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Autosomal Genes (autosomal + gene)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Inbreeding Coefficients for X-linked and Autosomal Genes in Consanguineous Marriages in Spanish Populations: The Case of Guipúzcoa (Basque Country)

ANNALS OF HUMAN GENETICS, Issue 2 2009
R. Calderón
Summary Inbreeding patterns over the past two centuries have been studied more extensively in Spain and Italy than anywhere else in Europe. Consanguinity studies in mainland Spain have shown that populations settled along the Cantabrian cornice share inbreeding patterns that distinguish them from other populations further south. A visual representation of spatial variations of two key inbreeding variables is presented here for the first time via contour maps. This paper also analyzes time trends of mean inbreeding coefficients for X-linked (Fx) and autosomal genes (F) (1862,1995) together with variations in Fx/F ratios in Guipúzcoa, the most autochthonous Spanish Basque province. Because close cousin marriages are a mark of identity of the study population, we evaluated the contribution of uncle-niece/aunt-nephew (M12) and first cousin (M22) marriages to Fx and F values and compared the frequencies of M12 and M22 pedigree subtypes and their corresponding Fx/F ratios to those found in other Spanish populations. The mean Fx and F inbreeding levels in Guipúzcoa for the 134-year period analyzed were 1.51 × 10,3 and 1.04 × 10,3, respectively, and the Fx/F ratio was seen to be very stable over time. Our findings show that major similarities exist for close consanguineous marriage subtypes between Basque and non-Basque Spanish populations, despite significant geographic variability in terms of first cousin pedigrees. The distortion seems to be caused by Guipúzcoa. The Fx/F ratios for first cousins in Spanish populations were higher than expected (1.25), with values ranging from 1.34 to 1.48. The findings of the present study may be useful for advancing knowledge on the effects of the interaction between biology and culture and for exploring associations between mating patterns and the prevalence of certain diseases. [source]

INTRODUCING DESIRABLE TRANSGENES INTO INSECT POPULATIONS USING Y-LINKED MEIOTIC DRIVE,A THEORETICAL ASSESSMENT

EVOLUTION, Issue 4 2007
Yunxin Huang
The use of genetic drive mechanisms to replace native mosquito genotypes with individuals bearing antipathogen transgenes is a potential strategy for repressing insect transmission of human diseases such as malaria and dengue. Antipathogen transgenes have been developed and tested, but efficient gene drive mechanisms are lacking. Here we theoretically assess the feasibility of introducing antipathogen genes into wild Aedes aegypti populations by using a naturally occurring meiotic drive system. We consider the release of males having both a Y-linked meiotic drive gene and an X-linked drive-insensitive response allele to which an antipathogen gene is linked. We use mathematical models and computer simulations to determine how the post-introduction dynamics of the antipathogen gene are affected by specific genetic characteristics of the system. The results show that when the natural population is uniformly sensitive to the meiotic drive gene, the antipathogen gene may be driven close to fixation if the fitness costs of the drive gene, the insensitive response allele, and the antipathogen gene are low. However, when the natural population has a small proportion of an X-linked insensitive response allele or an autosomal gene that strongly reduces the effect of the drive gene, the antipathogen gene does not spread if it has an associated fitness cost. Our modeling results provide a theoretical foundation for further experimental tests. [source]

Population differences in the International Multi-Centre ADHD Gene Project

GENETIC EPIDEMIOLOGY, Issue 2 2008
Benjamin M. Neale
Abstract The International Multi-Centre ADHD Gene sample consists of 674 families from eight countries (Belgium, England, Germany, Holland, Ireland, Israel, Spain, and Switzerland) ascertained from clinics for combined-type attention definity hyperactivity disorder in an offspring. 863 SNPs were successfully genotyped across 47 autosomal genes implicated in psychiatric disorders yielding a single nucleotide polymorphism (SNP) density of approximately one SNP per 2.5,kb. A global test of heterogeneity showed 269 SNPs nominally significant (expected 43). Inclusion of the Israeli population accounted for approximately 70% of these nominally significant tests. Hardy-Weinberg equilibrium tests suggest that combining all these populations would induce stratification, but that the Northern European populations (Belgium, England, Germany, Holland, and Ireland) could be appropriate. Tag SNPs were generated using pair-wise and aggressive tagging from Carlson et al. [2004] and de Bakker et al. [2005], respectively, in each population and applied to the other populations. Cross-population performance across Northern Europe was consistent with within population comparisons. Smaller sample size for each population tended to yield more problems for the generation of aggressive tags and the application of pair-wise tags. Any case-control sample employing an Israeli sample with Northern Europeans must consider stratification. A Northern European tag set, however, appears to be appropriate for capturing the variation across populations. Genet. Epidemiol. 2008. © 2007 Wiley-Liss, Inc. [source]

