosome. The second tandem repeat, TR1, co-localized with the 45S rDNA cluster in the subtelomeres of five pairs of autosomes. FISH analysis of other Silene species revealed that some elements (e.g., Ogre-like elements) are confined to the section Elisanthe while others (e.g. Copia or Athila-like elements) are present also in more distant species. Similarly, the centromeric satellite STAR-C was conserved in the genus Silene whereas the subtelomeric satellite X-43.1 was specific for Elisanthe section. Altogether, our data provide an overview of the repetitive sequences in Silene latifolia and revealed that genomic distribution and evolutionary dynamics differ among various repetitive elements. The unique pattern of repeat distribution is found on the Y chromosome, where some elements are accumulated while other elements are conspicuously absent, which probably reflects different forces shaping the Y chromosome. PMID:18853265

Cermak, Tomas; Kubat, Zdenek; Hobza, Roman; Koblizkova, Andrea; Widmer, Alex; Macas, Jiri; Vyskot, Boris; Kejnovsky, Eduard

2008-10-15

372

Sex preselection in mammals. Separation of sperm bearing Y and O chromosomes in the vole Microtus oregoni  

SciTech Connect

The two sex determining sperm populations of the vole Microtus oregoni were separated according to DNA content by use of flow sorting instrumentation. Although the sperm were not viable, they should be useful for addressing the question of haploid expression of genes linked to sex chromosomes and for efficiently searching for biochemical markers that differentiate the two populations.

Pinkel, D.; Gledhill, B.L.; Lake, S.; Stephenson, D.; Van Dilla, M.A.

1982-11-26

373

Diversity in the origins of sex chromosomes in anurans inferred from comparative mapping of sexual differentiation genes for three species of the Raninae and Xenopodinae  

Microsoft Academic Search

Amphibians employ genetic sex determination systems with male and female heterogamety. The ancestral state of sex determination\\u000a in amphibians has been suggested to be female heterogamety; however, the origins of the sex chromosomes and the sex-determining\\u000a genes are still unknown. In Xenopus laevis, chromosome 3 with a candidate for the sex- (ovary-) determining gene (DM-W) was recently identified as the

Yoshinobu Uno; Chizuko Nishida; Shin Yoshimoto; Michihiko Ito; Yuki Oshima; Satoshi Yokoyama; Masahisa Nakamura; Yoichi Matsuda

2008-01-01

374

Evolutionary history of novel genes on the tammar wallaby Y chromosome: Implications for sex chromosome evolution  

PubMed Central

We report here the isolation and sequencing of 10 Y-specific tammar wallaby (Macropus eugenii) BAC clones, revealing five hitherto undescribed tammar wallaby Y genes (in addition to the five genes already described) and several pseudogenes. Some genes on the wallaby Y display testis-specific expression, but most have low widespread expression. All have partners on the tammar X, along with homologs on the human X. Nonsynonymous and synonymous substitution ratios for nine of the tammar XY gene pairs indicate that they are each under purifying selection. All 10 were also identified as being on the Y in Tasmanian devil (Sarcophilus harrisii; a distantly related Australian marsupial); however, seven have been lost from the human Y. Maximum likelihood phylogenetic analyses of the wallaby YX genes, with respective homologs from other vertebrate representatives, revealed that three marsupial Y genes (HCFC1X/Y, MECP2X/Y, and HUWE1X/Y) were members of the ancestral therian pseudoautosomal region (PAR) at the time of the marsupial/eutherian split; three XY pairs (SOX3/SRY, RBMX/Y, and ATRX/Y) were isolated from each other before the marsupial/eutherian split, and the remaining three (RPL10X/Y, PHF6X/Y, and UBA1/UBE1Y) have a more complex evolutionary history. Thus, the small marsupial Y chromosome is surprisingly rich in ancient genes that are retained in at least Australian marsupials and evolved from testis–brain expressed genes on the X.

Murtagh, Veronica J.; O'Meally, Denis; Sankovic, Natasha; Delbridge, Margaret L.; Kuroki, Yoko; Boore, Jeffrey L.; Toyoda, Atsushi; Jordan, Kristen S.; Pask, Andrew J.; Renfree, Marilyn B.; Fujiyama, Asao; Graves, Jennifer A. Marshall; Waters, Paul D.

