Domingues, C P; Creer, S; Taylor, M I; Queiroga, H; Carvalho, G R
Despite the importance of larval biology in the life histories of many marine animals, relatively little information exists on the dynamics and genetic composition of larval cohorts. The supply of megalopae larvae of the shore crab, Carcinus maenas, was measured on a daily basis during 8 months spread along two larval periods (2006 and 2007) at the Ria de Aveiro estuary, on the Portuguese northwest coast. A total of 10 microsatellite DNA loci were employed to explore the genetic structure, variability and relatedness of temporally distinct megalopal events, selected from the major pulses of supply. Larval variation was also compared genetically with that of a previously studied adult crabs sample, at the same loci, collected in 2006 and 2007 along the Iberian Peninsula. Results revealed a lack of genetic differentiation and identical diversity levels among larval events over time. No evidence of reduced genetic diversity between megalopae relative to the diversity assessed from the pooled sample of adults was found. Moreover, there was no evidence of any family relatedness among larvae from temporal events. The results obtained for C. maenas contradict predictions made by the sweepstakes reproduction hypothesis, in which large variance in reproductive success is expected, which is presumably detectable as sharp genetic discontinuities among separate larval events. Data here indicate conversely a high degree of temporal genetic stability among larval supply to a given estuary under variable oceanographic conditions, consistent with the hypothesis that sampled larvae were drawn from a large number of adults that do not differ in reproductive success. PMID:20959862
Carcinus maenas (Decapoda: Portunidae) has proven a highly successful invasive marine species whose potential economic and ecological impacts are of great concern worldwide. Here, we characterize fourteen polymorphic microsatellite loci in C. maenas and its sister species C. Ae...
Cripps, Gemma; Widdicombe, Stephen; Spicer, John I; Findlay, Helen S
Further steps are needed to establish feasible alleviation strategies that are able to reduce the impacts of ocean acidification, whilst ensuring minimal biological side-effects in the process. Whilst there is a growing body of literature on the biological impacts of many other carbon dioxide reduction techniques, seemingly little is known about enhanced alkalinity. For this reason, we investigated the potential physiological impacts of using chemical sequestration as an alleviation strategy. In a controlled experiment, Carcinus maenas were acutely exposed to concentrations of Ca(OH)2 that would be required to reverse the decline in ocean surface pH and return it to pre-industrial levels. Acute exposure significantly affected all individuals' acid-base balance resulting in slight respiratory alkalosis and hyperkalemia, which was strongest in mature females. Although the trigger for both of these responses is currently unclear, this study has shown that alkalinity addition does alter acid-base balance in this comparatively robust crustacean species.
The European green crab Carcinus maenas is one of the world's most widely recognized marine invaders. The success of this species has provided opportunities to explore genetic patterns associated with establishment and population expansion following independent introduction event...
Robinson, Elizabeth M; Smee, Delbert L; Trussell, Geoffrey C
Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected the foraging behavior of the green crab (Carcinus maenas), which is invading marine habitats throughout the world. High flow velocities are known to reduce green crab predation rates and our study sought to identify the mechanisms by which flow affects green crabs. We performed a series of experiments with green crabs to determine: 1) if their ability to find prey was altered by flow in the field, 2) how flow velocity influenced their foraging efficiency, and 3) how flow velocity affected their handling time of prey. In a field study, we caught significantly fewer crabs in baited traps at sites with fast versus slow flows even though crabs were more abundant in high flow areas. This finding suggests that higher velocity flows impair the ability of green crabs to locate prey. In laboratory flume assays, green crabs foraged less efficiently when flow velocity was increased. Moreover, green crabs required significantly more time to consume prey in high velocity flows. Our data indicate that flow can impose significant chemosensory and physical constraints on green crabs. Hence, hydrodynamics may strongly influence the role that green crabs and other predators play in rocky intertidal communities.
Robinson, Elizabeth M.; Smee, Delbert L.; Trussell, Geoffrey C.
Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected the foraging behavior of the green crab (Carcinus maenas), which is invading marine habitats throughout the world. High flow velocities are known to reduce green crab predation rates and our study sought to identify the mechanisms by which flow affects green crabs. We performed a series of experiments with green crabs to determine: 1) if their ability to find prey was altered by flow in the field, 2) how flow velocity influenced their foraging efficiency, and 3) how flow velocity affected their handling time of prey. In a field study, we caught significantly fewer crabs in baited traps at sites with fast versus slow flows even though crabs were more abundant in high flow areas. This finding suggests that higher velocity flows impair the ability of green crabs to locate prey. In laboratory flume assays, green crabs foraged less efficiently when flow velocity was increased. Moreover, green crabs required significantly more time to consume prey in high velocity flows. Our data indicate that flow can impose significant chemosensory and physical constraints on green crabs. Hence, hydrodynamics may strongly influence the role that green crabs and other predators play in rocky intertidal communities. PMID:21687742
The European green crab Carcinus maenas is one of the world's most successful aquatic invaders, having established populations on every continent with temperate shores. Here we describe patterns of genetic diversity across both the native and introduced ranges of C. maenas and it...
Hogarth, P. J.
The shore crab (Carcinus maenas) is an excellent subject for school study, both in the field and the laboratory. It is easily collected and maintained and can be used for a wide range of investigations. Some background details are given and possible areas of investigation suggested. (Author)
The European green crab, Carcinus maenas, is a recent invader to Pacific Northwest (PNW) estuaries with a voracious appetite, especially for bivalves. To assess their potential impact, we estimated green crab consumption rates on four PNW bivalve species, Yaquina oyster (Ostrea ...
Dawirs, R. R.
Improved methods for experimental rearing of Pagurus bernhardus and Carcinus maenas larvae are presented. Isolated maintenance was found essential for reliable statistical evaluation of results obtained from stages older than zoea-1. Only by isolated rearing is it possible to calculate mean values ±95% confidence intervals of stage duration. Mean values (without confidence intervals) can only be given for group-reared larvae if mortality is zero. Compared to group rearing, isolated rearing led to better survival, shorter periods of development and stimulated growth. Due to different swimming behavior P. bernhardus zoeae needed larger water volumes than Carcinus maenas larvae. P. bernhardus zoeae were reared with best results when isolated in Petri dishes (ca. 50 ml). They fed on newly hatched brine shrimp nauplii ( Artemia spp.). P. bernhardus megalopa did not require any gastropod shell or substratum; it developed best in glass vials without any food. C. maenas larvae could be reared most sucessfully in glass vials (ca 20 ml) under a simulated day-night regime (LD 16:8); constant darkness had a detrimental effect on development, leading to prolonged stage-duration times. C. maenas larvae were fed a mixture of newly hatched brine shrimp naupli and rotifers ( Brachionus plicatilis).
Christie, Andrew E
Carcinus maenas is widely recognized as one of the world's most successful marine invasive species; its success as an invader is due largely to its ability to thrive under varied environmental conditions. The physiological/behavioral control systems that allow C. maenas to adapt to new environments are undoubtedly under hormonal control, the largest single class of hormones being peptides. While numerous studies have focused on identifying native C. maenas peptides, none has taken advantage of mining transcriptome shotgun assembly (TSA) sequence data, a strategy proven highly successful for peptide discovery in other crustaceans. Here, a C. maenas peptidome was predicted via in silico transcriptome mining. Thirty-seven peptide families were searched for in the extant TSA database, with transcripts encoding precursors for 29 groups identified. The pre/preprohormones deduced from the identified sequences allowed for the prediction of 263 distinct mature peptides, 193 of which are new discoveries for C. maenas. The predicted peptides include isoforms of adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin B, allatostatin C, bursicon, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone, diuretic hormone 31, diuretic hormone 44, eclosion hormone, FMRFamide-like peptide, HIGSLYRamide, intocin, leucokinin, myosuppressin, neuroparsin, neuropeptide F, orcokinin, pigment dispersing hormone, proctolin, pyrokinin, red pigment concentrating hormone, RYamide, short neuropeptide F, SIFamide, and tachykinin-related peptide. This peptidome is the largest predicted from any single crustacean using the in silico approach, and provides a platform for investigating peptidergic signaling in C. maenas, including control of the processes that allow for its success as a global marine invader.
Penney, Chantelle M; Patton, Richard L; Whiteley, Nia M; Driedzic, William R; McGaw, Iain J
Osmoregulation and digestion are energetically demanding, and crabs that move into low salinity environments to feed must be able to balance the demands of both processes. Achieving this balance may pose greater challenges for weak than for efficient osmoregulators. This study examined the rate of oxygen consumption (MO2) of Carcinus maenas (efficient osmoregulator) and Cancer irroratus (weak osmoregulator) as a function of feeding and hyposaline stress. The MO2 increased 2-fold in both species following feeding. The MO2 increased and remained elevated in fasted crabs during acute hyposaline exposure. When hyposaline stress occurred after feeding, C. maenas responded with an immediate summation of the MO2 associated with feeding and hyposaline stress, whereas C. irroratus reacted with a partial summation of responses in a salinity of 24‰, but were unable to sum responses in 16‰. C. irroratus exhibited longer gut transit times. This may be due to an inability to regulate osmotic water onload as efficiently as C. maenas. Mechanical digestion in crabs can account for a significant portion of SDA, and a short term interruption led to the delay in summation of metabolic demands. Although protein synthesis is reported to account for the majority of SDA, this did not appear to be the case here. Protein synthesis rates were higher in C. irroratus but neither feeding or salinity affected protein synthesis rates of either species which suggests that protein synthesis can continue in low salinity as long as substrates are available.
Zetlmeisl, C; Hermann, J; Petney, T; Glenner, H; Griffiths, C; Taraschewski, H
The European shore crab, Carcinus maenas, is one of the most successful marine invasive species. Its success has been in part attributed to the loss of parasites, rekindling an interest in host-parasite interactions and impacts on host fitness in this crab. In the present study, we investigated C. maenas populations from Europe, South Africa and Australia for parasites, and assessed their impact on the fitness of male crabs. For the shore crab, testes weight along with success in mating competition is traded off against other life-history traits. We therefore used this parameter as an indicator both for reproductive fitness and a possible resource trade-off in response to parasite infestation. In the native range, crabs infested with Sacculina carcini showed significantly lower testes weight than uninfected crabs. However, helminth parasites did not generally cause reduced testes weights. Crab populations from South Africa and Australia were either parasitized at very low prevalences, or were completely parasite free. However, no population level effect of this parasite release was reflected in testes weight. These findings do not support a severe fitness impact of helminth parasites on C. maenas, which questions the role of parasites on its population dynamics, both in the native area and for invasive success.
van den Brink, A. M.; Wijnhoven, S.; McLay, C. L.
In a combined study including a 20 year monitoring programme of the benthic communities of four Dutch delta waters and a snapshot survey conducted in the Oosterschelde tidal bay in 2011, the populations of the native portunid European shore crab Carcinus maenas and the introduced varunid crabs Hemigrapsus takanoi and Hemigrapsus sanguineus were investigated. Whereas C. maenas was the most common shore crab in these waters, its numbers have declined on the soft sediment substrates during the last 20 years. As the two exotic crab species were first recorded in the Dutch delta in 1999, they could not have initiated the decline of the native C. maenas. However, within a few years H. takanoi completely dominated the intertidal hard substrate environments; the same environments on which juvenile C. maenas depend. On soft sediment substrate the native and exotic shore crab species are presently more or less equally abundant. H. takanoi might initially have taken advantage of the fact that C. maenas numbers were declining. Additionally H. takanoi are thriving in expanding oyster reefs of Crassostrea gigas (Pacific oyster) in the Dutch delta waters, which provide new habitat. Nowadays H. takanoi appears to be a fierce interference competitor or predator for small C. maenas specimens by expelling them from their shelters. These interactions have led to increased mortality of juvenile C. maenas. At present the C. maenas populations seem to be maintained by crabs that survive and reproduce on available soft sediment habitats where H. takanoi densities are low.
Mesquita, Sofia Raquel; Guilhermino, Lúcia; Guimarães, Laura
The aim of this study was to assess the effects of the widely used anti-depressant fluoxetine on behaviour (locomotion), moulting, neuromuscular transmission, energy production and anti-oxidant defences' efficiency of the epibenthic crab Carcinus maenas. Crabs were individually exposed to fluoxetine concentrations for 7d. Effects on locomotion were assessed at the end of the exposure using an open field test adapted to C. maenas in the present study. Tissue samples were later collected to evaluate fluoxetine effects on physiological functions using the activity of key enzymes and other parameters as biomarkers, namely: N-acetyl-β-glucosaminidase (NAGase) in the epidermis (moulting) and the hepatopancreas; cholinesterases (ChE) in muscle (neuromuscular cholinergic transmission); NADP(+)-dependent isocitrate dehydrogenase (IDH) and lactate dehydrogenease (LDH) in muscle (energy production); glutathione S-transferases (GST) in hepatopancreas (biotransformation and oxidative stress system); glutathione reductase (GR), and glutathione peroxidade (GPx), total glutathione levels (TG) and lipid peroxidation levels in the hepatopancreas (anti-oxidant defences and oxidative damage). Because no information on C. maenas NAGase activity was previously available, its variation during the moult cycle was also investigated. The results showed that locomotion was significantly increased at fluoxetine concentrations equal or above 120 μg L⁻¹, with animals spending more time moving, walking longer distances than controls. Levels of NAGase activity were found to vary in relation to C. maenas moult cycle, but no alterations were observed after exposure to fluoxetine. Significant increases in the activity of ChE, GST and GR enzymes, and the levels of TG were found, with a lowest observed effect concentration (LOEC) of 120 μg L⁻¹. Effects on locomotion were significantly and positively correlated to those induced on ChE activity. The results raise concern when hypothesising
Rodrigues, Aurélie P; Santos, Lúcia H M L M; Oliva-Teles, Maria Teresa; Delerue-Matos, Cristina; Guimarães, Laura
Concurrent exposure of estuarine organisms to man-made and natural stressors has become a common occurrence. Numerous interactions of multiple stressors causing synergistic or antagonistic effects have been described. However, limited information is available on combined effects of emerging pharmaceuticals and natural stressors. This study investigated the joint effects of the antidepressant sertraline and salinity on Carcinus maenas. To improve knowledge about interactive effects and potential vulnerability, experiments were performed with organisms from two estuaries with differing histories of exposure to environmental contamination. Biomarkers related to mode of action of sertraline were employed to assess effects of environmentally realistic concentrations of sertraline at two salinity levels. Synergism and antagonism were identified for biomarkers of cholinergic neurotransmission, energy production, anti-oxidant defences and oxidative damage. Different interactions were found for the two study sites highlighting the need to account for differences in tolerance of local ecological receptors in risk evaluations.
Ledesma, Federico M.; Van der Molen, Silvina; Barón, Pedro J.
The European green crab Carcinus maenas is a widely spread invasive species. Studying the most recently introduced population of the species in the Atlantic coast off Patagonia, it became apparent to us that carapaces (the dorsal cover of the visceral-cavity detaching from the rest of the exoskeleton after ecdysis) accumulated on the intertidal may be used as a valuable complementary material to analyze the size structure of crabs. However, since growth rate (and consequently size at instar) of crabs differs between males and females, finding a method to distinguish crab sex by observation of carapace morphology was necessary to allow the construction of independent size frequency distributions for each sex. In this work, we examined the shape of the carapaces from both sexes of C. maenas, and using Elliptical Fourier Analysis successfully identified sexual dimorphism. Thus, a reliable method to identify sexes by visual observation of the carapace was developed. Based on our results, we discuss the evolutionary significance of carapace form differentiation of both sexes.
Böttcher, K.; Siebers, D.; Sender, S.
This paper summarizes investigations on the enzyme carbonic anhydrase (CA) in the gills of the osmoregulating shore crab Carcinus maenas. Carbonic anhydrase, an enzyme catalyzing the reversible hydration of CO2 to HCO3 - and H+, is localized with highest activities in the posterior salt-transporting gills of the shore crab- and here CA activity is strongly dependent on salinity. Contrary to the earlier hypothesis established for the blue crab Callinectes sapidus that cytoplasmic branchial CA provides the counter ions HCO3 - and H+ for apical exchange against Na+ and Cl-, the involvement of CA in NaCl uptake mechanisms can be excluded in Carcinus. Differential and density gradient centrifugations indicate that branchial CA is a predominantly membrane-associated protein. Branchial CA was greatly inhibited by the sulfonamide acetazolamide (AZ) Ki=2.4·10-8 mol/l). Using the preparation of the isolated perfused gill, application of 10-4 mol/l AZ resulted in an 80% decrease of CO2/HCO3 - excretion. Thus we conclude that CA is localized in plasma membranes, maintaining the CO2 gradient by accelerating adjustment of the pH-dependent CO2/HCO3 - equilibrium.
Sheehan, E. V.; Thompson, R. C.; Coleman, R. A.; Attrill, M. J.
Collection of marine invertebrates for use as fishing bait is a substantial activity in many parts of the world, often with unknown ecological consequences. As new fisheries develop, it is critical for environmental managers to have high quality ecological information regarding the potential impacts, in order to develop sound management strategies. Crab-tiling is a largely unregulated and un-researched fishery, which operates commercially in the south-west UK. The target species is the green crab Carcinus maenas. Those crabs which are pre-ecdysis and have a carapace width greater than 40 mm are collected to be sold to recreational anglers as bait. Collection involves laying artificial structures on intertidal sandflats and mudflats in estuaries. Crabs use these structures as refugia and are collected during low tide. However, the effect that this fishery has on populations of C. maenas is not known. The impact of crab-tiling on C. maenas population structure was determined by sampling crabs from tiled estuaries and non-tiled estuaries using baited drop-nets. A spatially and temporarily replicated, balanced design was used to compare crab abundance, sizes and sex ratios between estuaries. Typically, fisheries are associated with a reduction in the abundance of the target species. Crab-tiling, however, significantly increased C. maenas abundance. This was thought to be a result of the extra habitat in tiled estuaries, which probably provides protection from natural predators, such as birds and fish. Although crabs were more abundant in tiled estuaries than non-tiled estuaries, the overall percentage of reproductively active crabs in non-tiled estuaries was greater than in tiled estuaries. As with most exploited fisheries stocks, crabs in exploited (tiled) estuaries tended to be smaller, with a modal carapace width of 20-29 mm rather than 30-39 mm in non-tiled estuaries. The sex ratio of crabs however; was not significantly different between tiled and non
Cieluch, Ude; Anger, Klaus; Aujoulat, Fabien; Buchholz, Friedrich; Charmantier-Daures, Mireille; Charmantie, Guy
The ontogeny of osmoregulation, the development of branchial transporting epithelia and the expression of the enzyme Na+/K+-ATPase were studied in Carcinus maenas (L.) obtained from the North Sea, Germany. Laboratory-reared zoea larvae, megalopae and young crabs were exposed to a wide range of salinities, and hemolymph osmolality was measured after 24 h exposure time (72 h in juveniles). Zoea I larvae slightly hyper-regulated in dilute media (10.2 per thousand and 17.0 per thousand ) and osmoconformed at >17 per thousand. All later zoeal stages (II-IV) osmoconformed in salinities from 10.2 per thousand to 44.3 per thousand. The megalopa hyper-regulated at salinities from 10.2 to 25.5 per thousand. Young crabs hyperregulated at salinities from 5.3 per thousand to 25.5 per thousand, showing an increase in their osmoregulatory capacity. The development of transporting epithelia and the expression of Na+/K+-ATPase were investigated by means of transmission electron microscopy and immunofluorescence microscopy. In the zoea IV, only a very light fluorescence staining was observed in gill buds. Epithelial cells were rather undifferentiated, without showing any features of ionocytes. Gills were present in the megalopa, where Na+/K+-ATPase was located in basal filaments of the posterior gills. In crab I juveniles and adults, Na+/K+-ATPase was noted in the three most posterior pairs of gills, but lacking in anterior gills. Ionocytes could first be recognized in filaments of megalopal posterior gills, persisting through subsequent stages at the same location. Thus, the development of the gills and the expression of Na+/K+-ATPase are closely correlated with the ontogeny of osmoregulatory abilities. The morphological two-step metamorphosis of C. maenas can also be regarded as an osmo-physiological metamorphosis, (i) from the osmoconforming zoeal stages to the weakly regulating megalopa, and (ii) to the effectively hyper-regulating juvenile and adult crabs.
Lye, Christina M; Bentley, Matthew G; Galloway, Tamara
There is a considerable body of evidence to suggest that many anthropogenic chemicals, most notably xeno-estrogens, are able to disrupt the endocrine system of vertebrates. There have been few comparable studies on the effects of exposure to these chemicals that may serve as biomarkers of endocrine disruption in aquatic invertebrate species. In addition, the evidence available is complex, conflicting, and far from conclusive. The present study aimed to investigate the impact of the xeno-estrogen 4-nonylphenol (4-NP, nominal concentrations 10-100 microg L(-1)) on the regulation and functioning of the endocrine system of the shore crab Carcinus maenas. It also set out to establish whether 4-NP are causing the effects (i.e., changes of exoskeletons including secondary sexual characteristics, pheromonally mediated behavior and ecdysone levels, and the presence of vt in the male hepatopancreas) found recently in wild shore crabs (Lye et al.,2005). The study utilizes morphological (e.g., gonadosomatic and hepatosomatic indices) and hormonal (ecdysteroid moulting hormone levels and the induction of female specific proteins, vitellins) biomarkers using radioimmunoassay and an indirect enzyme linked immunosorbent assay applied to the soluble protein fraction of adult male hepatopancreatic homogenates. Exposure of C. maenas to an effective concentration as low as 1.5 microg L(-1) 4-NP resulted in a reduced testis weight, increased liver weight, and altered levels of ecdysone equivalents compared to controls. Induction of vitellin-like proteins was absent in all samples tested. The ecological implications and the possible mechanisms for the action of 4-NP on the response of the shore crab to xeno-estrogen exposure are discussed.
Aguirre-Martínez, G V; Del Valls, T A; Martín-Díaz, M L
A 28-day bioassay was performed with Carcinus maenas to evaluate chronic effects caused by exposure to caffeine and ibuprofen (0.1-50 μg L(-1)) in sea water. Lysosomal membrane stability (LMS) was evaluated in hemolymph applying the neutral red retention assay (NRRA); several biomarkers including ethoxyresorufin O-deethylase (EROD), dibenzylfluorescein dealkylase (DBF), glutathione S-transferase (GST), glutathione peroxidase (GPX), lipid peroxidation (LPO) and DNA damage were studied in gill, hepatopancreas, muscle and gonad tissues. In crabs exposed to environmental concentrations of the drugs, retention time was reduced by 50%. EROD and DBFOD activities were induced by caffeine in muscle and hepatopancreas tissues (p < 0.05); GST activity was activated by ibuprofen in gill, hepatopancreas and muscle at the highest concentrations tested (p < 0.05). All tissues showed GPX activity and LPO induction (p < 0.05). Crabs exposed to caffeine and ibuprofen showed evidence of DNA damage mainly in hepatopancreas tissues (p < 0.05). Environmental concentrations of pharmaceuticals induce LMS and the biochemical responses studied in this crab. This methodology is a suitable technique for assessing pharmaceutical toxicity in the marine environment.
Stevens, Martin; Lown, Alice E.; Wood, Louisa E.
Camouflage is widespread throughout the natural world and conceals animals from predators in a vast range of habitats. Because successful camouflage usually involves matching aspects of the background environment, species and populations should evolve appearances tuned to their local habitat, termed phenotype-environment associations. However, although this has been studied in various species, little work has objectively quantified the appearances of camouflaged animals from different habitats, or related this to factors such as ontogeny and individual variation. Here, we tested for phenotype-environment associations in the common shore crab (Carcinus maenas), a species highly variable in appearance and found in a wide range of habitats. We used field surveys and digital image analysis of the colors and patterns of crabs found in four locations around Cornwall in the UK to quantify how individuals vary with habitat (predominantly rockpool, mussel bed, and mudflat). We find that individuals from sites comprising different backgrounds show substantial differences in several aspects of color and pattern, and that this is also dependent on life stage (adult or juvenile). Furthermore, the level of individual variation is dependent on site and life stage, with juvenile crabs often more variable than adults, and individuals from more homogenous habitats less diverse. Ours is the most comprehensive study to date exploring phenotype-environment associations for camouflage and individual variation in a species, and we discuss the implications of our results in terms of the mechanisms and selection pressures that may drive this. PMID:25551233
Hayden, Dominic; Jennings, Alice; Müller, Carsten; Pascoe, David; Bublitz, Ralf; Webb, Heather; Breithaupt, Thomas; Watkins, Lloyd; Hardege, Jörg
Experiments were conducted to investigate the sex-specific differences to feeding responses of the shore crab Carcinus maenas throughout the year. Results demonstrate that female shore crabs exhibit stronger feeding responses than males throughout the year with a significantly reduced feeding response in males during the summer months' reproductive season. We also studied the possible function(s) of the moulting hormone, 20-hydroxyecdysone (Crustecdysone) that has been described as a potential female-produced sex pheromone to initiate male reproductive behaviour in a number of crustaceans. We recently presented evidence that for shore crabs this is not the case and now show that the steroid is instead functioning as a sex-specific feeding deterrent protecting the moulting 'soft' female crabs. Whilst male shore crabs were deterred from prey (Mytilus edulis) and synthetic feeding stimulants glycine and taurine when these feeding stimulants were spiked with crustecdysone, intermoult female crabs were significantly less affected and rarely deterred from feeding. This sex specificity of the moulting hormone, in combination with the female sex pheromone, which has no anti-feeding properties, ensures that male crabs mate with soft-shelled, moulted females rather than engage in cannibalism, such as found frequently in cases when soft-shelled females are exposed to intermoult females.
Watts, Andrew J R; Urbina, Mauricio A; Goodhead, Rhys; Moger, Julian; Lewis, Ceri; Galloway, Tamara S
Microscopic plastic debris (microplastics, <5 mm in diameter) is ubiquitous in the marine environment. Previous work has shown that microplastics may be ingested and inhaled by the shore crab Carcinus maenas, although the biological consequences are unknown. Here, we show that acute aqueous exposure to polystyrene microspheres (8 μm) with different surface coatings had significant but transient effects on branchial function. Microspheres inhaled into the gill chamber had a small but significant dose-dependent effect on oxygen consumption after 1 h of exposure, returning to normal levels after 16 h. Ion exchange was also affected, with a small but significant decrease in hemolymph sodium ions and an increase in calcium ions after 24 h post-exposure. To further asses the effects on osmoregulation, we challenged crabs with reduced salinity after microplastic exposure. Neither microspheres nor natural sediments altered the crab's response to osmotic stress regardless of plastic concentration added. Carboxylated (COOH) and aminated (NH2) polystyrene microspheres were distributed differently across the gill surface, although neither had a significant adverse impact on gill function. These results illustrate the extent of the physiological effects of microplastics compared to the physiological resilience of shore crabs in maintaining osmoregulatory and respiratory function after acute exposure to both anthropogenic plastics and natural particles.
Farrell, Paul; Nelson, Kathryn
This study investigated the trophic transfer of microplastic from mussels to crabs. Mussels (Mytilus edulis) were exposed to 0.5 μm fluorescent polystyrene microspheres, then fed to crabs (Carcinus maenas). Tissue samples were then taken at intervals up to 21 days. The number of microspheres in the haemolymph of the crabs was highest at 24 h (15 033 ml(-1) ± SE 3146), and was almost gone after 21 days (267 ml(-1) ± SE 120). The maximum amount of microspheres in the haemolymph was 0.04% of the amount to which the mussels were exposed. Microspheres were also found in the stomach, hepatopancreas, ovary and gills of the crabs, in decreasing numbers over the trial period. This study is the first to show 'natural' trophic transfer of microplastic, and its translocation to haemolymph and tissues of a crab. This has implications for the health of marine organisms, the wider food web and humans.
Watts, Andrew J R; Lewis, Ceri; Goodhead, Rhys M; Beckett, Stephen J; Moger, Julian; Tyler, Charles R; Galloway, Tamara S
Microplastics, plastics particles <5 mm in length, are a widespread pollutant of the marine environment. Oral ingestion of microplastics has been reported for a wide range of marine biota, but uptake into the body by other routes has received less attention. Here, we test the hypothesis that the shore crab (Carcinus maenas) can take up microplastics through inspiration across the gills as well as ingestion of pre-exposed food (common mussel Mytilus edulis). We used fluorescently labeled polystyrene microspheres (8-10 μm) to show that ingested microspheres were retained within the body tissues of the crabs for up to 14 days following ingestion and up to 21 days following inspiration across the gill, with uptake significantly higher into the posterior versus anterior gills. Multiphoton imaging suggested that most microspheres were retained in the foregut after dietary exposure due to adherence to the hairlike setae and were found on the external surface of gills following aqueous exposure. Results were used to construct a simple conceptual model of particle flow for the gills and the gut. These results identify ventilation as a route of uptake of microplastics into a common marine nonfilter feeding species.
Greco, G; Lanero, T Svaldo; Torrassa, S; Young, R; Vassalli, M; Cavaliere, A; Rolandi, R; Pelucchi, E; Faimali, M; Davenport, J
Marine biofouling causes problems for technologies based on the sea, including ships, power plants and marine sensors. Several antifouling techniques have been applied to marine sensors, but most of these methodologies are environmentally unfriendly or ineffective. Bioinspiration, seeking guidance from natural solutions, is a promising approach to antifouling. Here, the eye of the green crab Carcinus maenas was regarded as a marine sensor model and its surface characterized by means of atomic force microscopy. Engineered surface micro- and nanotopography is a new mechanism found to limit biofouling, promising an effective solution with much reduced environmental impact. Besides giving a new insight into the morphology of C. maenas eye and its characterization, our study indicates that the eye surface probably has antifouling/fouling-release potential. Furthermore, the topographical features of the surface may influence the wettability properties of the structure and its interaction with organic molecules. Results indicate that the eye surface micro- and nanotopography may lead to bioinspired solutions to antifouling protection.
Mesquita, Sofia Raquel; Ergen, Şeyda Fikirdeşici; Rodrigues, Aurélie Pinto; Oliva-Teles, M Teresa; Delerue-Matos, Cristina; Guimarães, Laura
Cadmium is a priority hazardous substance, persistent in the aquatic environment, with the capacity to interfere with crustacean moulting. Moulting is a vital process dictating crustacean growth, reproduction and metamorphosis. However, for many organisms, moult disruption is difficult to evaluate in the short term, what limits its inclusion in monitoring programmes. N-acetyl-β-D-glucosaminidase (NAGase) is an enzyme acting in the final steps of the endocrine-regulated moulting cascade, allowing for the cast off of the old exoskeleton, with potential interest as a biomarker of moult disruption. This study investigated responses to waterborne cadmium of NAGase activity of Carcinus maenas originating from estuaries with different histories of anthropogenic contamination: a low impacted and a moderately polluted one. Crabs from both sites were individually exposed for seven days to cadmium concentrations ranging from 1.3 to 2000 μg/L. At the end of the assays, NAGase activity was assessed in the epidermis and digestive gland. Detoxification, antioxidant, energy production, and oxidative stress biomarkers implicated in cadmium metabolism and tolerance were also assessed to better understand differential NAGase responses: activity of glutathione S-transferases (GST), glutathione peroxidase (GPx) glutathione reductase (GR), levels of total glutathiones (TG), lipid peroxidation (LPO), lactate dehydrogenase (LDH), and NADP(+)-dependent isocitrate dehydrogenase (IDH). Animals from the moderately polluted estuary had lower NAGase activity both in the epidermis and digestive gland than in the low impacted site. NAGase activity in the epidermis and digestive gland of C. maenas from both estuaries was sensitive to cadmium exposure suggesting its usefulness for inclusion in monitoring programmes. However, in the digestive gland NAGase inhibition was found in crabs from the less impacted site but not in those from the moderately contaminated one. Altered glutathione levels were
Tummon Flynn, Paula S.; Mellish, Cassandra L.; Pickering, Tyler R.; Quijón, Pedro A.
The European green crab (Carcinus maenas) is a voracious non-indigenous predator and a threat to Atlantic Canada's shellfish industry. Its foraging ability, however, may be affected by the occurrence of injuries such as the loss of a cheliped (claw). Given that green crab claws are differentiated into a major crusher and a minor cutter, we argue that autotomy (the reflexive loss of a limb) affects feeding rates, and that this effect depends on which particular claw is lost. We examined the incidence of injuries in two green crab populations of the southern Gulf of St. Lawrence during July-October, 2012. Then we experimentally assessed the influence of the loss of each type of claw upon crab feeding rates over two size-classes of American oysters (Crassostrea virginica) and soft-shell clams (Mya arenaria). Field injury surveys showed that 12.4% of the green crabs collected were missing a claw (the cutter and/or crusher claw). Injury rates increased linearly with crab size, and were found to vary with location. Laboratory experiments showed that, compared to intact crabs, the loss of the crusher claw reduced oyster mortality rates by ~ 93-100%. The loss of the crusher also reduced feeding on small soft-shell clams but only temporarily. The loss of the cutter claw had little impact on green crab feeding rates on oysters and soft-shell clams of either size. Combined, these results suggest that the loss of a claw has an effect on the ability of green crabs to consume commercially important species but this effect depends on which claw is lost and which prey is targeted. It follows that injury rates should be taken into consideration when monitoring and forecasting the potential impacts of green crab populations, particularly on oyster beds.
There is an increasing interest to restore the ecosystem services that eelgrass provides, after their continuous worldwide decline. Most attempts to restore eelgrass using seeds are challenged by very high seed losses and the reasons for these losses are not all clear. We assess the impact of predation on seed loss and eelgrass establishment, and explore methods to decrease seed loss during restoration in the Swedish northwest coast. In a laboratory study we identified three previously undescribed seed predators, the shore crab Carcinus maenas, the hermit crab Pagurus bernhardus and the sea urchin Strongylocentrotus droebachiensis, of which shore crabs consumed 2–7 times more seeds than the other two species. The importance of shore crabs as seed predators was supported in field cage experiments where one enclosed crab caused 73% loss of seeds over a 1-week period on average (~ 21 seeds per day). Seedling establishment was significantly higher (14%) in cages that excluded predators over an 8-month period than in uncaged plots and cages that allowed predators but prevented seed-transport (0.5%), suggesting that seed predation constitutes a major source of seed loss in the study area. Burying the seeds 2 cm below the sediment surface prevented seed predation in the laboratory and decreased predation in the field, constituting a way to decrease seed loss during restoration. Shore crabs may act as a key feedback mechanism that prevent the return of eelgrass both by direct consumption of eelgrass seeds and as a predator of algal mesograzers, allowing algal mats to overgrow eelgrass beds. This shore crab feedback mechanism could become self-generating by promoting the growth of its own nursery habitat (algal mats) and by decreasing the nursery habitat (seagrass meadow) of its dominant predator (cod). This double feedback-loop is supported by a strong increase of shore crab abundance in the last decades and may partly explain the regime shift in vegetation observed
Spaargaren, D. H.
Ammonia concentrations were measured in blood and external media of shore crabs, Carcinus maenas, acclimated to 6 different salinities at high (20° C) and low (4° C) temperatures. It is seen that environmental osmotic conditions (temperature and salinity) have a major influence on NH 4+ formation and thus on protein (amino acid) catabolism. Blood ammonia concentrations appear to be strongly stabilized, independent of environmental osmotic conditions, ranging between 0.25 and 0.55 mmol·l -1. At normal, low environmental NH 4+ concentrations blood NH 4+ is strongly hyper-ionic compared to external concentrations; at high environmental NH 4+ concentrations (even when artificially raised to 2.5 mmol·l -1), blood NH 4+ is strongly hypo-ionic. Regulation of the blood NH 4+ concentrations takes place by a variable efflux of NH 4+; at high environmental NH 4+ concentrations (> 0.28 mmol · l -1), in addition to a high NH 4+ efflux, stabilization of the blood NH 4+ concentrations is effectuated by the formation of urea. Ammonia efflux to the surrounding water is highly dependent to the osmotic conditions of the environment: viz. positively related to temperature and inversely related to external salinity, with relatively stable value near the isosmotic salinity. Related to the strong variations in ammonia efflux, external NH 4+ concentrations in a closed volume of water are highly variable. In the course of time very high values develop in media of low salinity at high temperature. A close connection between NH 4+ excretion and extracellular ion regulation is indicated.
Pringle, J. M.; Blakeslee, A. M.; Byers, J. E.; Roman, J.
Existing estimates of the downstream invasion speed of newly introduced species or novel genotypes with planktonic larvae have usually found that they invade much less rapidly downstream than would be expected from the mean alongshore currents in their habitat. For example, a new, genetically-distinct population of Carcinus maenas was introduced at the northern-edge of its range in Cape Breton, Nova Scotia (Roman 2006). Recently, we have found that this newly introduced genotype is being transported south- westward along the coast by the prevailing currents, displacing established populations of C. maenas. However, the rate of southward spread of the northern genotype is much less than what we would expect from the mean currents along the Scotian Shelf and Gulf of Maine. We examine four reasons for errors in the naive estimates of the rate of spread of an introduced species or genotype from mean currents. 1) Cross-shelf shear in the alongshore currents can interact with cross-shelf dispersion of larvae to bias larval settlement towards larvae which have spent more time in the weaker nearshore currents. 2) Weakly retentive embayments and other coastal features, even if unable to retain larvae for more than a small fraction of their planktonic duration, will tend to reduce the alongshelf transports of those larvae and increase the likelihood that they remain close enough to the coast to successfully recruit. This will reduce the mean alongshore transport of the larvae that recruit. 3) Alongshore gradients in the population density of competing species/genotypes will, if the population density increases in the direction of the mean currents, tend to retard the downstream spread of an introduced species/genotype. 4) Greater relative fitness or competitiveness in the downstream genotype/species will retard the spread of the upstream genotype/species. Examples of and evidence for and against these possible explanations will be provide for C. maenas in the Gulf of Maine
McGaw, Iain J; Penney, Chantelle M
The effect of meal type on specific dynamic action was investigated in the green shore crab, Carcinus maenas. When the crabs were offered a meal of fish, shrimp, or mussel of 3 % of their body mass the duration of the SDA response and thus the resultant SDA was lower for the mussel, compared with the shrimp or fish meals. In feeding behaviour experiments the crabs consumed almost twice as much mussel compared with fish or shrimp. When the animals were allowed to feed on each meal until satiated, the differences in the SDA response were abolished. The mussel was much softer (compression test) than the fish or shrimp meal, and meal texture is known to affect the SDA response in amphibians and reptiles. When the crabs were offered a meal of homogenized fish muscle or whole fish muscle, the SDA for the homogenized meal was approximately 35 % lower. This suggested that a significant portion of the SDA budget in decapod crustaceans may be related to mechanical digestion. This is not unexpected since the foregut is supplied by over forty muscles which control the cutting and grinding movements of the gastric mill apparatus. There were slight, but significant differences in protein, lipid, moisture and total energy content of each meal type. Three prepared meals that were high in either protein, lipid or carbohydrate were offered to the crabs to determine if the nutrient content was also a contributing factor to the observed differences in the SDA. The crabs did not eat the prepared meals as readily as the natural food items and as they are messy feeders there was a large variation in the amount of food eaten. The lack of significant differences in the SDA response as a function of nutrient content was likely due to differences in amount of food eaten, which is a major factor determining the SDA response. The differences in SDA when consuming natural food items were likely due to a combination of the costs of mechanical digestion, variation in nutrient content and food
Little, D I; Poat, P C; Giles, I G
The nature of the experimental error in the initial velocities of an enzyme-catalysed reaction is required if meaningful least-squares regression is to be applied. When a rate equation more complex that that of Michaelis and Menten is to be solved least-squares techniques are the method of choice and so determination of the error structure becomes mandatory. The use of residual analysis and Tukey's T statistics to determine the weights to use are described. This method has the advantage of requiring no additional experimentation over that required for the primary investigation. Using data obtained for Carcinus maenas phosphofructokinase the variance was found to increase with velocity and was approximated by either an empirical power function, var (vi) alpha vi1.8 or by the function, var (vi) alpha 0.007 + vi2. The latter function is preferred and suggests that the data contains both a constant absolute error and a constant percentage error component.
Williams, Larissa M.; Nivison, Camilla L.; Ambrose, William G.; Dobbin, Rebecca; Locke, William L.
Introduced over 200 yr ago to the east coast of North America, Carcinus maenas now ranges from New York to Newfoundland. In the 1980s, a secondary invasion of European lineages, termed northern haplotypes, occurred in Nova Scotia. Young-of-the-year sampled in 2007 revealed that northern haplotypes were present in low frequencies at several northwestern Atlantic sites as far south as New York; a model predicted an increase in their range and frequency over time. We collected samples in 2013 and 2014 to determine the haplotypes of adult crabs from New York to Nova Scotia. Six haplotypes, encompassing previously identified northern and southern haplotypes, 1 novel southern haplotype, and 1 Scandinavian haplotype, were identified in 275 crabs sampled at 11 sites. Northern haplotypes were only found in Nova Scotia, Beals Island (Maine), and Mount Desert Island (Maine) at a frequency of 60, 8, and 24%, respectively; remaining sites were predominantly composed of a previously identified southern haplotype. Northern haplotypes are limited in adult crabs to Mount Desert Island and north, indicating that the southern haplotype is selectively favored at some point during their life history, recruitment of northern larvae is limited south of Mount Desert Island, or entire year-classes post-2007 were lost. Our results do not support the predictions of an increase in the range and frequency of northern haplotypes, at least among adults, and indicate that a more complete knowledge of factors affecting C. maenas life stages is necessary to understand the current distribution of haplotypes. PMID:28127110
Greco, G.; Lanero, T. Svaldo; Torrassa, S.; Young, R.; Vassalli, M.; Cavaliere, A.; Rolandi, R.; Pelucchi, E.; Faimali, M.; Davenport, J.