Characterization of the methylation status of five imprinted genes in sheep gametes

ANIMAL GENETICS, Issue 6 2009
A. Colosimo
Summary Genomic imprinting is a mammalian developmental process that uses epigenetic mechanisms to induce monoallelic and parental-specific expression of particular autosomal genes. A crucial epigenetic event consists of DNA methylation of CpG-islands, which become differentially methylated regions (DMRs) on the maternal and paternal alleles during oogenesis or spermatogenesis (germline DMRs). By contrast, somatic DMRs are acquired after fertilization. While there are several studies referring to methylation acquisition within germline DMRs in the mouse and human, a comparable methylation analysis of orthologous sequences is still lacking in sheep. To identify germline DMRs, this study analysed the methylation status of the available CpG-islands of five ovine imprinted genes (H19, IGF2R, DLK1, DIO3 and BEGAIN) in mature spermatozoa and in female gametes at different stages of their follicle growth, including in vitro matured oocytes. The 5,-end CpG-island of H19 showed a full methylation in spermatozoa and an absent methylation in growing and fully grown oocytes. The intron 2 CpG-island of IGF2R was unmethylated in male gametes, while it showed a high level of methylation in early stages of oogenesis. The promoter CpG-islands of DLK1 and DIO3 were found to be unmethylated both in spermatozoa and oocytes. Finally, the exon 9 CpG-island of BEGAIN was hypermethylated in mature male gametes, while it showed an almost complete methylation only in late stages of oocyte development. Our findings suggest that DNA methylation establishment during early stages of sheep oogenesis and subsequent in vitro maturation is gene-specific and that, of the five genes investigated, only the CpG-islands of H19 and IGF2R might represent ovine germline DMRs. [source]

Nucleotide diversity on the ovine Y chromosome

ANIMAL GENETICS, Issue 5 2004
J. R. S. Meadows
Summary To investigate the impact of male-mediated introgression during the evolution of sheep breeds, a sequencing approach was used to identify single nucleotide polymorphisms (SNPs) from the male-specific region of the ovine Y chromosome (MSY). A total of 4380 bp, which comprised nine fragments from five MSY genes was sequenced within a panel of 14 males from seven breeds. Sequence alignment identified a single segregating site, an A/G SNP located approximately 1685 bp upstream of the ovine SRY gene. The resulting estimation of nucleotide diversity (,Y = 0.90 ± 0.50 × 10,4) falls towards the lower end of estimates from other species. This was compared with the nucleotide diversity estimated from the autosomal component of the genome. Sequence analysis of 2933 bp amplified from eight autosomal genes revealed a nucleotide diversity (,A = 2.15 ± 0.27 × 10,3) higher than previously reported for sheep. Following adjustment for the contrasting influence of effective population size and a male biased mutation rate, comparison revealed that approximately 10% of the expected nucleotide diversity is present on the ovine Y chromosome. [source]

Testing Hardy-Weinberg Equilibrium using Family Data from Complex Surveys

ANNALS OF HUMAN GENETICS, Issue 4 2009
Dewei She
Summary Genetic data collected during the second phase of the Third National Health and Nutrition Examination Survey (NHANES III) enable us to investigate the association of a wide variety of health factors with regard to genetic variation. The classic question when looking into the genetic variations in a population is whether the population is in the state of Hardy-Weinberg Equilibrium (HWE). Our objective was to develop test procedures using family data from complex surveys such as NHANES III. We developed six Pearson ,2 based tests for a diallelic locus of autosomal genes. The finite sample properties of the proposed test procedures were evaluated via Monte Carlo simulation studies and the Rao-Scott first order corrected test was recommended. Test procedures were applied to three loci from NHANES III genetic databases, i.e., ADRB2, TGFB1, and VDR. HWE was shown to hold at 0.05 level for all three loci when only families with genotypic information available for two parents and for one or more children were used in the analysis. [source]

Inbreeding Coefficients for X-linked and Autosomal Genes in Consanguineous Marriages in Spanish Populations: The Case of Guipúzcoa (Basque Country)

X-chromosome upregulation and inactivation: two sides of the dosage compensation mechanism in mammals

BIOESSAYS, Issue 1 2009
Elena V. Dementyeva
Abstract Mammals have a very complex, tightly controlled, and developmentally regulated process of dosage compensation. One form of the process equalizes expression of the X-linked genes, present as a single copy in males (XY) and as two copies in females (XX), by inactivation of one of the two X-chromosomes in females. The second form of the process leads to balanced expression between the X-linked and autosomal genes by transcriptional upregulation of the active X in males and females. However, not all X-linked genes are absolutely balanced. This review is focused on the recent advances in studying the dosage compensation phenomenon in mammals. [source]