2012-01-01

375

Male infertility in China: laboratory finding for AZF microdeletions and chromosomal abnormalities in infertile men from Northeastern China  

Microsoft Academic Search

Purposes  To investigate the frequencies of AZF microdeletions and chromosomal abnormalities in infertile men from Northeastern China.\\u000a Moreover, to compare the prevalence of these abnormalities with other countries and regions in the world.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  305 infertile men were enrolled. A complete semen analysis and reproductive hormones were measured according to standard methods.\\u000a Multiplex polymerase chain reaction (PCR) amplification using nine specific sequence-tagged

Rui-Xue Wang; Chao Fu; Ya-Ping Yang; Rong-Rong Han; Yuan Dong; Ru-Lin Dai; Rui-Zhi Liu

2010-01-01

376

Evolutionary Strata on the X Chromosomes of the Dioecious Plant Silene latifolia: Evidence From New Sex-Linked Genes  

PubMed Central

Despite its recent evolutionary origin, the sex chromosome system of the plant Silene latifolia shows signs of progressive suppression of recombination having created evolutionary strata of different X–Y divergence on sex chromosomes. However, even after 8 years of effort, this result is based on analyses of five sex-linked gene sequences, and the maximum divergence (and thus the age of this plant's sex chromosome system) has remained uncertain. More genes are therefore needed. Here, by segregation analysis of intron size variants (ISVS) and single nucleotide polymorphisms (SNPs), we identify three new Y-linked genes, one being duplicated on the Y chromosome, and test for evolutionary strata. All the new genes have homologs on the X and Y chromosomes. Synonymous divergence estimated between the X and Y homolog pairs is within the range of those already reported. Genetic mapping of the new X-linked loci shows that the map is the same in all three families that have been studied so far and that X–Y divergence increases with genetic distance from the pseudoautosomal region. We can now conclude that the divergence value is saturated, confirming the cessation of X–Y recombination in the evolution of the sex chromosomes at ?10–20 MYA.

Bergero, Roberta; Forrest, Alan; Kamau, Esther; Charlesworth, Deborah

2007-01-01

377

Mapping of sex determination loci on the white campion (Silene latifolia) Y chromosome using amplified fragment length polymorphism.  

PubMed Central

S. latifolia is a dioecious plant with morphologically distinct sex chromosomes. To genetically map the sex determination loci on the male-specific Y chromosome, we identified X-ray-induced sex determination mutants that had lost male traits. We used male-specific AFLP markers to characterize the extent of deletions in the Y chromosomes of the mutants. We then compared overlapping deletions to predict the order of the AFLP markers and to locate the mutated sex-determining genes. We found three regions on the Y chromosome where frequent deletions were significantly associated with loss of male traits. One was associated with hermaphroditic mutants. A second was associated with asexual mutants that lack genes needed for early stamen development and a third was associated with asexual mutants that lack genes for late stages of stamen development. Our observations confirmed a classical genetic prediction that S. latifolia has three dispersed male-determining loci on the Y chromosome, one for carpel suppression, one for early stamen development, and another for late stamen development. This AFLP map provides a framework for locating genes on the Y chromosome and for characterizing deletions on the Y chromosomes of potentially interesting mutants.

Lebel-Hardenack, Sabine; Hauser, Elizabeth; Law, Teresa F; Schmid, Jurg; Grant, Sarah R

2002-01-01

378

"Bouquet arrest", monopolar chromosomes segregation, and correction of the abnormal spindle.  

PubMed

According to our data, the arrest of univalents in bouquet arrangement is a widespread meiotic feature in cereal haploids and allohaploids (wide hybrids F(1)). We have analyzed 83 different genotypes of cereal haploids and allohaploids with visualization of the cytoskeleton and found a bouquet arrest in 45 of them (in 30% to 100% pollen mother cells (PMCs)). The meiotic plant cell division in 26 various genotypes with a zygotene bouquet arrest was analyzed in detail. In three of them in PMCs, a very specific monopolar conic-shaped figure at early prometaphase is formed. This monopolar figure consists of mono-oriented univalents and their kinetochore fibers converging in pointed pole. Such figures are never observed at wild-type prometaphase or in asynaptic meiosis in the variants without a bouquet arrest. Later at prometaphase, the bipolar central spindle fibers join in this monopolar figure, and a bipolar spindle with all univalents connected to one pole is formed. As a result of monopolar chromosome segregation at anaphase and normal cytokinesis at telophase, a dyad with one member carrying a restitution nucleus and the other enucleated is formed. However, such phenotype has only three genotypes among 26 analyzed with a bouquet arrest. In the remaining 23 haploids and allohaploids, the course of prometaphase was altered after the conic monopolar figure formation. In these variants, the completely formed conic monopolar figure was disintegrated into a chaotic network of spindle fibers and univalents acquired a random orientation. This arrangement looks like a mid-prometaphase in the wild-type meiosis. At late prometaphase, a bipolar spindle is formed with the univalents distributed more or less equally between two poles, similar to the phenotypes without a bouquet arrest. The product of cell division is a dyad with aneuploid members. Thus, the spindle abnormality-monopolar chromosome orientation-is corrected. In some cells the correction of the prometaphase monopolus occurs by means of its splitting into two half-spindles and their rotation along the future division axis. PMID:21274580

Shamina, Nataliya V

2011-01-28

379

Emergence of male-biased genes on the chicken Z-chromosome: sex-chromosome contrasts between male and female heterogametic systems.  