Marine biofouling causes problems for technologies based on the sea, including ships, power plants and marine sensors. Several antifouling techniques have been applied to marine sensors, but most of these methodologies are environmentally unfriendly or ineffective. Bioinspiration, seeking guidance from natural solutions, is a promising approach to antifouling. Here, the eye of the green crab Carcinus maenas was regarded as a marine sensor model and its surface characterized by means of atomic force microscopy. Engineered surface micro- and nanotopography is a new mechanism found to limit biofouling, promising an effective solution with much reduced environmental impact. Besides giving a new insight into the morphology of C. maenas eye and its characterization, our study indicates that the eye surface probably has antifouling/fouling-release potential. Furthermore, the topographical features of the surface may influence the wettability properties of the structure and its interaction with organic molecules. Results indicate that the eye surface micro- and nanotopography may lead to bioinspired solutions to antifouling protection. PMID:23635491
Williams, Larissa M; Nivison, Camilla L; Ambrose, William G; Dobbin, Rebecca; Locke, William L
Introduced over 200 yr ago to the east coast of North America, Carcinus maenas now ranges from New York to Newfoundland. In the 1980s, a secondary invasion of European lineages, termed northern haplotypes, occurred in Nova Scotia. Young-of-the-year sampled in 2007 revealed that northern haplotypes were present in low frequencies at several northwestern Atlantic sites as far south as New York; a model predicted an increase in their range and frequency over time. We collected samples in 2013 and 2014 to determine the haplotypes of adult crabs from New York to Nova Scotia. Six haplotypes, encompassing previously identified northern and southern haplotypes, 1 novel southern haplotype, and 1 Scandinavian haplotype, were identified in 275 crabs sampled at 11 sites. Northern haplotypes were only found in Nova Scotia, Beals Island (Maine), and Mount Desert Island (Maine) at a frequency of 60, 8, and 24%, respectively; remaining sites were predominantly composed of a previously identified southern haplotype. Northern haplotypes are limited in adult crabs to Mount Desert Island and north, indicating that the southern haplotype is selectively favored at some point during their life history, recruitment of northern larvae is limited south of Mount Desert Island, or entire year-classes post-2007 were lost. Our results do not support the predictions of an increase in the range and frequency of northern haplotypes, at least among adults, and indicate that a more complete knowledge of factors affecting C. maenas life stages is necessary to understand the current distribution of haplotypes.
Blewett, Tamzin A; Wood, Chris M
Nickel (Ni) is a metal of environmental concern, known to cause toxicity to freshwater organisms by impairing ionoregulation and/or respiratory gas exchange, and by inducing oxidative stress. However, little is known regarding how nickel toxicity is influenced by salinity. In the current study we investigated the salinity-dependence and mechanisms of sub-lethal Ni toxicity in a euryhaline crab (Carcinus maenas). Crabs were acclimated to three experimental salinities--20, 60 and 100% seawater (SW)--and exposed to 3mg/L Ni for 24h or 96 h. Tissues were dissected for analysis of Ni accumulation, gills were taken for oxidative stress analysis (catalase activity and protein carbonyl content), haemolymph ions were analysed for ionoregulatory disturbance, and oxygen consumption was determined in exercised crabs after 96 h of Ni exposure. Total Ni accumulation was strongly dependant on salinity, with crabs from 20% SW displaying the highest tissue Ni burdens after both 24 and 96-h exposures. After 96 h of exposure, the highest accumulation of Ni occurred in the posterior (ionoregulatory) gills at the lowest salinity, 20% SW. Posterior gill 8 exhibited elevated protein carbonyl levels and decreased catalase activity after Ni exposure, but only in 20% SW. Similarly, decreased levels of haemolymph Mg and K and an increased level of Ca were recorded but only in crabs exposed to Ni for 96 h in 20% SW. Oxygen consumption after exercise was also inhibited in crabs exposed to Ni in 20% SW. These data show for the first time the simultaneous presence of all three modes of sub-lethal Ni toxicity in exposed animals, and indicate a strong salinity dependence of sub-lethal Ni toxicity to the euryhaline crab, C. maenas, a pattern that corresponded to tissue Ni accumulation.
Rodrigues, Aurélie P; Santos, Lúcia H M L M; Ramalhosa, Maria João; Delerue-Matos, Cristina; Guimarães, Laura
Sertraline is widely prescribed worldwide and frequently detected in aquatic systems. There is, however, a remarkable gap of information on its potential impact on estuarine and coastal invertebrates. This study investigated sertraline accumulation and effects in Carcinus maenas. Crabs from a moderately contaminated (Lima) and a low-impacted (Minho) estuary were exposed to environmental and high levels of sertraline (0.05, 5, 500 μg L(-1)). A battery of biomarkers related to sertraline mode of action was employed to assess neurotransmission, energy metabolism, biotransformation and oxidative stress pathways. After a seven-day exposure, sertraline accumulation in crabs' soft tissues was found in Lima (5 μg L(-1): 15.3 ng L(-1) ww; 500 μg L(-1): 1010 ng L(-1) ww) and Minho (500 μg L(-1): 605 ng L(-1) ww) animals. Lima crabs were also more sensitive to sertraline than those from Minho, exhibiting decreased acetylcholinesterase activity, indicative of ventilatory and locomotory dysfunction, inhibition of anti-oxidant enzymes and increased oxidative damage at ≥ 0.05 μg L(-1). The Integrated Biomarker Response (IBR) index indicated their low health status. In addition, Minho crabs showed non-monotonic responses of acetylcholinesterase suggestive of hormesis. The results pointed an influence of the exposure history on differential sensitivity to sertraline and the need to perform evaluations with site-specific ecological receptors to increase relevance of risk estimations when extrapolating from laboratory to field conditions.
Rey, Felisa; Alves, Eliana; Melo, Tânia; Domingues, Pedro; Queiroga, Henrique; Rosa, Rui; Domingues, M. Rosário M.; Calado, Ricardo
Embryogenesis is an important stage of marine invertebrates with bi-phasic life cycles, as it conditions their larval and adult life. Throughout embryogenesis, phospholipids (PL) play a key role as an energy source, as well as constituents of biological membranes. However, the dynamics of PL during embryogenesis in marine invertebrates is still poorly studied. The present work used a lipidomic approach to determine how polar lipid profiles shift during embryogenesis in two sympatric estuarine crabs, Carcinus maenas and Necora puber. The combination of thin layer chromatography, liquid chromatography – mass spectrometry and gas chromatography – mass spectrometry allowed us to achieve an unprecedented resolution on PL classes and molecular species present on newly extruded embryos (stage 1) and those near hatching (stage 3). Embryogenesis proved to be a dynamic process, with four PL classes being recorded in stage 1 embryos (68 molecular species in total) and seven PL classes at stage 3 embryos (98 molecular species in total). The low interspecific difference recorded in the lipidomic profiles of stage 1 embryos appears to indicate the existence of similar maternal investment. The same pattern was recorded for stage 3 embryos revealing a similar catabolism of embryonic resources during incubation for both crab species. PMID:26419891
Harzsch, S.; Dawirs, R. R.
We investigated the morphology of the central nervous system throughout the larval development of Carcinus maenas. For that purpose single larvae were reared in the laboratory from hatching through metamorphosis. Complete series of whole mout semithin sections were obtained from individuals of all successive larval stages and analysed with a light microscope. Morphological feature and spatial arrangement of discernable neural cell clusters, fibre tracts and neuropile are described and compared with the adult pattern. We found that most of the morphological features characterizing the adult nervous system are already present in the zoea-1. Nevertheless, there are marked differences with respect to the arrangement of nerve cell bodies, organization of cerebral neuropile, and disposition of ganglia in the ventral nerve cord. It appears that complexity of the central nervous neuropile is selectively altered during postmetamorphotic development, probably reflecting adaptive changes of sensory-motor integration in response to behavioural maturation. In contrast, during larval development there was little change in the overall structural organization of the central nervous system despite some considerable growth. However, the transition from zoea-4 to megalopa brings about multiple fundamental changes in larval morphology and behavioural pattern. Since central nervous integration should properly adapt to the altered behavioural repertoire of the megalopa, it seems necessary to ask in which respect synaptic rearrangement might characterize development of the central nervous system.
Ben-Khedher, Sana; Jebali, Jamel; Kamel, Naouel; Banni, Mohamed; Rameh, Mohamed; Jrad, Amel; Boussetta, Hamadi
The biochemical effects in Carcinus maenas and contamination levels in seawater and sediments of Bizerta Lagoon (northeast of Tunisia) were investigated. The levels of metals and hydrocarbons were higher in seawater and sediments in Menzel Bourguiba and Cimentery in February and July than in the other sampling sites. Differences among sites for glutathione S-transferase, catalase, acetylcholinesterase activities, and the content of lipid peroxidation and metallothioneins in two important organs which accumulated contaminants (the gills and the digestive gland) of the C. maenas were found and possibly related to differences in metal and hydrocarbon levels. The seasonal variation of biomarkers was possibly associated with chemical contamination and also with the high fluctuation of physico-chemical characteristics of the sites. The integrated biomarker response values found in the five sites is in good agreement with hydrocarbon and trace metal concentrations detected in the water and sediments of the stressful places where crabs are living.
Aguirre-Martínez, G V; Del Valls, T A; Martín-Díaz, M L
One of the main consequences of the constant input of pharmaceuticals to the aquatic environment is that biota might develop unknown chronic effects, thus affecting their health even at low concentrations. The aim of this study is to evaluate the health status of Carcinus maenas employing a 2-tier approach, after 28 days of exposure to carbamazepine (CBZ) and novobiocin (NOV) at 0.1, 1, 10 and 50µgL(-1). Lysosomal membrane stability (LMS) is employed in tier 1. In tier 2 was applied a battery of biomarkers of exposure and effect (ethoxyresorufin O-deethylase (EROD), dibenzyl flourescein dealkylase (DBF), glutathione S-transferase (GST), glutathione peroxidase (GPx), lipid peroxidation (LPO) and DNA adducts) measured in gill, hepatopancreas, muscle and gonad tissues. Results show a dose-dependent effect. LMS in crabs exposed to environmental concentrations of pharmaceuticals was significantly lower compared to controls (p<0.05), indicating their stressed status. EROD activity was induced significantly (p<0.05) in all tissues by NOV (10-50µgL(-1)). DBF activity was induced significantly (p<0.05) in gill and hepatopancreas tissues by CBZ (10-50µgL(-1)). GST activity was activated in all tissues of crabs exposed to the highest concentrations tested (p<0.05). All tissues showed induction of GPX activity after exposure to selected drugs (p<0.05). LPO was activated in gill and hepatopancreas tissues by the pharmaceuticals at 50µgL(-1) (p<0.05). Crabs exposed to NOV (50µgL(-1)) presented DNA damage in gill and hepatopancreas tissues (p<0.05). Environmental concentrations of these pharmaceuticals have a measurable effect on the biomarkers studied. The 2-tier approach applied might be a suitable tool for the assessment of sublethal responses in crabs exposed to pharmaceuticals in the marine environment.
Krieger, Jakob; Sombke, Andy; Seefluth, Florian; Kenning, Matthes; Hansson, Bill S; Harzsch, Steffen
The European shore crab Carcinus maenas and the common hermit crab Pagurus bernhardus are members of the sister taxa Brachyura and Anomura (together forming the taxon Meiura) respectively. Both species share similar coastal marine habitats and thus are confronted with similar environmental conditions. This study sets out to explore variations of general brain architecture of species that live in seemingly similar habitats but belong to different major malacostracan taxa and to understand possible differences of sensory systems and related brain compartments. We examined the brains of Carcinus maenas, Pagurus bernhardus, and three other hermit crab species with immunohistochemistry against tyrosinated tubulin, f-actin, synaptic proteins, RF-amides and allatostatin. Our comparison showed that their optic neuropils within the eyestalks display strong resemblance in gross morphology as well as in detailed organization, suggesting a rather similar potential of processing visual input. Besides the well-developed visual system, the olfactory neuropils are distinct components in the brain of both C. maenas and P. bernhardus as well as the other hermit crabs, suggesting that close integration of olfactory and visual information may be useful in turbid marine environments with low visibility, as is typical for many habitats such as, e.g., the Baltic and the North Sea. Comparing the shape of the olfactory glomeruli in the anomurans showed some variations, ranging from a wedge shape to an elongate morphology. Furthermore, the tritocerebrum and the organization of the second antennae associated with the tritocerebrum seem to differ markedly in C. maenas and P. bernhardus, indicating better mechanosensory abilities in the latter close to those of other Decapoda with long second antennae, such as Astacida, Homarida, or Achelata. This aspect may also represent an adaptation to the "hermit lifestyle" in which competition for shells is a major aspect of their life history. The shore
Monitoring PAH contamination in the field (South west Iberian Peninsula): biomonitoring using fluorescence spectrophotometry and physiological assessments in the shore crab Carcinus maenas (L.) (Crustacea: Decapoda).
Dissanayake, Awantha; Bamber, Shaw D
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of the marine environment, arising predominantly from petrochemical contamination and pyrogenic sources. A biomarker of PAH exposure was employed in a field study (South West, Spain) in both captured (indigenous) and deployed (caged) shore crabs (Carcinus maenas) in the chronic PAH-exposed Bays of Algeciras and Gibraltar (from associated harbour and boating activity) compared to a relatively 'clean' site (Cadiz). Metabolite fluorescence was attributed to the following key priority PAH groups; naphthalenes (NAPs), pyrenes (PYRs) and benzo[a]pyrenes (BAPs). Temporal variability was assessed using deployed populations over an eight week period. Petrogenic and pyrogenic PAH contamination (as an indicator of the PAH type) was demonstrated using a ratio between FF(BAP + PYR)/FF(NAP). Physiological assessments from deployed crabs demonstrated both physiological and cellular alterations as shown by reduced heart rates (at rest) and increased cellular stress in crabs from the PAH contaminated sites.
Balcı, Fuat; Ramey-Balcı, Patricia A; Ruamps, Perrine
Spontaneous alternation refers to the tendency of organisms to explore places that they have least recently visited. Our previous work showed that alternation performance of Carcinus maenas (invasive European green crab) was significantly higher than Callinectes sapidus (native blue crab), and chance level performance (Ramey, P. A., Teichman, E., Oleksiak, J., & Balcı, F. . Spontaneous alternation in marine crabs: Invasive versus native species. Behavioural Processes, 82, 51-55.). In the current study, we first tested the robustness of these findings in the absence of visual cues, longer test durations, and wider maze dimensions. These manipulations enabled us to determine whether these two crab species relied on the visual cues provided during the spontaneous alternation task in our prior work, and allowed for better characterization of their exploratory activity in the maze. Our original findings were reproduced in the present study under these new task conditions, suggesting no role for visual cues during alternation, and emphasizing the robustness and generalizability of the corresponding interspecies differences in alternation performance. We also tested whether the lower alternation performance of C. sapidus also applied to another native crab species, Uca pugnax (fiddler crab). Spontaneous alternation performance of U. pugnax was significantly lower than C. maenas but indistinguishable from C. sapidus. Finally, we examined whether the potentially higher inherent risk-sensitivity of C. sapidus could have contributed to their lower alternation performance by testing C. maenas in the presence of a larger natural predator (stressor). Higher risk sensitivity presumably induced by the stressor led to locomotor activity patterns that better resembled those of C. sapidus, however the resultant reduction in alternation performance was not statistically significant.
Buratti, Sara; Ramos-Gómez, Julia; Fabbri, Elena; DelValls, T Angel; Martín-Díaz, M Laura
Dredged material management is a key issue for the protection of aquatic environments. The in situ approach using caged bioindicator species has been chosen lately as a new methodology for the assessment of dredged material. In a tier testing approach, neutral red retention (NRR) assay has been applied as a screening tool to detect adverse changes in health status associated with contamination. Nevertheless, to authors' knowledge, little is known about the application and validation of this technique in sediment bioindicator species and under field conditions. Caged Ruditapes decussatus and Carcinus maenas were exposed during 28 days to potentially contaminated sediments at three sites in Algeciras Bay (SW Spain) and one site in Cádiz Bay (SW Spain). Lysosomal membrane stability was measured over time in haemolymph samples of exposed clams and crabs using the NRR assay. Sediment characterization of the study sites was performed in parallel. NRR time did not vary significantly (p > 0.05) over time in organisms from Cádiz Bay. Conversely, significant differences (p < 0.05) in NRR time were found in clams and crabs exposed to sediments from Algeciras Bay, which exhibited a 30-70% decrease in haemocyte lysosome membrane stability compared to day 0. Statistical analysis showed a strong correlation between the drop of haemocyte lysosome membrane stability, in both crabs and clams, and the presence of metals (p < 0.05) and PAHs (p < 0.01) in the studied sediments. The results obtained confirmed the use of NRR assay as a suitable and sensitive method to be used in the assessment of sediment quality using as bioindicator species the clam R. philippinarum and the crab C. maenas.
Chung, J S; Dircksen, H; Webster, S G
Molting or ecdysis is the most fundamentally important process in arthropod life history, because shedding of the exoskeleton is an absolute prerequisite for growth and metamorphosis. Although the hormonal mechanisms driving ecdysis in insects have been studied extensively, nothing is known about these processes in crustaceans. During late premolt and during ecdysis in the crab Carcinus maenas, we observed a precise and reproducible surge in hemolymph hyperglycemic hormone (CHH) levels, which was over 100-fold greater than levels seen in intermolt animals. The source of this hormone surge was not from the eyestalk neurosecretory tissues but from previously undescribed endocrine cells (paraneurons), in defined areas of the foregut and hindgut. During premolt (the only time when CHH is expressed by these tissues), the gut is the largest endocrine tissue in the crab. The CHH surge, which is a result of an unusual, almost complete discharge of the contents of the gut endocrine cell, regulates water and ion uptake during molting, thus allowing the swelling necessary for successful ecdysis and the subsequent increase in size during postmolt. This study defines an endocrine brain/gut axis in the arthropods. We propose that the ionoregulatory process controlled by CHH may be common to arthropods, in that, for insects, a similar mechanism seems to be involved in antidiuresis. It also seems likely that a cascade of very precisely coordinated release of (neuro) hormones controls ecdysis.
Langhamer, Olivia; Holand, Håkon; Rosenqvist, Gunilla
Worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization in terms of artificial reefs. The artificial reef effect is important when planning offshore installations since it can create habitat enhancement. Wind power is the most advanced technology within offshore renewable energy sources and there is an urgent need to study its impacts on the marine environment. To test the hypothesis that offshore wind power increases the abundance of reef species relative to a reference area, we conduct an experiment on the model species common shore crab (Carcinus maenas).Overall, 3962 crabs were captured, observed, marked and released in 2011 and 1995 crabs in 2012. Additionally, carapace size, sex distribution, color morphs and body condition was recorded from captured crabs. We observed very low recapture rates at all sites during both years which made evaluating differences in population sizes very difficult. However, we were able to estimate population densities from the capture record for all three sites. There was no obvious artificial reef effect in the Lillgrund wind farm, but a spill-over effect to nearby habitats cannot be excluded. We could not find any effect of the wind farm on either, morphs, sex distribution or condition of the common shore crab. Our study found no evidence that Lillgrund wind farm has a negative effect on populations of the common shore crab. This study provides the first quantitative and experimental data on the common shore crab in relation to offshore wind farms. PMID:27780212
Brian, Jayne V
Environmental contaminants that are capable of causing endocrine disrupting effects are currently a major cause for concern. These chemicals are known to influence the reproductive development of vertebrates by mimicking or antagonising the actions of endogenous hormones. However, little is known regarding their potential effects on invertebrates. Here we examine variations in the reproductive morphology of the shore crab (Carcinus maenas) for evidence of endocrine disruption. Crabs were collected from a number of sites comprising a putative gradient of exposure to endocrine disrupting chemicals. Patterns of inter-population variability in the expression of sexually dimorphic traits were then examined for evidence of hormone disruption. Extensive variability was detected and patterns of chelal morphology were consistent with the gradient of endocrine disruption. However, overall, the patterns of morphological variability were not consistent with hormonally-mediated effects. This suggests that shore crabs are not susceptible to the same type of endocrine disrupting effects that have been detected in vertebrates, which are most commonly mediated via the oestrogen receptor. However, the potential for androgenic effects on crustacean morphology are discussed.
Background The green crab Carcinus maenas is known for its high acclimation potential to varying environmental abiotic conditions. A high ability for ion and acid-base regulation is mainly based on an efficient regulation apparatus located in gill epithelia. However, at present it is neither known which ion transport proteins play a key role in the acid-base compensation response nor how gill epithelia respond to elevated seawater pCO2 as predicted for the future. In order to promote our understanding of the responses of green crab acid-base regulatory epithelia to high pCO2, Baltic Sea green crabs were exposed to a pCO2 of 400 Pa. Gills were screened for differentially expressed gene transcripts using a 4,462-feature microarray and quantitative real-time PCR. Results Crabs responded mainly through fine scale adjustment of gene expression to elevated pCO2. However, 2% of all investigated transcripts were significantly regulated 1.3 to 2.2-fold upon one-week exposure to CO2 stress. Most of the genes known to code for proteins involved in osmo- and acid-base regulation, as well as cellular stress response, were were not impacted by elevated pCO2. However, after one week of exposure, significant changes were detected in a calcium-activated chloride channel, a hyperpolarization activated nucleotide-gated potassium channel, a tetraspanin, and an integrin. Furthermore, a putative syntaxin-binding protein, a protein of the transmembrane 9 superfamily, and a Cl-/HCO3- exchanger of the SLC 4 family were differentially regulated. These genes were also affected in a previously published hypoosmotic acclimation response study. Conclusions The moderate, but specific response of C. maenas gill gene expression indicates that (1) seawater acidification does not act as a strong stressor on the cellular level in gill epithelia; (2) the response to hypercapnia is to some degree comparable to a hypoosmotic acclimation response; (3) the specialization of each of the posterior gill
Wilcockson, David C; Webster, Simon G
Bursicon is the ultimate hormone in insect ecdysis, which is involved in cuticle hardening. Here we show that mRNAs encoding the heterodimeric cystine knot protein bursicon (Burs alpha, beta), are present in crustaceans, suggesting ubiquity of this hormone in arthropods. We firstly report the cloning, sequencing of mRNAs encoding subunits from the water flea, Daphnia arenata and the CNS of the crab, Carcinus maenas, in comparison with insect bursicon subunits. Expression patterns of alpha and beta burs mRNAs were examined by in-situ hybridisation (ISH) and quantitative RT-PCR. In the thoracic ganglion, burs alpha and beta mRNAs were completely colocalised in neurones expressing crustacean cardioactive peptide (CCAP). However, in the brain and eyestalk, bursicon transcripts were never observed, despite a complex expression pattern of CCAP interneurones. Patterns of expression of burs alpha and beta mRNAs were constitutive during the moult cycle of adult crabs, in stark contrast to the situation in insects. Whilst copy numbers of burs beta transcripts closely matched those of CCAP, those of burs alpha mRNA were around 3-fold higher than burs beta. This pattern was apparent during embryogenesis, where bursicon transcripts were first observed at around 50% development-the same time as first expression of CCAP mRNA. Transcript ratios (burs alpha: beta) increased during development. Our studies have shown, for the first time, that bursicon mRNAs are expressed in identified neurones in the nervous system of crustaceans. These findings will now promote further investigation into the functions of bursicon during the moult cycle and development of crustaceans.
Hammer, Karen M; Pedersen, Sindre A; Størseth, Trond R
Carbon dioxide (CO(2)) acts as a weak acid in water and the increasing level of CO(2) in the atmosphere leads to ocean acidification. In addition, possible leakage from sub-seabed storage of anthropogenic CO(2) may pose a threat to the marine environment. (1)H NMR spectroscopy was applied to extracts of hemolymph, gills and leg muscle from shore crabs (Carcinus maenas) to examine the metabolic response to elevated levels of CO(2). Crabs were exposed to different levels of CO(2)-acidified seawater with pH(NBS) 7.4, 6.6 and 6.3 (pCO(2)~2600, 16,000 and 30,000 μatm, respectively) for two weeks (level-dependent exposure). In addition, the metabolic response was followed for up to 4 weeks of exposure to seawater pH(NBS) 6.9 (pCO(2)~7600 μatm). Partial least squares regression analysis of data showed an increased differentiation between metabolic fingerprints of controls and exposed groups for all sample types with increasing CO(2) levels. Difference between controls and animals subjected to time-dependent exposure appeared after 4 weeks in the hemolymph and gills, and after 48 h of exposure in the leg muscle. Changes in metabolic profiles were mainly due to a reduced level of important intracellular osmolytes such as amino acids (glycine, proline), while the level of other metabolites varied between the different sample types. The results are similar to what is observed in animals exposed to hypo-osmotic stress and may suggest disturbances in intracellular iso-osmotic regulation. The results may also reflect increased catabolism of amino acids to supply the body fluids with proton-buffering ammonia (NH(3)). Alternatively, the findings may reflect an exhaustive effect of CO(2) exposure.
Della Longa, S; Bianconi, A; Palladino, L; Simonelli, B; Congiu Castellano, A; Borghi, E; Barteri, M; Beltramini, M; Rocco, G P; Salvato, B
High-resolution x-ray absorption near edge structure spectroscopy was used to characterize the metal sites in three different cobalt-substituted derivatives of Carcinus maenas hemocyanin (Hc), including a mononuclear cobalt, a dinuclear cobalt and a copper-cobalt hybrid derivative. Co(II) model complexes with structures exemplifying octahedral, trigonal bipyramidal, pseudo-tetrahedral, and square planar geometries were also studied. The results provide structural information about the metal binding site(s) in the Co-Hcs that extend earlier results from EPR and optical spectroscopy (Bubacco et al. 1992. Biochemistry. 31: 9294-9303). Experimental spectra were compared to those calculated for atomic clusters of idealized geometry, generated using a multiple scattering approach. The energy of the dipole forbidden 1s-->3d transition and of the absorption edge in the spectra for all cobalt Hc derivatives confirmed the cobaltous oxidation state which rules out the presence of an oxygenated site. Comparisons between data and simulations showed that the mononuclear and dinuclear Co(II) derivatives, as well as the hybrid derivative, contain four-coordinate Co(II) in distorted tetrahedral sites. Although the spectra for Co(II) in dinuclear metal sites more closely resemble the simulated spectrum for a tetrahedral complex than do spectra for the mononuclear derivative, the Co(II) sites in all derivatives are very similar. The Cu K-edge high resolution x-ray absorption near edge structure spectrum of the hybrid Cu-Co-Hc resembles that of deoxy-Hc demonstrating the presence of three-coordinate Cu(I). PMID:8312502
Robert, Alexandrine; Monsinjon, Tiphaine; Delbecque, Jean-Paul; Olivier, Stéphanie; Poret, Agnès; Foll, Frank Le; Durand, Fabrice; Knigge, Thomas
Serotonin, a highly conserved neurotransmitter, controls many biological functions in vertebrates, but also in invertebrates. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are commonly used in human medication to ease depression by affecting serotonin levels. Their residues and metabolites can be detected in the aquatic environment and its biota. They may also alter serotonin levels in aquatic invertebrates, thereby perturbing physiological functions. To investigate whether such perturbations can indeed be expected, shore crabs (Carcinus maenas) were injected either with serotonin, fluoxetine or a combination of both. Dose-dependent effects of fluoxetine ranging from 250 to 750nM were investigated. Gene expression of crustacean hyperglycemic hormone (chh) as well as moult inhibiting hormone (mih) was assessed by RT-qPCR at 2h and 12h after injection. Glucose and ecdysteroid levels in the haemolymph were monitored in regular intervals until 12h. Serotonin led to a rapid increase of chh and mih expression. On the contrary, fluoxetine only affected chh and mih expression after several hours, but kept expression levels significantly elevated. Correspondingly, serotonin rapidly increased glycaemia, which returned to normal or below normal levels after 12h. Fluoxetine, however, resulted in a persistent low-level increase of glycaemia, notably during the period when negative feedback regulation reduced glycaemia in the serotonin treated animals. Ecdysteroid levels were significantly decreased by serotonin and fluoxetine, with the latter showing less pronounced and less rapid, but longer lasting effects. Impacts of fluoxetine on glycaemia and ecdysteroids were mostly observed at higher doses (500 and 750nM) and affected principally the response dynamics, but not the amplitude of glycaemia and ecdysteroid-levels. These results suggest that psychoactive drugs are able to disrupt neuroendocrine control in decapod crustaceans, as they interfere with the
Tepolt, Carolyn K; Somero, George N
As global warming accelerates, there is increasing concern about how ecosystems may change as a result of species loss and replacement. Here, we examined the thermal physiology of the European green crab (Carcinus maenas Linnaeus 1758), a globally invasive species, along three parallel thermal gradients in its native and invasive ranges. At each site, we assessed cardiac physiology to determine heat and cold tolerance and acclimatory plasticity. We found that, overall, the species is highly tolerant of both heat and cold, and that it survives higher temperatures than co-occurring native marine crustaceans. Further, we found that both heat and cold tolerance are plastic in response to short-term acclimation (18-31 days at either 5 or 25°C). Comparing patterns within ranges, we found latitudinal gradients in thermal tolerance in the native European range and in the invasive range in eastern North America. This pattern is strongest in the native range, and likely evolved there. Because of a complicated invasion history, the latitudinal pattern in the eastern North American invasive range may be due either to rapid adaptation post-invasion or to adaptive differences between the ancestral populations that founded the invasion. Overall, the broad thermal tolerance ranges of green crabs, which may facilitate invasion of novel habitats, derive from high inherent eurythermality and acclimatory plasticity and potentially adaptive differentiation among populations. The highly flexible physiology that results from these capacities may represent the hallmark of a successful invasive species, and may provide a model for success in a changing world.
Rodríguez-Romero, Araceli; Jiménez-Tenorio, Natalia; Riba, Inmaculada; Blasco, Julián
The capture and storage of CO2 in sub-seabed geological formations has been proposed as one of the potential options to decrease atmospheric CO2 concentrations in order to mitigate the abrupt and irreversible consequences of climate change. However, it is possible that CO2 leakages could occur during the injection and sequestration procedure, with significant repercussions for the marine environment. We investigate the effects of acidification derived from possible CO2 leakage events on the European green crab, Carcinus maenas. To this end, a lab-scale experiment involving direct release of CO2 was conducted at pH values between 7.7 and 6.15. Female crabs were exposed for 10 days to sediment collected from two different coastal areas, one with relatively uncontaminated sediment (RSP) and the other with known contaminated sediment (MZ and ML), under the pre-established seawater pH conditions. Survival rate, histopathological damage and metal (Fe, Mn, Cu, Zn, Cr, Cd and Pb) and As accumulation in gills and hepatopancreas tissue were employed as endpoints. In addition, the obtained results were compared with the results of the physico-chemical characterization of the sediments, which included the determination of the metals Fe, Mn, Cu, Zn, Cr, Pb and Cd, the metalloid As, certain polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), as well as nonchemical sediment properties (grain size, organic carbon and total organic matter). Significant associations were observed between pH and the histological damage. Concentrations of Fe, Mn, Cr, Pb, Cd and PAHs in sediment, presented significant negative correlations with the damage to gills and hepatopancreas, and positive correlations with metal accumulation in both tissues. The results obtained in this study reveal the importance of sediment properties in the biological effects caused by possible CO2 leakage. However, a clear pattern was not observed between metal accumulation in tissues and p
First confirmation of human diarrhoeic poisonings by okadaic acid esters after ingestion of razor clams (Solen marginatus) and green crabs (Carcinus maenas) in Aveiro lagoon, Portugal and detection of okadaic acid esters in phytoplankton.
Vale, Paulo; de M Sampayo, Maria Antónia
A new outbreak of human diarrhoeic poisonings (DSP) with esters of okadaic acid (OA) was confirmed after ingestion of razor clams (Solen marginatus) harvested at Aveiro lagoon (NW Portugal) in the summer of 2001. Accumulation of marine toxins in second order consumers was investigated in the edible parts of a shellfish predator abundant at Aveiro lagoon, the green crab Carcinus maenas. Okadaic acid was found, also in a predominant esterified form. Levels in edible parts (comprising mainly viscera) surpassed 16microg/100g. We suggest that one patient may have developed profuse diarrhoea after ingestion of a large number of green crabs contaminated with okadaic acid esters. At least 32microg OA/100g were found in a remaining sample of its meal. Domoic acid was also found but under the allowable level in force in USA of 30microg/g crab viscera. In cooked crabs, significant losses of domoic acid were found and it is not suspected to have contributed to the poisoning event, although being a vector for this toxin. The low percentage of free okadaic acid found is in accordance with a predation predominantly on benthonic shellfish (razor clams, clams and common cockle) rather than on rock mussels. These last ones present usually higher percentages of free okadaic acid. Okadaic acid was confirmed with full-scan mass spectra either in plankton and mussel extracts. Okadaic acid esters were also found in plankton extracts. Percentages between 40-60% of esterified OA were found in samples freshly extracted. Ester's percentage diminished drastically if after sonication the extract was kept at room temperature. The major part of the esters was water-soluble.
Crustacean hyperglycaemic hormone (CHH)-like peptides and CHH-precursor-related peptides from pericardial organ neurosecretory cells in the shore crab, Carcinus maenas, are putatively spliced and modified products of multiple genes.
Dircksen, H; Böcking, D; Heyn, U; Mandel, C; Chung, J S; Baggerman, G; Verhaert, P; Daufeldt, S; Plösch, T; Jaros, P P; Waelkens, E; Keller, R; Webster, S G
About 24 intrinsic neurosecretory neurons within the pericardial organs (POs) of the crab Carcinus maenas produce a novel crustacean hyperglycaemic hormone (CHH)-like peptide (PO-CHH) and two CHH-precursor-related peptides (PO-CPRP I and II) as identified immunochemically and by peptide chemistry. Edman sequencing and MS revealed PO-CHH as a 73 amino acid peptide (8630 Da) with a free C-terminus. PO-CHH and sinus gland CHH (SG-CHH) share an identical N-terminal sequence, positions 1-40, but the remaining sequence, positions 41-73 or 41-72, differs considerably. PO-CHH may have different precursors, as cDNA cloning of PO-derived mRNAs has revealed several similar forms, one exactly encoding the peptide. All PO-CHH cDNAs contain a nucleotide stretch coding for the SG-CHH(41-76) sequence in the 3'-untranslated region (UTR). Cloning of crab testis genomic DNA revealed at least four CHH genes, the structure of which suggest that PO-CHH and SG-CHH arise by alternative splicing of precursors and possibly post-transcriptional modification of PO-CHH. The genes encode four exons, separated by three variable introns, encoding part of a signal peptide (exon I), the remaining signal peptide residues, a CPRP, the PO-CHH(1-40)/SG-CHH(1-40) sequences (exon II), the remaining PO-CHH residues (exon III) and the remaining SG-CHH residues and a 3'-UTR (exon IV). Precursor and gene structures are more closely related to those encoding related insect ion-transport peptides than to penaeid shrimp CHH genes. PO-CHH neither exhibits hyperglycaemic activity in vivo, nor does it inhibit Y-organ ecdysteroid synthesis in vitro. From the morphology of the neurons it seems likely that novel functions remain to be discovered. PMID:11336648
Leignel, V; Stillman, J H; Baringou, S; Thabet, R; Metais, I
Green crabs (Carcinus, Portunidae) include two species native to Europe--Carcinus aestuarii (Mediterranean species) and Carcinus maenas (Atlantic species). These small shore crabs (maximal length carapace, approximately 10 cm) show rapid growth, high fecundity, and long planktonic larval stages that facilitate broad dispersion. Carcinus spp. have a high tolerance to fluctuations of environmental factors including oxygen, salinity, temperature, xenobiotic compounds, and others. Shipping of Carcinus spp. over the past centuries has resulted in its invasions of America, Asia, and Australia. Classified as one of the world's 100 worst invaders by the International Union for Conservation of Nature, Carcinus spp. are the most widely distributed intertidal crabs in the world. Their voracious predatory activity makes them strong interactors in local communities, and they are recognized as a model for invasiveness in marine systems as well as a sentinel species in ecotoxicology. This review shows an exhaustive analysis of the literature on the life cycle, diversity, physiological tolerance, genomic investigations, ecotoxicological use, historical invasion, control programs, and putative economical valorization of shore crabs.
Atlantic salmon (Salmo salar) is an important cultured carnivorous species with wide comsumer acceptance. With the finite supply of available fishmeal and fish oil available for aquafeeds, research on and utilization of alternative protein and lipid sources is expandingWe examined the nutritional p...
Dolashka-Angelova, Pavlina; Hristova, Rumiyana; Stoeva, Stanka; Voelter, Wolfgang
Hemocyanin (Hc) of Carcinus aestuarii contains three major and one minor electrophoretically separable polypeptide chains which were purified by fast protein liquid chromatography (FPLC) ion exchange chromatography. N-terminal amino acid sequences of four structural subunits (SSs) from C. aestuarii were compared with known N-terminal sequences from other arthropodan hemocyanins. The conformational changes, induced by various treatments, were monitored by far UV, CD and fluorescence spectroscopy. The critical temperatures for the structural subunits, Tc, determined by fluorescence spectroscopy, are in the region of 52-59°C and coincide with the melting temperatures, Tm (49-55°C), determined by CD spectroscopy. The free energy of stabilization in water, Δ GDH 2O , toward guanidinium hydrochloride is about 1.3 times higher for the dodecameric Hc as compared to the isolated subunits and about one time higher for Ca1, comparing with other SSs. The studies reveal that the conformational stability of the native dodecamer towards various denaturants (temperature and guanidinium hydrochloride) indicate that the quaternary structure is stabilized by oligomerization between structural subunits, and the possibility of a structural role of the sugar mojeties cannot be excluded.
Pilot tests were performed to determine the level at which Zn(++) and Cu(++) ceased to be acutely toxic in Macrobrachium carcinus. The data indicated that the static 96h-LC(50) values for Zn(++) and Cu(++) were 0.2 and 0.1 mg litre(-1) respectively. A differential reduction in respiration and ammonia excretion rates was noted with increasing concentrations of these metals in the water. These levels may in a toxic body burden and a progressive deterioration of gill efficiency. A decrease in respiration and ammonia excretion rates resulted in a decrease in O:N ratios, upon exposure to Zn(++) and Cu(++) concentrations. The ratios obtained indicate that these metals, also increased dependence on carbohydrate or lipid reserves.
Casas-Sánchez, R; Vaillard-Nava, Y; Re-Araujo, A D
Juvenile prawn Macrobrachium carcinus were fed two different diets: restaurant by-products (diet I) and fish and vegetable market by-products (diet II). These diets were evaluated by proximal analysis, assimilation efficiency and the factor conversion rate (FCR). Diet I registered a higher efficiency, but there was no difference in the growth rate. The growth mean (G. L.) for three months was 0.254 +/- 0.13 cm (diet I) and 0.191 +/- 0.1 cm (diet II). The conversion rate was good for both, suggesting that 6 to 7 kg of food are needed to obtain 1 kg of prawn. Survival was 76% and 100% for diets I and II, respectively.
... Inheritance; Heterozygous; Inheritance patterns; Heredity and disease; Heritable; Genetic markers ... The chromosomes are made up of strands of genetic information called DNA. Each chromosome contains sections of ...
The genus Capsicum represents one of several well characterized Solanaceous genera. A wealth of classical and molecular genetics research is available for the genus. Information gleaned from its cultivated relatives, tomato and potato, provide further insight for basic and applied studies. Early ...
Maintaining genetic variation in wild populations of Arctic organisms is fundamental to the long-term persistence of high latitude biodiversity. Variability is important because it provides options for species to respond to changing environmental conditions and novel challenges such as emerging path...
Seeley, Robin Hadlock
Shell shape and shell thickness of the intertidal snail Littorina obtusata changed markedly between 1871 and 1984 in northern New England. Shells collected prior to 1900 were high-spired with thin walls, whereas shells collected in 1982-84 were low-spired with thick walls. An intertidal crab (Carcinus maenas) which preys on L. obtusata expanded its range into northern New England around 1900. This suggests that the change in snail shell form was a response to predation by Carcinus. Field and laboratory experiments demonstrated that the high-spired form of L. obtusata, which can still be found in some Maine localities, is more vulnerable to predation by Carcinus than is the low-spired form of L. obtusata. Electrophoretic comparisons of high- and low-spired populations of L. obtusata confirmed that these populations represent different morphological forms of L. obtusata rather than different species [Nei's D (unbiased measure of genetic distance) = 0.003]. These data demonstrate that classical Darwinian selection can produce a rapid morphological transition without speciation. Images PMID:16593760
pacific oyster (Crassostrea gigas), Asian oyster (Crassostrea ariakensis), Chinese mitten crab (Eriochirus sinensis), and green crab (Carcinus maenas...Crustaceans Eriocheir sinensis Chinese mitten crab * Mollusks Perna perna Brown (Mexihalo) mussel* Mollusks Perna viridis ( Asian ) green mussel...tinca), Asian clam, zebra mussel, yellow iris (Iris pseudacorus), dotted duckweed (Landoltia punctata), purple loosestrife (Lythrum salicaria
Schiavina, M; Marino, I A M; Zane, L; Melià, P
Investigating the interactions between the physical environment and early life history is crucial to understand the mechanisms that shape the genetic structure of marine populations. Here, we assessed the genetic differentiation in a species with larval dispersal, the Mediterranean shore crab (Carcinus aestuarii) in the Adriatic Sea (central Mediterranean), and we investigated the role of oceanic circulation in shaping population structure. To this end, we screened 11 polymorphic microsatellite loci from 431 individuals collected at eight different sites. We found a weak, yet significant, genetic structure into three major clusters: a northern Adriatic group, a central Adriatic group and one group including samples from southern Adriatic and Ionian seas. Genetic analyses were compared, under a seascape genetics approach, with estimates of potential larval connectivity obtained with a coupled physical-biological model that integrates a water circulation model and a description of biological traits affecting dispersal. The cross-validation of the results of the two approaches supported the view that genetic differentiation reflects an oceanographic subdivision of the Adriatic Sea into three subbasins, with circulation patterns allowing the exchange of larvae through permanent connections linking north Adriatic sites and ephemeral connections like those linking the central Adriatic with northern and southern locations.