PubMed

There has been extensive traffic of male-biased genes out of the mammalian and Drosophila X-chromosomes, and there are also reports of an under-representation of male-biased genes on the X. This may reflect an adaptive process driven by natural selection where an autosomal location of male-biased genes is favored since male genes are only exposed to selection one-third of the time when X-linked. However, there are several alternative explanations to "out-of-the-X" gene movement, including mutational bias and a means for X-linked genes to escape meiotic sex chromosome inactivation (MSCI) during spermatogenesis. As a critical test of the hypothesis that genomic relocation of sex-biased genes is an adaptive process, I examined the emergence, and loss, of genes on the chicken Z-chromosome, i.e., a female heterogametic system (males ZZ, females ZW). Here, the analogous prediction would be an emergence of male-biased genes onto, not a loss from, the Z-chromosome because Z is found more often in males than autosomes are. I found that genes expressed in testis but not in ovary are highly over-represented among genes that have emerged on the Z-chromosome during avian evolution. Moreover, genes with male-biased expression are similarly over-represented among new Z-chromosomal genes. Interestingly, genes with female-biased expression have more often moved from than to the Z-chromosome. These observations show that male and female heterogametic organisms display opposing directionalities in the emergence and loss of sex-biased genes on sex chromosomes. This is consistent with theoretical models on the evolution of sexually antagonistic genes in which new mutations are at least partly dominant. PMID:21868722

Ellegren, Hans

2011-08-25

380

Automated identification of abnormal metaphase chromosome cells for the detection of chronic myeloid leukemia using microscopic images  

PubMed Central

Karyotyping is an important process to classify chromosomes into standard classes and the results are routinely used by the clinicians to diagnose cancers and genetic diseases. However, visual karyotyping using microscopic images is time-consuming and tedious, which reduces the diagnostic efficiency and accuracy. Although many efforts have been made to develop computerized schemes for automated karyotyping, no schemes can get be performed without substantial human intervention. Instead of developing a method to classify all chromosome classes, we develop an automatic scheme to detect abnormal metaphase cells by identifying a specific class of chromosomes (class 22) and prescreen for suspicious chronic myeloid leukemia (CML). The scheme includes three steps: (1) iteratively segment randomly distributed individual chromosomes, (2) process segmented chromosomes and compute image features to identify the candidates, and (3) apply an adaptive matching template to identify chromosomes of class 22. An image data set of 451 metaphase cells extracted from bone marrow specimens of 30 positive and 30 negative cases for CML is selected to test the scheme’s performance. The overall case-based classification accuracy is 93.3% (100% sensitivity and 86.7% specificity). The results demonstrate the feasibility of applying an automated scheme to detect or prescreen the suspicious cancer cases.

Wang, Xingwei; Zheng, Bin; Li, Shibo; Mulvihill, John J.; Chen, Xiaodong; Liu, Hong

2010-01-01

381

Evolutionary history of novel genes on the tammar wallaby Y chromosome: Implications for sex chromosome evolution.  

PubMed

We report here the isolation and sequencing of 10 Y-specific tammar wallaby (Macropus eugenii) BAC clones, revealing five hitherto undescribed tammar wallaby Y genes (in addition to the five genes already described) and several pseudogenes. Some genes on the wallaby Y display testis-specific expression, but most have low widespread expression. All have partners on the tammar X, along with homologs on the human X. Nonsynonymous and synonymous substitution ratios for nine of the tammar XY gene pairs indicate that they are each under purifying selection. All 10 were also identified as being on the Y in Tasmanian devil (Sarcophilus harrisii; a distantly related Australian marsupial); however, seven have been lost from the human Y. Maximum likelihood phylogenetic analyses of the wallaby YX genes, with respective homologs from other vertebrate representatives, revealed that three marsupial Y genes (HCFC1X/Y, MECP2X/Y, and HUWE1X/Y) were members of the ancestral therian pseudoautosomal region (PAR) at the time of the marsupial/eutherian split; three XY pairs (SOX3/SRY, RBMX/Y, and ATRX/Y) were isolated from each other before the marsupial/eutherian split, and the remaining three (RPL10X/Y, PHF6X/Y, and UBA1/UBE1Y) have a more complex evolutionary history. Thus, the small marsupial Y chromosome is surprisingly rich in ancient genes that are retained in at least Australian marsupials and evolved from testis-brain expressed genes on the X. PMID:22128133

Murtagh, Veronica J; O'Meally, Denis; Sankovic, Natasha; Delbridge, Margaret L; Kuroki, Yoko; Boore, Jeffrey L; Toyoda, Atsushi; Jordan, Kristen S; Pask, Andrew J; Renfree, Marilyn B; Fujiyama, Asao; Graves, Jennifer A Marshall; Waters, Paul D

2011-11-29

382

Clinical and prognostic significance of chromosomal abnormalities in childhood acute myeloid leukemia de novo.  

PubMed

We report on the chromosomal pattern of 120 patients with childhood AML de novo. One hundred and fifteen patients (96%) had adequate samples for analysis; 98 (85%) of these showed clonal karyotypic abnormalities. They were classified into cytogenetic subgroups which were closely correlated with FAB subtypes: t(8;21) and M2 (n = 9); t(15;17) and M3 (n = 12); inv(16) and M4Eo (n = 9); t(9;11) and M5a (n = 10); t(11q23) other than t(9;11) and M4-M5 (n = 11); and t(1;22) and M7 (n = 4). In patients with -7/del(7q) (n = 6), leukemia was preceded by MDS in half of the cases, although they had diverse FAB subtypes. Thirty-seven patients had miscellaneous abnormalities. Despite a high CR rate, patients with t(8;21) had a very poor survival: only one child was event-free at 3 years from diagnosis. One third of patients with t(15;17) died during induction. Those eight who achieved CR fared well: only two relapsed, and six were event-free survivors. Patients with inv(16) had a high remission rate and a long survival: five children were in CR 20 to 136 months. Both groups with t(9;11) and t(11q23) had a high remission rate: however, outcome was superior for the t(9;11) group when compared to either the t(11q23) group (EFS at 3 years +/- SE, 56 +/- 17% vs. 11 +/- 10%, p = 0.07) or to the remaining patients (p = 0.06). Both -7/del(7q) and t(1;22) groups had low CR rates (50%) and poor survival. Cytogenetic analysis identifies clinically distinct subsets of childhood AML and is useful in tailoring treatment for these patients. Favorable cytogenetic groups (t(15;17), inv(16), and t(9;11)) may do well with current therapy protocols, whereas unfavorable groups (t(11q23), t(8;21), -7/del(7q), and t(1;22)) require more effective therapies. PMID:7845034

Martinez-Climent, J A; Lane, N J; Rubin, C M; Morgan, E; Johnstone, H S; Mick, R; Murphy, S B; Vardiman, J W; Larson, R A; Le Beau, M M

1995-01-01

383

Evolutionary erosion of yeast sex chromosomes by mating-type switching accidents  

PubMed Central

We investigate yeast sex chromosome evolution by comparing genome sequences from 16 species in the family Saccharomycetaceae, including data from genera Tetrapisispora, Kazachstania, Naumovozyma, and Torulaspora. We show that although most yeast species contain a mating-type (MAT) locus and silent HML and HMR loci structurally analogous to those of Saccharomyces cerevisiae, their detailed organization is highly variable and indicates that the MAT locus is a deletion hotspot. Over evolutionary time, chromosomal genes located immediately beside MAT have continually been deleted, truncated, or transposed to other places in the genome in a process that is gradually shortening the distance between MAT and HML. Each time a gene beside MAT is removed by deletion or transposition, the next gene on the chromosome is brought into proximity with MAT and is in turn put at risk for removal. This process has also continually replaced the triplicated sequence regions, called Z and X, that allow HML and HMR to be used as templates for DNA repair at MAT during mating-type switching. We propose that the deletion and transposition events are caused by evolutionary accidents during mating-type switching, combined with natural selection to keep MAT and HML on the same chromosome. The rate of deletion accelerated greatly after whole-genome duplication, probably because genes were redundant and could be deleted without requiring transposition. We suggest that, despite its mutational cost, switching confers an evolutionary benefit by providing a way for an isolated germinating spore to reform spores if the environment is too poor.