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Izzi, Claudia; Liut, Francesca; Dallera, Nadia; Mazza, Cinzia; Magistroni, Riccardo; Savoldi, Gianfranco; Scolari, Francesco
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most frequent genetic disease, characterized by progressive development of bilateral renal cysts. Two causative genes have been identified: PKD1 and PKD2. ADPKD phenotype is highly variable. Typically, ADPKD is an adult onset disease. However, occasionally, ADPKD manifests as very early onset disease. The phenotypic variability of ADPKD can be explained at three genetic levels: genic, allelic and gene modifier effects. Recent advances in molecular screening for PKD gene mutations and the introduction of the new next generation sequencing (NGS)- based genotyping approach have generated considerable improvement regarding the knowledge of genetic basis of ADPKD. The purpose of this article is to provide a comprehensive review of the genetics of ADPKD, focusing on new insights in genotype-phenotype correlation and exploring novel clinical approach to genetic testing. Evaluation of these new genetic information requires a multidisciplinary approach involving a nephrologist and a clinical geneticist.
... Home > Science Education > The New Genetics The New Genetics Living Laboratories Classroom Poster Order a Free Copy ... Piece to a Century-Old Evolutionary Puzzle Computing Genetics Model Organisms RNA Interference The New Genetics is ...
... Management Education & Events Advocacy For Patients About ACOG Genetic Disorders Home For Patients Search FAQs Genetic Disorders ... Spanish Genetic Disorders FAQ094, April 2014 PDF Format Genetic Disorders Pregnancy What are genes? What are chromosomes? ...
Nora, J.J.; Fraser, F.C.
This book presents a discussion of medical genetics for the practitioner treating or counseling patients with genetic disease. It includes a discussion of the relationship of heredity and diseases, the chromosomal basis for heredity, gene frequencies, and genetics of development and maldevelopment. The authors also focus on teratology, somatic cell genetics, genetics and cancer, genetics of behavior.
Chu, Nathaniel D; Miller, Luke P; Kaluziak, Stefan T; Trussell, Geoffrey C; Vollmer, Steven V
Thermal stress and predation risk have profound effects on rocky shore organisms, triggering changes in their feeding behaviour, morphology and metabolism. Studies of thermal stress have shown that underpinning such changes in several intertidal species are specific shifts in gene and protein expression (e.g. upregulation of heat-shock proteins). But relatively few studies have examined genetic responses to predation risk. Here, we use next-generation RNA sequencing (RNA-seq) to examine the transcriptomic (mRNA) response of the snail Nucella lapillus to thermal stress and predation risk. We found that like other intertidal species, N. lapillus displays a pronounced genetic response to thermal stress by upregulating many heat-shock proteins and other molecular chaperones. In contrast, the presence of a crab predator (Carcinus maenas) triggered few significant changes in gene expression in our experiment, and this response showed no significant overlap with the snail's response to thermal stress. These different gene expression profiles suggest that thermal stress and predation risk could pose distinct and potentially additive challenges for N. lapillus and that genetic responses to biotic stresses such as predation risk might be more complex and less uniform across species than genetic responses to abiotic stresses such as thermal stress.
Reagan, Dugan; Crivello, Joseph F.
To investigate community shelter effects of two invasive decapod species, Hemigrapsus sanguineus and Carcinus maenas, in the Long Island Sound (LIS), we deployed artificial shelters in the intertidal and immediate subtidal zones. These consisted of five groups during the summer: a control, a resident H. sanguineus male or female group, and a resident C. maenas male or female group. We quantified utilization of the shelters at 24 h by counting crabs and fish present. We found significant avoidance of H. sanguineus in the field by benthic hermit crabs (Pagurus spp.) and significant avoidance of C. maenas by the seaboard goby (Gobiosoma ginsburgi). The grubby (Myoxocephalus aenaeus) avoided neither treatment, probably since it tends to be a predator of invertebrates. H. sanguineus avoided C. maenas treatments, whereas C. maenas did not avoid any treatment. Seasonal deployments in the subtidal indicated cohabitation of a number of benthic species in the LIS, with peak shelter use corresponding with increased predation and likely reproductive activity in spring and summer for green crabs (C. maenas), hermit crabs (Pagurus spp.), seaboard gobies (G. ginsburgi), and grubbies (Myoxocephalus aenaeus). PMID:27547570
Hudson, David M; Reagan, Dugan; Crivello, Joseph F
To investigate community shelter effects of two invasive decapod species, Hemigrapsus sanguineus and Carcinus maenas, in the Long Island Sound (LIS), we deployed artificial shelters in the intertidal and immediate subtidal zones. These consisted of five groups during the summer: a control, a resident H. sanguineus male or female group, and a resident C. maenas male or female group. We quantified utilization of the shelters at 24 h by counting crabs and fish present. We found significant avoidance of H. sanguineus in the field by benthic hermit crabs (Pagurus spp.) and significant avoidance of C. maenas by the seaboard goby (Gobiosoma ginsburgi). The grubby (Myoxocephalus aenaeus) avoided neither treatment, probably since it tends to be a predator of invertebrates. H. sanguineus avoided C. maenas treatments, whereas C. maenas did not avoid any treatment. Seasonal deployments in the subtidal indicated cohabitation of a number of benthic species in the LIS, with peak shelter use corresponding with increased predation and likely reproductive activity in spring and summer for green crabs (C. maenas), hermit crabs (Pagurus spp.), seaboard gobies (G. ginsburgi), and grubbies (Myoxocephalus aenaeus).
Jorde, L.B.; Carey, J.C.; White, R.L.
This book on the subject of medical genetics is a textbook aimed at a very broad audience: principally, medical students, nursing students, graduate, and undergraduate students. The book is actually a primer of general genetics as applied to humans and provides a well-balanced introduction to the scientific and clinical basis of human genetics. The twelve chapters include: Introduction, Basic Cell Biology, Genetic Variation, Autosomal Dominant and Recessive Inheritance, Sex-linked and Mitochondrial Inheritance, Clinical Cytogenetics, Gene Mapping, Immunogenetics, Cancer Genetics, Multifactorial Inheritance and Common Disease, Genetic Screening, Genetic Diagnosis and Gene Therapy, and Clinical Genetics and Genetic Counseling.
Wang, Lui; Bayer, Steven E.
Genetic algorithms are mathematical, highly parallel, adaptive search procedures (i.e., problem solving methods) based loosely on the processes of natural genetics and Darwinian survival of the fittest. Basic genetic algorithms concepts are introduced, genetic algorithm applications are introduced, and results are presented from a project to develop a software tool that will enable the widespread use of genetic algorithm technology.
Most invasion histories include an estimated arrival time, followed by range expansion. Yet, such linear progression may not tell the entire story. The European green crab (Carcinus maenas) was first recorded in the US in 1817, followed by an episodic expansion of range to the north. Its population has recently exploded in the Canadian Maritimes. Although it has been suggested that this northern expansion is the result of warming sea temperatures or cold-water adaptation, Canadian populations have higher genetic diversity than southern populations, indicating that multiple introductions have occurred in the Maritimes since the 1980s. These new genetic lineages, probably from the northern end of the green crab's native range in Europe, persist in areas that were once thought to be too cold for the original southern invasion front. It is well established that ballast water can contain a wide array of nonindigenous species. Ballast discharge can also deliver genetic variation on a level comparable to that of native populations. Such gene flow not only increases the likelihood of persistence of invasive species, but it can also rapidly expand the range of long-established nonindigenous species. PMID:16959635
Vermeij, Geerat J.
The phenotypic stability of many species in the face of changing conditions suggests that adaptive evolution can occur only under limited circumstances. One of the necessary conditions may be the lack of genetic mixing between dispersed populations inhabiting different environments. Intertidal molluscs on the east coast of North America between Cape Cod and Nova Scotia were exposed to an increase in the abundance of shell breaking predators when the green crab Carcinus maenas spread gradually northward from Cape Cod in the first half of the twentieth century1. The periwinkle Littorina littorea, which produces larvae that become widely dispersed, did not show an increase in shell thickness as an adaptation to shell-breaking predation1. However, I show here that the dog whelk Nucella lapillus, which is poorly dispersed in the bottom-dwelling juvenile phase, did adapt phenotypically after establishment of the green crab. This suggests that phenotypic stasis and gradual change are alternative responses depending on the degree of genetic mixing between populations.
... this page: //medlineplus.gov/ency/patientinstructions/000510.htm Genetic counseling To use the sharing features on this ... cystic fibrosis or Down syndrome. Who May Want Genetic Counseling? It is up to you whether or ...
... This can cause a medical condition called a genetic disorder. You can inherit a gene mutation from ... during your lifetime. There are three types of genetic disorders: Single-gene disorders, where a mutation affects ...
Resnik, David B; Vorhaus, Daniel B
In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions.
Resnik, David B; Vorhaus, Daniel B
In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions. PMID:16800884
Munoz, Karen E.; Hyde, Luke W.; Hariri, Ahmad R.
Imaging genetics is an experimental strategy that integrates molecular genetics and neuroimaging technology to examine biological mechanisms that mediate differences in behavior and the risks for psychiatric disorder. The basic principles in imaging genetics and the development of the field are discussed.
Griffen, Blaine D; Guy, Travis; Buck, Julia C
1. With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. Interactions between invasive species may provide important mechanisms that moderate their impacts on native species. 2. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid-1800 s and is capable of rapid consumption of bivalve prey. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions as C. maenas within the Gulf of Maine. Using a series of field and laboratory investigations, we examined the consequences of interactions between these predators. 3. Density patterns of these two species at different spatial scales are consistent with negative interactions. As a result of these interactions, C. maenas alters its diet to consume fewer mussels, its preferred prey, in the presence of H. sanguineus. Decreased mussel consumption in turn leads to lower growth rates for C. maenas, with potential detrimental effects on C. maenas populations. 4. Rather than an invasional meltdown, this study demonstrates that, within the Gulf of Maine, this new invasive predator can moderate the impacts of the older invasive predator.
Moore, P. G.; Howarth, J.
Field studies using fish-baited creels have confirmed that Carcinus maenas, Necora puber and Pagurus bernhardus (Crustacea: Decapoda), Buccinum undatum (Gastropoda) and Asterias rubens (Echinodermata) are prominent scavenging species in shallow waters in the Clyde Sea area. Capture rates of these species by creels baited with dead fish plus variously damaged C. maenas were examined in the field. The addition of substantially fractured C. maenas significantly reduced the capture of conspecifics, but significantly enhanced the capture of the taxonomically unrelated species A. rubens. The remaining crustacean taxa (of the above) were unaffected by this treatment. The magnitude of th response was related strongly to the extent to which C. maenas were damaged. The effects of hunger on these responses were tested in a laboratory experiment in which the responses of starved and fed batches of C. maenas were investigated. Starved crabs remained attracted to fish bait, despite the proximity of dead conspecifics. Conversely, crabs of the fed batch were significantly more reluctant to enter creels containing damaged conspecifics. The localized presence of odours emanating from dead conspecifics did not cause crabs to remain inactive in shelter. We conclude that taxonomic relatedness to bait, degree of carcass damage and hunger of the scavenger all interact in determining foraging decision-making even by so-called generalist scavengers.
Weier, Heinz -Ulrich G
Herein are described multicolor FISH probe sets termed "genetic barcodes" targeting several cancer or disease-related loci to assess gene rearrangements and copy number changes in tumor cells. Two, three or more different fluorophores are used to detect the genetic barcode sections thus permitting unique labeling and multilocus analysis in individual cell nuclei. Gene specific barcodes can be generated and combined to provide both numerical and structural genetic information for these and other pertinent disease associated genes.
Presents a review of genetic engineering, in which the genotypes of plants and animals (including human genotypes) may be manipulated for the benefit of the human species. Discusses associated problems and solutions and provides an extensive bibliography of literature relating to genetic engineering. (JR)
... all things Genetic Alliance, Expecting Health and more... Co-Creating A Healthy Future See all the photos, videos, slideshows and more that we co-created at our 30th Anniversary conference. BioTrust BioTrust ...
... chromosomes to their child, 22 autosomal and 1 sex chromosome. The inheritance of genetic diseases, abnormalities, or traits ... chromosome the abnormal gene resides on (autosomal or sex chromosome), and by whether the gene itself is dominant ...
Reid, Kathryn J.; Sakati, Nadia; Prichard, Lorraine L.; Schneiderman, Lawrence J.; Jones, Oliver W.; Dixson, Barbara K.
The geographic distribution of County Health Department clinic facilities in the state of California has made it readily possible to establish a regionalized program for genetic counseling services, using public health nurses as a major source of case-finding. From both consumer and health professional standpoints, regionalized satellite genetic counseling clinics have been successful, and in particular, the effectiveness of public health nurses in identifying clinical genetic problems is readily apparent. Long-term follow-up reinforcement of genetic counseling appears to be an important conclusion from these studies. It is our suggestion that reinforcement of counseling would best be accomplished through the health team member (physician, nurse and so forth) following the patient or family rather than through the consulting geneticist. PMID:946335
Andermann, Anne; Blancquaert, Ingeborg
Abstract OBJECTIVE To provide a primer for primary care professionals who are increasingly called upon to discuss the growing number of genetic screening services available and to help patients make informed decisions about whether to participate in genetic screening, how to interpret results, and which interventions are most appropriate. QUALITY OF EVIDENCE As part of a larger research program, a wide literature relating to genetic screening was reviewed. PubMed and Internet searches were conducted using broad search terms. Effort was also made to identify the gray literature. MAIN MESSAGE Genetic screening is a type of public health program that is systematically offered to a specified population of asymptomatic individuals with the aim of providing those identified as high risk with prevention, early treatment, or reproductive options. Ensuring an added benefit from screening, as compared with standard clinical care, and preventing unintended harms, such as undue anxiety or stigmatization, depends on the design and implementation of screening programs, including the recruitment methods, education and counseling provided, timing of screening, predictive value of tests, interventions available, and presence of oversight mechanisms and safeguards. There is therefore growing apprehension that economic interests might lead to a market-driven approach to introducing and expanding screening before program effectiveness, acceptability, and feasibility have been demonstrated. As with any medical intervention, there is a moral imperative for genetic screening to do more good than harm, not only from the perspective of individuals and families, but also for the target population and society as a whole. CONCLUSION Primary care professionals have an important role to play in helping their patients navigate the rapidly changing terrain of genetic screening services by informing them about the benefits and risks of new genetic and genomic technologies and empowering them to
... seeing a genetic counselor? Q. What is a genetic counselor? A. Genetic counselors are healthcare professionals with ... and serve as patient advocates. Q. What is genetic counseling? A. Genetic counseling is the process of ...
... of Genetic Terms Definitions for genetic terms Specific Genetic Disorders Many human diseases have a genetic component. ... Condition in an Adult The Undiagnosed Diseases Program Genetic Disorders Achondroplasia Alpha-1 Antitrypsin Deficiency Antiphospholipid Syndrome ...
Domingo, E. ); Holland, J.J. . Dept. of Biology); Ahlquist, P. . Dept. of Plant Pathology)
This book contains the proceedings on RNA genetics: RNA-directed virus replication Volume 1. Topics covered include: Replication of the poliovirus genome; Influenza viral RNA transcription and replication; and Relication of the reoviridal: Information derived from gene cloning and expression.
Whitehouse, H. L. K.
Discusses the mechanisms of genetic recombination with particular emphasis on the study of the fungus Sordaria brevicollis. The study of recombination is facilitated by the use of mutants of this fungus in which the color of the ascospores is affected. (JR)
Koenig, Samuel; Savage, Candida; Kim, Jonathan P
The detection of urinary polycyclic aromatic hydrocarbon (PAH) metabolites by fluorescence spectrophotometry is particularly effective as a practical means to assess PAH exposure in decapod crabs. However, the practical application of this technique has thus far only been tested for the European shore crab (Carcinus maenas) and only a few field studies have been conducted in heavily polluted areas. The present study evaluated the adaptability of this method as a rapid, cost-effective and non-destructive biomonitoring tool for the New Zealand crab species, Macrophthalmus hirtipes (stalk-eyed mud crab). A field gradient could be detected among the sites and different input sources of PAH contamination could be discerned through the differentiation of pyrogenic and petrogenic PAH signatures. The present study shows that the fluorescence screening method is sensitive to relatively low levels of PAH contamination and more broadly applicable to smaller crab species than C. maenas, for which the technique was developed.
Blakeslee, April M.; Keogh, Carolyn L.; Byers, James E.; Kuris, Armand M.; Lafferty, Kevin D.; Torchin, Mark E.
Although introduced species often interact with one another in their novel communities, the role of parasites in these interactions remains less clear. We examined parasite richness and prevalence in 2 shorecrab species with different invasion histories and residency times in an introduced region where their distributions overlap broadly. On the northeastern coast of the USA, the Asian shorecrab Hemigrapsus sanguineus was discovered 20 yr ago, while the European green crab Carcinus maenas has been established for over 200 yr. We used literature and field surveys to evaluate parasitism in both crabs in their native and introduced ranges. We found only 1 parasite species infecting H. sanguineus on the US East Coast compared to 6 species in its native range, while C. maenas was host to 3 parasite species on the East Coast compared to 10 in its native range. The prevalence of parasite infection was also lower for both crabs in the introduced range compared to their native ranges; however, the difference was almost twice as much for H. sanguineus as for C. maenas. There are several explanations that could contribute to C. maenas' greater parasite diversity than that of H. sanguineus on the US East Coast, including differences in susceptibility, time since introduction, manner of introduction (vector), distance from native range, taxonomic isolation, and the potential for parasite identification bias. Our study underscores not just that non-native species lose parasites upon introduction, but that they may do so differentially, with ramifications for their direct interactions and with potential community-level influences.
Bertness, Mark D; Coverdale, Tyler C
With global increases in human impacts, invasive species have become a major threat to ecosystems worldwide. While they have been traditionally viewed as harmful, invasive species may facilitate the restoration of degraded ecosystems outside their native ranges. In New England (USA) overfishing has depleted salt marsh predators, allowing the herbivorous crab Sesarma reticulatum to denude hundreds of hectares of low marsh. Here, using multiple site surveys and field caging experiments, we show that the subsequent invasion of green crabs, Carcinus maenas, into heavily burrowed marshes partially reverses decades of cordgrass die-off. By consuming Sesarma, eliciting a nonlethal escape response, and evicting Sesarma from burrows, Carcinus reduces Sesarma herbivory and promotes cordgrass recovery. These results suggest that invasive species can contribute to restoring degraded ecosystems and underscores the potential for invasive species to return ecological functions lost to human impacts.
This text provides full and balanced coverage of the concepts requisite for a thorough understanding of human genetics. Applications to both the individual and society are integrated throughout the lively and personal narrative, and the essential principles of heredity are clearly presented to prepare students for informed participation in public controversies. High-interest, controversial topics, including recombinant DNA technology, oncogenes, embryo transfer, environmental mutagens and carcinogens, IQ testing, and eugenics encourage understanding of important social issues.
Chinnery, Patrick Francis; Hudson, Gavin
Introduction In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. Sources of data In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. Areas of agreement The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. Areas of controversy The exact mechanisms which govern the inheritance of mtDNA are hotly debated. Growing points Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease. PMID:23704099
Raffaelli, D.; Conacher, A.; McLachlan, H.; Emes, C.
Two field experiments were carried out on an estuarine intertidal mudflat, enclosing varying densities of the crustacean predators Carcinus maenas and Crangon crangon. Effects of predation on prey densities were few and limited to cages with abnormally high densities of crabs. In both experiments there were significant effects on the size structure of the amphipod Corophium volutator. The results are compared with those from other caging experiments and it is suggested that, where marked, predation effects have been recorded unnaturally high densities of predators were used.
Freeman, Aaren S; Byers, James E
Invasive species may precipitate evolutionary change in invaded communities. In southern New England (USA) the invasive Asian shore crab, Hemigrapsus sanguineus, preys on mussels (Mytlius edulis), but the crab has not yet invaded northern New England. We show that southern New England mussels express inducible shell thickening when exposed to waterborne cues from Hemigrapsus, whereas naïve northern mussel populations do not respond. Yet, both populations thicken their shells in response to a long-established crab, Carcinus maenas. Our findings are consistent with the rapid evolution of an inducible morphological response to Hemigrapsus within 15 years of its introduction.
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Gero, J S; Kazakov, V
We present an extension to the standard genetic algorithm (GA), which is based on concepts of genetic engineering. The motivation is to discover useful and harmful genetic materials and then execute an evolutionary process in such a way that the population becomes increasingly composed of useful genetic material and increasingly free of the harmful genetic material. Compared to the standard GA, it provides some computational advantages as well as a tool for automatic generation of hierarchical genetic representations specifically tailored to suit certain classes of problems.
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New developments in the prediction and treatment of genetic diseases are presented. Genetic counseling and the role of the counselor, and rights of individuals to reproduce versus societal impact of genetic disorders, are discussed. (RW)
... MENU Toggle navigation Home Page Search Share: Email Facebook Twitter Home Health Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Genetics Home Reference provides consumer-friendly information about the effects of genetic variation ...
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Hublin, Christer; Kaprio, Jaakko
Parasomnias are undesirable phenomena associated with sleep. Many of them run in families, and genetic factors have been long suggested to be involved in their occurrence. This article reviews the present knowledge of the genetics of the major classical behavioral parasomnias as well as present results from genetic epidemiological studies. The level and type of evidence for genetic effects varies much from parasomnia to parasomnia. The genetic factors are best established in enuresis, with several linkages to chromosomal loci, but their functions are not so far known. Environmental causes and gene-environment interactions are most probably also of great importance in the origin of complex traits or disorders such as parasomnias.
Mach, Megan E; Chan, Kai MA
Nonnative species pose a threat to native biodiversity and can have immense impacts on biological communities, altering the function of ecosystems. How much value is at risk from high-impact invasive species, and which parameters determine variation in that value, constitutes critical knowledge for directing both management and research, but it is rarely available. We evaluated the value of the commercial shellfish harvest that is at risk in nearshore ecosystems of Puget Sound, Washington State, USA, from the invasive European green crab, Carcinus maenas. We assessed this value using a simple static ecological model combined with an economic model using data from Puget Sound’s shellfish harvest and revenue and the relationship between C. maenas abundance and the consumption rate of shellfish. The model incorporates a range in C. maenas diet preference, calories consumed per year, and crab densities. C. maenas is likely to prey on commercially harvested hardshell clams, oysters, and mussels, which would likely reduce additional revenue from processing and distribution, and the number of jobs associated with these fisheries. The model results suggest possible revenue losses of these shellfish ranging from $1.03-23.8 million USD year -1 (2.8-64% losses), with additional processing and distribution losses up to $17.6 million USD and 442 job positions each year associated with a range of plausible parameter values. The broad range of values reflects the uncertainty in key factors underlying impacts, factors that are highly variable across invaded regions and so not knowable a priori. However, future research evaluating species invasions can reduce the uncertainty of impacts by characterizing several key parameters: density of individuals, number of arrivals, predation and competition interactions, and economic impacts. This study therefore provides direction for research to inform more accurate estimates of value-at-risk, and suggests substantial motivation for
van der Veer, Henk W.; Jung, Alexa Sarina; Freitas, Vânia; Philippart, Catharina J. M.; Witte, Johannes IJ.
Growth variability within individuals and among groups and locations and the phenomenon of summer growth reduction has been described for juvenile flatfish in a variety of European coastal areas whereby the underlying causes still remain elusive. Potential mechanisms were tested for juvenile plaice Pleuronectes platessa L. in the western Dutch Wadden Sea, by analysing published and unpublished information from long-term investigations (1986-present). Growth variability did occur and could be explained by differences induced by environmental variability (water temperature), and by non-genetic irreversible adaptation and sex. Dynamic Energy Budget analysis indicated that especially sexually-dimorphic growth in combination with variability in sex ratio could explain most of the variability in growth and the increase in the range of the size of individuals within the population over time. Summer growth reduction was not only observed among 0-group plaice in the intertidal, but also in the subtidal and tidal gullies as well as among I- and II-group plaice. Intraspecific competition for food was not detected but some support for interspecific competition with other predators was found. Also resource competition (due to crowding) with the other abundant epibenthic species (0-, I- and II-group flounder Platichthys flesus; the brown shrimp Crangon crangon; the shore crab Carcinus maenas; the goby species Pomatoschistus minutus and Pomatoschistus microps) could not explain the summer growth reduction. The observed growth reduction coincided with a decrease in stomach content, especially of regenerating body parts of benthic prey items. It is hypothesised that macrozoobenthos becomes less active after the spring phytoplankton bloom, reducing prey availability for juvenile plaice in summer, causing a reduction in food intake and hence in growth.
Wisconsin Univ., Madison. Dept. of Curriculum and Instruction.
The Interactive Genetics Tutorial (IGT) project and the Intelligent Tutoring System for the IGT project named MENDEL supplement genetics instruction in biology courses by providing students with experience in designing, conducting, and evaluating genetics experiments. The MENDEL software is designed to: (1) simulate genetics experiments that…
Lazzaro, Brian P; Schneider, David S
In this commentary, Brian P. Lazzaro and David S. Schneider examine the topic of the Genetics of Immunity as explored in this month's issues of GENETICS and G3: Genes|Genomes|Genetics. These inaugural articles are part of a joint Genetics of Immunity collection (ongoing) in the GSA journals.
Bogaard, Kali; Johnson, Marlene
Genetics is playing an increasingly important role in the diagnosis, monitoring and treatment of diseases, and the expansion of genetics into health care has generated the field of genomic medicine. Health care delivery is shifting away from general diagnostic evaluation toward a generation of therapeutics based on a patient's genetic makeup. Meanwhile, the scientific community debates how best to incorporate genetics and genomic medicine into practice. While obstacles remain, the ultimate goal is to use information generated from the study of human genetics to improve disease treatment, cure and prevention. As the use of genetics in medical diagnosis and treatment increases, health care workers will require an understanding of genetics and genomic medicine.
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Barker, G. R.
Various topics on the biochemistry of genetic manipulation are discussed. These include genetic transformation and DNA; genetic expression; DNA replication, repair, and mutation; technology of genetic manipulation; and applications of genetic manipulation. Other techniques employed are also considered. (JN)
By comparing strategies of genetic alterations introduced in genetic engineering with spontaneously occurring genetic variation, we have come to conclude that both processes depend on several distinct and specific molecular mechanisms. These mechanisms can be attributed, with regard to their evolutionary impact, to three different strategies of genetic variation. These are local nucleotide sequence changes, intragenomic rearrangement of DNA segments and the acquisition of a foreign DNA segment by horizontal gene transfer. Both the strategies followed in genetic engineering and the amounts of DNA sequences thereby involved are identical to, or at least very comparable with, those involved in natural genetic variation. Therefore, conjectural risks of genetic engineering must be of the same order as those for natural biological evolution and for conventional breeding methods. These risks are known to be quite low. There is no scientific reason to assume special long-term risks for GM crops. For future agricultural developments, a road map is designed that can be expected to lead, by a combination of genetic engineering and conventional plant breeding, to crops that can insure food security and eliminate malnutrition and hunger for the entire human population on our planet. Public-private partnerships should be formed with the mission to reach the set goals in the coming decades.
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Wang, Lui; Bayer, Steve E.
SPLICER computer program is genetic-algorithm software tool used to solve search and optimization problems. Provides underlying framework and structure for building genetic-algorithm application program. Written in Think C.
A genetic brain disorder is caused by a variation or a mutation in a gene. A variation is a different form ... mutation is a change in a gene. Genetic brain disorders affect the development and function of the ...
Lewis, Jenny; Wood-Robinson, Colin
Presents the results of investigations into young people's awareness of, and attitudes toward, genetics and DNA technology. Summarizes survey results and explores the process by which students form an opinion of new technology in the field of genetics. (DDR)
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This book begins with an overview of the current principles of genetics and molecular genetics. Over this foundation, it adds detailed and specialized information: a description of the translation, transcription, expression and regulation of DNA and RNA; a description of the manipulation of genetic material via promoters, enhancers, and gene splicing; and a description of cloning techniques, especially those for blood group genes. The last chapter looks to the impact of molecular genetics on transfusion medicine.
Mahil, Satveer K; Capon, Francesca; Barker, Jonathan N
Psoriasis is a common and debilitating immune-mediated skin disease with a complex genetic basis. Genetic studies have provided critical insights into the pathogenesis of disease. This article focuses on the results of genetic association studies, which provide evidence that psoriasis susceptibility genes are involved in innate and adaptive immunity and skin barrier functions. The potential for disease stratification and the development of more effective treatments with fewer side effects using genetic data are highlighted.
Boughter, John D; Bachmanov, Alexander A
This review focuses on behavioral genetic studies of sweet, umami, bitter and salt taste responses in mammals. Studies involving mouse inbred strain comparisons and genetic analyses, and their impact on elucidation of taste receptors and transduction mechanisms are discussed. Finally, the effect of genetic variation in taste responsiveness on complex traits such as drug intake is considered. Recent advances in development of genomic resources make behavioral genetics a powerful approach for understanding mechanisms of taste. PMID:17903279
Shendure, Jay; Fields, Stanley
Human genetics has historically depended on the identification of individuals whose natural genetic variation underlies an observable trait or disease risk. Here we argue that new technologies now augment this historical approach by allowing the use of massively parallel assays in model systems to measure the functional effects of genetic variation in many human genes. These studies will help establish the disease risk of both observed and potential genetic variants and to overcome the problem of "variants of uncertain significance."
Charles, Abigail Sheena
This study investigated the knowledge and skills that biology students may need to help them understand statistics/mathematics as it applies to genetics. The data are based on analyses of current representative genetics texts, practicing genetics professors' perspectives, and more directly, students' perceptions of, and performance in, doing…
After agreeing to host over 200 students on a daylong genetics field trip, the author needed an easy-to-prepare genetics experiment to accompany the DNA-necklace and gel-electrophoresis activities already planned. One of the student's mothers is a pediatric physician at the local hospital, and she suggested exploring genetic-disease screening…
Lyons, Leslie A.
DNA testing for domestic cat diseases and appearance traits is a rapidly growing asset for veterinary medicine. Approximately thirty-three genes contain fifty mutations that cause feline health problems or alterations in the cat’s appearance. A variety of commercial laboratories can now perform cat genetic diagnostics, allowing both the veterinary clinician and the private owner to obtain DNA test results. DNA is easily obtained from a cat via a buccal swab using a standard cotton bud or cytological brush, allowing DNA samples to be easily sent to any laboratory in the world. The DNA test results identify carriers of the traits, predict the incidence of traits from breeding programs, and influence medical prognoses and treatments. An overall goal of identifying these genetic mutations is the correction of the defect via gene therapies and designer drug therapies. Thus, genetic testing is an effective preventative medicine and a potential ultimate cure. However, genetic diagnostic tests may still be novel for many veterinary practitioners and their application in the clinical setting needs to have the same scrutiny as any other diagnostic procedure. This article will review the genetic tests for the domestic cat, potential sources of error for genetic testing, and the pros and cons of DNA results in veterinary medicine. Highlighted are genetic tests specific to the individual cat, which are a part of the cat’s internal genome. PMID:21147473
Lyons, Leslie A
DNA testing for domestic cat diseases and appearance traits is a rapidly growing asset for veterinary medicine. Approximately 33 genes contain 50 mutations that cause feline health problems or alterations in the cat's appearance. A variety of commercial laboratories can now perform cat genetic diagnostics, allowing both the veterinary clinician and the private owner to obtain DNA test results. DNA is easily obtained from a cat via a buccal swab with a standard cotton bud or cytological brush, allowing DNA samples to be easily sent to any laboratory in the world. The DNA test results identify carriers of the traits, predict the incidence of traits from breeding programs, and influence medical prognoses and treatments. An overall goal of identifying these genetic mutations is the correction of the defect via gene therapies and designer drug therapies. Thus, genetic testing is an effective preventative medicine and a potential ultimate cure. However, genetic diagnostic tests may still be novel for many veterinary practitioners and their application in the clinical setting needs to have the same scrutiny as any other diagnostic procedure. This article will review the genetic tests for the domestic cat, potential sources of error for genetic testing, and the pros and cons of DNA results in veterinary medicine. Highlighted are genetic tests specific to the individual cat, which are a part of the cat's internal genome.
Frankel, M. S.
Issues concerning the use of genetic technology are discussed. Some areas discussed include treating genetic disease, prenatal diagnosis and selective abortion, screening for genetic disease, and genetic counseling. Policy issues stemming from these capabilities are considered.
... Testing How is genetic testing done? How is genetic testing done? Once a person decides to proceed ... is called informed consent . For more information about genetic testing procedures: The National Society of Genetic Counselors ...
... Your 1- to 2-Year-Old All About Genetics KidsHealth > For Parents > All About Genetics Print A ... way they pick up special laboratory dyes. continue Genetic Problems Errors in the genetic code or "gene ...
... Feeding Your 1- to 2-Year-Old Prenatal Genetic Counseling KidsHealth > For Parents > Prenatal Genetic Counseling Print ... how can they help your family? What Is Genetic Counseling? Genetic counseling is the process of: evaluating ...
Genetics is becoming increasingly integrated into peoples' lives. Different measures have been taken to try and better genetics education. This thesis examined undergraduate students at the University of North Texas not majoring in the life sciences interest in genetic concepts through the means of a Likert style survey. ANOVA analysis showed there was variation amongst the interest level in different genetic concepts. In addition age and lecture were also analyzed as contributing factors to students' interest. Both age and lecture were evaluated to see if they contributed to the interest of students in genetic concepts and neither showed statistical significance. The Genetic Interest Assessment (GIA) serves to help mediate the gap between genetic curriculum and students' interest.
Shearer, A. Eliot; Smith, Richard J.H.
Purpose of review To provide an update on recently discovered human deafness genes and to describe advances in comprehensive genetic testing platforms for deafness, both of which have been enabled by new massively parallel sequencing technologies. Recent findings Over the review period, three syndromic and six nonsyndromic deafness genes have been discovered, bringing the total number of nonsyndromic deafness genes to 64. Four studies have shown the utility of massively parallel sequencing for comprehensive genetic testing for deafness. Three of these platforms have been released on a clinical or commercial basis. Summary Deafness is the most common sensory deficit in humans. Genetic diagnosis has traditionally been difficult due to extreme genetic heterogeneity and a lack of phenotypic variability. For these reasons, comprehensive genetic screening platforms have been developed with the use of massively parallel sequencing. These technologies are also accelerating the pace of gene discovery for deafness. Because genetic diagnosis is the basis for molecular therapies, these advances lay the foundation for the clinical care of deaf and hard-of-hearing persons in the future. PMID:23042251
Blackburn, H D
For 100s of years, livestock producers have employed various types of selection to alter livestock populations. Current selection strategies are little different, except our technologies for selection have become more powerful. Genetic resources at the breed level have been in and out of favour over time. These resources are the raw materials used to manipulate populations, and therefore, they are critical to the past and future success of the livestock sector. With increasing ability to rapidly change genetic composition of livestock populations, the conservation of these genetic resources becomes more critical. Globally, awareness of the need to steward genetic resources has increased. A growing number of countries have embarked on large scale conservation efforts by using in situ, ex situ (gene banking), or both approaches. Gene banking efforts have substantially increased and data suggest that gene banks are successfully capturing genetic diversity for research or industry use. It is also noteworthy that both industry and the research community are utilizing gene bank holdings. As pressures grow to meet consumer demands and potential changes in production systems, the linkage between selection goals and genetic conservation will increase as a mechanism to facilitate continued livestock sector development.
He, Min; Li, Wei
In April 2005, with the voluntary involvement of more than 50 worldwide genetic counselors or medical geneticists, we developed a website for online genetic counseling and genetic education on common genetic disease throughout China (URL: http://www.gcnet.org.cn). This website is offering professional online genetic counseling, as well as providing information about common genetic diseases which is a resource for genetic counselors and online genetic counselees. Online genetic counseling is an alternative method to the widely accepted face-to-face counseling. The data warehouse of China Genetic Counseling Network (CGCN) will be a unique supplement to current status of Clinical Genetics and healthcare system in China.
Casillas, Sònia; Barbadilla, Antonio
Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data. PMID:28270526
Casillas, Sònia; Barbadilla, Antonio
Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data.
Lind, Mackenzie J.; Gehrman, Philip R.
This review summarizes current research on the genetics of insomnia, as genetic contributions are thought to be important for insomnia etiology. We begin by providing an overview of genetic methods (both quantitative and measured gene), followed by a discussion of the insomnia genetics literature with regard to each of the following common methodologies: twin and family studies, candidate gene studies, and genome-wide association studies (GWAS). Next, we summarize the most recent gene identification efforts (primarily GWAS results) and propose several potential mechanisms through which identified genes may contribute to the disorder. Finally, we discuss new genetic approaches and how these may prove useful for insomnia, proposing an agenda for future insomnia genetics research. PMID:27999387
Smith, Richard J H; Hone, Stephen
Genetic testing for deafness has become a reality. It has changed the paradigm for evaluating deaf and hard-of-hearing persons and will be used by physicians for diagnostic purposes and as a basis for treatment and management options. Although mutation screening is currently available for only a limited number of genes, in these specific instances, diagnosis, carrier detection, and reproductive risk counseling can be provided. In the coming years there will be an expansion of the role of genetic testing and counseling will not be limited to reproductive issues. Treatment and management decisions will be made based on specific genetic diagnoses. Although genetic testing may be a confusing service for the practicing otolaryngologist, it is an important part of medical care. New discoveries and technologies will expand and increase the complexity of genetic testing options and it will become the responsibility of otolaryngologists to familiarize themselves with current discoveries and accepted protocols for genetic testing.
Holderegger, Rolf; Buehler, Dominique; Gugerli, Felix; Manel, Stéphanie
Landscape genetics is the amalgamation of landscape ecology and population genetics to help with understanding microevolutionary processes such as gene flow and adaptation. In this review, we examine why landscape genetics of plants lags behind that of animals, both in number of studies and consideration of landscape elements. The classical landscape distance/resistance approach to study gene flow is challenging in plants, whereas boundary detection and the assessment of contemporary gene flow are more feasible. By contrast, the new field of landscape genetics of adaptive genetic variation, establishing the relationship between adaptive genomic regions and environmental factors in natural populations, is prominent in plant studies. Landscape genetics is ideally suited to study processes such as migration and adaptation under global change.
Young, Robert R
Genetic toxicology is the scientific discipline dealing with the effects of chemical, physical and biological agents on the heredity of living organisms. The Internet offers a wide range of online digital resources for the field of Genetic Toxicology. The history of genetic toxicology and electronic data collections are reviewed. Web-based resources at US National Library of Medicine (NLM), including MEDLINE, PUBMED, Gateway, Entrez, and TOXNET, are discussed. Search strategies and Medical Subject Headings (MeSH) are reviewed in the context of genetic toxicology. The TOXNET group of databases are discussed with emphasis on those databases with genetic toxicology content including GENE-TOX, TOXLINE, Hazardous Substances Data Bank, Integrated Risk Information System, and Chemical Carcinogenesis Research Information System. Location of chemical information including chemical structure and linkage to health and regulatory information using CHEMIDPLUS at NLM and other databases is reviewed. Various government agencies have active genetic toxicology research programs or use genetic toxicology data to assist fulfilling the agency's mission. Online resources at the US Food and Drug Administration (FDA), the US Environmental Protection Agency (EPA), the National Institutes of Environmental Health Sciences, and the National Toxicology Program (NTP) are outlined. Much of the genetic toxicology for pharmaceuticals, industrial chemicals and pesticides that is performed in the world is regulatory-driven. Regulatory web resources are presented for the laws mandating testing, guidelines on study design, Good Laboratory Practice (GLP) regulations, and requirements for electronic data collection and reporting. The Internet provides a range of other supporting resources to the field of genetic toxicology. The web links for key professional societies and journals in genetic toxicology are listed. Distance education, educational media resources, and job placement services are also
Morse, Stephen J
Some believe that genetics threatens privacy and autonomy and will eviscerate the concept of human nature. Despite the astonishing research advances, however, none of these dire predictions and no radical transformation of the law have occurred. Advocates have tried to use genetic evidence to affect judgments of criminal responsibility. At present, however genetic research can provide little aid to assessments of criminal responsibility and it does not suggest a radical critique of responsibility.
Since the introduction in the mid-1980s of analyses of minisatellites for DNA analyses, a revolution has taken place in forensic genetics. The subsequent invention of the PCR made it possible to develop forensic genetics tools that allow both very informative routine investigations and still more and more advanced, special investigations in cases concerning crime, paternity, relationship, disaster victim identification etc. The present review gives an update on the use of DNA investigations in forensic genetics.
Some argue that genetic enhancements and environmental enhancements are not importantly different: environmental enhancements such as private schools and chess lessons are simply the old-school way to have a designer baby. I argue that there is an important distinction between the two practices--a distinction that makes state restrictions on genetic enhancements more justifiable than state restrictions on environmental enhancements. The difference is that parents have no settled expectations about genetic enhancements.
This book provides a conceptual understanding of the biology of genes and also gives current events and controversies in the field. Basic transmission genetics, molecular genetics, and population genetics are covered, with additional discussions relating to such topics as agriculture, aging, forensic science, genetic counseling, gene splicing, and recombinant DNA. Low level radiation and its effects, drugs and heredity, IQ, heredity and racial variation, and creationism versus evolution are also described. ''Billboard'' style diagrams visually explain important concepts. Boldfaced key terms are defined within the text and in a comprehensive glossary. Selected readings, discussion questions and problems, and excellent chapter summaries further aid study.
Moresco, Eva Marie Y.; Li, Xiaohong; Beutler, Bruce
Forward genetic analysis is an unbiased approach for identifying genes essential to defined biological phenomena. When applied to mice, it is one of the most powerful methods to facilitate understanding of the genetic basis of human biology and disease. The speed at which disease-causing mutations can be identified in mutagenized mice has been markedly increased by recent advances in DNA sequencing technology. Creating and analyzing mutant phenotypes may therefore become rate-limiting in forward genetic experimentation. We review the forward genetic approach and its future in the context of recent technological advances, in particular massively parallel DNA sequencing, induced pluripotent stem cells, and haploid embryonic stem cells. PMID:23608223
... Genetic Testing Registry: Congenital aniridia Other Diagnosis and Management Resources (1 link) GeneReview: Aniridia General Information from MedlinePlus (5 links) Diagnostic Tests Drug Therapy ...
Nowak, Dorota M.; Gajecka, Marzena
Keratoconus (KTCN) is non-inflammatory thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive error, and decreased vision. Keratoconus is a complex condition of multifactorial etiology. Both genetic and environmental factors are associated with KTCN. Evidence of genetic etiology includes familial inheritance, discordance between dizygotic twins, and association with other known genetic disorders. Several loci responsible for a familial form of KTCN have been mapped; however, no mutations in any genes have been identified for any of these loci. This article focuses on the genetic aspects. In addition, bioinformatics methods applied in KTCN gene identification process are discussed. PMID:21572727
Chenoweth, Peter J
Genetic sperm defects are specific sperm defects, which have been shown to have a genetic mode of transmission. Such genetic linkage, either direct or indirect, has been associated with a number of sperm defects in different species, with this number increasing with improved diagnostic capabilities. A number of sperm defects, which have proven or suspected genetic modes of transmission are discussed herein, with particular emphasis on cattle. These include: 1. Acrosome defects (knobbed, ruffled and incomplete); 2. Head defects (abnormal condensation, decapitated, round head, rolled head, nuclear crest); 3. Midpiece abnormalities ("Dag" defect, "corkscrew" defect, "pseudo-droplet" defect); 4. Tail defects ("tail stump" defect, primary ciliary dyskinesia).
Stern, David L.; Orgogozo, Virginie
Ever since the integration of Mendelian genetics into evolutionary biology in the early 20th century, evolutionary geneticists have for the most part treated genes and mutations as generic entities. However, recent observations indicate that all genes are not equal in the eyes of evolution. Evolutionarily relevant mutations tend to accumulate in hotspot genes and at specific positions within genes. Genetic evolution is constrained by gene function, the structure of genetic networks, and population biology. The genetic basis of evolution may be predictable to some extent, and further understanding of this predictability requires incorporation of the specific functions and characteristics of genes into evolutionary theory. PMID:19197055
Genetic screening, gene therapy and other applications of genetic engineering are permissible in Judaism when used for the treatment, cure, or prevention of disease. Such genetic manipulation is not considered to be a violation of God's natural law, but a legitimate implementation of the biblical mandate to heal. If Tay-Sachs disease, diabetes, hemophilia, cystic fibrosis, Huntington's disease or other genetic diseases can be cured or prevented by "gene surgery," then it is certainly permitted in Jewish law. Genetic premarital screening is encouraged in Judaism for the purpose of discouraging at-risk marriages for a fatal illness such as Tay-Sachs disease. Neonatal screening for treatable conditions such as phenylketonuria is certainly desirable and perhaps required in Jewish law. Preimplantation screening and the implantation of only "healthy" zygotes into the mother's womb to prevent the birth of an affected child are probably sanctioned in Jewish law. Whether or not these assisted reproduction techniques may be used to choose the sex of one's offspring, to prevent the birth of a child with a sex-linked disease such as hemophilia, has not yet been ruled on by modern rabbinic decisions. Prenatal screening with the specific intent of aborting an affected fetus is not allowed according to most rabbinic authorities, although a minority view permits it "for great need." Not to have children if both parents are carriers of genetic diseases such as Tay-Sachs is not a Jewish option. Preimplantation screening is preferable. All screening test results must remain confidential. Judaism does not permit the alteration or manipulation of physical traits and characteristics such as height, eye and hair color, facial features and the like, when such change provides no useful benefit to mankind. On the other hand, it is permissible to clone organisms and microorganisms to facilitate the production of insulin, growth hormone, and other agents intended to benefit mankind and to
Lovely, Christina M.; Judge, Michael L.
Marine habitats containing complex physical structure (e.g., crevices) can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock) and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m2 with 62 mm2 mesh openings). The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width) whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1–15 mm carapace width), and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m−2 [mean ± S.D.]) and fewest in bags without shells (4.9 ± 3.7 m−2). Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks). The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations. PMID:26401456
Lovely, Christina M; O'Connor, Nancy J; Judge, Michael L
Marine habitats containing complex physical structure (e.g., crevices) can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock) and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m(2) with 62 mm(2) mesh openings). The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width) whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1-15 mm carapace width), and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m(-2) [mean ± S.D.]) and fewest in bags without shells (4.9 ± 3.7 m(-2)). Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks). The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations.
Czeizel, Andrew E.
The beginning of human genetics and its medical part:
Coyle, Heather; Drell, Dan
Various: (1)TriState 2000 Genetics in the Courts (2) Growing impact of the new genetics on the courts (3)Human testing (4) Legal analysis - in re G.C. (5) Legal analysis - GM ''peanots'', and (6) Legal analysis for State vs Miller
Sloan, Chantel D.; Sayarath, Vicki; Moore, Jason H.
Alcoholism is a common disease resulting from the complex interaction of genetic, social, and environmental factors. Interest in the high heritability of alcoholism has resulted in many studies of how single genes, as well as an individual’s entire genetic content (i.e., genome) and the proteins expressed by the genome, influence alcoholism risk. The use of large-scale methods to identify and characterize genetic material (i.e., high-throughput technologies) for data gathering and analysis recently has made it possible to investigate the complexity of the genetic architecture of susceptibility to common diseases such as alcoholism on a systems level. Systems genetics is the study of all genetic variations, their interactions with each other (i.e., epistasis), their interactions with the environment (i.e., plastic reaction norms), their relationship with interindividual variation in traits that are influenced by many genes and contribute to disease susceptibility (i.e., intermediate quantitative traits or endophenotypes1) defined at different levels of hierarchical biochemical and physiological systems, and their relationship with health and disease. The goal of systems genetics is to provide an understanding of the complex relationship between the genome and disease by investigating intermediate biological processes. After investigating main effects, the first step in a systems genetics approach, as described here, is to search for gene–gene (i.e., epistatic) reactions. PMID:23584748
One of the major changes in developmental psychology during the past 50 years has been the acceptance of the important role of nature (genetics) as well as nurture (environment). Past research consisting of twin and adoption studies has shown that genetic influence is substantial for most domains of developmental psychology. Present research…
Paaby, Annalise B; Gibson, Greg
Evolutionary developmental genetics has traditionally been conducted by two groups: Molecular evolutionists who emphasize divergence between species or higher taxa, and quantitative geneticists who study variation within species. Neither approach really comes to grips with the complexities of evolutionary transitions, particularly in light of the realization from genome-wide association studies that most complex traits fit an infinitesimal architecture, being influenced by thousands of loci. This paper discusses robustness, plasticity and lability, phenomena that we argue potentiate major evolutionary changes and provide a bridge between the conceptual treatments of macro- and micro-evolution. We offer cryptic genetic variation and conditional neutrality as mechanisms by which standing genetic variation can lead to developmental system drift and, sheltered within canalized processes, may facilitate developmental transitions and the evolution of novelty. Synthesis of the two dominant perspectives will require recognition that adaptation, divergence, drift and stability all depend on similar underlying quantitative genetic processes-processes that cannot be fully observed in continuously varying visible traits.
Paaby, Annalise B.; Gibson, Greg
Evolutionary developmental genetics has traditionally been conducted by two groups: Molecular evolutionists who emphasize divergence between species or higher taxa, and quantitative geneticists who study variation within species. Neither approach really comes to grips with the complexities of evolutionary transitions, particularly in light of the realization from genome-wide association studies that most complex traits fit an infinitesimal architecture, being influenced by thousands of loci. This paper discusses robustness, plasticity and lability, phenomena that we argue potentiate major evolutionary changes and provide a bridge between the conceptual treatments of macro- and micro-evolution. We offer cryptic genetic variation and conditional neutrality as mechanisms by which standing genetic variation can lead to developmental system drift and, sheltered within canalized processes, may facilitate developmental transitions and the evolution of novelty. Synthesis of the two dominant perspectives will require recognition that adaptation, divergence, drift and stability all depend on similar underlying quantitative genetic processes—processes that cannot be fully observed in continuously varying visible traits. PMID:27304973
Zietsch, Brendan P.; de Candia, Teresa R; Keller, Matthew C.
We describe the scientific enterprise at the intersection of evolutionary psychology and behavioral genetics—a field that could be termed Evolutionary Behavioral Genetics—and how modern genetic data is revolutionizing our ability to test questions in this field. We first explain how genetically informative data and designs can be used to investigate questions about the evolution of human behavior, and describe some of the findings arising from these approaches. Second, we explain how evolutionary theory can be applied to the investigation of behavioral genetic variation. We give examples of how new data and methods provide insight into the genetic architecture of behavioral variation and what this tells us about the evolutionary processes that acted on the underlying causal genetic variants. PMID:25587556
Smith, Shelley D.; Pennington, Bruce F.
A discussion of basic genetic principles is followed by a review of selected genetic syndromes involving learning disabilites (such as Noonan Syndrome, Neurofibromatosis, Pheuylketonuria, and cleft lip and palate). Guidelines for securing a genetic evaluation are given. (CL)
Roberts, D.F.; De Stefano, G.F.
This book contains several papers divided among three sections. The section titles are: Genetic Diversity--Its Dimensions; Genetic Diversity--Its Origin and Maintenance; and Genetic Diversity--Applications and Problems of Complex Characters.
... for the genetic terms used on this page Genetics, Disease Prevention and Treatment Overview How can learning ... gov] Top of page How can knowing about genetics help treat disease? Every year, more than two ...
McInerney, Joseph D.
Describes the contribution made to the quality of human life by the study of genetics. Presents a description of the current status of genetics education. Suggests changes in genetics education necessary to keep up with new developments. (39 references) (CW)
Vidal Gallardo, Mercedes
The continuous advances in our society in the last decades have allowed us to get to know the personal genetic data. Although this discovery has important benefits, it also causes a great paradox, since the genetic information can be an element of social stigma, and its inappropriate use can damage the fundamental rights. It is obvious that there are cases in which the genetic risk, that is, the predisposition of a person to suffer some illnesses, can be a discriminatory element, especially in the contractual field.
Zhou, Ruanbao (Inventor); Gibbons, William (Inventor)
The disclosed embodiments provide cyanobacteria spp. that have been genetically engineered to have increased production of carbon-based products of interest. These genetically engineered hosts efficiently convert carbon dioxide and light into carbon-based products of interest such as long chained hydrocarbons. Several constructs containing polynucleotides encoding enzymes active in the metabolic pathways of cyanobacteria are disclosed. In many instances, the cyanobacteria strains have been further genetically modified to optimize production of the carbon-based products of interest. The optimization includes both up-regulation and down-regulation of particular genes.
Charles, Abigail Sheena
This study investigated the knowledge and skills that biology students may need to help them understand statistics/mathematics as it applies to genetics. The data are based on analyses of current representative genetics texts, practicing genetics professors' perspectives, and more directly, students' perceptions of, and performance in, doing statistically-based genetics problems. This issue is at the emerging edge of modern college-level genetics instruction, and this study attempts to identify key theoretical components for creating a specialized biological statistics curriculum. The goal of this curriculum will be to prepare biology students with the skills for assimilating quantitatively-based genetic processes, increasingly at the forefront of modern genetics. To fulfill this, two college level classes at two universities were surveyed. One university was located in the northeastern US and the other in the West Indies. There was a sample size of 42 students and a supplementary interview was administered to a select 9 students. Interviews were also administered to professors in the field in order to gain insight into the teaching of statistics in genetics. Key findings indicated that students had very little to no background in statistics (55%). Although students did perform well on exams with 60% of the population receiving an A or B grade, 77% of them did not offer good explanations on a probability question associated with the normal distribution provided in the survey. The scope and presentation of the applicable statistics/mathematics in some of the most used textbooks in genetics teaching, as well as genetics syllabi used by instructors do not help the issue. It was found that the text books, often times, either did not give effective explanations for students, or completely left out certain topics. The omission of certain statistical/mathematical oriented topics was seen to be also true with the genetics syllabi reviewed for this study. Nonetheless
This commentary article reviews a recent meta-analysis of genetic influences on antisocial behavior by Rhee and Waldman (2002). The authors combined the results of 51 twin and adoption studies and concluded that antisocial behavior has an important genetic component. However, twin and adoption studies contain several methodological flaws and are subject to the confounding influence of environmental factors. Therefore, Rhee and Waldman's conclusions in favor of genetic influences are not supported by the evidence. Two additional topics are Rhee and Waldman's incorrect description of the heritability concept and their failure to discuss several German criminal twin studies published during the Nazi era.
Komoto, Satoshi; Taniguchi, Koki
The rotavirus genome is composed of 11 gene segments of dsRNA. A recent breakthrough in the field of rotaviruses is the development of a reverse genetics system for generating recombinant rotaviruses possessing a gene segment derived from cloned cDNA. Although this approach is a helper virus-driven system that is technically limited and gives low levels of recombinant viruses, it allows alteration of the rotavirus genome, thus contributing to our understanding of these medically important viruses. So far, this approach has successfully been applied to three of the 11 viral segments in our laboratory and others, and the efficiency of recovery of recombinant viruses has been improved. However, we are still waiting for the development of a helper virus-free reverse genetics system for generating an infectious rotavirus entirely from cDNAs, as has been achieved for other members of the Reoviridae family.
... Encyclopedia: Semen Analysis MedlinePlus Health Topic: Assisted Reproductive Technology General Information from MedlinePlus (5 links) Diagnostic Tests Drug Therapy Genetic Counseling Palliative Care Surgery and ...
... Encyclopedia: Semen Analysis MedlinePlus Health Topic: Assisted Reproductive Technology General Information from MedlinePlus (5 links) Diagnostic Tests Drug Therapy Genetic Counseling Palliative Care Surgery and ...
Ridge, Perry G.; Ebbert, Mark T. W.; Kauwe, John S. K.
Alzheimer's disease is the most common form of dementia and is the only top 10 cause of death in the United States that lacks disease-altering treatments. It is a complex disorder with environmental and genetic components. There are two major types of Alzheimer's disease, early onset and the more common late onset. The genetics of early-onset Alzheimer's disease are largely understood with variants in three different genes leading to disease. In contrast, while several common alleles associated with late-onset Alzheimer's disease, including APOE, have been identified using association studies, the genetics of late-onset Alzheimer's disease are not fully understood. Here we review the known genetics of early- and late-onset Alzheimer's disease. PMID:23984328
Rodriguez-Fontenla, Cristina; Gonzalez, Antonio
Osteoarthritis (OA) is a complex disease caused by the interaction of multiple genetic and environmental factors. This review focuses on the studies that have contributed to the discovery of genetic susceptibility factors in OA. The most relevant associations discovered until now are discussed in detail: GDF-5, 7q22 locus, MCF2L, DOT1L, NCOA3 and also some important findings from the arcOGEN study. Moreover, the different approaches that can be used to minimize the specific problems of the study of OA genetics are discussed. These include the study of microsatellites, phenotype standardization and other methods such as meta-analysis of GWAS and gene-based analysis. It is expected that these new approaches contribute to finding new susceptibility genetic factors for OA.
OHAMA, Takeshi; INAGAKI, Yuji; BESSHO, Yoshitaka; OSAWA, Syozo
In 1985, we reported that a bacterium, Mycoplasma capricolum, used a deviant genetic code, namely UGA, a “universal” stop codon, was read as tryptophan. This finding, together with the deviant nuclear genetic codes in not a few organisms and a number of mitochondria, shows that the genetic code is not universal, and is in a state of evolution. To account for the changes in codon meanings, we proposed the codon capture theory stating that all the code changes are non-disruptive without accompanied changes of amino acid sequences of proteins. Supporting evidence for the theory is presented in this review. A possible evolutionary process from the ancient to the present-day genetic code is also discussed. PMID:18941287
Sadagopan, Karthikeyan A; Capasso, Jenina; Levin, Alex V
The eye has played a major role in human genomics including gene therapy. It is the fourth most common organ system after integument (skin, hair and nails), nervous system, and musculoskeletal system to be involved in genetic disorders. The eye is involved in single gene disorders and those caused by multifactorial etiology. Retinoblastoma was the first human cancer gene to be cloned. Leber hereditary optic neuropathy was the first mitochondrial disorder described. X-Linked red-green color deficiency was the first X-linked disorder described. The eye, unlike any other body organ, allows directly visualization of genetic phenomena such as skewed X-inactivation in the fundus of a female carrier of ocular albinism. Basic concepts of genetics and their application to clinical ophthalmological practice are important not only in making a precise diagnosis and appropriate referral, but also in management and genetic counseling.
... abnormal swelling caused by a buildup of fluid (lymphedema) and a condition called anhydrotic ectodermal dysplasia that ... Registry: Ectodermal dysplasia, anhidrotic, with immunodeficiency, osteopetrosis, and lymphedema Genetic Testing Registry: Osteopetrosis and infantile neuroaxonal dystrophy ...
For the last 20 years the concepts of identity and identification have been subject to much interest in the humanities and social sciences. However, the implications of genetics for identity and identification have been largely neglected. In this paper, I distinguish various conceptions of identity (as continuity over time, as basic kind of being, as unique set of properties, and as social role) and identification (as subjective experience of identity in various senses and as social ascription of identity in various senses), and investigate systematically genetic perspectives on each of these conceptions. I stress the importance of taking the genetic perspectives seriously but also their limitations. In particular, I pinpoint conceptual problems that arise when a genetic approach to identity is adopted.
... homogentisate oxidase. This enzyme helps break down the amino acids phenylalanine and tyrosine, which are important building blocks ... Resources MedlinePlus (2 links) Encyclopedia: Alkaptonuria Health Topic: Amino Acid Metabolism Disorders Genetic and Rare Diseases Information Center ( ...
... condition characterized by elevated blood levels of the amino acid histidine, a building block of most proteins. Histidinemia ... Additional Information & Resources MedlinePlus (2 links) Health Topic: Amino Acid Metabolism Disorders Health Topic: Newborn Screening Genetic and ...
... condition characterized by elevated blood levels of the amino acid lysine, a building block of most proteins. Hyperlysinemia ... Additional Information & Resources MedlinePlus (2 links) Health Topic: Amino Acid Metabolism Disorders Health Topic: Newborn Screening Genetic and ...
... in my area? Other Names for This Condition French type sialuria Sialuria, French type Related Information How are genetic conditions and ... and Rare Diseases Information Center (1 link) Sialuria, French type Educational Resources (5 links) Cincinnati Children's Hospital ...
... Information & Resources MedlinePlus (4 links) Encyclopedia: Phenylketonuria Encyclopedia: Serum Phenylalanine Screening Health Topic: Newborn Screening Health Topic: Phenylketonuria Genetic and Rare Diseases Information Center (1 link) Phenylketonuria Additional NIH Resources ( ...
Dishotsky, Norman I.; And Others
Reviews studies of the effects of lysergic acid diethylamide (LSD) on man and other organisms. Concludes that pure LSD injected in moderate doses does not cause chromosome or detectable genetic damage and is not a teratogen or carcinogen. (JM)
Wells, Kevin D
Historically, genetic engineering for mammalian reproductive questions has been accomplished primarily in the mouse. However, all the genetic manipulations that can be done in the mouse can now be accomplished in most domesticated mammals. Random integration of transgenes, homologous recombination and gene editing are now routine for several mammalian species. For livestock, queries related to fertility can be asked directly for the species in question, without a need for a mouse model. For human clinical concerns, the most appropriate model should be selected based on physiology, anatomy, or even size. The mouse will continue to be a useful genetically engineered model. However, other species are now amenable to the full range of genetic manipulations and should be considered as possible models for human conditions when appropriate.
... A A A Listen En Español Genetics of Diabetes You've probably wondered how you developed diabetes. ... to develop diabetes than others. What Leads to Diabetes? Type 1 and type 2 diabetes have different ...
Steinlein, Ortrud K.
The term “epilepsy” describes a heterogeneous group of disorders, most of them caused by interactions between several or even many genes and environmental factors. Much rarer are the genetic epilepsies that are due to single-gene mutations or defined structural chromosomal aberrations, such as microdeletions. The discovery of several of the genes underlying these rare genetic epilepsies has already considerably contributed to our understanding of the basic mechanisms epileptogenesis. The progress made in the last 15 years in the genetics of epilepsy is providing new possibilities for diagnosis and therapy. Here, different genetic epilepsies are reviewed as examples, to demonstrate the various pathways that can lead from genes to seizures. PMID:18472482
... particular ethnic groups? Genetic Changes Mutations in the CAT gene can cause acatalasemia . This gene provides instructions ... DNA, proteins, and cell membranes. Mutations in the CAT gene greatly reduce the activity of catalase. A ...
This report is taken from the April 1992 draft of the DOE Human Genome 1991--1992 Program Report, which is expected to be published in May 1992. The primer is intended to be an introduction to basic principles of molecular genetics pertaining to the genome project. The material contained herein is not final and may be incomplete. Techniques of genetic mapping and DNA sequencing are described.
Kolettis, Peter N
Genetic diseases that do not primarily affect the genitourinary tract may have urologic manifestations. These urologic manifestations range from benign and malignant renal disease to infertility. Thus, the practicing urologist may be involved in the care of these patients and should have knowledge of these diseases. Continued improvements in the diagnosis and treatment of these genetic diseases will likely result in improved survival and will increase the number of patients who may develop urologic manifestations of these diseases.
Allen, Carolyn M; Founds, Sandra A
Although the etiology of preterm birth is incompletely understood, phenotype classifications combined with recent technologies such as genome-wide association studies and next-generation sequencing could lead to discovering genotypes associated with preterm birth. Identifying genetic contributions will allow for genetic screening tests to predict or detect pregnancies with potential for preterm birth. In this article we discuss current knowledge regarding phenotype classifications, genotypes, and their associations with preterm birth.
Bilen, Ozlem; Pokharel, Yashashwi; Ballantyne, Christie M
Hereditary dyslipidemias are often underdiagnosed and undertreated, yet with significant health implications, most importantly causing preventable premature cardiovascular diseases. The commonly used clinical criteria to diagnose hereditary lipid disorders are specific but are not very sensitive. Genetic testing may be of value in making accurate diagnosis and improving cascade screening of family members, and potentially, in risk assessment and choice of therapy. This review focuses on using genetic testing in the clinical setting for lipid disorders, particularly familial hypercholesterolemia.
Bilen, Ozlem; Pokharel, Yashashwi; Ballantyne, Christie M
Hereditary dyslipidemias are often underdiagnosed and undertreated, yet with significant health implications, most importantly causing preventable premature cardiovascular diseases. The commonly used clinical criteria to diagnose hereditary lipid disorders are specific but are not very sensitive. Genetic testing may be of value in making accurate diagnosis and improving cascade screening of family members, and potentially, in risk assessment and choice of therapy. This review focuses on using genetic testing in the clinical setting for lipid disorders, particularly familial hypercholesterolemia.
Vadlamudi, Lata; Milne, Roger L.; Lawrence, Kate; Heron, Sarah E.; Eckhaus, Jazmin; Keay, Deborah; Connellan, Mary; Torn-Broers, Yvonne; Howell, R. Anne; Mulley, John C.; Scheffer, Ingrid E.; Dibbens, Leanne M.; Hopper, John L.
Objective: Analysis of twins with epilepsy to explore the genetic architecture of specific epilepsies, to evaluate the applicability of the 2010 International League Against Epilepsy (ILAE) organization of epilepsy syndromes, and to integrate molecular genetics with phenotypic analyses. Methods: A total of 558 twin pairs suspected to have epilepsy were ascertained from twin registries (69%) or referral (31%). Casewise concordance estimates were calculated for epilepsy syndromes. Epilepsies were then grouped according to the 2010 ILAE organizational scheme. Molecular genetic information was utilized where applicable. Results: Of 558 twin pairs, 418 had confirmed seizures. A total of 534 twin individuals were affected. There were higher twin concordance estimates for monozygotic (MZ) than for dizygotic (DZ) twins for idiopathic generalized epilepsies (MZ = 0.77; DZ = 0.35), genetic epilepsy with febrile seizures plus (MZ = 0.85; DZ = 0.25), and focal epilepsies (MZ = 0.40; DZ = 0.03). Utilizing the 2010 ILAE scheme, the twin data clearly demonstrated genetic influences in the syndromes designated as genetic. Of the 384 tested twin individuals, 10.9% had mutations of large effect in known epilepsy genes or carried validated susceptibility alleles. Conclusions: Twin studies confirm clear genetic influences for specific epilepsies. Analysis of the twin sample using the 2010 ILAE scheme strongly supported the validity of grouping the “genetic” syndromes together and shows this organizational scheme to be a more flexible and biologically meaningful system than previous classifications. Successful selected molecular testing applied to this cohort is the prelude to future large-scale next-generation sequencing of epilepsy research cohorts. Insights into genetic architecture provided by twin studies provide essential data for optimizing such approaches. PMID:25107880
Moreno García, M; Gómez Rodríguez, M J; Barreiro Miranda, E
Congenital heart malformations are the most common of all birth defects, affecting 0.5-1% of all live births. Some of these malformations are due to genetic anomalies. Patterns of autosomal dominant, autosomal recessive and X-linked inheritance have been described. Mitochondrial inheritance and chromosomal anomalies can also be responsible for congenital heart malformations. Several genes for congenital heart defects have been identified. We review current knowledge on the genetic etiology of congenital heart disease.
Salk, Rachel H.; Hyde, Janet S.
Over the past century, much of genetics was deterministic, and feminist researchers framed justified criticisms of genetics research. However, over the past two decades, genetics research has evolved remarkably and has moved far from earlier deterministic approaches. Our article provides a brief primer on modern genetics, emphasizing contemporary…
This paper provides an overview of the ethical issues pertaining to the use of genetic insights and techniques in sport. Initially, it considers a range of scientific findings that have stimulated debate about the ethical issues associated with genetics applied to sport. It also outlines some of the early policy responses to these discoveries from world leading sports organizations, along with knowledge about actual use of gene technologies in sport. Subsequently, it considers the challenges with distinguishing between therapeutic use and human enhancement within genetic science, which is a particularly important issue for the world of sport. Next, particular attention is given to the use of genetic information, which raises questions about the legitimacy and reliability of genetic tests, along with the potential public value of having DNA databanks to economize in health care. Finally, the ethics of gene transfer are considered, inviting questions into the values of sport and humanity. It argues that, while gene modification may seem conceptually similar to other forms of doping, the requirements upon athletes are such that new forms of enhancement become increasingly necessary to discover. Insofar as genetic science is able to create safer, more effective techniques of human modification, then it may be an appealing route through which to modify athletes to safeguard the future of elite sports as enterprises of human excellence.
Schellenberg, Gerard D
The genetics community working on Alzheimer's disease and related dementias has made remarkable progress in the past 20 years. The cumulative efforts by multiple groups have lead to the identification of three autosomal dominant genes for early onset AD. These are the amyloid-beta protein precursor gene (APP), and the genes encoding presenilin1 and 2. The knowledge derived from this work has firmly established Abeta as a critical disease molecule and lead to candidate drugs currently in treatment trials. Work on a related disease, frontotemporal dementia with parkinsonism - chromosome 17 type has also added to our understanding of pathogenesis by revealing that tau, the protein component of neurofibrillary tangles, is also a critical molecule in neurodegeneration. Lessons learned that still influence work on human genetics include the need to recognize and deal with genetic heterogeneity, a feature common to many genetic disorders. Genetic heterogeneity, if recognized, can be source of information. Another critical lesson is that clinical, molecular, and statistical scientists need to work closely on disease projects to succeed in solving the complex problems of common genetic disorders.
Zhou, Tianshou; Zhang, Jiajun; Yuan, Zhanjiang; Chen, Luonan
Synchronization of genetic or cellular oscillators is a central topic in understanding the rhythmicity of living organisms at both molecular and cellular levels. Here, we show how a collective rhythm across a population of genetic oscillators through synchronization-induced intercellular communication is achieved, and how an ensemble of independent genetic oscillators is synchronized by a common noisy signaling molecule. Our main purpose is to elucidate various synchronization mechanisms from the viewpoint of dynamics, by investigating the effects of various biologically plausible couplings, several kinds of noise, and external stimuli. To have a comprehensive understanding on the synchronization of genetic oscillators, we consider three classes of genetic oscillators: smooth oscillators (exhibiting sine-like oscillations), relaxation oscillators (displaying jump dynamics), and stochastic oscillators (noise-induced oscillation). For every class, we further study two cases: with intercellular communication (including phase-attractive and repulsive coupling) and without communication between cells. We find that an ensemble of smooth oscillators has different synchronization phenomena from those in the case of relaxation oscillators, where noise plays a different but key role in synchronization. To show differences in synchronization between them, we make comparisons in many aspects. We also show that a population of genetic stochastic oscillators have their own synchronization mechanisms. In addition, we present interesting phenomena, e.g., for relaxation-type stochastic oscillators coupled to a quorum-sensing mechanism, different noise intensities can induce different periodic motions (i.e., inhomogeneous limit cycles).
Schuckit, M A; Li, T K; Cloninger, C R; Deitrich, R A
Great progress has been made by research on the contribution genetic factors make to a vulnerability toward alcoholism. Animal studies have demonstrated the importance of genetics in ethanol preference and levels of consumption, and human family, twin, and adoption research have revealed a 4-fold higher risk for offspring of alcoholics, even if they were adopted out at birth. The work presented in this symposium reviews the ongoing search for genetic trait markers of a vulnerability toward alcoholism. Dr. Li has used both animal and human research to demonstrate the possible importance of the genetic control of enzymes involved in ethanol metabolism and has worked to help develop an animal model of alcoholism. The possible importance of subgroups with different levels of predisposition toward alcoholism is emphasized by Dr. Cloninger. An overview of the studies of sons of alcoholics, given by Dr. Schuckit, reveals the potential importance of a decreased intensity of reaction to ethanol as part of a predisposition toward alcoholism and discusses the possible impact of some brain waves and ethanol metabolites to an alcoholism vulnerability. Dr. Deitrich reviews interrelationships between studies of animals and humans in the search for factors involved in a genetic vulnerability toward alcoholism. Taken together, these presentations underscore the importance of genetic factors in alcoholism, review animal and human research attempting to identify markers of a vulnerability, and reveal the high level of interaction between human and animal research.
McLaughlin, Russell L.; Heverin, Mark; Thorpe, Owen; Abrahams, Sharon; Al-Chalabi, Ammar; Hardiman, Orla
Objective: To determine the degree of consensus among clinicians on the clinical use of genetic testing in amyotrophic lateral sclerosis (ALS) and the factors that determine decision-making. Methods: ALS researchers worldwide were invited to participate in a detailed online survey to determine their attitudes and practices relating to genetic testing. Results: Responses from 167 clinicians from 21 different countries were analyzed. The majority of respondents (73.3%) do not consider that there is a consensus definition of familial ALS (FALS). Fifty-seven percent consider a family history of frontotemporal dementia and 48.5% the presence of a known ALS genetic mutation as sufficient for a diagnosis of FALS. Most respondents (90.2%) offer genetic testing to patients they define as having FALS and 49.4% to patients with sporadic ALS. Four main genes (SOD1, C9orf72, TARDBP, and FUS) are commonly tested. A total of 55.2% of respondents would seek genetic testing if they had personally received a diagnosis of ALS. Forty-two percent never offer presymptomatic testing to family members of patients with FALS. Responses varied between ALS specialists and nonspecialists and based on the number of new patients seen per year. Conclusions: There is a lack of consensus among clinicians as to the definition of FALS. Substantial variation exists in attitude and practices related to genetic testing of patients and presymptomatic testing of their relatives across geographic regions and between experienced specialists in ALS and nonspecialists. PMID:28159885
Discusses such high points of human genetics as the study of chromosomes, somatic cell hybrids, the population formula: the Hardy-Weinberg Law, biochemical genetics, the single-active X Theory, behavioral genetics and finally how genetics can serve humanity. (BR)
Morton, N E
Starting from a broad definition of genetic epidemiology, current developments in association, segregation, and linkage analysis of complex inheritance are considered together with integration of genetic and physical maps and resolution of genetic heterogeneity. Mitochondrial inheritance, imprinting, uniparental disomy, pregressive amplification, and gonadal mosaicism are some of the novel mechanisms discussed, with speculation about the future of genetic epidemiology.
Tetushkin, E Iu
The supplementary historical discipline genealogy is also a supplementary genetic discipline. In its formation, genetics borrowed from genealogy some methods of pedigree analysis. In the 21th century, it started receiving contribution from computer-aided genealogy and genetic (molecular) genealogy. The former provides novel tools for genetics, while the latter, which employing genetic methods, enriches genetics with new evidence. Genealogists formulated three main laws ofgenealogy: the law of three generations, the law of doubling the ancestry number, and the law of declining ancestry. The significance and meaning of these laws can be fully understood only in light of genetics. For instance, a controversy between the exponential growth of the number of ancestors of an individual, i.e., the law of doubling the ancestry number, and the limited number of the humankind is explained by the presence of weak inbreeding because of sibs' interference; the latter causes the pedigrees' collapse, i.e., explains also the law of diminishing ancestry number. Mathematic modeling of pedigrees' collapse presented in a number of studies showed that the number of ancestors of each individual attains maximum in a particular generation termed ancestry saturated generation. All representatives of this and preceding generation that left progeny are common ancestors of all current members of the population. In subdivided populations, these generations are more ancient than in panmictic ones, whereas in small isolates and social strata with limited numbers of partners, they are younger. The genealogical law of three generations, according to which each hundred years contain on average three generation intervals, holds for generation lengths for Y-chromosomal DNA, typically equal to 31-32 years; for autosomal and mtDNA, this time is somewhat shorter. Moving along ascending lineas, the number of genetically effective ancestors transmitting their DNA fragment to descendants increases far
Van Tintelen, J Peter; Pieper, Petronella G; Van Spaendonck-Zwarts, Karin Y; Van Den Berg, Maarten P
Although familial forms of cardiomyopathy such as hypertrophic or dilated cardiomyopathy have been recognized for decades, it is only recently that much of the genetic basis of these inherited cardiomyopathies has been elucidated. This has provided important insights into the pathophysiological mechanisms underlying the disease phenotype. This increased knowledge and the availability of genetic testing has resulted in increasing numbers of mutation carriers who are being monitored, including many who are now of child-bearing age. Pregnancy is generally well tolerated in asymptomatic patients or mutation carriers with inherited cardiomyopathies. However, since pregnancy leads to major physiological changes in the cardiovascular system, in women with genetic cardiomyopathies or who carry a mutation pre-disposing to a genetic cardiomyopathy, pregnancy entails a risk of developing heart failure and/or arrhythmias. This deterioration of cardiac function may occur despite optimal medical treatment. Advanced left ventricular dysfunction, poor functional class (NYHA class III or IV), or prior cardiac events appear to increase the risk of maternal cardiac complications. However, there are no large series of cardiomyopathy patients who are regularly evaluated for cardiac complications during pregnancy and for certain types of inherited cardiomyopathy, only case reports on individual pregnancies are available. Pre-conception cardiologic evaluation and genetic counselling are important for every woman with a cardiomyopathy or a cardiomyopathy-related mutation who is considering having a family. In this article, we give an overview of the basic clinical aspects, genetics, and pregnancy outcome in women with different types of inherited cardiomyopathies. We also discuss the genetic aspects of pregnancy-associated cardiomyopathy, including peripartum cardiomyopathy.
Pichi, Francesco; Carrai, Paola; Srivastava, Sunil K; Lowder, Careen Y; Nucci, Paolo; Neri, Piergiorgio
Immune-mediated uveitis may be associated with a systemic disease or may be localized to the eye. T-cell-dependent immunological events are increasingly being regarded as extremely important in the pathogenesis of uveitis. Several studies have also shown that macrophages are major effectors of tissue damage in uveitis. Uveitis phenotypes can differ substantially, and most uveitis diseases are considered polygenic with complex inheritance patterns. This review attempts to present the current state of knowledge from in vitro and in vivo research on the role of genetics in the development and clinical course of uveitis. A review of the literature in the PubMed, MEDLINE, and Cochrane databases was conducted to identify clinical trials, comparative studies, case series, and case reports describing host genetic factors as well as immune imbalance which contribute to the development of uveitis. The search was limited to primary reports published in English with human subjects from 1990 to the present, yielding 3590 manuscripts. In addition, referenced articles from the initial searches were hand searched to identify additional relevant reports. After title and abstract selection, duplicate elimination, and manual search, 55 papers were selected for analysis and reviewed by the authors for inclusion in this review. Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system. When considering the genetics of uveitis, common threads can be identified. Genome-wide scans and other genetic methods are becoming increasingly successful in identifying genetic loci and candidate genes in many inflammatory disorders that have a uveitic component. It will be important to test these findings as uveitis-specific genetic factors. Therefore, the
Zucker, A; Patriquin, D
Gene therapy, pre-natal diagnosis, genetically altered bacteria, patenting new life forms: these are all outgrowths from the development of genetics. Our focus will be on the moral issues engendered by some of the genetic techniques which are now so well integrated into clinical medicine. The section on genetic counseling is meant to show the most frequent moral problems encountered as they might really occur. Genetic screening is presented as a mix of preventive medicine and aid for genetic counseling. Genetic engineering is discussed in the context of evolution and human needs and desires.
Morton, Newton E
Genetic epidemiology developed in the middle of the last century, focused on inherited causes of disease but with methods and results applicable to other traits and even forensics. Early success with linkage led to the localization of genes contributing to disease, and ultimately to the Human Genome Project. The discovery of millions of DNA markers has encouraged more efficient positional cloning by linkage disequilibrium (LD), using LD maps and haplotypes in ways that are rapidly evolving. This has led to large international programmes, some promising and others alarming, with laws about DNA patenting and ethical guidelines for responsible research still struggling to be born. PMID:14561327
... Handouts Genetic counseling (Medical Encyclopedia) Also in Spanish Topic Image MedlinePlus Email Updates Get Genetic Counseling updates ... GO GO MEDICAL ENCYCLOPEDIA Genetic counseling Related Health Topics Birth Defects Family History Genetic Disorders Genetic Testing ...
... sobre las pruebas genéticas Frequently Asked Questions About Genetic Testing What is genetic testing? What can I ... find more information about genetic testing? What is genetic testing? Genetic testing uses laboratory methods to look ...
... of genetic tests? What are the types of genetic tests? Genetic testing can provide information about a ... paternity). For more information about the uses of genetic testing: A Brief Primer on Genetic Testing , which ...
Janikow, Cezary Z.
Genetic programming refers to a class of genetic algorithms utilizing generic representation in the form of program trees. For a particular application, one needs to provide the set of functions, whose compositions determine the space of program structures being evolved, and the set of terminals, which determine the space of specific instances of those programs. The algorithm searches the space for the best program for a given problem, applying evolutionary mechanisms borrowed from nature. Genetic algorithms have shown great capabilities in approximately solving optimization problems which could not be approximated or solved with other methods. Genetic programming extends their capabilities to deal with a broader variety of problems. However, it also extends the size of the search space, which often becomes too large to be effectively searched even by evolutionary methods. Therefore, our objective is to utilize problem constraints, if such can be identified, to restrict this space. In this publication, we propose a generic constraint specification language, powerful enough for a broad class of problem constraints. This language has two elements -- one reduces only the number of program instances, the other reduces both the space of program structures as well as their instances. With this language, we define the minimal set of complete constraints, and a set of operators guaranteeing offspring validity from valid parents. We also show that these operators are not less efficient than the standard genetic programming operators if one preprocesses the constraints - the necessary mechanisms are identified.
Luquetti, Daniela V; Heike, Carrie L; Hing, Anne V; Cunningham, Michael L; Cox, Timothy C
Microtia is a congenital anomaly of the ear that ranges in severity from mild structural abnormalities to complete absence of the ear, and can occur as an isolated birth defect or as part of a spectrum of anomalies or a syndrome. Microtia is often associated with hearing loss and patients typically require treatment for hearing impairment and surgical ear reconstruction. The reported prevalence varies among regions, from 0.83 to 17.4 per 10,000 births, and the prevalence is considered to be higher in Hispanics, Asians, Native Americans, and Andeans. The etiology of microtia and the cause of this wide variability in prevalence are poorly understood. Strong evidence supports the role of environmental and genetic causes for microtia. Although some studies have identified candidate genetic variants for microtia, no causal genetic mutation has been confirmed. The application of novel strategies in developmental biology and genetics has facilitated elucidation of mechanisms controlling craniofacial development. In this paper we review current knowledge of the epidemiology and genetics of microtia, including potential candidate genes supported by evidence from human syndromes and animal models. We also discuss the possible etiopathogenesis in light of the hypotheses formulated to date: Neural crest cells disturbance, vascular disruption, and altitude.
Peralta-Romero, José de Jesús; Gómez-Zamudio, Jaime Héctor; Estrada-Velasco, Bárbara; Karam-Araujo, Roberto; Cruz-López, Miguel
Obesity is a major health problem around the globe. The statistics of overweight and obesity at early ages have reached alarming levels and placed our country in the first place in regard to childhood obesity. In the development of obesity two major factors take part, one genetic and the other one environmental. From the perspective of environmental changes both overweight and obesity result from the imbalance in the energy balance: people ingest more energy than they expend. Despite people live in the same obesogenic environment not all of them develop obesity; it requires genetic factors for this to happen. This review focuses on the description of the main methodologies to find genetic markers, as well as the main loci in candidate genes, whose single nucleotide polymorphisms (SNPs) are associated with obesity and its comorbidities in children, highlighting the association of these genes in the Mexican population. Knowledge of the genetic markers associated with obesity will help to understand the molecular and physiological mechanisms, the genetic background and changes in body mass index in the Mexican population. This information is useful for the planning of new hypotheses in the search for new biomarkers that can be used in a predictive and preventive way, as well as for the development of new therapeutic strategies.