Gordon, Jonathan L.; Armisen, David; Proux-Wera, Estelle; OhEigeartaigh, Sean S.; Byrne, Kevin P.; Wolfe, Kenneth H.

2011-01-01

384

Many X-linked microRNAs escape meiotic sex chromosome inactivation.  

PubMed

Meiotic sex chromosome inactivation (MSCI) during spermatogenesis is characterized by transcriptional silencing of genes on both the X and Y chromosomes in mid-to-late pachytene spermatocytes. MSCI is believed to result from meiotic silencing of unpaired DNA because the X and Y chromosomes remain largely unpaired throughout first meiotic prophase. However, unlike X-chromosome inactivation in female embryonic cells, where 25-30% of X-linked structural genes have been reported to escape inactivation, previous microarray- and RT-PCR-based studies of expression of >364 X-linked mRNA-encoding genes during spermatogenesis have failed to reveal any X-linked gene that escapes the silencing effects of MSCI in primary spermatocytes. Here we show that many X-linked miRNAs are transcribed and processed in pachytene spermatocytes. This unprecedented escape from MSCI by these X-linked miRNAs suggests that they may participate in a critical function at this stage of spermatogenesis, including the possibility that they contribute to the process of MSCI itself, or that they may be essential for post-transcriptional regulation of autosomal mRNAs during the late meiotic and early postmeiotic stages of spermatogenesis. PMID:19305411

Song, Rui; Ro, Seungil; Michaels, Jason D; Park, Chanjae; McCarrey, John R; Yan, Wei

2009-03-22

385

Evidence that meiotic sex chromosome inactivation is essential for male fertility.  

PubMed

The mammalian X and Y chromosomes share little homology and are largely unsynapsed during normal meiosis. This asynapsis triggers inactivation of X- and Y-linked genes, or meiotic sex chromosome inactivation (MSCI). Whether MSCI is essential for male meiosis is unclear. Pachytene arrest and apoptosis is observed in mouse mutants in which MSCI fails, e.g., Brca1(-/-), H2afx(-/-), Sycp1(-/-), and Msh5(-/-). However, these also harbor defects in synapsis and/or recombination and as such may activate a putative pachytene checkpoint. Here we present evidence that MSCI failure is sufficient to cause pachytene arrest. XYY males exhibit Y-Y synapsis and Y chromosomal escape from MSCI without accompanying synapsis/recombination defects. We find that XYY males, like synapsis/recombination mutants, display pachytene arrest and that this can be circumvented by preventing Y-Y synapsis and associated Y gene expression. Pachytene expression of individual Y genes inserted as transgenes on autosomes shows that expression of the Zfy 1/2 paralogs in XY males is sufficient to phenocopy the pachytene arrest phenotype; insertion of Zfy 1/2 on the X chromosome where they are subject to MSCI prevents this response. Our findings show that MSCI is essential for male meiosis and, as such, provide insight into the differential severity of meiotic mutations' effects on male and female meiosis. PMID:21093264

Royo, Hélène; Polikiewicz, Grzegorz; Mahadevaiah, Shantha K; Prosser, Haydn; Mitchell, Mike; Bradley, Allan; de Rooij, Dirk G; Burgoyne, Paul S; Turner, James M A

2010-11-18

386

Chromosome abnormalities in 10 lung cancer cell lines of the NCI-H series analyzed with spectral karyotyping  

Microsoft Academic Search

The karyotypes of 10 lung cancer cell lines of the NCI-H series were analyzed with spectral karyotyping (SKY): 7 non-small lung cancer (NSCLC) lines and 3 small cell lung cancer (SCLC) lines. Modal chromosome number ranged from 42 (NCI-H2171) to 72 (NCI-H2126). All lines showed at least six structural abnormalities, and most had amplifications visible as double minutes or homogeneously

Mira Grigorova; Rachel C. Lyman; Carlos Caldas; Paul A. W. Edwards

2005-01-01

387

Analysis of chromosome abnormalities by comparative genomic hybridization in malignant peripheral primitive neuroectodermal tumor of the ovary  

Microsoft Academic Search

Objective. Malignant primitive neuroectodermal tumor (PNET) originating from the ovary rather than from the central nervous system is extremely rare. The aim of this study is to demonstrate the chromosomal abnormalities in a case of peripheral primitive neuroectodermal tumor (PPNET) arising from the ovary of a girl.Methods. The 13-year-old girl underwent exploratory laparotomy because of a huge pelvic tumor in

Song-Nan Chow; Ming-Chieh Lin; Jenta Shen; Sheng Wang; Yiin-Jeng Jong; Chin-Hsiang Chien

2004-01-01