Skibola, Christine F.; Curry, John D.; Nieters, Alexandra
BACKGROUND Genetic susceptibility studies of lymphoma may serve to identify at risk populations and to elucidate important disease mechanisms. METHODS This review considered all studies published through October 2006 on the contribution of genetic polymorphisms in the risk of lymphoma. RESULTS Numerous studies implicate the role of genetic variants that promote B-cell survival and growth with increased risk of lymphoma. Several reports including a large pooled study by InterLymph, an international consortium of non-Hodgkin lymphoma (NHL) case-control studies, found positive associations between variant alleles in TNF -308G>A and IL10 -3575T>A genes and risk of diffuse large B-cell lymphoma. Four studies reported positive associations between a GSTT1 deletion and risk of Hodgkin and non-Hodgkin lymphoma. Genetic studies of folate-metabolizing genes implicate folate in NHL risk, but further studies that include folate and alcohol assessments are needed. Links between NHL and genes involved in energy regulation and hormone production and metabolism may provide insights into novel mechanisms implicating neuro- and endocrine-immune cross-talk with lymphomagenesis, but will need replication in larger populations. CONCLUSIONS Numerous studies suggest that common genetic variants with low penetrance influence lymphoma risk, though replication studies will be needed to eliminate false positive associations. PMID:17606447
Loukola, Anu; Hällfors, Jenni; Korhonen, Tellervo; Kaprio, Jaakko
Regular smoking is the major risk factor for cardiovascular disease and cancers, and thus is one of the most preventable causes of morbidity and mortality worldwide. Intake of nicotine, its central nervous system effects, and its metabolism are regulated by biological pathways; some of these are well known, but others are not. Genetic studies offer a method for developing insights into the genes contributing to those pathways. In recent years, large genome-wide association study (GWAS) meta-analyses have consistently revealed that the strongest genetic contribution to smoking-related traits comes from variation in the nicotinic receptor subunit genes. Many other genes, including those coding for enzymes involved in nicotine metabolism, also have been implicated. However, the proportion of phenotypic variance explained by the identified genetic variants is very modest. This review intends to cover progress made in genetics and genetic epidemiology of smoking behavior in recent years, and focuses on studies revealing the nicotinic receptor gene cluster on chromosome 15q25. Evidence supporting the involvement of a novel pathway in the shared pathophysiology of nicotine dependence and schizophrenia is also briefly reviewed. A summary of the current knowledge on gene–environment interactions involved in smoking behavior is included. PMID:24778978
Ninoa, F.; Ilaria, M.; Noviello, C.; Santoro, L.; Rätsch, I.M.; Martino, A.; Cobellis, G.
Vesicoureteral reflux (VUR) is the retrograde passage of urine from the bladder to the upper urinary tract. It is the most common congenital urological anomaly affecting 1-2% of children and 30-40% of patients with urinary tract infections. VUR is a major risk factor for pyelonephritic scarring and chronic renal failure in children. It is the result of a shortened intravesical ureter with an enlarged or malpositioned ureteric orifice. An ectopic embryonal ureteric budding development is implicated in the pathogenesis of VUR, which is a complex genetic developmental disorder. Many genes are involved in the ureteric budding formation and subsequently in the urinary tract and kidney development. Previous studies demonstrate an heterogeneous genetic pattern of VUR. In fact no single major locus or gene for primary VUR has been identified. It is likely that different forms of VUR with different genetic determinantes are present. Moreover genetic studies of syndromes with associated VUR have revealed several possible candidate genes involved in the pathogenesis of VUR and related urinary tract malformations. Mutations in genes essential for urinary tract morphogenesis are linked to numerous congenital syndromes, and in most of those VUR is a feature. The Authors provide an overview of the developmental processes leading to the VUR. The different genes and signaling pathways controlling the embryonal urinary tract development are analyzed. A better understanding of VUR genetic bases could improve the management of this condition in children. PMID:27013925
Fernández-Moreno, Mercedes; Rego, Ignacio; Carreira-Garcia, Vanessa; Blanco, Francisco J
Osteoarthritis is a degenerative articular disease with complex pathogeny because diverse factors interact causing a process of deterioration of the cartilage. Despite the multifactorial nature of this pathology, from the 50’s it´s known that certain forms of osteoarthritis are related to a strong genetic component. The genetic bases of this disease do not follow the typical patterns of mendelian inheritance and probably they are related to alterations in multiple genes. The identification of a high number of candidate genes to confer susceptibility to the development of the osteoarthritis shows the complex nature of this disease. At the moment, the genetic mechanisms of this disease are not known, however, which seems clear is that expression levels of several genes are altered, and that the inheritance will become a substantial factor in future considerations of diagnosis and treatment of the osteoarthritis. PMID:19516961
DOBBS, Matthew B; GURNETT, Christina A
Modern advances in genetics have allowed investigators to begin to identify the complex etiology of clubfoot. It has become increasingly apparent that clubfoot is a heterogeneous disorder with a polygenetic threshold model explaining its inheritance patterns. Several recent genetics studies have identified a key developmental pathway, the PITX1-TBX4 transriptional pathway, as being important in clubfoot etiology. Both PITX1 and TBX4 are uniquely expressed in the hindlimb which helps explain the foot phenotype seen with mutations in these transcription factors. Future studies are needed to develop animal models to determine the exact mechanisms by which these genetic abnormalities cause clubfoot and to test other hypotheses of clubfoot pathogenesis. PMID:21817922
This paper provides part of an analysis of the use of the Maori term whakapapa in a study designed to test the compatibility and commensurability of views of members of the indigenous culture of New Zealand with other views of genetic technologies extant in the country. It is concerned with the narrow sense of whakapapa as denoting biological ancestry, leaving the wider sense of whakapapa as denoting cultural identity for discussion elsewhere. The phenomenon of genetic curiosity is employed to facilitate this comparison. Four levels of curiosity are identified, in the Maori data, which penetrate more or less deeply into the psyche of individuals, affecting their health and wellbeing. These phenomena are compared with non-Maori experiences and considerable commonalities are discovered together with a point of marked difference. The results raise important questions for the ethical application of genetic technologies.
Escamilla, Michael A; Zavala, Juan M
Bipolar disorder especially the most severe type (type I), has a strong genetic component. Family studies suggest that a small number of genes of modest effect are involved in this disorder. Family-based studies have identified a number of chromosomal regions linked to bipolar disorder, and progress is currently being made in identifying positional candidate genes within those regions. A number of candidate genes have also shown evidence of association with bipolar disorder, and genome-wide association studies are now under way, using dense genetic maps. Replication studies in larger or combined datasets are needed to definitively assign a role for specific genes in this disorder. This review covers our current knowledge of the genetics of bipolar disorder, and provides a commentary on current approaches used to identify the genes involved in this complex behavioral disorder.
Buskila, Dan; Neumann, Lily
The pathogenesis of fibromyalgia (FM) and related conditions is not entirely understood. Recent evidence suggests that these syndromes may share heritable pathophysiologic features. Familial studies suggest that genetic and familial factors may play a role in the etiopathogenesis of these conditions. There is evidence that polymorphisms of genes in the serotoninergic and catecholaminergic systems are linked to the pathophysiology of FM and related conditions and are associated with personality traits. The precise role of genetic factors in the etiopathology of FM remains unknown, but it is likely that several genes are operating together to initiate this syndrome. Larger longitudinal studies are needed to better clarify the role of genetics in the development of FM.
This chapter describes the resources held at the Maize Genetics Cooperation • Stock Center in detail and also provides some information about the North Central Regional Plant Introduction Station (NCRPIS) in Ames, IA, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) in Mexico, and the N...
Radford, A.; Bird-Stewart, J. A.
Discusses the genetics content in secondary school curricula, suggesting possible revisions to current A- and 0-level syllabi. Present teaching methods, textbooks, and General Certificate of Education (GCE) examination questions are reviewed, problems identified, and suggestions made regarding possible improvements. (Author/JN)
Knowing the location and make-up of each of the 50,000 to 100,000 human genes will revolutionize the practice of medicine. This knowledge will lead to tailor-made therapies not only for treating disease but also for preventing it - in short, to a new concept of patient care. The Human Genome Project, a 15-year, $3 billion quest to determine the nucleotide sequence of the entire human genome, will make this possible. In The New Genetics, Leon Jaroff recounts the long path of discovery thatt has led to this huge new scientific venture - from the theory of heredity put forth by Aristotle more than 2,000 years ago to the current attempts to treat adenosine deaminase (ADA) deficiency and malignant melanoma via gene therapy. Against this background, the geneticists, molecular biologists, clinicians, and ethicists involved in the Human Genome Project describe their work and how it will provide physicians with ever more precise and effective tools to treat human disease. Jaroff also reveals the other, more problematic side of the story. Patients with an undesirable genetic profile may be subject to discrimination by private insurers. Physicians who fail to recommend genetic screening may find themselves victims of malpractice or wrongful-life suits. Indeed, these issues and others have already begun to affect physicians. The New Genetics makes it abundantly clear tha a revolution has arrived, and that physicians must be prepared to cope with the new order.
Aznar, Mercedes Martinez; Orcajo, Teresa Ibanez
A teaching unit on genetics and human inheritance using problem-solving methodology was undertaken with fourth-level Spanish Secondary Education students (15 year olds). The goal was to study certain aspects of the students' learning process (concepts, procedures and attitude) when using this methodology in the school environment. The change…
Mallipatna, Ashwin; Marino, Meghan; Singh, Arun D
Retinoblastoma is a malignant retinal tumor that affects young children. Mutations in the RB1 gene cause retinoblastoma. Mutations in both RB1 alleles within the precursor retinal cell are essential, with one mutation that may be germline or somatic and the second one that is always somatic. Identification of the RB1 germline status of a patient allows differentiation between sporadic and heritable retinoblastoma variants. Application of this knowledge is crucial for assessing short-term (risk of additional tumors in the same eye and other eye) and long-term (risk of nonocular malignant tumors) prognosis and offering cost-effective surveillance strategies. Genetic testing and genetic counseling are therefore essential components of care for all children diagnosed with retinoblastoma. The American Joint Committee on Cancer has acknowledged the importance of detecting this heritable trait and has introduced the letter "H" to denote a heritable trait of all cancers, starting with retinoblastoma (in publication). In this article, we discuss the clinically relevant aspects of genetic testing and genetic counseling for a child with retinoblastoma.
Stančáková, Alena; Laakso, Markku
Metabolic syndrome (MetS) is a cluster of metabolic traits associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. Central obesity and insulin resistance are thought to play key roles in the pathogenesis of the MetS. The MetS has a significant genetic component, and therefore linkage analysis, candidate gene approach, and genome-wide association (GWA) studies have been applied in the search of gene variants for the MetS. A few variants have been identified, located mostly in or near genes regulating lipid metabolism. GWA studies for the individual components of the MetS have reported several loci having pleiotropic effects on multiple MetS-related traits. Genetic studies have provided so far only limited evidence for a common genetic background of the MetS. Epigenetic factors (DNA methylation and histone modification) are likely to play important roles in the pathogenesis of the MetS, and they might mediate the effects of environmental exposures on the risk of the MetS. Further research is needed to clarify the role of genetic variation and epigenetic mechanisms in the development of the MetS.
Corn breeding has been historically remarkably successful. Much research has investigated optimal breeding procedures, which are detailed here. A smaller effort has been put into identifying useful genetic resources for maize and how to best use them, but results from long-term base broadening effor...
Snyder, Alexandra; Makarov, Vladimir; Hellmann, Matthew; Rizvi, Naiyer; Merghoub, Taha; Wolchok, Jedd D; Chan, Timothy A
Immune checkpoint blockade therapy is changing oncology by improving the outcome of patients with advanced malignancies. Our research has revealed the genetic features of tumors present in patients who initiate a successful antitumor immune response and derive clinical benefit from immune checkpoint blockade therapy versus non-responders. PMID:26451299
The "Central Dogma" of genetics states that one gene, located in a DNA molecule, is ultimately translated into one protein. As important as this idea is, many teachers shy away from teaching the actual mechanism of gene translation, and many students find the concepts abstract and inaccessible. This article describes a unit, called Genetics…
McGillivray, Barbara C.
Genetic concerns and indications for prenatal diagnosis are first recognized by the family physician. Review of personal, pregnancy and family history may indicate concerns beyond that of advanced maternal age. Amniocentesis is still the most frequently used modality for prenatal diagnosis, but detailed ultrasound is valuable for structural abnormalities, and chorionic villus sampling is now being tested as an alternative to amniocentesis. PMID:21267316
Rosellini, D.; Veronesi, F.
The application of genetic engineering to plants has provided genetically modified plants (GMPs, or transgenic plants) that are cultivated worldwide on increasing areas. The most widespread GMPs are herbicide-resistant soybean and canola and insect-resistant corn and cotton. New GMPs that produce vaccines, pharmaceutical or industrial proteins, and fortified food are approaching the market. The techniques employed to introduce foreign genes into plants allow a quite good degree of predictability of the results, and their genome is minimally modified. However, some aspects of GMPs have raised concern: (a) control of the insertion site of the introduced DNA sequences into the plant genome and of its mutagenic effect; (b) presence of selectable marker genes conferring resistance to an antibiotic or an herbicide, linked to the useful gene; (c) insertion of undesired bacterial plasmid sequences; and (d) gene flow from transgenic plants to non-transgenic crops or wild plants. In response to public concerns, genetic engineering techniques are continuously being improved. Techniques to direct foreign gene integration into chosen genomic sites, to avoid the use of selectable genes or to remove them from the cultivated plants, to reduce the transfer of undesired bacterial sequences, and make use of alternative, safer selectable genes, are all fields of active research. In our laboratory, some of these new techniques are applied to alfalfa, an important forage plant. These emerging methods for plant genetic engineering are briefly reviewed in this work.
Genetic studies have helped us gain basic knowledge of the Tamarix invasion. We now have a better understanding of the species identities involved in the invasion, their evolutionary relationships, and the contribution of hybridization to the invasion. This information can be used to enhance the eff...
Good progress is being made on genetics and genomics of sugar beet, however it is in process and the tools are now being generated and some results are being analyzed. The GABI BeetSeq project released a first draft of the sugar beet genome of KWS2320, a dihaploid (see http://bvseq.molgen.mpg.de/Gen...
Atkins, Thomas; Roderick, Joyce
In order for students to understand genetics and evolution, they must first understand the structure of the DNA molecule. The function of DNA proceeds from its unique structure, a structure beautifully adapted for information storage, transcription, translation into amino acid sequences, replication, and time travel. The activity described in this…
Seager, Robert D.
In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…
Genetic research of the sunflower research unit, USDA-ARS, in Fargo, ND, was discussed in a presentation to a group of Canadian producers, industry representatives, and scientists. Because this was an international audience, I introduced the audience to ARS and the structure of the sunflower unit, a...
MacClintic, Scott D.; Nelson, Genevieve M.
Bacterial transformation is a commonly used technique in genetic engineering that involves transferring a gene of interest into a bacterial host so that the bacteria can be used to produce large quantities of the gene product. Although several kits are available for performing bacterial transformation in the classroom, students do not always…
A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed usingeight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Md...
Edenberg, Howard J; Foroud, Tatiana
Multiple lines of evidence strongly indicate that genetic factors contribute to the risk for alcohol use disorders (AUD). There is substantial heterogeneity in AUD, which complicates studies seeking to identify specific genetic factors. To identify these genetic effects, several different alcohol-related phenotypes have been analyzed, including diagnosis and quantitative measures related to AUDs. Study designs have used candidate gene analyses, genetic linkage studies, genomewide association studies (GWAS), and analyses of rare variants. Two genes that encode enzymes of alcohol metabolism have the strongest effect on AUD: aldehyde dehydrogenase 2 and alcohol dehydrogenase 1B each has strongly protective variants that reduce risk, with odds ratios approximately 0.2-0.4. A number of other genes important in AUD have been identified and replicated, including GABRA2 and alcohol dehydrogenases 1B and 4. GWAS have identified additional candidates. Rare variants are likely also to play a role; studies of these are just beginning. A multifaceted approach to gene identification, targeting both rare and common variations and assembling much larger datasets for meta-analyses, is critical for identifying the key genes and pathways important in AUD.
Spivak, Eduardo D.
Neohelice granulata (previously known as Chasmagnathus granulata and C. granulatus) is a burrowing semiterrestrial crab found in the intertidal zone of estuaries, salt marshes and mangroves of the South-western Atlantic Ocean. Beginning in the late 1989s, an explosion of publications appeared in international journals dealing with its ecology, physiology, toxicology and behavior. A bibliometric analysis using the Scopus database allowed detecting 309 papers that deal with this species during the period 1986-2009. The number of papers per year increased continuously, reaching a mean annual value of 22.6 during the last 5 years; a great majority of them were authored by researchers from Argentina and Brazil. Neohelice granulata has become now one of the most studied crab species, after Carcinus maenas, Callinectes sapidus, Scylla serrata and Cancer pagurus and C. magister, and it can be considered as an emergent animal model for biochemical, physiological and ecological research.
Brookes, J I; Rochette, Rémy
Phenotypic plasticity has been the object of considerable interest over the past several decades, but in few cases are mechanisms underlying plastic responses well understood. For example, it is unclear whether predator-induced changes in gastropod shell morphology represent an active physiological response or a by-product of reduced feeding. We address this question by manipulating feeding and growth of intertidal snails, Littorina obtusata, using two approaches: (i) exposure to predation cues from green crabs Carcinus maenas and (ii) reduced food availability, and quantifying growth in shell length, shell mass, and body mass, as well as production of faecal material and shell micro-structural characteristics (mineralogy and organic fraction) after 96 days. We demonstrate that L. obtusata actively increases calcification rate in response to predation threat, and that this response entails energetic and developmental costs. That this induced response is not strictly tied to the animal's behaviour should enhance its evolutionary potential.
Cardoso, P G; Pereira, E; Duarte, A C; Azeiteiro, U M
The main goal of this study was to assess temporal mercury variations along an estuarine food web to evaluate the mercury contamination level of the system and the risks that humans are exposed to, due to mercury biomagnification. The highest mercury concentrations in the sediments and primary producers (macrophytes) were observed during winter sampling. Instead, the highest mercury concentrations in the water, suspended particulate matter as well as in the zooplanktonic and suprabenthic communities were observed during summer sampling. Evidences of mercury biomagnification along the food web were corroborated by the positive biomagnification factors, particularly for omnivorous macrobenthic species. Comparing the mercury levels at distinct components with several environmental quality criteria it suggests that sediments, water and edible species (e.g., bivalve Scrobicularia plana and the crustacean Carcinus maenas) presented higher mercury levels than the values accepted by legislation which represent a matter of concern for the environment and human health.
Nunan, Linda M; Poulos, Bonnie T; Navarro, Solangel; Redman, Rita M; Lightner, Donald V
Black tiger shrimp Penaeus monodon, European shore crab Carcinus maenas and spiny lobster Panulirus spp. can be affected by milky hemolymph syndrome (MHS). Four rickettsia-like bacteria (RLB) isolates of MHS originating from 5 geographical areas have been identified to date. The histopathology of the disease was characterized and a multiplex PCR assay was developed for detection of the 4 bacterial isolates. The 16S rRNA gene and 16-23S rRNA intergenic spacer region (ISR) were used to examine the phylogeny of the MHS isolates. Although the pathology of this disease appears similar in the various different hosts, sequencing and examination of the phylogenetic relationships reveal 4 distinct RLB involved in the infection process.
Balanids are the numerically dominant epibionts on mussel beds in the Wadden Sea. Near the island of Sylt (German Bight, North Sea), Semibalanus balanoides dominated intertidally and Balanus crenatus subtidally. Field experiments were conducted to test the effects of predation on the density of barnacle recruits. Subtidally, predator exclusion resulted in significantly increased abundances of B. crenatus, while predator exclusion had no significant effects on the density of S. balanoides intertidally. It is suggested that recruitment of B. crenatus to subtidal mussel beds is strongly affected by adult shore crabs ( Carcinus maenas) and juvenile starfish ( Asterias rubens), whereas recruits of S. balanoides in the intertidal zone are mainly influenced by grazing and bulldozing of the very abundant periwinkle Littorina littorea, which is rare subtidally. Thus, not only do the barnacle species differ between intertidal and subtidal mussel beds, but the biotic control factors do so as well.
Meusy, J J; Martin, G; Soyez, D; van Deijnen, J E; Gallo, J M
Immunochemical investigations, using dot immunobinding assay (DIA) and enzyme-linked immunosorbent assay (ELISA), and immunocytochemical studies reveal the following new information about crustacean vitellogenesis-inhibiting hormone (VIH): (1) The structure of VIH is sufficiently different from that of the other sinus gland neuropeptides to allow a selective recognition of VIH by polyclonal antibodies. (2) From immunochemical criteria, VIH does not seem strictly species specific. The antisera raised against VIH of Homarus americanus cross-react with sinus gland extracts of Palaemonetes varians, Palaemon serratus, Macrobrachium rosenbergii, Carcinus maenas, and Porcellio dilatatus. (3) In the sinus gland of H. americanus, VIH immunoreactivity is localized mainly in electron-dense granules of medium size (110-185 nm in diameter) while, in P. dilatatus, the labeling is mostly on the largest granules (200-270 nm in diameter).
Smallegange, Isabel M; van der Meer, Jaap; Sabelis, Maurice W
1. Ideal-free distribution theory assumes that in a patchy environment foragers maximize fitness and hence their feeding rate by balancing gains from more food against losses from more competition. Ultimately, individuals cannot increase their feeding rate by moving to another patch and they distribute themselves over patches in proportion to prey density per patch. 2. In our experiments with shore crabs Carcinus maenas foraging on two adjacent patches with mussels Mytilus edulis, the implicit assumption of ideal-free distribution theory that catch should match time spent in a prey patch is not met, however. Despite aggregating their attack where it is most profitable shore crabs distributed themselves homogeneously across mussel patches: they 'take away' the prey caught and consume it elsewhere to reduce interference. 3. Thus, predator distributions can be quite different from prey-attack distributions. This is important because the latter is shown to be decisive for persistence of predator and prey populations in ecological models.
Nance, Walter E
Deafness is an etiologically heterogeneous trait with many known genetic and environmental causes. Genetic factors account for at least half of all cases of profound congenital deafness, and can be classified by the mode of inheritance and the presence or absence of characteristic clinical features that may permit the diagnosis of a specific form of syndromic deafness. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing, as well as many unexpected surprises. Although a large number of genes can clearly cause deafness, recessive mutations at a single locus, GJB2 or Connexin 26, account for more than half of all genetic cases in some, but not all populations. The high frequency may well be related to the greatly improved social, educational, and economic circumstances of the deaf that began with the introduction of sign language 300-400 years ago, along with a high frequency of marriages among the deaf in many countries. Similar mechanisms may account for the rapid fixation of genes for speech after the first mutations appeared 50,000-100,000 years ago. Molecular studies have shown that mutations involving several different loci may be the cause for the same form of syndromic deafness. Even within a single locus, different mutations can have profoundly different effects, leading to a different pattern of inheritance in some cases, or isolated hearing loss without the characteristic syndromic features in others. Most cases of genetic deafness result from mutations at a single locus, but an increasing number of examples are being recognized in which recessive mutations at two loci are involved. For example, digenic interactions are now known to be an important cause of deafness in individuals who carry a single mutation at the Connexin 26 locus along with a deletion involving the functionally related Connexin 30 locus. This mechanism complicates genetic evaluation and counseling, but
Chen, Chi-Hua; Fiecas, Mark; Gutiérrez, E. D.; Panizzon, Matthew S.; Eyler, Lisa T.; Vuoksimaa, Eero; Thompson, Wesley K.; Fennema-Notestine, Christine; Hagler, Donald J.; Jernigan, Terry L.; Neale, Michael C.; Franz, Carol E.; Lyons, Michael J.; Fischl, Bruce; Tsuang, Ming T.; Dale, Anders M.; Kremen, William S.
Animal data show that cortical development is initially patterned by genetic gradients largely along three orthogonal axes. We previously reported differences in genetic influences on cortical surface area along an anterior-posterior axis using neuroimaging data of adult human twins. Here, we demonstrate differences in genetic influences on cortical thickness along a dorsal-ventral axis in the same cohort. The phenomenon of orthogonal gradations in cortical organization evident in different structural and functional properties may originate from genetic gradients. Another emerging theme of cortical patterning is that patterns of genetic influences recapitulate the spatial topography of the cortex within hemispheres. The genetic patterning of both cortical thickness and surface area corresponds to cortical functional specializations. Intriguingly, in contrast to broad similarities in genetic patterning, two sets of analyses distinguish cortical thickness and surface area genetically. First, genetic contributions to cortical thickness and surface area are largely distinct; there is very little genetic correlation (i.e., shared genetic influences) between them. Second, organizing principles among genetically defined regions differ between thickness and surface area. Examining the structure of the genetic similarity matrix among clusters revealed that, whereas surface area clusters showed great genetic proximity with clusters from the same lobe, thickness clusters appear to have close genetic relatedness with clusters that have similar maturational timing. The discrepancies are in line with evidence that the two traits follow different mechanisms in neurodevelopment. Our findings highlight the complexity of genetic influences on cortical morphology and provide a glimpse into emerging principles of genetic organization of the cortex. PMID:24082094
Discusses the claims for a brave new world of genetic manipulation" and concludes that if we could agree upon applying genetic (or any other effective) remedies to global problems we probably would need no rescourse to them. Suggests that effective methods of preventing genetic disease are prevention of mutations and detection and…
... Facebook Share on Twitter Your Guide to Understanding Genetic Conditions Search MENU Toggle navigation Home Page Search ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions thanatophoric dysplasia thanatophoric dysplasia Enable ...
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... a combination of genetic variations and environmental factors influence the development of this complex condition. Asperger syndrome ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...
... Share: Email Facebook Twitter Home Health Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health ... with a rearrangement (translocation) of genetic material between chromosomes 17 and 22. This translocation, written as t( ...
Kottow, Miguel H
Genetics research has shown enormous developments in recent decades, although as yet with only limited clinical application. Bioethical analysis has been unable to deal with the vast problems of genetics because emphasis has been put on the principlism applied to both clinical and research bioethics. Genetics nevertheless poses its most complex moral dilemmas at the public level, where a social brand of ethics ought to supersede the essentially interpersonal perspective of principlism. A more social understanding of ethics in genetics is required to unravel issues such as research and clinical explorations, ownership and patents, genetic manipulation, and allocation of resources. All these issues require reflection based on the requirements of citizenry, consideration of common assets, and definition of public policies in regulating genetic endeavors and protecting the society as a whole Bioethics has privileged the approach to individual ethical issues derived from genetic intervention, thereby neglecting the more salient aspects of genetics and social ethics.
Rapid technological advances in genetic analysis have revealed the genetic background of various diseases. Elucidation of the genes responsible for a disease enables better clinical management of the disease and helps to develop targeted drugs. Also, early diagnosis and management of at-risk family members can be made by identification of a genetic disease in the proband. On the other hand, genetic issues often cause psychological distress to the family. To perform genetic testing appropriately and to protect patients and family members from any harm, guidelines for genetic testing were released from the alliance of Japanese genetics-related academic societies in 2003. As genetic testing is becoming incorporated into clinical practice more broadly, the guideline was revised and released by the Japanese Society of Medical Sciences in 2011. All medical professionals in Japan are expected to follow this guideline.
... more common in particular ethnic groups? Genetic Changes Mutations in the IKBKG gene cause incontinentia pigmenti . The ... About 80 percent of affected individuals have a mutation that deletes some genetic material from the IKBKG ...
... Brunner HG. Feingold syndrome: clinical review and genetic mapping. Am J Med Genet A. 2003 Nov 1; ... Brunner HG. MYCN haploinsufficiency is associated with reduced brain size and intestinal atresias in Feingold syndrome. Nat ...
Miller, Charles J J; Matute, Daniel R
Our understanding of how genetic changes underlie the evolution of traits is growing fast. Two new studies now show that changes in the same genetic loci can drive the evolution of the same trait in multiple Drosophila species.
Miller, P S
Author argues that the Americans with Disabilities Act prohibits discrimination against workers based on their genetic makeup. He also examines state legislation and recently proposed federal legislation prohibiting genetic discrimination.
... MKS Related Information How are genetic conditions and genes named? Additional Information & Resources MedlinePlus (3 links) Health Topic: Brain Malformations Health Topic: Kidney Cysts Health Topic: Neural Tube Defects Genetic and Rare Diseases Information Center (1 link) ...
Mertens, Thomas R.; Robinson, Sandra K.
Describes different sources of readings for understanding issues and concepts of genetic engineering. Broad categories of reading materials are: concerns about genetic engineering; its background; procedures; and social, ethical and legal issues. References are listed. (PS)
The need for education of nurses in genetics was articulated more than 25 years ago. This article reviews the knowledge of practicing nurses about genetics as well as the content of genetics in nursing curricula. Implementation of federal legislation that mandated increased availability of genetic services and genetics education provided support for the examination of genetics content in curricula for health professionals, including nurses, and for the development of model programs to expand this content. Recent efforts to begin to develop a pool of nurse faculty who are well prepared in genetics will be described, as well as programs to provide the necessary content through continuing-education efforts. These efforts are expected to substantially improve the capability of nurses to contribute more effectively in the delivery of genetic services. PMID:3177390
Oftedal, Gry; Parkkinen, Veli-Pekka
Synthetic biology research is often described in terms of programming cells through the introduction of synthetic genes. Genetic material is seemingly attributed with a high level of causal responsibility. We discuss genetic causation in synthetic biology and distinguish three gene concepts differing in their assumptions of genetic control. We argue that synthetic biology generally employs a difference-making approach to establishing genetic causes, and that this approach does not commit to a specific notion of genetic program or genetic control. Still, we suggest that a strong program concept of genetic material can be used as a successful heuristic in certain areas of synthetic biology. Its application requires control of causal context, and may stand in need of a modular decomposition of the target system. We relate different modularity concepts to the discussion of genetic causation and point to possible advantages of and important limitations to seeking modularity in synthetic biology systems.
... other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The ... Some people do not have apparent structural brain abnormalities but have some of the facial features ... deletion syndrome Genetic Testing Registry: Holoprosencephaly ...
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... Y Z Test Your Knowledge Talking Glossary of Genetic Terms Designed to help learners at any level ... in a reference paper. The Talking Glossary of Genetic Terms The Human Genome Defined by Professionals at ...
... Facebook Share on Twitter Your Guide to Understanding Genetic Conditions Search MENU Toggle navigation Home Page Search ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions Friedreich ataxia Friedreich ataxia Enable ...
... a History of Eye Disease, Do You Need Genetic Testing? Mar. 23, 2012 Thanks to news coverage, ... of breast or ovarian cancer. Physicians now use genetic tests to decide on treatment for some types ...
... 84 Alcohol Alert Number 84 Print Version The Genetics of Alcoholism Why can some people have a ... to an increased risk of alcoholism. Cutting-Edge Genetic Research in Alcoholism Although researchers already have made ...
A dictionary of more than 150 genetics-related terms written for healthcare professionals, developed to support the comprehensive, evidence-based, peer-reviewed PDQ cancer genetics information summaries.
The task of the genetic counselor who identifies genetic causes of mental retardation and assists families to understand risk of recurrence is described. Considered are chromosomal genetic disorders such as Down's syndrome, inherited disorders such as Tay-Sachs disease, identification by testing the amniotic fluid cells (amniocentresis) in time…
Caspari, E.W.; Scandalios, J.G.
This book presents articles on genetics and the advances made in this field. Topics covered include the following: recovery, repair, and mutagenesis in Schizosaccharomyces pombe; gene transfer in fungi; Y chromosome function and spermatogenesis in Drosophila hydei; recent developments in population genetics; and genetics, cytology and evolution of Gossypium.
Teaches genetics and inheritance using the characters from Sesame Street. Asks students to create a gene map of their favorite character and determine those genes passing to the next generation. Includes a genetics activity sheet and genetic information on the characters. (YDS)
de Souza, P V
This article analyses the Brasilia criminal regulation on genetic. Act No. 8.974/95 is examined because it regulates some criminal typologies on genetic engineering and assisted reproduction. Moreover, it presents information about the Act Project No. 149/97, on genetic discrimination.
Stewart, J. Bird
Claims that most instruction dealing with genetics is limited to sex education and personal hygiene. Suggests that the biology curriculum should begin to deal with other issues related to genetics, including genetic normality, prenatal diagnoses, race, and intelligence. Predicts these topics will begin to appear in British examination programs.…
... 23(3):157-65. Review. Citation on PubMed Bird TD. Genetic aspects of Alzheimer disease. Genet Med. ... on PubMed or Free article on PubMed Central Bird TD. Genetic factors in Alzheimer's disease. N Engl ...
Boone, C. Keith
Discusses the main ethical issues generated by the new genetics and suggests ways to think about them. Concerns include "playing God," violation of the natural order of the universe, and abuse of genetic technology. Critical distinctions for making difficult decisions about genetic engineering issues are noted. (DH)
Bevilacqua, Laura; Goldman, David
Impulsivity, defined as the tendency to act without foresight, comprises a multitude of constructs and is associated with a variety of psychiatric disorders. Dissecting different aspects of impulsive behaviour and relating these to specific neurobiological circuits would improve our understanding of the etiology of complex behaviours for which impulsivity is key, and advance genetic studies in this behavioural domain. In this review, we will discuss the heritability of some impulsivity constructs and their possible use as endophenotypes (heritable, disease-associated intermediate phenotypes). Several functional genetic variants associated with impulsive behaviour have been identified by the candidate gene approach and re-sequencing, and whole genome strategies can be implemented for discovery of novel rare and common alleles influencing impulsivity. Via deep sequencing an uncommon HTR2B stop codon, common in one population, was discovered, with implications for understanding impulsive behaviour in both humans and rodents and for future gene discovery.
Bevilacqua, Laura; Goldman, David
Impulsivity, defined as the tendency to act without foresight, comprises a multitude of constructs and is associated with a variety of psychiatric disorders. Dissecting different aspects of impulsive behaviour and relating these to specific neurobiological circuits would improve our understanding of the etiology of complex behaviours for which impulsivity is key, and advance genetic studies in this behavioural domain. In this review, we will discuss the heritability of some impulsivity constructs and their possible use as endophenotypes (heritable, disease-associated intermediate phenotypes). Several functional genetic variants associated with impulsive behaviour have been identified by the candidate gene approach and re-sequencing, and whole genome strategies can be implemented for discovery of novel rare and common alleles influencing impulsivity. Via deep sequencing an uncommon HTR2B stop codon, common in one population, was discovered, with implications for understanding impulsive behaviour in both humans and rodents and for future gene discovery. PMID:23440466
Klimeck, Gerhard; Salazar-Lazaro, Carlos H.; Stoica, Adrian; Cwik, Thomas
The quantum mechanical functionality of nanoelectronic devices such as resonant tunneling diodes (RTDs), quantum well infrared-photodetectors (QWIPs), quantum well lasers, and heterostructure field effect transistors (HFETs) is enabled by material variations on an atomic scale. The design and optimization of such devices requires a fundamental understanding of electron transport in such dimensions. The Nanoelectronic Modeling Tool (NEMO) is a general-purpose quantum device design and analysis tool based on a fundamental non-equilibrium electron transport theory. NEW was combined with a parallelized genetic algorithm package (PGAPACK) to evolve structural and material parameters to match a desired set of experimental data. A numerical experiment that evolves structural variations such as layer widths and doping concentrations is performed to analyze an experimental current voltage characteristic. The genetic algorithm is found to drive the NEMO simulation parameters close to the experimentally prescribed layer thicknesses and doping profiles. With such a quantitative agreement between theory and experiment design synthesis can be performed.
Jin, Huilin; Ralston, Stuart H
Genetic factors play an important role in regulating bone mineral density and other phenotypes relevant to the pathogenesis of osteoporosis such as ultrasound properties of bone, skeletal geometry, and bone turnover. Progress has been made in identifying quantitative traits for regulation of bone mineral density by linkage studies in man and mouse, but relatively few causal genes have been identified. Dramatic progress has been made in identifying the genes responsible for monogenic bone diseases and it appears that polymorphisms in many of these genes also play a role in regulating bone mineral density in the general population. Advances in knowledge about the genetic basis of osteoporosis and other bone diseases offer the prospect of developing new markers for assessment of fracture risk and the identification of novel molecular targets for the design of new drug treatments for osteoporosis.
Malyshev, Denis A; Romesberg, Floyd E
All biological information, since the last common ancestor of all life on Earth, has been encoded by a genetic alphabet consisting of only four nucleotides that form two base pairs. Long-standing efforts to develop two synthetic nucleotides that form a third, unnatural base pair (UBP) have recently yielded three promising candidates, one based on alternative hydrogen bonding, and two based on hydrophobic and packing forces. All three of these UBPs are replicated and transcribed with remarkable efficiency and fidelity, and the latter two thus demonstrate that hydrogen bonding is not unique in its ability to underlie the storage and retrieval of genetic information. This Review highlights these recent developments as well as the applications enabled by the UBPs, including the expansion of the evolution process to include new functionality and the creation of semi-synthetic life that stores increased information.
Zhao, Hongyu; Speed, T.P.
Various genetic map functions have been proposed to infer the unobservable genetic distance between two loci from the observable recombination fraction between them. Some map functions were found to fit data better than others. When there are more than three markers, multilocus recombination probabilities cannot be uniquely determined by the defining property of map functions, and different methods have been proposed to permit the use of map functions to analyze multilocus data. If for a given map function, there is a probability model for recombination that can give rise to it, then joint recombination probabilities can be deduced from this model. This provides another way to use map functions in multilocus analysis. In this paper we show that stationary renewal processes give rise to most of the map functions in the literature. Furthermore, we show that the interevent distributions of these renewal processes can all be approximated quite well by gamma distributions. 43 refs., 4 figs.
Goodenberger, McKinsey L; Jenkins, Robert B
Gliomas make up approximately 30% of all brain and central nervous system tumors and 80% of all malignant brain tumors. Despite the frequency of gliomas, the etiology of these tumors remains largely unknown. Diffuse gliomas, including astrocytomas and oligodendrogliomas, belong to a single pathologic class but have very different histologies and molecular etiologies. Recent genomic studies have identified separate molecular subtypes within the glioma classification that appear to correlate with biological etiology, prognosis, and response to therapy. The discovery of these subtypes suggests that molecular genetic tests are and will be useful, beyond classical histology, for the clinical classification of gliomas. While a familial susceptibility to glioma has been identified, only a small percentage of gliomas are thought to be due to single-gene hereditary cancer syndromes. Through the use of linkage studies and genome-wide association studies, multiple germline variants have been identified that are beginning to define the genetic susceptibility to glioma.
Few developments are likely to affect human beings more profoundly in the long run than the discoveries resulting from advances in modern genetics. Although the developments in genetic technology promise to provide many additional benefits, their application to genetic screening poses ethical, social, and legal questions, many of which are rooted in issues of privacy and confidentiality. The ethical, practical, and legal ramifications of these and related questions are explored in depth. The broad range of topics includes: the privacy and confidentiality of genetic information; the challenges to privacy and confidentiality that may be projected to result from the emerging genetic technologies; the role of informed consent in protecting the confidentiality of genetic information in the clinical setting; the potential uses of genetic information by third parties; the implications of changes in the health care delivery system for privacy and confidentiality; relevant national and international developments in public policies, professional standards, and laws; recommendations; and the identification of research needs.
Solomon, Sheila; Whitcomb, David C
With novel genetic technologies available, there is a paradigm shift in the way that risk assessments, diagnoses,and therapies for genetic susceptibility syndromes are addressed. Hereditary pancreatitis is among these conditions, for which genetic counseling and next generation sequencing, help families better understand, cope with and live healthier lives. Identifying a genetic etiology to a condition formally believed to be solely environmentally induced can alter the path for treatment for many patients. This finding introduces the concept of gene-environment interactions in human disease and the relationship between genetic predisposition and exposure risk in disease development. The genetic counseling process is complex with medical explanations, psychosocial issues relating to coping with diagnosis, potential future health problems, recurrence risks and family planning. These sometimes difficult conversations can be facilitated by a genetic counselor as a member of the multidisciplinary team. This chapter addresses the intricate medical and psychosocial issues that can arise in the setting of treating patients with hereditary pancreatitis.
Clinical geneticists and genetic counselors provide diagnosis and counseling for genetic disorders affecting every organ system and every age group. Genetic counselors are more focused on informing patients and families about the inheritance of a genetic disorder and providing recurrence risk counseling, support and information about a diagnosis and reproductive options. Medical geneticists may also share some of these roles in addition to establishing a diagnosis and providing medical management. Medical Geneticists receive training in ACGME-accredited residency programs and are certified by the American Board of Medical Genetics. Genetic counseling is a masters degree program and certification is granted by the American Board of Genetic Counseling. When a patient/family is referred to a Clinical Geneticist, they may expect a thorough evaluation in an effort to establish a diagnosis that may provide information about etiology, prognosis, therapy and recurrence risk.
staining for major basic protein in esophageal tissue (arrowheads) in WT than IL21R-/- mice (A) is quantified morphometrically in (B). Quantitative PCR... morphometric analysis was used to measure IL21 receptor expression in patient esophageal biopsies. RESULTS: A number of genetic variants on chromosome 4q26-27...variants in the locus. Immunofluorescent microscopy and morphometric analysis demonstrate a marked increase in IL21 receptor- expressing cells within
in esophageal tissue (arrowheads) in WT than IL21R-/- mice (A) is quantified morphometrically in (B). Quantitative PCR (C) for esophageal...microscopy and morphometric analysis was used to measure IL21 receptor expression in patient esophageal biopsies. RESULTS: A number of genetic variants...most highly associated variants in the locus. Immunofluorescent microscopy and morphometric analysis demonstrate a marked increase in IL21 receptor
Hardelin, Jean-Pierre; Denoyelle, Françoise; Levilliers, Jacqueline; Simmler, Marie-Christine; Petit, Christine
This article outlines recent advances in explaining hereditary deafness in molecular terms, focusing on isolated (i.e. nonsyndromic) hearing loss. The number of genes identified (36 to date) is growing rapidly. However, difficulties inherent in genetic linkage analysis, coupled with the possible involvement of environmental causes, have so far prevented the characterization of the main genes causative or predisposing to the late-onset forms of deafness.
Charlesworth, Brian; Charlesworth, Deborah
Darwin's theory of natural selection lacked an adequate account of inheritance, making it logically incomplete. We review the interaction between evolution and genetics, showing how, unlike Mendel, Darwin's lack of a model of the mechanism of inheritance left him unable to interpret his own data that showed Mendelian ratios, even though he shared with Mendel a more mathematical and probabilistic outlook than most biologists of his time. Darwin's own "pangenesis" model provided a mechanism for generating ample variability on which selection could act. It involved, however, the inheritance of characters acquired during an organism's life, which Darwin himself knew could not explain some evolutionary situations. Once the particulate basis of genetics was understood, it was seen to allow variation to be passed intact to new generations, and evolution could then be understood as a process of changes in the frequencies of stable variants. Evolutionary genetics subsequently developed as a central part of biology. Darwinian principles now play a greater role in biology than ever before, which we illustrate with some examples of studies of natural selection that use DNA sequence data and with some recent advances in answering questions first asked by Darwin.
Cohen-Solal, M; de Vernejoul, M C
Osteoporosis is a multifactorial disease involving genetic component and several environmental factors. Some rare diseases that are associated with osteoporosis such as Lobstein disease or the "pseudoglial osteoporosis" syndrom are monogenetic. Nevertheless common osteoporosis is a polygenic affection resulting from the interaction between the polymorphism of different genes and the environmental factors. The genetic component of osteoporosis encompasses roughly 60 to 70% of bone mineral density, whereas the effect on fracture risk seems lower because of the importance of other environmental factors as falls. Many polymorphisms of candidate genes involved in the regulation of bone mass have been correlated to bone density. It is likely that many genes participate to the regulation of bone density although the existence of a major gene is highly suspected. Moreover linkage analysis after genome-wide search in populations with severe osteoporosis has focused on some regions of interest (QTL) on the chromosomes. This will allow to localize one or more specific genes. The current genetic studies on different populations affected by osteoporosis or not will be useful in order to better predict the fracture risk in association with bone density and biochemical markers of bone turnover. Moreover, this will lead to the development of new treatments of osfeoporosis and will help to adapt the therapy for individual patients.
Pichi, Francesco; Lembo, Andrea; Serafino, Massimiliano; Nucci, Paolo
Congenital cataract is a type of cataract that presents at birth or during early childhood, and it is one of the most easily treatable causes of visual impairment and blindness during infancy, with an estimated prevalence of 1-6 cases per 10,000 live births. Approximately 50% of all congenital cataract cases may have a genetic cause, and such cases are quite heterogeneous. Although congenital nuclear cataract can be caused by multiple factors, genetic mutation remains the most common cause. All three types of Mendelian inheritance have been reported for cataract; however, autosomal dominant transmission seems to be the most frequent. The transparency and high refractive index of the lens are achieved by the precise architecture of fiber cells and homeostasis of the lens proteins in terms of their concentrations, stabilities, and supramolecular organization. Research on hereditary congenital cataract has led to the identification of several classes of candidate genes that encode proteins such crystallins, lens-specific connexins, aquaporin, cytoskeletal structural proteins, and developmental regulators. In this review, we highlight the identified genetic mutations that account for congenital nuclear cataract.
Ribas, A; Butterfield, L H; Economou, J S
Genetic immunization refers to treatment strategies where gene transfer methods are used to generate immune responses against cancer. Our growing knowledge of the mechanisms regulating the initiation and maintenance of cytotoxic immune responses has provided the rationale for the design of several genetic immunization strategies. Tumor cells have been gene-modified to express immune stimulatory genes and are then administered as tumor vaccines, in an attempt to overcome tumor cell ignorance by the immune system. With the description of well-characterized tumor antigens, multiple strategies have been proposed mainly aimed at optimal tumor antigen presentation by antigen-presenting cells (APC). Among APC, the dendritic cells have been recognized as the most powerful cells in this class, and have become the target for introducing tumor antigen genes to initiate antitumor immune responses. The detailed knowledge of how the immune system can be activated to specifically recognize tumor antigens, and the mechanisms involved in the control of this immune response, provide the basis for modern genetic immunization strategies for cancer treatment.
Panoutsopoulou, Kalliope; Zeggini, Eleftheria
Osteoarthritis (OA), the most common form of arthritis, is a highly debilitating disease of the joints and can lead to severe pain and disability. There is no cure for OA. Current treatments often fail to alleviate its symptoms leading to an increased demand for joint replacement surgery. Previous epidemiological and genetic research has established that OA is a multifactorial disease with both environmental and genetic components. Over the past 6 years, a candidate gene study and several genome-wide association scans (GWAS) in populations of Asian and European descent have collectively established 15 loci associated with knee or hip OA that have been replicated with genome-wide significance, shedding some light on the aetiogenesis of the disease. All OA associated variants to date are common in frequency and appear to confer moderate to small effect sizes. Some of the associated variants are found within or near genes with clear roles in OA pathogenesis, whereas others point to unsuspected, less characterised pathways. These studies have also provided further evidence in support of the existence of ethnic, sex, and joint specific effects in OA and have highlighted the importance of expanded and more homogeneous phenotype definitions in genetic studies of OA.
Preimplantational Genetics Diagnosis (PGD) is requested by geneticists and reproductive specialists. Usually geneticists ask for PGD because one or both members of the couple have an increased genetic risk for having an affected offspring. On the other hand, reproductive specialists ask for embryo aneuploidy screening (PGS) to assures an euploid embryo transfer, with the purpose to achieve an ongoing pregnancy, although the couple have normal karyotypes. As embryonic aneuploidies are responsible for pre and post implantation abortions, it is logical to considerer that the screening of the embryonic aneuploidies prior to embryo transfer could improve the efficiency of the in vitro fertilization procedures. Nevertheless, it is still premature to affirm this until well-designed clinical trials were done, especially in women of advanced age where the rate of embryos with aneuploidies is much greater. Although the indications of PGD are similar to conventional prenatal diagnosis (PND), PGD has less ethical objections than the PND. As with the PGD/PGS results only unaffected embryos are transferred, both methods can avoid the decision to interrupt the pregnancy due to a genetic problem; this makes an important difference when compared to conventional prenatal diagnosis. PMID:24764761
Preimplantational Genetics Diagnosis (PGD) is requested by geneticists and reproductive specialists. Usually geneticists ask for PGD because one or both members of the couple have an increased genetic risk for having an affected offspring. On the other hand, reproductive specialists ask for embryo aneuploidy screening (PGS) to assures an euploid embryo transfer, with the purpose to achieve an ongoing pregnancy, although the couple have normal karyotypes. As embryonic aneuploidies are responsible for pre and post implantation abortions, it is logical to considerer that the screening of the embryonic aneuploidies prior to embryo transfer could improve the efficiency of the in vitro fertilization procedures. Nevertheless, it is still premature to affirm this until well-designed clinical trials were done, especially in women of advanced age where the rate of embryos with aneuploidies is much greater. Although the indications of PGD are similar to conventional prenatal diagnosis (PND), PGD has less ethical objections than the PND. As with the PGD/PGS results only unaffected embryos are transferred, both methods can avoid the decision to interrupt the pregnancy due to a genetic problem; this makes an important difference when compared to conventional prenatal diagnosis.
Jacoby, Daniel; McKenna, William J
During the past two decades, numerous disease-causing genes for different cardiomyopathies have been identified. These discoveries have led to better understanding of disease pathogenesis and initial steps in the application of mutation analysis in the evaluation of affected individuals and their family members. As knowledge of the genetic abnormalities, and insight into cellular and organ biology has grown, so has appreciation of the level of complexity of interaction between genotype and phenotype across disease states. What were initially thought to be one-to-one gene-disease correlates have turned out to display important relational plasticity dependent in large part on the genetic and environmental backgrounds into which the genes of interest express. The current state of knowledge with regard to genetics of cardiomyopathy represents a starting point to address the biology of disease, but is not yet developed sufficiently to supplant clinically based classification systems or, in most cases, to guide therapy to any significant extent. Future work will of necessity be directed towards elucidation of the biological mechanisms of both rare and common gene variants and environmental determinants of plasticity in the genotype-phenotype relationship with the ultimate goal of furthering our ability to identify, diagnose, risk stratify, and treat this group of disorders which cause heart failure and sudden death in the young.
Alsobrook, J P; Pauls, D L
As is evident from this brief review, the genetic study of violence is maturing at an ever-increasing rate; much more work is needed to examine specific molecular genetic markers and their associated phenotypes, particularly in subjects with juvenile onset. It is also becoming clear that more work is needed to help delineate the specific phenotypes that are being transmitted within families. It is unlikely that we will find a gene or genes that are both necessary and sufficient for the manifestation of aggression and violence. It is more likely that specific genes will be associated with discrete factors that either increase the risk for the expression of violence or that are components of the violent phenotype. Thus, in addition to continuing research that examines the role of specific genetic factors in the manifestation of violence, more work is needed that will help further develop the nosology of violence and related behaviors. As noted previously, an understanding of the inherited phenotype is critical in the study of any disorder. It is especially important in the study of complex behaviors such as violence in which there may be several behavioral components that comprise the complete diagnostic category.
Ishihara, M; Ohno, S
To investigate the genetic influences underlying the development of sarcoidosis, HLA class II genotyping was performed in Japanese patients with sarcoidosis and healthy controls using the PCR-RFLP method. The frequencies of both DR52 group antigen-associated alleles (HLA-DRB1*11, -DRB1*12 and -DRB1*14) and DRB1*08 alleles were higher in the patient group, suggesting that the common, specific amino acid residue on the DRB1 molecule of these alleles may determine susceptibility to sarcoidosis. Alternatively, it is possible that another susceptibility gene, linked to these DRB1 alleles, exists within the MHC region. We screened the TNFA, TNFB, HSP70-1 and Hum70t genes around the class III region, as well as the HLA-DMA and -DMB genes in the class II region, for genetic polymorphism in sarcoidosis. None of these genes suggested a susceptibility to sarcoidosis. These studies support the thesis that one of the major genetic factors controlling the development of sarcoidosis is located within the DRB1 locus in the HLA class II region.
Del Vecchio, F; Filareto, A; Spitalieri, P; Sangiuolo, F; Novelli, G
Cellular genetic therapy is the ultimate frontier for those pathologies that are consequent to a specific nonfunctional cellular type. A viable cure for there kinds of diseases is the replacement of sick cells with healthy ones, which can be obtained from the same patient or a different donor. In fact, structures can be corrected and strengthened with the introduction of undifferentiated cells within specific target tissues, where they will specialize into the desired cellular types. Furthermore, consequent to the recent results obtained with the transdifferentiation experiments, a process that allows the in vitro differentiation of embryonic and adult stem cells, it has also became clear that many advantages may be obtained from the use of stem cells to produce drugs, vaccines, and therapeutic molecules. Since stem cells can sustain lineage potentials, the capacity for differentiation, and better tolerance for the introduction of exogenous genes, they are also considered as feasible therapeutic vehicles for gene therapy. In fact, it is strongly believed that the combination of cellular genetic and gene therapy approaches will definitely allow the development of new therapeutic strategies as well as the production of totipotent cell lines to be used as experimental models for the cure of genetic disorders.
Chinnery, P.; Howell, N.; Andrews, R.; Turnbull, D.
The last decade has been an age of enlightenment as far as mitochondrial pathology is concerned. Well established nuclear genetic diseases, such as Friedreich's ataxia,12 Wilson disease,3 and autosomal recessive hereditary spastic paraplegia,4 have been shown to have a mitochondrial basis, and we are just starting to unravel the complex nuclear genetic disorders which directly cause mitochondrial dysfunction (table 1). However, in addition to the 3 billion base pair nuclear genome, each human cell typically contains thousands of copies of a small, 16.5 kb circular molecule of double stranded DNA (fig 1). Mitochondrial DNA (mtDNA) accounts for only 1% of the total cellular nucleic acid content. It encodes for 13 polypeptides which are essential for aerobic metabolism and defects of the mitochondrial genome are an important cause of human disease.9293 Since the characterisation of the first pathogenic mtDNA defects in 1988,513 over 50 point mutations and well over 100 rearrangements of the mitochondrial genome have been associated with human disease9495 (http://www.gen.emory.edu/mitomap.html). These disorders form the focus of this article. Keywords: mitochondrial DNA; mitochondrial disease; heteroplasmy; genetic counselling PMID:10874629
Urano, Tomohiko; Inoue, Satoshi
Highlights: • Single-nucleotide polymorphisms (SNPs) associated with osteoporosis were identified. • SNPs mapped close to or within VDR and ESR1 are associated with bone mineral density. • WNT signaling pathway plays a pivotal role in regulating bone mineral density. • Genetic studies will be useful for identification of new therapeutic targets. - Abstract: Osteoporosis is a skeletal disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue, which increases susceptibility to fractures. BMD is a complex quantitative trait with normal distribution and seems to be genetically controlled (in 50–90% of the cases), according to studies on twins and families. Over the last 20 years, candidate gene approach and genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs) that are associated with low BMD, osteoporosis, and osteoporotic fractures. These SNPs have been mapped close to or within genes including those encoding nuclear receptors and WNT-β-catenin signaling proteins. Understanding the genetics of osteoporosis will help identify novel candidates for diagnostic and therapeutic targets.
Alshahni, Mohamed Mahdi; Yamada, Tsuyoshi
Dermatophytes are a group of closely related fungi that nourish on keratinized materials for their survival. They infect stratum corneum, nails, and hair of human and animals, accounting the largest portion of fungi causing superficial mycoses. Huge populations are suffering from dermatophytoses, though the biology of these fungi is largely unknown yet. Reasons are partially attributed to the poor amenability of dermatophytes to genetic manipulation. However, advancements in this field over the last decade made it possible to conduct genetic studies to satisfying extents. These included genetic transformation methods, indispensable molecular tools, i.e., dominant selectable markers, inducible promoter, and marker recycling system, along with improving homologous recombination frequency and gene silencing. Furthermore, annotated genome sequences of several dermatophytic species have recently been available, ensuring an optimal recruitment of the molecular tools to expand our knowledge on these fungi. In conclusion, the establishment of basic molecular tools and the availability of genomic data will open a new era that might change our understanding on the biology and pathogenicity of this fungal group.
One of the principle goals of neuroscience has been to understand the cellular basis of information processing and the plasticity that underlies learning and memory. Efforts in this area have mainly relied on electrical recording and optical imaging with chemical dyes. Over the last few years we and others have begun to develop genetically-encoded optical reporter "dyes" which should provide several important advantages over the classical methods for monitoring signal transmission in the nervous system. The advantages are that genetically-encoded reporters can be molecularly targeted a) to specific cell types via cell-specific promoters, and b) to specific subcellular compartments by peptides that are recognized by the protein sorting machinery of the cell. This makes it possible, in principle, to exclude signals from non-neuronal cells and to visualize selectively, in a brain region that contains many cell types with numerous kinds of synaptic connections, the activity of specific types of neurons (e.g. GABAergic interneurons) and specific synaptic elements (e.g. nerve terminals or dendrites), something that has hitherto not been possible. An additional advantage is that protein reporters may be rationally and irrationally "tuned" with mutations in functional domains known to control their dynamic range of operation. The general idea behind genetically-encoded reporters of cell signaling is to encode a protein that is either intrinsically fluorescent, or that can be labeled orthogonally with a fluorescent probe, and where the physiological signal changes fluorescence emission. I will describe recent progress employing both kinds of approaches.
Safranski, T J
Selection of boars by visual appraisal is the simplest and oldest method used by the swine industry. However, individual performance testing, and later use of computers to incorporate relatives' data and account for environmental variation, resulted in greater rate of improvement for economically important traits. Examples of molecular genetic tools that have increased improvement for some traits are also discussed. Accurate identification of genetic merit is increasingly important with widespread use of AI and resultant greater progeny number per sire. Historically, selection was to produce desirable progeny; however, with the majority of boars now housed in dedicated boar facilities, and the efficiency of sperm production being recorded, boar stud personnel are increasingly interested in selection of boars for fertility traits. Selecting boars that are lean and heavily muscled and have good semen parameters may be problematic, given the genetic relationships among the traits. Whereas conventional animal breeding methods will remain important, use of molecular tools will increase, and identification of a boar's fertility potential at birth will allow earlier and more efficient selection of high-fertility boars. Ability to achieve acceptable female reproduction with frozen semen would facilitate selection for longevity. However, this would lengthen the generation interval and could dilute selection intensity for other traits, as it requires indirect selection for semen freezability.
Charlesworth, Brian; Charlesworth, Deborah
Darwin's theory of natural selection lacked an adequate account of inheritance, making it logically incomplete. We review the interaction between evolution and genetics, showing how, unlike Mendel, Darwin's lack of a model of the mechanism of inheritance left him unable to interpret his own data that showed Mendelian ratios, even though he shared with Mendel a more mathematical and probabilistic outlook than most biologists of his time. Darwin's own “pangenesis” model provided a mechanism for generating ample variability on which selection could act. It involved, however, the inheritance of characters acquired during an organism's life, which Darwin himself knew could not explain some evolutionary situations. Once the particulate basis of genetics was understood, it was seen to allow variation to be passed intact to new generations, and evolution could then be understood as a process of changes in the frequencies of stable variants. Evolutionary genetics subsequently developed as a central part of biology. Darwinian principles now play a greater role in biology than ever before, which we illustrate with some examples of studies of natural selection that use DNA sequence data and with some recent advances in answering questions first asked by Darwin. PMID:19933231
The first part of this presentation is a tutorial level introduction to the principles of genetic search and models of simple genetic algorithms. The second half covers the combination of genetic algorithms with local search methods to produce hybrid genetic algorithms. Hybrid algorithms can be modeled within the existing theoretical framework developed for simple genetic algorithms. An application of a hybrid to geometric model matching is given. The hybrid algorithm yields results that improve on the current state-of-the-art for this problem.
Rice, William R
Experimental genetics with model organisms and mathematically explicit genetic theory are generally considered to be the major paradigms by which progress in genetics is achieved. Here I argue that this view is incomplete and that pivotal advances in genetics--and other fields of biology--are also made by synthesizing disparate threads of extant information rather than generating new information from experiments or formal theory. Because of the explosive expansion of information in numerous "-omics" data banks, and the fragmentation of genetics into numerous subdisciplines, the importance of the synthesis paradigm will likely expand with time.
... used on this page Frequently Asked Questions About Genetic Counseling What are genetic professionals and what do ... see a geneticist or other specialist? What are genetic professionals and what do they do? Genetics professionals ...
... used on this page Frequently Asked Questions About Genetic Disorders What are genetic disorders? A genetic disorder is a disease caused ... significant risk of developing the disease. . Geneticists group genetic disorders into three categories: Monogenetic disorders are caused ...
... are genetic conditions treated or managed? How are genetic conditions treated or managed? Many genetic disorders result ... out more about the treatment and management of genetic conditions: Links to information about the treatment of ...
Hodgkinson, Kathleen A; Murphy, Jillian; O’Neill, Sheri; Brzustowicz, Linda; Bassett, Anne S
Objective To review the role of genetic counselling for individuals with psychiatric illnesses. Method Using schizophrenia as an example and including updated information about a genetic subtype (22q deletion syndrome), we discuss the value of the genetic counselling process in psychiatry, with support from the literature and our clinical experience. Results Genetic counselling, the process through which knowledge about the genetics of illnesses is shared, provides information on the inheritance of illnesses and their recurrence risks; addresses the concerns of patients, their families, and their health care providers; and supports patients and their families dealing with these illnesses. For comprehensive medical management, this service should be available to all individuals with schizophrenia and their families. Conclusions New findings in the genetics of psychiatric illness may have important clinical implications for patients and their families. PMID:11280080
Hamada, Alaa J; Esteves, Sandro C; Agarwal, Ashok
Azoospermia due to obstructive and non-obstructive mechanisms is a common manifestation of male infertility accounting for 10-15% of such cases. Known genetic factors are responsible for approximately 1/3 of cases of azoospermia. Nonetheless, at least 40% of cases are currently categorized as idiopathic and may be linked to unknown genetic abnormalities. It is recommended that various genetic screening tests are performed in azoospermic men, given that their results may play vital role in not only identifying the etiology but also in preventing the iatrogenic transmission of genetic defects to offspring via advanced assisted conception techniques. In the present review, we examine the current genetic information associated with azoospermia based on results from search engines, such as PUBMED, OVID, SCIENCE DIRECT and SCOPUS. We also present a critical appraisal of use of genetic testing in this subset of infertile patients. PMID:23503954
Fletcher, J C; Evans, M I
Ethics in reproductive genetics comprise descriptive ethics and normative ethics. Ethical problems before prenatal diagnosis involve genetic counseling and informed consent for the choice patients must make. Prenatal diagnosis using amniocentesis is controversial. An international survey of geneticists showed that 25% would do prenatal diagnosis for sex selection, and 17% would refer the couple elsewhere. Hungary (60%), India (37%), the US (34%), Canada (30%), Greece (29%), and Sweden (28%) would do prenatal diagnosis. The statistical incidence of positive findings after prenatal diagnosis does not exceed 4% of all cases when most couples choose abortion. Respect for parental choice and for nondirective counseling was supported in responses to 3 cases in the international survey that also had disclosure dilemmas included with abortion choices. 84% of respondents would be nondirective for XYY and 88% for XO. In India, Hungary, Turkey, and Norway, 46%, 40%, 40%, and 33%, respectively, would advise aborting an XO (Turner) fetus. A survey of 737 genetics and obstetricians and ethicists and clergy showed acceptability of abortion in singleton pregnancies and in twins associated strongly with the trimester of pregnancy, indication for selective termination, and fetal number. Prior group review of risks and benefits of experimental fetal therapy, case selection for experimental fetal therapy, the optimal informed-consent process for fetal therapy, twin pregnancies, refusal of proven fetal therapy, the lack of federal support for research in fetal diagnosis (preimplantation embryo diagnosis) and therapy, and sources of a moral obligation are also addressed. The Belmont Report on the ethics of biomedical research in the US proposed ethical principles to guide research with human subjects including the fetus: respect for parsons, beneficence, and justice.
Strand, Malin; Hedström, Martin; Seth, Henrik; McEvoy, Eric G.; Jacobsson, Erik; Göransson, Ulf; Andersson, Håkan S.; Sundberg, Per
We test previous claims that the bacteria Vibrio alginolyticus produces tetrodotoxin (TTX) when living in symbiosis with the nemertean Lineus longissimus by a setup with bacteria cultivation for TTX production. Toxicity experiments on the shore crab, Carcinus maenas, demonstrated the presence of a paralytic toxin, but evidence from LC-MS and electrophysiological measurements of voltage-gated sodium channel–dependent nerve conductance in male Wistar rat tissue showed conclusively that this effect did not originate from TTX. However, a compound of similar molecular weight was found, albeit apparently non-toxic, and with different LC retention time and MS/MS fragmentation pattern than those of TTX. We conclude that C. maenas paralysis and death likely emanate from a compound <5 kDa, and via a different mechanism of action than that of TTX. The similarity in mass between TTX and the Vibrio-produced low-molecular-weight, non-toxic compound invokes that thorough analysis is required when assessing TTX production. Based on our findings, we suggest that re-examination of some published claims of TTX production may be warranted. PMID:27023570
Tian, Jianjun; Li, Bai-Lian
Although in the broadly defined genetic algebra, multiplication suggests a forward direction of from parents to progeny, when looking from the reverse direction, it also suggests to us a new algebraic structure-coalge- braic structure, which we call genetic coalgebras. It is not the dual coalgebraic structure and can be used in the construction of phylogenetic trees. Math- ematically, to construct phylogenetic trees means we need to solve equations x([n]) = a, or x([n]) = b. It is generally impossible to solve these equations inalgebras. However, we can solve them in coalgebras in the sense of tracing back for their ancestors. A thorough exploration of coalgebraic structure in genetics is apparently necessary. Here, we develop a theoretical framework of the coalgebraic structure of genetics. From biological viewpoint, we defined various fundamental concepts and examined their elementary properties that contain genetic significance. Mathematically, by genetic coalgebra, we mean any coalgebra that occurs in genetics. They are generally noncoassociative and without counit; and in the case of non-sex-linked inheritance, they are cocommutative. Each coalgebra with genetic realization has a baric property. We have also discussed the methods to construct new genetic coalgebras, including cocommutative duplication, the tensor product, linear combinations and the skew linear map, which allow us to describe complex genetic traits. We also put forward certain theorems that state the relationship between gametic coalgebra and gametic algebra. By Brower's theorem in topology, we prove the existence of equilibrium state for the in-evolution operator.
Peters, Ulrike; Bien, Stephanie; Zubair, Niha
Colorectal cancer (CRC) is a complex disease that develops as a consequence of both genetic and environmental risk factors. A small proportion (3–5%) of cases arises from hereditary syndromes predisposing to early onset CRC as a result of mutations in over a dozen well-defined genes. In contrast, CRC is predominantly a late-onset “sporadic” disease, developing in individuals with no obvious hereditary syndrome. In recent years genome-wide association studies have discovered over 40 genetic regions to be associated with weak effects on sporadic CRC and it has been estimated that increasingly large genome-wide scans will identify many additional novel genetic regions. Subsequent experimental validations have identified the causally related variant(s) in a limited number of these genetic regions. Further biological insight could be obtained through ethnically diverse study populations, larger genetic sequencing studies, and development of higher-throughput functional experiments. Along with inherited variation, integration of the tumour genome may shed light on the carcinogenic processes in CRC. In addition to summarizing the genetic architecture of CRC, this review discusses genetic factors that modify environmental predictors of CRC, as well as examples of how genetic insight has improved clinical surveillance, prevention, and treatment strategies. In summary, substantial progress has been made in uncovering the genetic architecture of CRC and continued research efforts are expected to identify additional genetic risk factors that further our biological understanding of this disease. PMID:26187503
Sadiq, Mohammad Ali; Vanderveen, Deborah
Hereditary ectopia lentis or lens subluxation can occur with and without systemic associations. Significant overlap can be found in the genetic mutations and pathogenesis of subluxated lenses in their isolated forms as well as with associated syndromes. Gene mutations have been identified for lens subluxation associated with Marfan syndrome, Weill Marchesani syndrome, Ectopia Lentis simplex, Ectopia Lentis et pupillae, Ehlers Danlos syndrome, homocystinuria, and sulfite oxidase deficiency. Herein we describe the ocular and systemic characteristics found in patients with ectopia lentis, as well as the gene mutations identified thus far.
Researchers in Robert Ferl's lab at the University of Florida in Gainesville, genetically altered this Arabdopsis Thaliana (a brassica species) plant to learn how extreme environments, such as the low atmospheric pressure on Mars, affect plant genes. They inserted green fluorescent protein (GFP) near the on/off switches for anoxia and drought genes. When those genes were turned on after exposure to reduced atmospheric pressure, GFP was turned on as well, causing cells expressing those genes to glow green under a blue light. The natural fluorescence of chlorophyll accounts for the red glow.
Sen-Chowdhry, Srijita; Syrris, Petros; McKenna, William J
Restrictive physiology, a severe form of diastolic dysfunction, is characteristically observed in the setting of constrictive pericarditis and myocardial restriction. The latter is commonly due to systemic diseases, some of which are inherited as mendelian traits (eg, hereditary amyloidosis), while others are multifactorial (eg, sarcoidosis). When restrictive physiology occurs as an early and dominant feature of a primary myocardial disorder, it may be termed restrictive cardiomyopathy. In the past decade, clinical and genetic studies have demonstrated that restrictive cardiomyopathy as such is part of the spectrum of sarcomeric disease and frequently coexists with hypertrophic cardiomyopathy in affected families.
Hani, Abeer J; Mikati, Husam M; Mikati, Mohamad A
As the genetic etiologies of an expanding number of epilepsy syndromes are revealed, the complexity of the phenotype genotype correlation increases. As our review will show, multiple gene mutations cause different epilepsy syndromes, making identification of the specific mutation increasingly more important for prognostication and often more directed treatment. Examples of that include the need to avoid specific drugs in Dravet syndrome and the ongoing investigations of the potential use of new directed therapies such as retigabine in KCNQ2-related epilepsies, quinidine in KCNT1-related epilepsies, and memantine in GRIN2A-related epilepsies.
Thermodynamics and evolutionary genetics have something in common. Thus, the randomness of mutation of cells may be likened to the random thermal fluctuations in a gas. And the probabilistic nature of entropy in statistical thermodynamics can be carried over to a population of haploid and diploid cells without any conceptual change. The energetic potential wells in which the atoms of a liquid are caught correspond to selective advantages for some phenotype over others. Thus, the eventual stable state in a population comes about as a compromise in the universal competition between entropy and energy.
Digital genetics, or the genetics of digital organisms, is a new field of research that has become possible as a result of the remarkable power of evolution experiments that use computers. Self-replicating strands of computer code that inhabit specially prepared computers can mutate, evolve and adapt to their environment. Digital organisms make it easy to conduct repeatable, controlled experiments, which have a perfect genetic 'fossil record'. This allows researchers to address fundamental questions about the genetic basis of the evolution of complexity, genome organization, robustness and evolvability, and to test the consequences of mutations, including their interaction and recombination, on the fate of populations and lineages.
Dingel, Molly J.; Ostergren, Jenny; McCormick, Jennifer B.; Hammer, Rachel; Koenig, Barbara A.
To understand public discourse in the U.S. on genetic causation of behavioral disorders, we analyzed media representations of genetic research on addiction published between 1990 and 2010. We conclude first that the media simplistically represent biological bases of addiction and willpower as being mutually exclusive: behaviors are either genetically determined, or they are a choice. Second, most articles provide only cursory or no treatment of the environmental contribution. A media focus on genetics directs attention away from environmental factors. Rhetorically, media neglect the complexity underlying of the etiology of addiction and direct focus back toward individual causation and responsibility. PMID:26392644
MacPherson, A; Nuismer, S L
Parallel evolution is often assumed to result from repeated adaptation to novel, yet ecologically similar, environments. Here, we develop and analyse a mathematical model that predicts the probability of parallel genetic evolution from standing genetic variation as a function of the strength of phenotypic selection and constraints imposed by genetic architecture. Our results show that the probability of parallel genetic evolution increases with the strength of natural selection and effective population size and is particularly likely to occur for genes with large phenotypic effects. Building on these results, we develop a Bayesian framework for estimating the strength of parallel phenotypic selection from genetic data. Using extensive individual-based simulations, we show that our estimator is robust across a wide range of genetic and evolutionary scenarios and provides a useful tool for rigorously testing the hypothesis that parallel genetic evolution is the result of adaptive evolution. An important result that emerges from our analyses is that existing studies of parallel genetic evolution frequently rely on data that is insufficient for distinguishing between adaptive evolution and neutral evolution driven by random genetic drift. Overcoming this challenge will require sampling more populations and the inclusion of larger numbers of loci.
Mente, Eleni; Legeay, Alexia; Houlihan, Dominic F; Massabuau, Jean-Charles
Many water-breathing animals have a strategy that consists of maintaining low blood PO2 values in a large range of water oxygenation level (4-40 kPa). This study examines the postprandial changes in O2 consumption, arterial blood PO2, and tissue protein synthesis in the shore crab Carcinus maenas in normoxic, O2-depleted, and O2-enriched waters to study the effects of this strategy on the O2 consumption and peptide bond formation after feeding. In normoxic water (21 kPa), the arterial PO2 was 1.1 kPa before feeding and 1.2 kPa 24 h later. In water with a PO2 of 3 kPa (arterial PO2 0.6 kPa), postprandial stimulation of protein synthesis and O2 consumption were blocked. The blockade was partial at a water PO2 of 4 kPa (arterial PO2 0.8 kPa). An increase in environmental PO2 (60 kPa, arterial PO2 10 kPa) resulted in an increase in protein synthesis compared with normoxic rates. It is concluded that the arterial PO2 spontaneously set in normoxic Carcinus limits the rates of protein synthesis. The rationale for such a strategy is discussed.
Mfuna-Endam, Leandra; Zhang, Yuan; Desrosiers, Martin Y
Suggestion for a potential genetic basis to chronic rhinosinusitis (CRS) is afforded by degree of inheritability suggested from family and twin studies, existence of CRS in simple mendelian diseases, and development of sinusitis as part of the phenotype of certain gene "knockout" murine models. Genetic association studies are expected to identify novel genes associated with CRS and suggest novel mechanisms implicated in disease development. Although these studies are subject to methodologic difficulties, associations of CRS and polymorphisms in more than 30 genes have been published, with single nucleotide polymorphisms in 3 (IL1A, TNFA, AOAH) replicated. While the individual risk conferred by these single nucleotide polymorphisms remains modest, taken as a group, they suggest an important implication of pathways of innate immune recognition and in regulation of downstream signaling in the development of CRS. In a demonstration of these techniques' potential to identify new targets for research, the authors present a functional investigation of LAMB1, the top-rated gene from a pooling-based genome-wide association study of CRS. Upregulation of gene expression in LAMB1 and associated laminin genes in primary epithelial cells from CRS patients implicates the extracellular matrix in development of CRS and offers a new avenue for further study.
Abdullah, Alyasa Gan; Wah, Yap Bee
The computation of the approximate values of the trigonometric sines was discovered by Bhaskara I (c. 600-c.680), a seventh century Indian mathematician and is known as the Bjaskara's I's sine approximation formula. The formula is given in his treatise titled Mahabhaskariya. In the 14th century, Madhava of Sangamagrama, a Kerala mathematician astronomer constructed the table of trigonometric sines of various angles. Madhava's table gives the measure of angles in arcminutes, arcseconds and sixtieths of an arcsecond. The search for more accurate formulas led to the discovery of the power series expansion by Madhava of Sangamagrama (c.1350-c. 1425), the founder of the Kerala school of astronomy and mathematics. In 1715, the Taylor series was introduced by Brook Taylor an English mathematician. If the Taylor series is centered at zero, it is called a Maclaurin series, named after the Scottish mathematician Colin Maclaurin. Some of the important Maclaurin series expansions include trigonometric functions. This paper introduces the genetic code of the sine of an angle without using power series expansion. The genetic code using square root approach reveals the pattern in the signs (plus, minus) and sequence of numbers in the sine of an angle. The square root approach complements the Pythagoras method, provides a better understanding of calculating an angle and will be useful for teaching the concepts of angles in trigonometry.
Roh, Mi Ryung; Eliades, Philip; Gupta, Sameer; Tsao, Hensin
Melanocytic nevi are a benign clonal proliferation of cells expressing the melanocytic phenotype, with heterogeneous clinical and molecular characteristics. In this review, we discuss the genetics of nevi by salient nevi subtypes: congenital melanocytic nevi, acquired melanocytic nevi, blue nevi, and Spitz nevi. While the molecular etiology of nevi has been less thoroughly studied than melanoma, it is clear that nevi and melanoma share common driver mutations. Acquired melanocytic nevi harbor oncogenic mutations in BRAF, which is the predominant oncogene associated with melanoma. Congenital melanocytic nevi and blue nevi frequently harbor NRAS mutations and GNAQ mutations, respectively, while Spitz and atypical Spitz tumors often exhibit HRAS and kinase rearrangements. These initial “driver” mutations are thought to trigger the establishment of benign nevi. After this initial phase of cell proliferation, a senescence program is executed, causing termination of nevi growth. Only upon the emergence of additional tumorigenic alterations, which may provide an escape from oncogene-induced senescence, can malignant progression occur. Here, we review the current literature on the pathobiology and genetics of nevi in the hope that additional studies of nevi promise to inform our understanding of the transition from benign neoplasm to malignancy. PMID:26300491
Genetic factors contribute to the development of digital osteoarthritis, whose heritability has been estimated at 48 to 65%. Among the manifestations of digital osteoarthritis, only Heberden's nodes are transmitted by Mendelian inheritance, as a dominant trait in women and a recessive trait in men. The other forms of digital osteoarthritis are multifactorial, with a major gene and a residual multifactorial component that probably interacts with environmental factors. Hindrances to molecular studies include the absence to date of a universally accepted definition of the phenotype and the late onset of the manifestations. Genetic association studies of selected class I and II HLA genes produced conflicting results. The T303M polymorphism of the MATN3 gene, which was initially described as associated with hand osteoarthritis, may be more closely linked to trapeziometacarpal osteoarthritis than to digital osteoarthritis. Genome-wide scans have identified numerous loci linked to digital osteoarthritis. Replication has been achieved for some of these loci, most notably those located at 2p, 2q, 3p, 4q, and 7p. A recently published genome-wide association study showed that an A2BP1 gene polymorphism was significantly associated with hand osteoarthritis. Many candidate-gene studies found associations with AGC1, ASPN, ENPP1, HFE, KL, VDR, IL-1 cluster, and IL-6, although the results were not consistently reproducible. In one study, women with hand osteoarthritis had significant telomere shortening. Telomere shortening has also been reported in other age-related conditions.
Human SCID (Severe Combined Immunodeficiency) is a prenatal disorder of T lymphocyte development, that depends on the expression of numerous genes. The knowledge of the genetic basis of SCID is essential for diagnosis (e.g., clinical phenotype, lymphocyte profile) and treatment (e.g., use and type of pre-hematopoietic stem cell transplant conditioning).Over the last years novel genetic defects causing SCID have been discovered, and the molecular and immunological mechanisms of SCID have been better characterized. Distinct forms of SCID show both common and peculiar (e.g., absence or presence of nonimmunological features) aspects, and they are currently classified into six groups according to prevalent pathophysiological mechanisms: impaired cytokine-mediated signaling; pre-T cell receptor defects; increased lymphocyte apoptosis; defects in thymus embryogenesis; impaired calcium flux; other mechanisms.This review is the updated, extended and largely modified translation of the article "Cossu F: Le basi genetiche delle SCID", originally published in Italian language in the journal "Prospettive in Pediatria" 2009, 156:228-238.
Park, S; Chatterjee, V
Congenital hypothyroidism is the most common neonatal metabolic disorder and results in severe neurodevelopmental impairment and infertility if untreated. Congenital hypothyroidism is usually sporadic but up to 2% of thyroid dysgenesis is familial, and congenital hypothyroidism caused by organification defects is often recessively inherited. The candidate genes associated with this genetically heterogeneous disorder form two main groups: those causing thyroid gland dysgenesis and those causing dyshormonogenesis. Genes associated with thyroid gland dysgenesis include the TSH receptor in non-syndromic congenital hypothyroidism, and Gsα and the thyroid transcription factors (TTF-1, TTF-2, and Pax-8), associated with different complex syndromes that include congenital hypothyroidism. Among those causing dyshormonogenesis, the thyroid peroxidase and thyroglobulin genes were initially described, and more recently PDS (Pendred syndrome), NIS (sodium iodide symporter), and THOX2 (thyroid oxidase 2) gene defects. There is also early evidence for a third group of congenital hypothyroid conditions associated with iodothyronine transporter defects associated with severe neurological sequelae. This review focuses on the genetic aspects of primary congenital hypothyroidism. PMID:15863666
Forestiere, Carlo; Pasquale, Alyssa J; Capretti, Antonio; Miano, Giovanni; Tamburrino, Antonello; Lee, Sylvanus Y; Reinhard, Björn M; Dal Negro, Luca
In the present Letter, we demonstrate how the design of metallic nanoparticle arrays with large electric field enhancement can be performed using the basic paradigm of engineering, namely the optimization of a well-defined objective function. Such optimization is carried out by coupling a genetic algorithm with the analytical multiparticle Mie theory. General design criteria for best enhancement of electric fields are obtained, unveiling the fundamental interplay between the near-field plasmonic and radiative photonic coupling. Our optimization approach is experimentally validated by surface-enhanced Raman scattering measurements, which demonstrate how genetically optimized arrays, fabricated using electron beam lithography, lead to order of ten improvement of Raman enhancement over nanoparticle dimer antennas, and order of one hundred improvement over optimal nanoparticle gratings. A rigorous design of nanoparticle arrays with optimal field enhancement is essential to the engineering of numerous nanoscale optical devices such as plasmon-enhanced biosensors, photodetectors, light sources and more efficient nonlinear optical elements for on chip integration.
LeDoux, Mark S.
Dystonia has been defined as a syndrome of involuntary, sustained muscle contractions affecting one or more sites of the body, frequently causing twisting and repetitive movements or abnormal postures. Dystonia is also a clinical sign that can be the presenting or prominent manifestation of many neurodegenerative and neuro-metabolic disorders. Etiological categories include primary dystonia, secondary dystonia, heredodegenerative diseases with dystonia, and dystonia plus. Primary dystonia includes syndromes in which dystonia is the sole phenotypic manifestation with the exception that tremor can be present as well. Most primary dystonia begins in adults, and approximately 10% of probands report one or more affected family members. Many cases of childhood- and adolescent-onset dystonia are due to mutations in TOR1A and THAP1. Mutations in THAP1 and CIZ1 have been associated with sporadic and familial adult-onset dystonia. Although significant recent progress had been made in defining the genetic basis for most of the dystonia-plus and heredodegenerative diseases with dystonia, a major gap remains in understanding the genetic etiologies for most cases of adult-onset primary dystonia. Common themes in the cellular biology of dystonia include G1/S cell cycle control, monoaminergic neurotransmission, mitochondrial dysfunction, and the neuronal stress response. PMID:22989765
Chinushi, Masaomi; Sato, Akinori
Recent studies have demonstrated that genetic abnormalities associated with the regulation of myocardial ionic channels, receptors, transporters, cell membranous proteins etc, can create an arrhythmogenic substrate in some patients with structurally normal hearts, and these are called hereditary arrhythmic diseases. Various arrhythmic diseases (such as congenital long or short QT syndrome, Brugada syndrome, catecholamine-sensitive polymorphic ventricular tachycardia, arrhythmogenic right ventricular cardiomyopathy, early repolarization syndrome etc.) are categorized as hereditary arrhythmic diseases. Among them, we focused on long QT syndrome and Brugada syndrome in this review. In congenital long QT syndrome, either attenuation of the net outward current or augmentation of the net inward current is responsible for prolonging the myocardial action potential duration and QT interval on ECG. Premature ventricular beats triggered due to early after-depolarization infringe on the large spatial dispersion of ventricular repolarization and initiate polymorphic ventricular tachycardia with a specific form (torsade de pointes). Currently, thirteen genotypes in Romano-Ward syndrome and two genotypes in Jervell-Lange Nielsen syndrome have been reported. In Brugada syndrome, large transient outward current (Ito) creates a deep phase 1 notch in the action potential, especially at the epicardial myocardium of the right ventricular outflow tract. In combination with the delayed completion of repolarization and loss of the phase 2 dome in some epicardial myocardium in this area, coved-type ECG abnormality and ventricular fibrillation due to phase 2 reentry are believed to be induced in Brugada syndrome. Eleven genetic abnormalities are presently listed as a possible cause of Brugada syndrome.
Prunet, Nathanaël; Meyerowitz, Elliot M
There are only three grand theories in biology: the theory of the cell, the theory of the gene, and the theory of evolution. Two of these, the cell and gene theories, originated in the study of plants, with the third resulting in part from botanical considerations as well. Mendel's elucidation of the rules of inheritance was a result of his experiments on peas. The rediscovery of Mendel's work in 1900 was by the botanists de Vries, Correns, and Tschermak. It was only in subsequent years that animals were also shown to have segregation of genetic elements in the exact same manner as had been shown in plants. The story of developmental biology is different - while the development of plants has long been studied, the experimental and genetic approaches to developmental mechanism were developed via experiments on animals, and the importance of genes in development (e.g., Waddington, 1940) and their use for understanding developmental mechanisms came to botanical science much later - as late as the 1980s.
Dominiczak, A F; Clark, J S; Jeffs, B; Anderson, N H; Negrin, C D; Lee, W K; Brosnan, M J
Experimental models of genetic hypertension are used to develop paradigms to study human essential hypertension while removing some of the complexity inherent in the study of human subjects. Since 1991 several quantitative trait loci responsible for blood pressure regulation have been identified in various rat crosses. More recently, a series of interesting quantitative trait loci influencing cardiac hypertrophy, stroke, metabolic syndrome and renal damage has also been described. It is recognized that the identification of large chromosomal regions containing a quantitative trait locus is only a first step towards gene identification. The next step is the production of congenic strains and substrains to confirm the existence of the quantitative trait locus and to narrow down the chromosomal region of interest. Several congenic strains have already been produced, with further refinement of the methodology currently in progress. The ultimate goal is to achieve positional cloning of the causal gene, a task which has so far been elusive. There are several areas of cross-fertilization between experimental and human genetics of hypertension, with a successful transfer of two loci directly from rats to humans and with new pharmacogenetic approaches which may be utilized in both experimental and clinical settings.
Wall, Tamara L.; Luczak, Susan E.; Hiller-Sturmhöfel, Susanne
Gene variants encoding several of the alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), are among the largest genetic associations with risk for alcohol dependence. Certain genetic variants (i.e., alleles)—particularly the ADH1B*2, ADH1B*3, ADH1C*1, and ALDH2*2 alleles—have been associated with lower rates of alcohol dependence. These alleles may lead to an accumulation of acetaldehyde during alcohol metabolism, which can result in heightened subjective and objective effects. The prevalence of these alleles differs among ethnic groups; ADH1B*2 is found frequently in northeast Asians and occasionally Caucasians, ADH1B*3 is found predominantly in people of African ancestry, ADH1C*1 varies substantially across populations, and ALDH2*2 is found almost exclusively in northeast Asians. Differences in the prevalence of these alleles may account at least in part for ethnic differences in alcohol consumption and alcohol use disorder (AUD). However, these alleles do not act in isolation to influence the risk of AUD. For example, the gene effects of ALDH2*2 and ADH1B*2 seem to interact. Moreover, other factors have been found to influence the extent to which these alleles affect a person’s alcohol involvement, including developmental stage, individual characteristics (e.g., ethnicity, antisocial behavior, and behavioral undercontrol), and environmental factors (e.g., culture, religion, family environment, and childhood adversity). PMID:27163368
Faundes, Víctor; Pardo, Rosa Andrea; Castillo Taucher, Silvia
Congenital deafness is defined as the hearing loss which is present at birth and, consequently, before speech development. It is the most prevalent sensor neural disorder in developed countries, and its incidence is estimated between 1-3 children per 1,000 newborns, of which more than 50% are attributable to genetics causes. Deafness can be classified as syndromic or non-syndromic. In the first case, it is associated with outer ear malformations and/or systemic findings. More than 400 syndromes accompanied of deafness have been described, which represent about 30% of cases of congenital hearing loss. The remaining percentage corresponds to non-syndromic cases: 75-85% are autosomal recessive, 15-24% are autosomal dominant, and 1-2% are X-linked. The evaluation of a child with deafness requires a multidisciplinary collaboration among specialists, who must coordinate themselves and give information to the affected family. The aims of establishing a diagnosis are to predict other manifestations that may suggest some syndrome and to anticipate their management, as well as to perform genetic counseling to parents and affected individuals.
Luo, Liqun; Callaway, Edward M.; Svoboda, Karel
Understanding the principles of information processing in neural circuits requires systematic characterization of the participating cell types and their connections, and the ability to measure and perturb their activity. Genetic approaches promise to bring experimental access to complex neural systems, including genetic stalwarts such as the fly and mouse, but also to nongenetic systems such as primates. Together with anatomical and physiological methods, cell-type-specific expression of protein markers and sensors and transducers will be critical to construct circuit diagrams and to measure the activity of genetically defined neurons. Inactivation and activation of genetically defined cell types will establish causal relationships between activity in specific groups of neurons, circuit function, and animal behavior. Genetic analysis thus promises to reveal the logic of the neural circuits in complex brains that guide behaviors. Here we review progress in the genetic analysis of neural circuits and discuss directions for future research and development. PMID:18341986
Shakeshaft, Nicholas G; Plomin, Robert
Specific cognitive abilities in diverse domains are typically found to be highly heritable and substantially correlated with general cognitive ability (g), both phenotypically and genetically. Recent twin studies have found the ability to memorize and recognize faces to be an exception, being similarly heritable but phenotypically substantially uncorrelated both with g and with general object recognition. However, the genetic relationships between face recognition and other abilities (the extent to which they share a common genetic etiology) cannot be determined from phenotypic associations. In this, to our knowledge, first study of the genetic associations between face recognition and other domains, 2,000 18- and 19-year-old United Kingdom twins completed tests assessing their face recognition, object recognition, and general cognitive abilities. Results confirmed the substantial heritability of face recognition (61%), and multivariate genetic analyses found that most of this genetic influence is unique and not shared with other cognitive abilities.
Blakeslee, April M. H.; Keogh, Carolyn L.; Fowler, Amy E.; Griffen, Blaine D.
A common signature of marine invasions worldwide is a significant loss of parasites (= parasite escape) in non-native host populations, which may confer a release from some of the harmful effects of parasitism (e.g., castration, energy extraction, immune activation, behavioral manipulation) and possibly enhance the success of non-indigenous species. In eastern North America, the notorious invader Carcinus maenas (European green crab) has escaped more than two-thirds its native parasite load. However, one of its parasites, a trematode (Microphallus similis), can be highly prevalent in the non-native region; yet little is known about its potential impacts. We employed a series of laboratory experiments to determine whether and how M. similis infection intensity influences C. maenas, focusing on physiological assays of body mass index, energy storage, and immune activation, as well as behavioral analyses of foraging, shelter utilization, and conspicuousness. We found little evidence for enduring physiological or behavioral impacts four weeks after experimental infection, with the exception of mussel handling time which positively correlated with cyst intensity. However, we did find evidence for a short-term effect of M. similis infection during early stages of infection (soon after cercarial penetration) via a significant drop in circulating immune cells, and a significant increase in the crabs’ righting response time. Considering M. similis is the only common parasite infecting C. maenas in eastern North America, our results for minimal lasting effects of the trematode on the crab’s physiology and behavior may help explain the crab’s continued prominence as a strong predator and competitor in the region. PMID:26030816
New technologies for mutation detection in the human genome have greatly increased our understanding of epilepsy genetics. Application of genomic technologies in the clinical setting allows for more efficient genetic diagnosis in some patients; therefore, it is important to understand the types of tests available and the types of mutations that can be detected. Making a genetic diagnosis improves overall patient care by enhancing prognosis and recurrence risk counseling and informing treatment decisions. PMID:26316867
Rowley, P T
Genetic screening is a systematic search in the population for persons of certain genotypes. The usual purpose is to detect persons who themselves or whose offspring are at risk for genetic diseases or genetically determined susceptibilities to environmental agents. Is genetic screening a marvel about to free us from the scourge of genetic disease or a menace about to invade our privacy and determine who may reproduce? There are three different types of genetic screening. Newborn screening identifies serious genetic disease at birth, permitting prompt treatment to prevent mental and physical retardation. Fetal screening and prenatal diagnosis identify genetic disease in the fetus permitting selective termination of pregnancy and the opportunity to have children free of defects detectable in utero. Carrier screening identifies individuals heterozygous for a gene for a serious recessive disease who may be at risk for affected offspring. The challenge to society is to provide (by way of cost-effective programs) expert services, including genetic counseling and follow-up, to all who may benefit, to ensure confidentiality and freedom of choice, and to avoid misunderstanding and stigmatization. It is recommended that the objective of screening programs should be to maximize the options available to families at risk rather than to reduce the incidence of genetic diseases. Whenever possible, the providers of these services should be the providers of primary health care. Urgently needed are a greater awareness of avoidable genetic diseases on the part of primary care providers and efforts to familiarize the public with the basic concepts of human genetics through the public school system.
Rice, William R.
Experimental genetics with model organisms and mathematically explicit genetic theory are generally considered to be the major paradigms by which progress in genetics is achieved. Here I argue that this view is incomplete and that pivotal advances in genetics—and other fields of biology—are also made by synthesizing disparate threads of extant information rather than generating new information from experiments or formal theory. Because of the explosive expansion of information in numerous “-omics” data banks, and the fragmentation of genetics into numerous subdisciplines, the importance of the synthesis paradigm will likely expand with time. PMID:24496401
Crow, James F
Before the Second World War, there were only two North-American journals exclusively devoted to genetics - the Journal of Heredity and Genetics. In the late 1940s, Genetics spawned two progeny - the American Journal of Human Genetics and Evolution. This article recounts the early days of these journals, their influential and often colourful founding editors, and their contents. It emphasizes the contrast between those years, when a reader had a realistic chance of keeping up with the whole field, and the current plethora of journals that makes it impossible to keep up with even the tables of contents.
... as substances called bile alcohols. Cholestanol and bile alcohols are increased in the blood, while blood cholesterol levels are typically ... Disorders Genetic and Rare Diseases Information Center (1 ...
Dellefave, Lisa; McNally, Elizabeth M.
Purpose of review More than forty different individual genes have been implicated in the inheritance of dilated cardiomyopathy. For a subset of these genes, mutations can lead to a spectrum of cardiomyopathy that extends to hypertrophic cardiomyopathy and left ventricular noncompaction. In nearly all cases, there is an increased risk of arrhythmias. With some genetic mutations, extracardiac manifestations are likely to be present. The precise genetic etiology can usually not be discerned from the cardiac and/or extracardiac manifestations and requires molecular genetic diagnosis for prognostic determination and cardiac care. Recent findings Newer technologies are influencing genetic testing, especially cardiomyopathy genetic testing, where an increased number of genes are now routinely being tested simultaneously. While this approach to testing multiple genes is increasing the diagnostic yield, the analysis of multiple genes in one test is also resulting in a large amount of genetic information of unclear significance. Summary Genetic testing is highly useful in the care of patients and families, since it guides diagnosis, influences care and aids in prognosis. However, the large amount of benign human genetic variation may complicate genetic results, and often requires a skilled team to accurately interpret the findings. PMID:20186049
Nalls, Mike A; Saad, Mohamad; Noyce, Alastair J; Keller, Margaux F; Schrag, Anette; Bestwick, Jonathan P; Traynor, Bryan J; Gibbs, J Raphael; Hernandez, Dena G; Cookson, Mark R; Morris, Huw R; Williams, Nigel; Gasser, Thomas; Heutink, Peter; Wood, Nick; Hardy, John; Martinez, Maria; Singleton, Andrew B
Parkinson's disease (PD) has a number of known genetic risk factors. Clinical and epidemiological studies have suggested the existence of intermediate factors that may be associated with additional risk of PD. We construct genetic risk profiles for additional epidemiological and clinical factors using known genome-wide association studies (GWAS) loci related to these specific phenotypes to estimate genetic comorbidity in a systematic review. We identify genetic risk profiles based on GWAS variants associated with schizophrenia and Crohn's disease as significantly associated with risk of PD. Conditional analyses adjusting for SNPs near loci associated with PD and schizophrenia or PD and Crohn's disease suggest that spatially overlapping loci associated with schizophrenia and PD account for most of the shared comorbidity, while variation outside of known proximal loci shared by PD and Crohn's disease accounts for their shared genetic comorbidity. We examine brain methylation and expression signatures proximal to schizophrenia and Crohn's disease loci to infer functional changes in the brain associated with the variants contributing to genetic comorbidity. We compare our results with a systematic review of epidemiological literature, while the findings are dissimilar to a degree; marginal genetic associations corroborate the directionality of associations across genetic and epidemiological data. We show a strong genetically defined level of comorbidity between PD and Crohn's disease as well as between PD and schizophrenia, with likely functional consequences of associated variants occurring in brain.
Nalls, Mike A.; Saad, Mohamad; Noyce, Alastair J.; Keller, Margaux F.; Schrag, Anette; Bestwick, Jonathan P.; Traynor, Bryan J.; Gibbs, J. Raphael; Hernandez, Dena G.; Cookson, Mark R.; Morris, Huw R.; Williams, Nigel; Gasser, Thomas; Heutink, Peter; Wood, Nick; Hardy, John; Martinez, Maria; Singleton, Andrew B.
Parkinson's disease (PD) has a number of known genetic risk factors. Clinical and epidemiological studies have suggested the existence of intermediate factors that may be associated with additional risk of PD. We construct genetic risk profiles for additional epidemiological and clinical factors using known genome-wide association studies (GWAS) loci related to these specific phenotypes to estimate genetic comorbidity in a systematic review. We identify genetic risk profiles based on GWAS variants associated with schizophrenia and Crohn's disease as significantly associated with risk of PD. Conditional analyses adjusting for SNPs near loci associated with PD and schizophrenia or PD and Crohn's disease suggest that spatially overlapping loci associated with schizophrenia and PD account for most of the shared comorbidity, while variation outside of known proximal loci shared by PD and Crohn's disease accounts for their shared genetic comorbidity. We examine brain methylation and expression signatures proximal to schizophrenia and Crohn's disease loci to infer functional changes in the brain associated with the variants contributing to genetic comorbidity. We compare our results with a systematic review of epidemiological literature, while the findings are dissimilar to a degree; marginal genetic associations corroborate the directionality of associations across genetic and epidemiological data. We show a strong genetically defined level of comorbidity between PD and Crohn's disease as well as between PD and schizophrenia, with likely functional consequences of associated variants occurring in brain. PMID:24057672
Clement, Karine; Boutin, Philippe; Froguel, Philippe
Obesity is a typical common multifactorial disease in which environmental and genetic factors interact. In rare cases of severe obesity with childhood onset, a single gene has a major effect in determining the occurrence of obesity, with the environment having only a permissive role in the severity of the phenotype. Exceptional mutations of the leptin gene and its receptor, pro-opiomelanocortine (POMC), prohormone convertase 1 (PC1) and more frequently, mutations in the melanocortin receptor 4 (1 to 4% of very obese cases) have been described. All these obesity genes encode proteins that are strongly connected as part of the same loop of the regulation of food intake. They all involve the leptin axis and one of its hypothalamic targets; the melanocortin pathway. Pathways of bodyweight regulation involved in monogenic forms of obesity might represent targets for future drug development. Successful leptin protein replacement in a leptin-deficient child has contributed to the validation of the usefulness of gene screening in humans. However, the individual variability in response to leptin treatment might be related to genetic variability. The efficiency of leptin itself or of small-molecule agonists of the leptin receptor should be studied in relation with genetic variations in the leptin gene promoter. The most common forms of obesity are polygenic. Two general approaches have been used to date in the search for genes underlying common polygenic obesity in humans. The first approach focuses on selected genes having some plausible role in obesity on the basis of their known or presumed biological role. This approach yielded putative susceptibility genes with only small or uncertain effects. The second approach attempts to map genes purely by position and requires no presumptions on the function of genes. Genome-wide scans identify chromosomal regions showing linkage with obesity in large collections of nuclear families. Genome-wide scans in different ethnic
Peters, Elizabeth; McCarthy Veach, Patricia; Ward, Erin E; LeRoy, Bonnie S
This study was an investigation of whether genetic counselors have received genetic counseling and if so, how they believe it affects their practice. One thousand genetic counselors were mailed surveys about the nature of genetic counseling services received, impact on their clinical practice, frequency and reasons for disclosing about their receipt of counseling to their clients, and demographics. Ninety-three of the 510 respondents reported receiving genetic counseling. Of these, almost three-fourths were practicing genetic counselors while receiving services. Reasons for services include prenatal concerns, family history of cancer, and history/risk of other genetic conditions. Frequently endorsed effects on practice include increased empathy and understanding of client decisions, feeling more connected with clients, greater emphasis on psychosocial support, and sympathy. Forty-six respondents disclosed to clients about their receipt of genetic counseling. Prevalent reasons include client asked, help clients feel they are not alone, demonstrate counselor understanding, decrease client anxiety, build rapport, and normalize client feelings. Practice and research recommendations are given.
Burian, Richard M.
This paper addresses the teaching of advanced high school courses or undergraduate courses for non-biology majors about genetics or history of genetics. It will probably be difficult to take the approach described here in a high school science course, although the general approach could help improve such courses. It would be ideal for a college…
Hagymási, Krisztina; Tulassay, Zsolt
The goal of the Human Genome Project to elucidate the complete sequence of the human genome has been achieved. The aims of the "post-genome" era are explaining the genetic information, characterisation of functional elements encoded in the human genome and mapping the human genetic variability as well. Two unrelated human beings also share 99.9% of their genomic sequence. The difference of 0.1% is the result of genetic polymorphisms: single nucleotide polymorphisms, repetitive sequences and insertion/deletion. The genetic differences, coupled with environmental exposures will determine the phenotypic variation we observe in health or disease. The disease-causing genetic variants can be identified by linkage analysis or association studies. The knowledge of human genome and application of multiple biomarkers will improve our ability to identify individuals at risk, so that preventive interventions can be applied, earlier diagnosis can be made and treatment can be optimized.
Bukvic, Nenad; Elling, John W
"Healing is best accomplished when art and science are conjoined, when body and spirit are probed together", says Bernard Lown, in his book "The Lost Art of Healing". Art has long been a witness to disease either through diseases which affected artists or diseases afflicting objects of their art. In particular, artists have often portrayed genetic disorders and malformations in their work. Sometimes genetic disorders have mystical significance; other times simply have intrinsic interest. Recognizing genetic disorders is also an art form. From the very beginning of my work as a Medical Geneticist I have composed personal "algorithms" to piece together evidence of genetics syndromes and diseases from the observable signs and symptoms. In this paper we apply some 'gestalt' Genetic Syndrome Diagnostic algorithms to virtual patients found in some art masterpieces. In some the diagnosis is clear and in others the artists' depiction only supports a speculative differential diagnosis.
Mathias, Rasika Ann
While asthma is a heterogeneous disease, a strong genetic basis has been firmly established. Rather than being a single disease entity, asthma consists of related, overlapping syndromes [Barnes (Proc Am Thor Soc 8:143-148, 2011)] including three general domains: variable airway obstruction, airway hyper-responsiveness, and airway inflammation with a considerable proportion, but not all, of asthma being IgE-mediated further adding to its heterogeneity. This chapter reviews the approaches to the elucidation of genetics of asthma from the early evidence of familial clustering to the current state of knowledge with genome-wide approaches. The conclusion is that research efforts have led to a tremendous repository of genetic determinants of asthma, most of which fall into the above phenotypic domains of the syndrome. We now look to future integrative approaches of genetics, genomics (Chap. 10), and epigenetics (Chap. 11) to better understand the causal mechanism through which, these genetic loci act in manifesting asthma.
Wagemakers, Alexandre; Buldú, Javier M.; Sanjuán, Miguel A. F.; de Luis, Oscar; Izquierdo, Adriana; Coloma, Antonio
We propose a new approach for synchronizing a population of synthetic genetic oscillators, which consists in the entrainment of a colony of repressilators by external modulation. We present a model where the repressilator dynamics is affected by periodic changes in temperature. We introduce an additional plasmid in the bacteria in order to correlate the temperature variations with the enhancement of the transcription rate of a certain gene. This can be done by introducing a promoter that is related to the heat shock response. This way, the expression of that gene results in a protein that enhances the overall oscillations. Numerical results show coherent oscillations of the population for a certain range of the external frequency, which is in turn related to the natural oscillation frequency of the modified repressilator. Finally we study the transient times related with the loss of synchronization and we discuss possible applications in biotechnology of large-scale production coupled to synchronization events induced by heat shock.
Human biobanks, and genetic research databases, as referred to by the Organisation for Economic Co-operation and Development (OECD), are essential tools for modern biomedical research. Biobanks may consist in collections created in clinical diagnosis (such as pathology tissue samples in hospitals) or collections created for large-scale longitudinal research (such as the UK Biobank). Human tissue collections are regulated by a patchwork of national laws. However, there is an increasing international uniformity in national privacy laws based on 1980s OECD standards. There are similar uniform standards developing in national research ethics guidelines. As biobanks develop collaborations and linkages, international harmonisation of legislation and human research regulation will be required across jurisdictions. It is essential that international public trust is maintained in biobanking research.
Sagona, Antonia P; Grigonyte, Aurelija M; MacDonald, Paul R; Jaramillo, Alfonso
Phages or bacteriophages, viruses that infect and replicate inside bacteria, are the most abundant microorganisms on earth. The realization that antibiotic resistance poses a substantial risk to the world's health and global economy is revitalizing phage therapy as a potential solution. The increasing ease by which phage genomes can be modified, owing to the influx of new technologies, has led to an expansion of their natural capabilities, and a reduced dependence on phage isolation from environmental sources. This review will discuss the way synthetic biology has accelerated the construction of genetically modified phages and will describe the wide range of their applications. It will further provide insight into the societal and economic benefits that derive from the use of recombinant phages in various sectors, from health to biodetection, biocontrol and the food industry.
Harris, Andreas W K; Dolan, James A; Kelly, Ciarán L; Anderson, James; Papachristodoulou, Antonis
By incorporating feedback around systems we wish to manipulate, it is possible to improve their performance and robustness properties to meet pre-specified design objectives. For decades control engineers have been successfully implementing feedback controllers for complex mechanical and electrical systems such as aircraft and sports cars. Natural biological systems use feedback extensively for regulation and adaptation but apart from the most basic designs, there is no systematic framework for designing feedback controllers in Synthetic Biology. In this paper we describe how classical approaches from linear control theory can be used to close the loop. This includes the design of genetic circuits using feedback control and the presentation of a biological phase lag controller.
The review focuses on the molecular background of an inborn error of lipid metabolism -familial hypercholesterolemia. FH describes a group of genetic defects resulting in severe elevations of blood cholesterol levels and increased risk of premature coronary heart disease. Most cases are due to the mutations decreasing and/or destroying the function of the LDL receptor (85-90 % of cases), smaller portion of cases is caused by defects in the gene encoding the ligand for LDL receptor - apolipoprotein B-100 (5-10 %). Less than 5 % of cases has gain-of-function station of the PCSK9 gene that increases the rate of degradation of the LDL receptor molecules. Autosomal recessive form of the disease, caused by the mutations in LDLR adaptor protein 1 gene, is extremely rare.Key words: APOB - familial hypercholesterolemia - LDLR - LDLRAP1 - PCSK9.
Hall, E. J.; Brenner, D. J.; Worgul, B.; Smilenov, L.
In the context of space radiation, it is important to know whether the human population includes genetically predisposed radiosensitive subsets. One possibility is that haploinsufficiency for ATM confers radiosensitivity, and this defect involves 1-3% of the population. Using knock-out mice we chose to study cataractogenesis in the lens and oncogenic transformation in mouse embryo fibroblasts to assay for effects of ATM deficiency. Radiation induced cataracts appeared earlier in the heterozygous versus wild-type animals following exposure to either gamma rays or 1 GeV/nucleon iron ions. In addition, it was found that embryo fibroblasts of Atm heterozygotes showed an increased incidence of oncogenic transformation compared with their normal litter-matched counterparts. From these data we suggest that Ataxia Telangiectasia heterozygotes could indeed represent a societally-significant radiosensitive subpopulation.
Makrantonaki, Evgenia; Bekou, Vassiliki; Zouboulis, Christos C.
Skin aging is a complex process and underlies multiple influences with the probable involvement of heritable and various environmental factors. Several theories have been conducted regarding the pathomechanisms of aged skin, however fundamental mechanisms still remain poorly understood. This article addresses the influence of genetics on skin aging and in particular deals with the differences observed in ethnic populations and between both genders. Recent studies indicate that male and female aged skin differs as far as the type, the consistency and the sensitivity to external factors is concerned. The same has been also documented between elderly people of different origin. Consequently, the aging process taking place in both genders and in diverse ethnic groups should be examined separately and products specialized to each population should be developed in order to satisfy the special needs. PMID:23467395
Jones, Jonathan D G
This paper is intended to convey the message of the talk I gave at the Theo Murphy meeting at the Kavli Centre in July 2010. It, like the talk, is polemical, and conveys the exasperation felt by a practitioner of genetically modified (GM) plant science at its widespread misrepresentation. I argue that sustainable intensification of agriculture, using GM as well as other technologies, reduces its environmental impact by reducing pesticide applications and conserving soil carbon by enabling low till methods. Current technologies (primarily insect resistance and herbicide tolerance) have been beneficial. Moreover, the near-term pipeline of new GM methods and traits to enhance our diet, increase crop yields and reduce losses to disease is substantial. It would be perverse to spurn this approach at a time when we need every tool in the toolbox to ensure adequate food production in the short, medium and long term.
Manco, Melania; Dallapiccola, Bruno
Onset of obesity has been anticipated at earlier ages, and prevalence has dramatically increased worldwide over the past decades. Epidemic obesity is mainly attributable to modern lifestyle, but family studies prove the significant role of genes in the individual's predisposition to obesity. Advances in genotyping technologies have raised great hope and expectations that genetic testing will pave the way to personalized medicine and that complex traits such as obesity will be prevented even before birth. In the presence of the pressing offer of direct-to-consumer genetic testing services from private companies to estimate the individual's risk for complex phenotypes including obesity, the present review offers pediatricians an update of the state of the art on genomics obesity in childhood. Discrepancies with respect to genomics of adult obesity are discussed. After an appraisal of findings from genome-wide association studies in pediatric populations, the rare variant-common disease hypothesis, the theoretical soil for next-generation sequencing techniques, is discussed as opposite to the common disease-common variant hypothesis. Next-generation sequencing techniques are expected to fill the gap of "missing heritability" of obesity, identifying rare variants associated with the trait and clarifying the role of epigenetics in its heritability. Pediatric obesity emerges as a complex phenotype, modulated by unique gene-environment interactions that occur in periods of life and are "permissive" for the programming of adult obesity. With the advent of next-generation sequencing techniques and advances in the field of exposomics, sensitive and specific tools to predict the obesity risk as early as possible are the challenge for the next decade.
Thomas, Wayne R; Hales, Belinda J; Smith, Wendy-Anne
The application of recombinant DNA technology to allergen research has provided the sequence information and genetic material to produce new types of allergy vaccines. One general strategy has been to use the knowledge to produce synthetic peptides that represent selected T-cell or B-cell epitopes. The production of genetically engineered allergens provides an alternative strategy to construct hypoallergenic vaccines, which can provide a better and less selected representation of the epitopes. Many strategies have been used to produce such hypoallergens, and their ability to reduce allergenicity has been amply demonstrated by skin and nasal provocation tests. The retention of T cell-stimulating activity has also been demonstrated, and a consistent feature of the vaccines has been, despite the reduced immunoglobulin E (IgE)-binding reactivity, the ability to induce anti-allergen IgG antibody. The lead hypoallergens have been polypeptide fragments and trimeric constructs of the birch allergen Bet v 1. A clinical trial with these medicaments has shown the ability to modify IgE and IgG antibody production, skin test reactivity, and symptom scores. This is the first trial of a recombinant allergy vaccine, and it has set a benchmark for further studies. A new generation of hypoallergens is now being produced based on the detailed knowledge of the tertiary structures of the allergens and of the T-cell and B-cell epitopes. The modifications have been made to change the topography of the allergens while retaining a stable, folding structure. In the case of Bet v 1, tertiary structures of hypoallergens have been determined. Structurally modeled hypoallergens have been produced for pollen, venom, food, and latex allergens, with promising characteristics from preclinical studies.
Wang, Haina; Peng, Nan; Shah, Shiraz A.
SUMMARY Research on archaeal extrachromosomal genetic elements (ECEs) has progressed rapidly in the past decade. To date, over 60 archaeal viruses and 60 plasmids have been isolated. These archaeal viruses exhibit an exceptional diversity in morphology, with a wide array of shapes, such as spindles, rods, filaments, spheres, head-tails, bottles, and droplets, and some of these new viruses have been classified into one order, 10 families, and 16 genera. Investigation of model archaeal viruses has yielded important insights into mechanisms underlining various steps in the viral life cycle, including infection, DNA replication and transcription, and virion egression. Many of these mechanisms are unprecedented for any known bacterial or eukaryal viruses. Studies of plasmids isolated from different archaeal hosts have also revealed a striking diversity in gene content and innovation in replication strategies. Highly divergent replication proteins are identified in both viral and plasmid genomes. Genomic studies of archaeal ECEs have revealed a modular sequence structure in which modules of DNA sequence are exchangeable within, as well as among, plasmid families and probably also between viruses and plasmids. In particular, it has been suggested that ECE-host interactions have shaped the coevolution of ECEs and their archaeal hosts. Furthermore, archaeal hosts have developed defense systems, including the innate restriction-modification (R-M) system and the adaptive CRISPR (clustered regularly interspaced short palindromic repeats) system, to restrict invasive plasmids and viruses. Together, these interactions permit a delicate balance between ECEs and their hosts, which is vitally important for maintaining an innovative gene reservoir carried by ECEs. In conclusion, while research on archaeal ECEs has just started to unravel the molecular biology of these genetic entities and their interactions with archaeal hosts, it is expected to accelerate in the next decade. PMID
Hermisson, Joachim; Wagner, Günter P
One of the most solid generalizations of transmission genetics is that the phenotypic variance of populations carrying a major mutation is increased relative to the wild type. At least some part of this higher variance is genetic and due to release of previously hidden variation. Similarly, stressful environments also lead to the expression of hidden variation. These two observations have been considered as evidence that the wild type has evolved robustness against genetic variation, i.e., genetic canalization. In this article we present a general model for the interaction of a major mutation or a novel environment with the additive genetic basis of a quantitative character under stabilizing selection. We introduce an approximation to the genetic variance in mutation-selection-drift balance that includes the previously used stochastic Gaussian and house-of-cards approximations as limiting cases. We then show that the release of hidden genetic variation is a generic property of models with epistasis or genotype-environment interaction, regardless of whether the wild-type genotype is canalized or not. As a consequence, the additive genetic variance increases upon a change in the environment or the genetic background even if the mutant character state is as robust as the wild-type character. Estimates show that this predicted increase can be considerable, in particular in large populations and if there are conditionally neutral alleles at the loci underlying the trait. A brief review of the relevant literature suggests that the assumptions of this model are likely to be generic for polygenic traits. We conclude that the release of hidden genetic variance due to a major mutation or environmental stress does not demonstrate canalization of the wild-type genotype.
Spinello, Richard A
The primary theme of this paper is the normative case against ownership of one's genetic information along with the source of that information (usually human tissues samples). The argument presented here against such "upstream" property rights is based primarily on utilitarian grounds. This issue has new salience thanks to the Human Genome Project and "bio-prospecting" initiatives based on the aggregation of genetic information, such as the one being managed by deCODE Genetics in Iceland. The rationale for ownership is twofold: ownership will protect the basic human rights of privacy and autonomy and it will enable the data subjects to share in the tangible benefits of the genetic research. Proponents of this viewpoint often cite the principle of genetic exceptionalism, which asserts that genetic information needs a higher level of protection than other kinds of personal information such as financial data. We argue, however, that the recognition of such ownership rights would lead to inefficiency along with the disutility of genetic discoveries. Biomedical research will be hampered if property rights in genes and genetic material are too extensive. We contend that other mechanisms such as informed consent and strict confidentiality rules can accomplish the same result as a property right without the liabilities of an exclusive entitlement.
Child, Anne H; Aragon-Martin, Jose A; Sage, Karen
Genetic testing is aiding rapid diagnosis of Marfan syndrome as a basis for management of eye, heart and skeletal disease. The affected patient's mutation can be used as a basis for prenatal or postnatal diagnosis of offspring. Preimplantation genetic diagnosis, the technique of choice, can ensure an unaffected pregnancy.
Although genetic models were in the ascendance within psychology during the early 20(th) century, the association of early behavioral genetic research with the eugenics movement served to discredit the field in the eyes of many. Twin and adoption studies throughout the latter half of the 20(th) century helped to reestablish the importance of behavioral genetic models and set the stage for the current focus of the field on developing and testing models of gene-environment interplay. Research findings on developmental behavioral genetic research, gene-environment interaction, and the use of behavioral genetic models to test causal hypotheses are used to highlight the contributions of contemporary behavioral genetic research to psychological research. It is argued that future efforts to investigate models of gene-environment interplay will depend heavily of the field's ability to identify the specific genetic variants that contribute to individual differences in behavior. The anticipated yield from genome-wide association studies gives much reason to be optimistic about the future vitality of behavior genetics.
Genetic and physical maps illustrate the arrangement of genes and DNA markers on a chromosome. The relative distances between positions on a genetic map are calculated using recombination frequencies while a physical map is based on the actual number of nucleotide pairs between loci. These maps ar...
... Old Feeding Your 1- to 2-Year-Old All About Genetics KidsHealth > For Parents > All About Genetics A A A What's in this ... if a recipe is missing many ingredients — or all of them) or small (if just one ingredient ...
When genetic evaluations for Productive Life were introduced by USDA in 1994, U.S. dairy producers had an opportunity to produce healthier cows, and it happened. The genetic evaluations were incorporated into selection programs and the deterioration occurring in pregnancy rate and somatic cell score...
An overview of avian metapneumovirus (aMPV) infection in turkeys and development of a reverse genetics system for aMPV subgroup C (aMPV-C) virus will be presented. By using reverse genetics technology, we generated recombinant aMPV-C viruses containing a different length of glycoprotein (G) gene or...
A brief history of classical genetic mapping in soybean [Glycine max (L.) Merr.] is described. Detailed descriptions are given of the development of molecular genetic linkage maps based upon various types of DNA markers Like many plant and animal species, the first molecular map of soybean was bas...
Although genetic models were in the ascendance within psychology during the early 20th century, the association of early behavioral genetic research with the eugenics movement served to discredit the field in the eyes of many. Twin and adoption studies throughout the latter half of the 20th century helped to reestablish the importance of behavioral genetic models and set the stage for the current focus of the field on developing and testing models of gene-environment interplay. Research findings on developmental behavioral genetic research, gene-environment interaction, and the use of behavioral genetic models to test causal hypotheses are used to highlight the contributions of contemporary behavioral genetic research to psychological research. It is argued that future efforts to investigate models of gene-environment interplay will depend heavily of the field’s ability to identify the specific genetic variants that contribute to individual differences in behavior. The anticipated yield from genome-wide association studies gives much reason to be optimistic about the future vitality of behavior genetics. PMID:20072716
Cowan, Ruth Schwartz
The connection that critics make between medical genetics and eugenics is historically fallacious. Activists on the political right are as mistaken as activists on the political left: Genetic screening was not eugenics in the past, is not eugenics in the present, and, unless its technological systems become radically transformed, will not be…
Information is presented on genetic algorithms in outline form. The following topics are discussed: how are new samples generated, a genotypic viewpoint, a phenotypic viewpoint, an optimization viewpoint, an intuitive view, parameter optimization problems, evolving production rates, genetic programming, GAs and NNs, formal analysis, Lemmas and theorems, discrete Walsh transforms, deceptive problems, Markov chain analysis, and PAC learning analysis.
Porter, I.H.; Hatcher, N.H.; Willey, A.M.
This book consists of six sections, each containing several chapters. Some of the chapter titles are: Prenatal Diagnosis of the Fragile X Syndrome; Prenatal Genetic Diagnosis by Chorionic Villus Sampling; Prenatal Treatment of Biochemical Disorders; H-Y Antigen, Sex Determination and Gender Control; and Environmental Factors and Human Birth Defects: Interpretation of Relative Risks in Clinical Genetics.
Tolman, Richard R.
Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)
The National Dairy Genetic Evaluation Program is a continuation of ongoing USDA collaboration with the U.S. dairy industry on genetic evaluation of dairy cattle since 1908. Data are provided by dairy records processing centers (yield, health, pedigree, and reproduction traits), breed registry societ...
Christiani, D C; Mehta, A J; Yu, C-L
Because of their high prevalence in the general population, genetic variants that determine susceptibility to environmental exposures may contribute greatly to the development of occupational diseases in the setting of specific exposures occurring in the workplace. Studies investigating genetic susceptibilities in the workplace may: (1) provide mechanistic insight into the aetiology of disease, in particular the determination of environmentally responsive genes; (2) identify susceptible subpopulations with respect to exposure; and (3) provide valuable input in setting occupational exposure limits by taking genetic susceptibility into account. Polymorphisms in the NAT2 and the HLA-DPB1Glu69 genes provide classic examples of how genetic susceptibility markers have a clear role in identifying disease risk in bladder cancer and chronic beryllium disease, respectively. For diseases with more complex and multifactorial aetiology such as occupational asthma and chronic airways disease, susceptibility studies for selected genetic polymorphisms provide additional insight into the biological mechanisms of disease. Even when polymorphisms for genetic susceptibility have a clear role in identifying disease risk, the value of wide scale genetic screening in occupational settings remains limited due to primarily ethical and social concerns. Thus, large scale genetic screening in the workplace is not currently recommended. PMID:18487431
Wartski, Bert; Wartski, Lynn Marie
Some concepts in genetics are difficult for many students to understand. This document provides hands-on, cost efficient, fun activities for students to help them better understand abstract concepts in genetics. Each activity includes: purpose, introduction, materials, procedures, results and conclusion. Some of the topics explored are: (1)…
Rosenfeld, Ron G.
Context: Genetics plays a major role in determining an individual's height. Although there are many monogenic disorders that lead to perturbations in growth and result in short stature, there is still no consensus as to the role that genetic diagnostics should play in the evaluation of a child with short stature. Evidence Acquisition: A search of PubMed was performed, focusing on the genetic diagnosis of short stature as well as on specific diagnostic subgroups included in this article. Consensus guidelines were reviewed. Evidence Synthesis: There are a multitude of rare genetic causes of severe short stature. There is no high-quality evidence to define the optimal approach to the genetic evaluation of short stature. We review genetic etiologies of a number of diagnostic subgroups and propose an algorithm for genetic testing based on these subgroups. Conclusion: Advances in genomic technologies are revolutionizing the diagnostic approach to short stature. Endocrinologists must become facile with the use of genetic testing in order to identify the various monogenic disorders that present with short stature. PMID:24915122
Biological Sciences Curriculum Study, Colorado Springs, CO. Center for Education in Human and Medical Genetics.
This document (which has the form of a magazine) provides a variety of articles, stories, editorials, letters, interviews, and other types of magazine features (such as book reviews) which focus on human genetics. In addition to providing information about the principles of genetics, nearly all of the sections in the "magazine" address moral,…
Havird, Justin C.; Fitzpatrick, Sarah W.; Kronenberger, John; Funk, W. Chris; Angeloni, Lisa M.; Sloan, Daniel B.
Genetic rescue is a potentially effective management tool to offset the effects of reduced genetic diversity in imperiled populations. However, implementation requires complex choices. Here, we address the consequences of introducing males vs. females, highlighting the possibility that introduced females might lead to maladapted mitonuclear genomes and reduced offspring fitness. PMID:26712562
The overall objectives of this paper are to report on cotton germplasm resources, morphobiological and agronomic diversity of Gossypium genus and review efforts on molecular genetic diversity of cotton gene pools as well as on the challenges and perspectives of exploiting genetic diversity in cotton...
Tsui, Chi-Yan; Treagust, David
Over the past decades, genetics has remained a difficult topic in school science. This paper presents an interactive multimedia program, "BioLogica", used to teach Grade 10 (14- and 15-year-olds) Australian students about genetics. Over six weeks, the teacher used different representations in the teaching and engaged students in computer…
Finnerty, Valerie Raunig
By the end of the eighth grade, students are expected to have a basic understanding of the mechanism of basic genetic inheritance. However, these concepts can be difficult to teach. In this article, the author introduces a new learning tool that will help facilitate student learning and enthusiasm to the basic concepts of genetic inheritance. This…
When it first emerged about 50 years ago, genetic counseling focused primarily on prenatal testing to detect genetic conditions. But counseling services have evolved to keep pace with a greater knowledge of genetics and wider application of genetic diagnostic testing. Today, there are several types of genetic counselors, and their expertise covers…
The traveler attended the Thirty-sixth session of UNSCEAR where he took an active part in the deliberations of the Genetic Sub-subgroup. Good progress was made in discussing the two documents that are in preparation that deal with genetics. Approximately one-third of the traveler's time was spent observing sessions of the main UNSCEAR committee itself, and the remainder was spent in the Genetic Sub-subgroup. Important contacts were made with several prominent geneticists. It was apparent how important it is to ORNL, to DOE, to the United States Government, and to UNSCEAR itself to have at least one representative from the United States on the Genetic Sub-subgroup who has firsthand familiarity with the mouse data that are used to such an important extent in genetic risk estimation. Many of these data were collected in the Biology Division of ORNL.
Potato has a variety of reproductive uniquenesses besides its clonal propagation by tubers. These traits are controlled by a different kind of genetic control. The reproductive information has been applied to enable interspecific hybridization to enhance valuable traits, such as disease and pest resistances, from the tuber-bearing Solanum gene pool. While progress has been made in potato breeding, many resources have been invested due to the requirements of large populations and long time frame. This is not only due to the general pitfalls in plant breeding, but also due to the complexity of polyploid genetics. Tetraploid genetics is the most prominent aspect associated with potato breeding. Genetic maps and markers have contributed to potato breeding, and genome information further elucidates questions in potato evolution and supports comprehensive potato breeding. Challenges yet remain on recognizing intellectual property rights to breeding and germplasm, and also on regulatory aspects to incorporate modern biotechnology for increasing genetic variation in potato breeding. PMID:25931980
Bezzina, Connie R; Lahrouchi, Najim; Priori, Silvia G
Sudden cardiac death occurs in a broad spectrum of cardiac pathologies and is an important cause of mortality in the general population. Genetic studies conducted during the past 20 years have markedly illuminated the genetic basis of the inherited cardiac disorders associated with sudden cardiac death. Here, we review the genetic basis of sudden cardiac death with a focus on the current knowledge on the genetics of the primary electric disorders caused primarily by mutations in genes encoding ion channels, and the cardiomyopathies, which have been attributed to mutations in genes encoding a broader category of proteins, including those of the sarcomere, the cytoskeleton, and desmosomes. We discuss the challenges currently faced in unraveling genetic factors that predispose to sudden cardiac death in the setting of sequela of coronary artery disease and present the genome-wide association studies conducted in recent years on electrocardiographic parameters, highlighting their potential in uncovering new biological insights into cardiac electric function.
Meade, John C; Carlton, Jane M
Recent advances in genetic characterisation of Trichomonas vaginalis isolates show that the extensive clinical variability in trichomoniasis and its disease sequelae are matched by significant genetic diversity in the organism itself, suggesting a connection between the genetic identity of isolates and their clinical manifestations. Indeed, a high degree of genetic heterogeneity in T vaginalis isolates has been observed using multiple genotyping techniques. A unique two-type population structure that is both local and global in distribution has been identified, and there is evidence of recombination within each group, although sexual recombination between the groups appears to be constrained. There is conflicting evidence in these studies for correlations between T vaginalis genetic identity and clinical presentation, metronidazole susceptibility, and the presence of T vaginalis virus, underscoring the need for adoption of a common standard for genotyping the parasite. Moving forward, microsatellite genotyping and multilocus sequence typing are the most robust techniques for future investigations of T vaginalis genotype-phenotype associations.
The Genetic Society of America's Thomas Hunt Morgan Medal is awarded to an individual GSA member for lifetime achievement in the field of genetics. For over 40 years, 2015 recipient Brian Charlesworth has been a leader in both theoretical and empirical evolutionary genetics, making substantial contributions to our understanding of how evolution acts on genetic variation. Some of the areas in which Charlesworth's research has been most influential are the evolution of sex chromosomes, transposable elements, deleterious mutations, sexual reproduction, and life history. He also developed the influential theory of background selection, whereby the recurrent elimination of deleterious mutations reduces variation at linked sites, providing a general explanation for the correlation between recombination rate and genetic variation.
Wray, N R; Visscher, P M
John James authored two key papers on the theory of risk to relatives for binary disease traits and the relationship between parameters on the observed binary scale and an unobserved scale of liability (James Annals of Human Genetics, 1971; 35: 47; Reich, James and Morris Annals of Human Genetics, 1972; 36: 163). These two papers are John James' most cited papers (198 and 328 citations, November 2014). They have been influential in human genetics and have recently gained renewed popularity because of their relevance to the estimation of quantitative genetics parameters for disease traits using SNP data. In this review, we summarize the two early papers and put them into context. We show recent extensions of the theory for ascertained case-control data and review recent applications in human genetics.
The Genetic Society of America’s Thomas Hunt Morgan Medal is awarded to an individual GSA member for lifetime achievement in the field of genetics. For over 40 years, 2015 recipient Brian Charlesworth has been a leader in both theoretical and empirical evolutionary genetics, making substantial contributions to our understanding of how evolution acts on genetic variation. Some of the areas in which Charlesworth’s research has been most influential are the evolution of sex chromosomes, transposable elements, deleterious mutations, sexual reproduction, and life history. He also developed the influential theory of background selection, whereby the recurrent elimination of deleterious mutations reduces variation at linked sites, providing a general explanation for the correlation between recombination rate and genetic variation. PMID:26170438
Belsky, Daniel W; Israel, Salomon
The sequencing of the human genome and the advent of low-cost genome-wide assays that generate millions of observations of individual genomes in a matter of hours constitute a disruptive innovation for social science. Many public use social science datasets have or will soon add genome-wide genetic data. With these new data come technical challenges, but also new possibilities. Among these, the lowest-hanging fruit and the most potentially disruptive to existing research programs is the ability to measure previously invisible contours of health and disease risk within populations. In this article, we outline why now is the time for social scientists to bring genetics into their research programs. We discuss how to select genetic variants to study. We explain how the polygenic architecture of complex traits and the low penetrance of individual genetic loci pose challenges to research integrating genetics and social science. We introduce genetic risk scores as a method of addressing these challenges and provide guidance on how genetic risk scores can be constructed. We conclude by outlining research questions that are ripe for social science inquiry.
Belsky, Daniel W.; Israel, Salomon
The sequencing of the human genome and the advent of low-cost genome-wide assays that generate millions of observations of individual genomes in a matter of hours constitute a disruptive innovation for social science. Many public-use social science datasets have or will soon add genome-wide genetic data. With these new data come technical challenges, but also new possibilities. Among these, the lowest hanging fruit and the most potentially disruptive to existing research programs is the ability to measure previously invisible contours of health and disease risk within populations. In this article, we outline why now is the time for social scientists to bring genetics into their research programs. We discuss how to select genetic variants to study. We explain how the polygenic architecture of complex traits and the low penetrance of individual genetic loci pose challenges to research integrating genetics and social science. We introduce genetic risk scores as a method of addressing these challenges and provide guidance on how genetic risk scores can be constructed. We conclude by outlining research questions that are ripe for social science inquiry. PMID:25343363
Normark, Benjamin B.; Ross, Laura
Genetic conflict may have played an important role in the evolution of novel genetic systems. The ancestral system of eumendelian genetics is highly symmetrical. Those derived from it (e.g. thelytokous parthenogenesis, haplodiploidy and parent-specific allele expression) are more asymmetrical in the genetic role played by maternal versus paternal alleles. These asymmetries may have arisen from maternal–paternal genetic conflict, or cytonuclear conflict, or from an interaction between them. Asymmetric genetic systems are much more common in terrestrial and freshwater taxa than in marine taxa. We suggest three reasons for this, based on the relative inhospitability of terrestrial environments to three types of organism: (i) pathogens—departure from the marine realm meant escape from many pathogens and parasites, reducing the need for sexual reproduction; (ii) symbionts—symbionts are no more important in the terrestrial realm than the marine realm but are more likely to be obligately intracellular and vertically transmitted, making them more likely to disrupt their host's genetic systems; (iii) Gametes and embryos—because neither gametes nor embryos can be shed into air as easily as into seawater, the mother's body is a more important environment for both types of organisms in the terrestrial realm than in the marine realm. This environment of asymmetric kinship (with neighbours more closely related by maternal alleles than by paternal alleles) may have helped to drive asymmetries in expression and transmission. PMID:24686935
Burian, Richard M.
This paper addresses the teaching of advanced high school courses or undergraduate courses for non-biology majors about genetics or history of genetics. It will probably be difficult to take the approach described here in a high school science course, although the general approach could help improve such courses. It would be ideal for a college course in history of genetics or a course designed to teach non-science majors how science works or the rudiments of the genetics in a way that will help them as citizens. The approach aims to teach the processes of discovery, correction, and validation by utilizing illustrative episodes from the history of genetics. The episodes are treated in way that should foster understanding of basic questions about genes, the sorts of techniques used to answer questions about the constitution and structure of genes, how they function, and what they determine, and some of the major biological disagreements that arose in dealing with these questions. The material covered here could be connected to social and political issues raised by genetics, but these connections are not surveyed here. As it is, to cover this much territory, the article is limited to four major episodes from Mendel's paper to the beginning of World War II. A sequel will deal with the molecularization of genetics and with molecular gene concepts through the Human Genome Project.
Boonsirichai, K.; Chen, R.; Guan, C.; Rosen, E.; Young, L.; Masson, P.
Gravitropism guides the growth of plant organs at a defined angle from the gravity vector. Accordingly, most roots grow downward, undergoing positive gravitropism. Gravity perception by roots appears to involve the sedimentation of amyloplasts within the columella cells of the cap. Amyloplast sedimentation triggers a signal transduction pathway that promotes the development of an auxin gradient across the root tip. This gradient is then transmitted to the elongation zones where it promotes a differential cellular elongation, partly responsible for the development of a root-tip curvature. To better understand the mechanisms involved in gravity signal transduction, we have identified and characterized several Arabidopsis thaliana mutants that show specific defects in root gravitropism. Several of these genes were characterized. ARG1 functions in gravity signal transduction, and encodes a dnaJ-like protein whose structure suggests an interaction with the cytoskeleton. Two other genes encode similar proteins (ARL1 and ARL2) in Arabidopsis. One of them (ARL2) also appears to function in gravity signal transduction. Because loss-of-function mutations in ARG1 result in partial alterations of gravitropism, we were able to identify and characterize two genetic enhancers of arg1-2: mar1-1 and mar2-1. These enhancers increased the gravitropism defect of arg1-2 roots and hypocotyls, and changed its orientation. Hence, MAR1 and MAR2 also appear to function in gravity signal transduction. AGR1, on the other hand, encodes a transmembrane component of the auxin efflux carrier complex involved in polar auxin transport through the elongation zones of Arabidopsis root tips. It belongs to a large gene family, several members of which are expressed in the root cap. Upon gravistimulation, the AGR3 protein appears to quickly relocate within the columella cells, accumulating in membranes at the new physical bottom. Hence, the gravity signal transduction pathway that includes the ARG1, ARL
... People with this condition have multiple noncancerous (benign) bone tumors called osteochondromas. Multiple osteochondromas may result in pain, ... disorders inherited? More about Inheriting Genetic Conditions Diagnosis & Management Genetic Testing (1 link) Genetic Testing Registry: Langer- ...
... can be inherited? More about Inheriting Genetic Conditions Diagnosis & Management Genetic Testing (1 link) Genetic Testing Registry: Familial amyloid nephropathy with urticaria AND deafness General Information from MedlinePlus ( ...
DeYoung, H. Garrett
Current research in plant genetics is described. Benefits of this research (which includes genetic engineering applications) will include reduction/elimination of crop diseases, assurance of genetic stability, and the creation of new crop varieties. (JN)
Ingles, Jodie; Semsarian, Christopher
Genetic testing is an important and necessary aspect of the management of families with cardiac genetic conditions. Commercial genetic tests are available for most cardiac genetic diseases, and increasing uptake amongst patients has contributed to a vastly improved knowledge of the genetic basis of these diseases. The incredible advances in genetic technologies have translated to faster, more comprehensive, and inexpensive commercial genetic tests and has completely changed the landscape of commercial genetic testing in recent years. While there are enormous challenges, mostly relating to interpretation of variants, the value of a genetic diagnosis should not be underestimated. In almost all cases, the single greatest utility is for the predictive genetic testing of family members. This review will describe the value of cardiac genetic testing in the current climate of rapid genetic advancements.
... Bender BG, Robinson A. Genetic counseling for sex chromosome abnormalities. Am J Med Genet. 2002 Jun 1;110( ... one prenatally diagnosed children and adolescents with sex chromosome abnormalities. Am J Med Genet. 2002 Jun 1;110( ...
... Donnell L, Hale DE, Cody JD. Adults with Chromosome 18 Abnormalities. J Genet Couns. 2015 Aug;24(4):663- ... J, Escamilla M. Psychiatric syndromes in individuals with chromosome 18 abnormalities. Am J Med Genet B Neuropsychiatr Genet. 2010 ...
... Bender BG, Robinson A. Genetic counseling for sex chromosome abnormalities. Am J Med Genet. 2002 Jun 1;110( ... one prenatally diagnosed children and adolescents with sex chromosome abnormalities. Am J Med Genet. 2002 Jun 1;110( ...
... of the American Heart Association Cardiology Patient Page Genetic Testing for Inherited Heart Disease Allison L. Cirino , ... for developing the family’s heart condition. What Is Genetic Testing and What Can it Tell Me? Genetic ...
Edenberg, Howard J; Foroud, Tatiana
Alcohol is widely consumed; however, excessive use creates serious physical, psychological and social problems and contributes to the pathogenesis of many diseases. Alcohol use disorders (that is, alcohol dependence and alcohol abuse) are maladaptive patterns of excessive drinking that lead to serious problems. Abundant evidence indicates that alcohol dependence (alcoholism) is a complex genetic disease, with variations in a large number of genes affecting a person's risk of alcoholism. Some of these genes have been identified, including two genes involved in the metabolism of alcohol (ADH1B and ALDH2) that have the strongest known affects on the risk of alcoholism. Studies continue to reveal other genes in which variants affect the risk of alcoholism or related traits, including GABRA2, CHRM2, KCNJ6 and AUTS2. As more variants are analysed and studies are combined for meta-analysis to achieve increased sample sizes, an improved picture of the many genes and pathways that affect the risk of alcoholism will be possible.
Alentorn, Agusti; Labussière, Marianne; Sanson, Marc; Delattre, Jean-Yves; Hoang-Xuan, Khê; Idbaih, Ahmed
Chromosome arms 1p and 19q codeletion, corresponding to an unbalanced reciprocal translocation t(1;19)(q10;p10), is seen in oligodendroglial tumours and is associated with better prognosis and better chemosensitivity. BRAF abnormalities are observed in pilocytic astrocytomas (tandem duplication-rearrangement) and in pleomorphic xanthoastrocytomas (BRAF V600E mutation). The vast majority of primary or de novo glioblastomas exhibit genetic abnormalities disrupting the intracellular signaling pathways of: transmembrane tyrosine kinase receptors to growth factors and their downstream signaling pathways (i.e. NF1-RAS-RAF-MAPK and PTEN-PI3K-AKT-TSC-mTOR); RB and; TP53. IDH1 and IDH2 mutations are frequent in diffuse grade II and grade III gliomas and in secondary glioblastomas. They are diagnostic and favorable independent prognostic biomarkers. In contrast, they are rare in primary or de novo glioblastomas and not reported in pilocytic astrocytomas. Germlin mutations in MSH2/MLH1/PMS2/MSH6, CDKN2A, TSC1/TSC2, PTEN, TP53 and NF1/NF2 predispose to glial tumors in the setting of hereditary cancer predisposition syndromes. Single nucleotide polymorphisms in TERT,CCDC26, CDKN2A/CDKN2B, RTEL, EGFR and PHLDB1 confer an inherited susceptibility to glial tumors.
Engelhart, Aaron E.; Hud, Nicholas V.
Since the structure of DNA was elucidated more than 50 years ago, Watson-Crick base pairing has been widely speculated to be the likely mode of both information storage and transfer in the earliest genetic polymers. The discovery of catalytic RNA molecules subsequently provided support for the hypothesis that RNA was perhaps even the first polymer of life. However, the de novo synthesis of RNA using only plausible prebiotic chemistry has proven difficult, to say the least. Experimental investigations, made possible by the application of synthetic and physical organic chemistry, have now provided evidence that the nucleobases (A, G, C, and T/U), the trifunctional moiety ([deoxy]ribose), and the linkage chemistry (phosphate esters) of contemporary nucleic acids may be optimally suited for their present roles—a situation that suggests refinement by evolution. Here, we consider studies of variations in these three distinct components of nucleic acids with regard to the question: Is RNA, as is generally acknowledged of DNA, the product of evolution? If so, what chemical and structural features might have been more likely and advantageous for a proto-RNA? PMID:20462999
Prusiner, S B; Scott, M R
Prions are unprecedented infectious pathogens that cause a group of invariably fatal, neurodegenerative diseases by an entirely novel mechanism. Prion diseases may present as genetic, infectious, or sporadic disorders, all of which involve modification of the prion protein (PrP). The human prion disease Creutzfeldt-Jakob disease (CJD) generally presents as a progressive dementia, whereas scrapie of sheep and bovine spongiform encephalopathy (BSE) are manifest as ataxic illnesses. Prions are devoid of nucleic acid and seem to be composed exclusively of a modified isoform of PrP designated PrPSc. The normal, cellular PrP designated PrPC is converted into PrPSc through a process whereby some of its alpha-helical structure is converted into beta-sheet. The species of a particular prion is encoded by the sequence of the chromosomal PrP gene of the mammals in which it last replicated. In contrast to pathogens with a nucleic acid genome, prions encipher strain-specific properties in the tertiary structure of PrPSc. Transgenetic studies argue that PrPSc acts as a template upon which PrPC is refolded into a nascent PrPSc molecule through a process facilitated by another protein.
Hall, E. J.; Brenner, D. J.; Worgul, B.; Smilenov, L.
In the context of space radiation, it is important to know whether the human population includes genetically predisposed radiosensitive subsets. One possibility is that haploinsufficiency for ATM confers radiosensitivity, and this defect involves 1 3% of the population. Using knock-out mice we chose to study cataractogenesis in the lens and oncogenic transformation in mouse embryo fibroblasts to assay for effects of ATM deficiency. Radiation induced cataracts appeared earlier in the heterozygous versus wild-type animals following exposure to either gamma rays or 1 GeV/nucleon iron ions. In addition, it was found that embryo fibroblasts of Atm heterozygotes showed an increased incidence of oncogenic transformation compared with their normal litter-matched counterparts. From these data we suggest that Ataxia Telangiectasia heterozygotes could indeed represent a societally significant radiosensitive subpopulation. Knock-out mice are now available for other genes including BRCA1 and 2, and Mrad9. An exciting possibility is the creation of double heterozygotes for pairs of mutated genes that function in the same signal transduction pathway, and consequently confer even greater radiosensitivity.
Bevilacqua, Laura; Goldman, David
Emotion is critical to most aspects of human behavior, and individual differences in systems recruited to process emotional stimuli, expressed as variation in emotionality, are characteristic of several neuropsychiatric disorders. We examine the genetic origins of individual differences in emotion processing by focusing on functional variants at five genes: catechol-O-methyltransferase (COMT), serotonin transporter (SLC6A4), neuropeptide Y (NPY), a glucocorticoid receptor-regulating co-chaperone of stress proteins (FKBP5) and pituitary adenylate cyclase-activating polypeptide receptor (ADCYAP1R1). These represent a range of effects of genes on emotion as well as the variety of mechanisms and factors, such as stress, that modify these effects. The new genomic era of genome-wide association studies (GWAS) and deep sequencing may yield a wealth of new loci modulating emotion. The effects of these genes can be validated by neuroimaging, neuroendocrine and other studies accessing intermediate phenotypes, deepening our understanding of mechanisms of emotion and variation in emotionality.
Amundadottir, Laufey T.
Although relatively rare, pancreatic tumors are highly lethal . In the United States, an estimated 48,960 individuals will be diagnosed with pancreatic cancer and 40,560 will die from this disease in 2015 . Globally, 337,872 new pancreatic cancer cases and 330,391 deaths were estimated in 2012 . In contrast to most other cancers, mortality rates for pancreatic cancer are not improving; in the US, it is predicted to become the second leading cause of cancer related deaths by 2030 [3, 4]. The vast majority of tumors arise in the exocrine pancreas, with pancreatic ductal adenocarcinoma (PDAC) accounting for approximately 95% of tumors. Tumors arising in the endocrine pancreas (pancreatic neuroendocrine tumors) represent less than 5% of all pancreatic tumors . Smoking, type 2 diabetes mellitus (T2D), obesity and pancreatitis are the most consistent epidemiological risk factors for pancreatic cancer . Family history is also a risk factor for developing pancreatic cancer with odds ratios (OR) ranging from 1.7-2.3 for first-degree relatives in most studies, indicating that shared genetic factors may play a role in the etiology of this disease [6-9]. This review summarizes the current knowledge of germline pancreatic cancer risk variants with a special emphasis on common susceptibility alleles identified through Genome Wide Association Studies (GWAS). PMID:26929738
Rutsch, Frank; Nitschke, Yvonne; Terkeltaub, Robert
Artery calcification reflects an admixture of factors such as ectopic osteochondral differentiation with primary host pathological conditions. We review how genetic factors, as identified by human genome-wide association studies, and incomplete correlations with various mouse studies, including knockout and strain analyses, fit into “pieces of the puzzle” in intimal calcification in human atherosclerosis, and artery tunica media calcification in aging, diabetes mellitus, and chronic kidney disease. We also describe in sharp contrast how ENPP1, CD73, and ABCC6 serve as “cogs in a wheel” of arterial calcification. Specifically, each is a minor component in the function of a much larger network of factors that exert balanced effects to promote and suppress arterial calcification. For the network to normally suppress spontaneous arterial calcification, the “cogs” ENPP1, CD73, and ABCC6 must be present and in working order. Monogenic ENPP1, CD73, and ABCC6 deficiencies each drive a molecular pathophysiology of closely related but phenotypically different diseases (generalized arterial calcification of infancy (GACI), pseudoxan-thoma elasticum (PXE) and arterial calcification caused by CD73 deficiency (ACDC)), in which premature onset arterial calcification is a prominent but not the sole feature. PMID:21852556
Selection is the major tool used by breeders to improve the genetic quality of their livestock. Traditional methods of selection are well proven and useful in improving the economic merit of livestock. The performance of an animal is affected by its genetic quality and by the environment in which it is reared. While environmental improvement is expensive and requires continuous inputs, genetic improvement is cumulative and permanent, provided that selection is maintained. To select an animal on its genetic merit account must be taken of the environmental effects on its performance. Comparisons between the performance of animals on different farms or in different years are not valid unless they have genetic material in common. The speed at which genetic improvement is passed on to the rest of a population is affected by the variation and heritability of the traits being selected, the selection intensity and the generation interval. The deer population in the United Kingdom has a high degree of variation for important traits but the selection intensity is low and the generation intervals are larger than in other farmed species. Central performance testing, group breeding schemes and the use of artificial insemination are tools which will be important in the genetic improvement of farmed deer.
Boyle, Philip J
... Such moral problems raise the question whether society should make all or only some of the potential and existing genetic technologies widely available. Add to this the very real concern that the throng of products and services generated through this research has the potential to put significant further pressure on a health care system that already cannot provide adequate services to all persons. Given current restructuring of U.S. health services along the lines of managed health care, the need and desire of public and private parties to manage health resources aggressively by controlling costs and quality of care will call the question about what services to make available, to whom, on what basis. By what criteria should priorities be set? Should genetic services sought by only a few be made available? Should genetic screening and testing be offered for conditions for which there is no cure? Should specific groups be targeted for the distribution of genetic services? Are any genetic services more important than others? Where do genetic services fit relative to other health services? And -- the perennial question -- who should make these decisions? What does the newly emerging debate over the fair distribution of health resources mean for genetics?
Templeton, Alan R
Starting with "mitochondrial Eve" in 1987, genetics has played an increasingly important role in studies of the last two million years of human evolution. It initially appeared that genetic data resolved the basic models of recent human evolution in favor of the "out-of-Africa replacement" hypothesis in which anatomically modern humans evolved in Africa about 150,000 years ago, started to spread throughout the world about 100,000 years ago, and subsequently drove to complete genetic extinction (replacement) all other human populations in Eurasia. Unfortunately, many of the genetic studies on recent human evolution have suffered from scientific flaws, including misrepresenting the models of recent human evolution, focusing upon hypothesis compatibility rather than hypothesis testing, committing the ecological fallacy, and failing to consider a broader array of alternative hypotheses. Once these flaws are corrected, there is actually little genetic support for the out-of-Africa replacement hypothesis. Indeed, when genetic data are used in a hypothesis-testing framework, the out-of-Africa replacement hypothesis is strongly rejected. The model of recent human evolution that emerges from a statistical hypothesis-testing framework does not correspond to any of the traditional models of human evolution, but it is compatible with fossil and archaeological data. These studies also reveal that any one gene or DNA region captures only a small part of human evolutionary history, so multilocus studies are essential. As more and more loci became available, genetics will undoubtedly offer additional insights and resolutions of human evolution.
Dick, Danielle M; Adkins, Amy E; Kuo, Sally I-Chun
Adolescence is a transitional, developmental phase with marked shifts in behavior, particularly as related to risk-taking and experimentation. Genetic influences on adolescent behavior also show marked changes across this developmental period; in fact, adolescence showcases the dynamic nature of genetic influences on human behavior. Using the twin studies literature on alcohol use and misuse, we highlight several principles of genetic influence on adolescent behavior. We illustrate how genetic influences change (increase) across adolescence, as individuals have more freedom to express their predispositions and to shape their social worlds. We show how there are multiple genetic pathways to risk, and how the environment can moderate the importance of genetic predispositions. Finally, we review the literature aimed at identifying specific genes involved in adolescent behavior and understanding how identified genes impact adolescent outcomes. Ultimately, understanding how genetic predispositions combine with environmental influences to impact pathways of risk and resilience should be translated into improved prevention and intervention efforts; this remains a rich area for future research.
Hashimoto, R; Ohi, K; Yamamori, H; Yasuda, Y; Fujimoto, M; Umeda-Yano, S; Watanabe, Y; Fukunaga, M; Takeda, M
Imaging genetics is an integrated research method that uses neuroimaging and genetics to assess the impact of genetic variation on brain function and structure. Imaging genetics is both a tool for the discovery of risk genes for psychiatric disorders and a strategy for characterizing the neural systems affected by risk gene variants to elucidate quantitative and mechanistic aspects of brain function implicated in psychiatric disease. Early studies of imaging genetics included association analyses between brain morphology and single nucleotide polymorphisms whose function is well known, such as catechol-Omethyltransferase (COMT) and brain-derived neurotrophic factor (BDNF). GWAS of psychiatric disorders have identified genes with unknown functions, such as ZNF804A, and imaging genetics has been used to investigate clues of the biological function of these genes. The difficulty in replicating the findings of studies with small sample sizes has motivated the creation of largescale collaborative consortiums, such as ENIGMA, CHARGE and IMAGEN, to collect thousands of images. In a genome-wide association study, the ENIGMA consortium successfully identified common variants in the genome associated with hippocampal volume at 12q24, and the CHARGE consortium replicated this finding. The new era of imaging genetics has just begun, and the next challenge we face is the discovery of small effect size signals from large data sets obtained from genetics and neuroimaging. New methods and technologies for data reduction with appropriate statistical thresholds, such as polygenic analysis and parallel independent component analysis (ICA), are warranted. Future advances in imaging genetics will aid in the discovery of genes and provide mechanistic insight into psychiatric disorders.
Hashimoto, R; Ohi, K; Yamamori, H; Yasuda, Y; Fujimoto, M; Umeda-Yano, S; Watanabe, Y; Fukunaga, M; Takeda, M
Imaging genetics is an integrated research method that uses neuroimaging and genetics to assess the impact of genetic variation on brain function and structure. Imaging genetics is both a tool for the discovery of risk genes for psychiatric disorders and a strategy for characterizing the neural systems affected by risk gene variants to elucidate quantitative and mechanistic aspects of brain function implicated in psychiatric disease. Early studies of imaging genetics included association analyses between brain morphology and single nucleotide polymorphisms whose function is well known, such as catechol-O-methyltransferase (COMT) and brain-derived neurotrophic factor (BDNF). GWAS of psychiatric disorders have identified genes with unknown functions, such as ZNF804A, and imaging genetics has been used to investigate clues of the biological function of these genes. The difficulty in replicating the findings of studies with small sample sizes has motivated the creation of large-scale collaborative consortiums, such as ENIGMA, CHARGE and IMAGEN, to collect thousands of images. In a genome-wide association study, the ENIGMA consortium successfully identified common variants in the genome associated with hippocampal volume at 12q24, and the CHARGE consortium replicated this finding. The new era of imaging genetics has just begun, and the next challenge we face is the discovery of small effect size signals from large data sets obtained from genetics and neuroimaging. New methods and technologies for data reduction with appropriate statistical thresholds, such as polygenic analysis and parallel independent component analysis (ICA), are warranted. Future advances in imaging genetics will aid in the discovery of genes and provide mechanistic insight into psychiatric disorders. PMID:25732148
Klitzman, Robert L.
Critical questions arise about misunderstandings of genetics. We interviewed for 2 h each, 64 individuals who had or were at risk for Huntington’s disease (HD), breast cancer or Alpha-1 antitrypsin deficiency. These individuals revealed various misunderstandings that can affect coping, and testing, treatment and reproductive decisions. A therapeutic misconception about testing appeared: that testing would be helpful in and of itself. Many believed they could control genetic disorders (even HD), yet these beliefs were often incorrect, and could impede coping, testing, and treatment. Misunderstandings about statistics and genetics often fueled each other, and reflected denial, and desires for hope and control. Emotional needs can thus outweigh understandings of genetics and statistics, and providers’ input. Individuals often maintained non-scientific beliefs, though embarrassed by these. These data have implications for care, and public and professional education. Misunderstandings’ persistence, despite realization of their inaccuracy, suggests that providers need to address not just cognitive facts, but underlying emotional issues. PMID:20512408
The family trees of 16 homosexual males are evaluated in the material of their Genetic Counselling Clinic. The familial cluster of three cases corresponded to the X-linked recessive inheritance. The results of family, twin and adoption studies are reviewed and the recent findings of molecular genetic and brain researches are summarised. Male homosexuality comprises of different subgroups, but one major entity is caused by X-linked recessive gene(s). This genetic background represent a predisposition which is triggered or suppressed by external factors.
Merriman, Tony R; Choi, Hyon K; Dalbeth, Nicola
Gout results from deposition of monosodium urate (MSU) crystals. Elevated serum urate concentrations (hyperuricemia) are not sufficient for the development of disease. Genome-wide association studies (GWAS) have identified 28 loci controlling serum urate levels. The largest genetic effects are seen in genes involved in the renal excretion of uric acid, with others being involved in glycolysis. Whereas much is understood about the genetic control of serum urate levels, little is known about the genetic control of inflammatory responses to MSU crystals. Extending knowledge in this area depends on recruitment of large, clinically ascertained gout sample sets suitable for GWAS.
It is argued that justice in some cases provides a pro tanto reason genetically to enhance victims of the genetic lottery. Various arguments--both to the effect that justice provides no such reason and to the effect that while there may be such reasons, they are overridden by certain moral constraints--are considered and rejected. Finally, it is argued that justice provides stronger reasons to perform more traditional medical tasks (treatments), and that therefore genetic enhancements should not play an important role in a public health care system.
Liepins, G.E. ); Vose, M.D. )
We address deceptiveness, one of at least four reasons genetic algorithms can fail to converge to function optima. We construct fully deceptive functions and other functions of intermediate deceptiveness. For the fully deceptive functions of our construction, we generate linear transformations that induce changes of representation to render the functions fully easy. We further model genetic algorithm selection recombination as the interleaving of linear and quadratic operators. Spectral analysis of the underlying matrices allows us to draw preliminary conclusions about fixed points and their stability. We also obtain an explicit formula relating the nonuniform Walsh transform to the dynamics of genetic search. 21 refs.
Tetushkin, E Ia
The review surveys the development and the current state of genetic genealogy, a branch of science dealing with the history of individuals, families, and kins using molecular genetic methods. The main milestones in the development of genetic genealogy are established: the appearance of essential prerequisites (development of DNA genotyping and forensic techniques of evaluating biological kinship); the first publications on the topic in the late 1990s; the establishment of commercial companies, periodicals, and noncommercial organizations dealing with this subject. The theory and practical applications of dating individuals back to the most recent common ancestors on the basis of Y-chromosomal amd mitochondrial DNA data are briefly considered.
von Hinke, Stephanie; Davey Smith, George; Lawlor, Debbie A.; Propper, Carol; Windmeijer, Frank
The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists, statisticians, epidemiologists and social scientists. Although IV is commonly used in economics, the appropriate conditions for the use of genetic variants as instruments have not been well defined. The increasing availability of biomedical data, however, makes understanding of these conditions crucial to the successful use of genotypes as instruments. We combine the econometric IV literature with that from genetic epidemiology, and discuss the biological conditions and IV assumptions within the statistical potential outcomes framework. We review this in the context of two illustrative applications. PMID:26614692
Dutch professional groups involved in drawing up this guideline: cardiologists, paediatric cardiologists, clinical geneticists, clinical molecular geneticists, genetic counsellors, psychosocial workers, associated with or cooperating with the university hospitals’ outpatient clinics for cardiogenetics. Approved by the NVVC, VKGN and NVK (paediatric cardiology section). NVVC - Nederlandse Vereniging voor Cardiologie – Dutch Society for Cardiology; VKGN - Vereniging Klinische Genetica Nederland – the Netherlands Society for Clinical Genetics; NVK - Nederlandse Vereniging Kindergeneeskunde – Dutch Society for Paediatrics. First published in Dutch in June 2009. PMID:20390065
... More than 200 affected individuals have been identified worldwide. Related Information What information about a genetic condition can statistics provide? Why are some genetic conditions more common ...
... rare; about 50 affected individuals have been identified worldwide. Related Information What information about a genetic condition can statistics provide? Why are some genetic conditions more common ...
Fennel, Theron R.; Underbrink, A. J., Jr.; Williams, George P. W., Jr.
In many domains, scheduling a sequence of jobs is an important function contributing to the overall efficiency of the operation. At Boeing, we develop schedules for many different domains, including assembly of military and commercial aircraft, weapons systems, and space vehicles. Boeing is under contract to develop scheduling systems for the Space Station Payload Planning System (PPS) and Payload Operations and Integration Center (POIC). These applications require that we respect certain sequencing restrictions among the jobs to be scheduled while at the same time assigning resources to the jobs. We call this general problem scheduling and resource allocation. Genetic algorithms (GA's) offer a search method that uses a population of solutions and benefits from intrinsic parallelism to search the problem space rapidly, producing near-optimal solutions. Good intermediate solutions are probabalistically recombined to produce better offspring (based upon some application specific measure of solution fitness, e.g., minimum flowtime, or schedule completeness). Also, at any point in the search, any intermediate solution can be accepted as a final solution; allowing the search to proceed longer usually produces a better solution while terminating the search at virtually any time may yield an acceptable solution. Many processes are constrained by restrictions of sequence among the individual jobs. For a specific job, other jobs must be completed beforehand. While there are obviously many other constraints on processes, it is these on which we focussed for this research: how to allocate crews to jobs while satisfying job precedence requirements and personnel, and tooling and fixture (or, more generally, resource) requirements.
... gene SERAC1 impair mitochondrial function and intracellular cholesterol trafficking and cause dystonia and deafness. Nat Genet. 2012 ... Accessibility FOIA Viewers & Players U.S. Department of Health & Human Services National Institutes of Health National Library of ...
Grimaldi, Keith Anthony; Paoli, Antonio; Smith, Graeme John
Personal genetic testing which is not strictly related to medicine or health is becoming more and more popular covering areas from ancestry, genealogy, nutrition& lifestyle and more recently sports and exercise. The reasons are compelling - if it were possible to read in our genes our potential sporting attributes and how to achieve them it would be valuable information. But is it possible? This overview will look at the current situation and future prospects the authors believe that there is utility in sports genetic testing exactly what can be interpreted from our genetic results needs to be precisely defined and limited to what has been demonstrated by repeated scientific studies. Current areas of interest include optimizing exercise/training routines, VO2max improvement and predisposition to some common sports related injuries such as tendonitis. The interest and the scientific progress is reflected both in increasing rate of publication of geneexercise studies as well as in patent applications concerning genetic associations with commercial potential.
... contribute to the formation of thromboses. However, the contribution of these genetic changes to the development of ... Koike T. Antiphospholipid syndrome: 30 years and our contribution. Int J Rheum Dis. 2015 Feb;18(2): ...
Lyons, Leslie A
Varieties of genetic tests are currently available for the domestic cat that support veterinary health care, breed management, species identification, and forensic investigations. Approximately thirty-five genes contain over fifty mutations that cause feline health problems or alterations in the cat's appearance. Specific genes, such as sweet and drug receptors, have been knocked-out of Felidae during evolution and can be used along with mtDNA markers for species identification. Both STR and SNP panels differentiate cat race, breed, and individual identity, as well as gender-specific markers to determine sex of an individual. Cat genetic tests are common offerings for commercial laboratories, allowing both the veterinary clinician and the private owner to obtain DNA test results. This article will review the genetic tests for the domestic cat, and their various applications in different fields of science. Highlighted are genetic tests specific to the individual cat, which are a part of the cat's genome.
... Pachyonychia Congenita McLean WH, Hansen CD, Eliason MJ, Smith FJ. The phenotypic and molecular genetic features of ... 10.1001/jamadermatol.2013.6448. Citation on PubMed Smith FJ, Liao H, Cassidy AJ, Stewart A, Hamill ...
... a new hair. Increased levels of androgens in hair follicles can lead to a shorter cycle of hair ... lead to increased activity of androgen receptors in hair follicles. It remains unclear, however, how these genetic changes ...
... body such as cells of the nail beds, hair follicles, skin, lining of the mouth (oral mucosa), and ... Testing Registry: Dyskeratosis congenita autosomal recessive 1 Genetic Testing Registry: Dyskeratosis congenita X-linked ... Care Surgery and Rehabilitation ...
Nyhan, W.L.; Sakati, N.A.
This book discusses the diagnosis and management of genetically determined diseases. Genetics are also discussed, but the major focus is on diagnosis. Patients with genetically determined disorders have clinical pictures that cross most of the boundaries of subspecialty practice, and are frequently seen by a variety of physicians. The pediatrician will often be the first to come in contact with these patients, but internists are increasingly concerned with these patients, especially those with inborn errors of metabolism. The hematologist may be the first to see a patient with Fanconi anemia, and the gynecologist, the patient with Turner's syndrome. In brief this book emphasizes the diagnosis of various genetic diseases in relation to different medical specialties.
... have clouding of the lenses of the eyes ( cataracts ) from birth (congenital) or beginning in infancy. CLPB ... link) Genetic Testing Registry: 3-methylglutaconic aciduria with cataracts, neurologic involvement, and neutropenia Other Diagnosis and Management ...
... breakdown and use of fats in the body (lipid metabolism). In affected individuals, lipids accumulate abnormally in cells ... Additional Information & Resources MedlinePlus (1 link) Health Topic: Lipid Metabolism Disorders Genetic and Rare Diseases Information Center (1 ...
Park, Dong-Jin; Kang, Ji-Hyoun; Yim, Yi-Rang; Kim, Ji-Eun; Lee, Jeong-Won; Lee, Kyung-Eun; Wen, Lihui; Kim, Tae-Jong; Park, Yong-Wook
Fibromyalgia (FM) affects 1% to 5% of the population, and approximately 90% of the affected individuals are women. FM patients experience impaired quality of life and the disorder places a considerable economic burden on the medical care system. With the recognition of FM as a major health problem, many recent studies have evaluated the pathophysiology of FM. Although the etiology of FM remains unknown, it is thought to involve some combination of genetic susceptibility and environmental exposure that triggers further alterations in gene expression. Because FM shows marked familial aggregation, most previous research has focused on genetic predisposition to FM and has revealed associations between genetic factors and the development of FM, including specific gene polymorphisms involved in the serotonergic, dopaminergic, and catecholaminergic pathways. The aim of this review was to discuss the current evidence regarding genetic factors that may play a role in the development and symptom severity of FM. PMID:26306300
The responsibility to provide accessible, useful genetic counseling to individuals from many cultures and ethnicities arises from the increasing ethnocultural diversity of the populations served, coupled with the ethical goal of providing equal access and quality of services for all individuals. The multicultural education, training, and practice of genetic counseling involves three major components: knowledge of relevant ethnocultural groups, ethnocultural self-awareness, and an understanding of institutional and social barriers to services. Despite the diversity of ethnocultural groups served and the critical role of direct experience and training for the genetic counselor, some general guidelines for multicultural genetic counseling can be identified. These include the importance of establishing and maintaining trust, the essential need to respect the counselee's healthcare beliefs and practices, and the necessity of understanding the impact of culture on the process of decision making and on counselee responses to nondirective counseling.
... AL. Obesity, diabetes and cancer: insight into the relationship from a cohort with growth hormone receptor deficiency. ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...
... Itoyama Y. Dysferlin mutations in Japanese Miyoshi myopathy: relationship to phenotype. Neurology. 2003 Jun 10;60(11): ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...
Zhu, Wen; Zhan, Jia-Sui
Comparing to natural ecosystems, the evolution of plant pathogens in agricultural ecosystems is generally faster due to high-density monocultures, large-scale application of agrochemicals, and international trade in agricultural products. Knowledge of the population genetics and evolutionary biology of plant pathogens is necessary to understand disease epidemiology, effectively breed and use resistant cultivars, and control plant diseases. In this article, we outlined the aims of population genetic studies in plant pathogens, discuss contributions of five evolutionary forces (i.e., mutation, gene flow, recombination, random genetic drift, and natural selection) to origin, maintenance, and distribution of genetic variation in time and space, and gave an overview of current research status in this field.
... ichthyosis), headaches, and difficulty with reading and spelling (dyslexia). Related Information What does it mean if a ... new syndrome: thrombocytopathia, muscle fatigue, asplenia, miosis, migraine, dyslexia and ichthyosis. Clin Genet. 1985 Nov;28(5): ...
... individuals may also experience nearsightedness ( myopia ), progressive night blindness, or a narrowing of their field of vision. ... Topic: Retinal Disorders Health Topic: Vision Impairment and Blindness Genetic and Rare Diseases Information Center (1 link) ...
... Brain Tumor Association: Medulloblastoma American Cancer Society: Skin Cancer - Basal and Squamous Cell Basal Cell ... Sources for This Page Bale AE, Yu KP. The hedgehog pathway and basal cell carcinomas. Hum Mol Genet. 2001 ...
... of the THAP1 protein, reducing the amount of functional THAP1 protein available for DNA binding. Other mutations ... THAP1 (DYT6) in early-onset dystonia: a genetic screening study. Lancet Neurol. 2009 May;8(5):441- ...
... group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and, frequently, development of paralysis of the lower limbs (paraplegia). Hereditary spastic paraplegias ...
Donnell, G N; Alfi, O S
Genetic disorders involving the ear, nose and throat can be looked at in essentially the same way that one would view other genetic problems. It is important to differentiate genetic disorders from those due to environmental influences. This may be difficult on clinical grounds, since similar clinical features may be produced by different environmental factors or by different genes or groups of genes. When the cause of the disorder can be established, the risks involved in a family having further offspring usually can be determined reasonably readily. In the uncharacterized situations, empiric risk figures are employed. Abnormalities of genetic origin fall into one of three main groupings: chromosomal abnormalities, single gene mutations or polygenic inheritance. These situations are discussed and examples are given.
... Share: Email Facebook Twitter Home Health Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health ... trisomy 13 result from having three copies of chromosome 13 in each cell in the body instead ...