Search results for "ALLELES"
showing 10 items of 478 documents
Comparative evolution of P–M system and infection by the sigma virus in French and Spanish populations ofDrosophila melanogaster
1992
SummaryIn 1983, an extensive survey of populations ofD. melanogasterwas started in a southern French region (Languedoc) in two non-Mendelian systems: the P–M system of transposable elements and the hereditary Rhabdovirus sigma. Unexpectedly fast-evolving phenomena were observed and interesting correlations were noted, giving similar geographical pattern to the region in both systems. For these reasons, the analysis was continued and extended towards the north (Rhône Valley) and the south (Spain). In the P–M system, all the Languedoc populations evolved from 1983 to 1991 towards the Q type which is characteristic of the Rhône Valley populations. In contrast, M′ strains are currently observed…
Investigations on the geographical variability of the human transferrins.
1971
On the basis of own and from the widely scattered literature compiled materials the geographical distribution of the transferrin alleles is discussed. They reveal a characteristic distribution pattern, as the slow Tf variants produced by TfD alleles are obviously more frequent in tropical than in non-tropical populations. Considering similar results in cattle and its interpretation by Ashton (1958, 1965), it is hypothesized, that the relatively high TfΓ frequencies in tropical biotops might be a selective adaptation to their special climatic conditions. In this connection an association between slowly moving transferrin proteins in man and tolerance to hotter climates — as could be found in…
Population structure of a parasitic plant and its perennial host
2002
Characterization of host and parasite population genetic structure and estimation of gene flow among populations are essential for the understanding of parasite local adaptation and coevolutionary interactions between hosts and parasites. We examined two aspects of population structure in a parasitic plant, the greater dodder (Cuscuta europaea) and its host plant, the stinging nettle (Urtica dioica), using allozyme data from 12 host and eight parasite populations. First, we examined whether hosts exposed to parasitism in the past contain higher levels of genetic variation. Second, we examined whether host and parasite populations differ in terms of population structure and if their populati…
Regulatory cytokine gene polymorphisms and risk of colorectal carcinoma.
2006
It is well established that cancer arises in chronically inflamed tissue, and this is particularly notable in the gastrointestinal tract. Classic examples include Helicobacter pylori-associated gastric cancer, hepatocellular carcinoma, and inflammatory bowel disease-associated colorectal cancer. Growing evidence suggests that these associations might be not casual findings. Focusing on individual cytokines has generated evidence that anti-inflammatory cytokine interleukin (IL)-10 and transforming growth factor-beta1 (TGF-beta1) may have a complex role in gastrointestinal carcinogenesis. As an example, IL-10-deficient mice develop severe atrophic gastritis and a chronic enterocolitis, develo…
Stable polymorphism for mutant eye colour geues in populations of Drosophila melanogaster in two different media
1988
In previous work analyzing variability of eye colour alleles existing in natural populations of D. melanogaster, it was observed that the number of females heterozygous for some eye colour alleles was greater in a wine cellar population than in populations outside this cellar. In order to determine which mechanisms caused these eye colour alleles to be favored in the heterozygotes, the changes in the frequency of four eye colour alleles frequently seen in the cellar population (se77o, sf77m, cd77o and multichromosomal 77o) was studied in artificial populations. Two different culture media, one supplemented with 10% ethanol and the other without ethanol were used. It was found that each of t…
cis-regulatory variation modulates susceptibility to enteric infection in the Drosophila genetic reference panel
2020
Abstract Background Resistance to enteric pathogens is a complex trait at the crossroads of multiple biological processes. We have previously shown in the Drosophila Genetic Reference Panel (DGRP) that resistance to infection is highly heritable, but our understanding of how the effects of genetic variants affect different molecular mechanisms to determine gut immunocompetence is still limited. Results To address this, we perform a systems genetics analysis of the gut transcriptomes from 38 DGRP lines that were orally infected with Pseudomonas entomophila. We identify a large number of condition-specific, expression quantitative trait loci (local-eQTLs) with infection-specific ones located …
Alleles and haplotypes of the estrogen receptor alpha gene are associated with an increased risk of spontaneous abortion.
2010
Objective To investigate whether polymorphisms in estrogen receptor alpha (ERα) or beta (ERβ) genes are associated with a risk of miscarriage. Design A retrospectively analyzed, prospectively obtained database of cases and controls. Setting University hospital menopause unit. Patient(s) 177 women with at least one spontaneous abortion and 442 controls with at least one live birth and no history of miscarriage. Intervention(s) None. Main Outcome Measure(s) Genotype frequencies and odd ratios for abortion risk in cases and controls for four single nucleotide polymorphisms (SNPs) located in intron 1 (C>T and A>G), intron 4 (A>T), and exon 8 (T>C) for the ERα gene, and two SNPs located in intro…
Distribution of Ha-ras alleles in patients with colorectal cancer and Crohn's disease.
1991
The allele distribution of the Ha-ras gene on chromosome 11p was analysed by the restriction fragment length polymorphism of the enzymes Mspl/Hpall in 238 individuals. The investigation covered 116 patients with colorectal carcinoma and 122 patients with Crohn's disease, representing two patient populations with the same ethnic origin, one with a malignant and the other a benign disease of the same organ system. A total of 17 different alleles were detected belonging to the common, intermediate, and rare classes according to the original nomenclature of Ha-ras alleles. Patients with Crohn's disease showed no difference in the distribution of Ha-ras alleles when compared with expected freque…
Microarray-based mutation analysis of 183 Spanish families with Usher syndrome.
2010
PURPOSE. The purpose of this study was to test the ability of the genotyping microarray for Usher syndrome (USH) to identify the mutations responsible for the disease in a cohort of 183 patients with USH. METHODS. DNA from 183 patients with Usher syndrome from the Spanish population was analyzed using a genotyping microarray containing 429 previously identified disease-associated variants in eight USH genes. Mutations detected by the array were confirmed by direct sequencing. Haplotype analysis was also performed in families carrying common Spanish mutations. RESULTS. The genotyping microarray identified 43 different variants, divided into 32 disease causative and 11 probably non-pathologic…
Association analysis between gene variants of the tyrosine hydroxylase and the serotonin transporter in borderline personality disorder.
2010
For patients with borderline personality disorder (BPD), we previously reported an independent effect of the catechol-o-methyl-transferase (COMT) low-activity (Met(158)) allele and an interaction with the low-expression allele of the deletion/insertion (short/long or S/L, resp.) polymorphism in the serotonin transporter-linked promoter region (5-HTTLPR). The purpose of the present study was to extend these findings to the tyrosine hydroxylase (TH) Val(81)Met single nucleotide polymorphism (SNP), the 5-HTTLPR S/L polymorphism incorporating the recently described functional A/G SNP within the long allele of the 5-HTTLPR (rs25531) as well as the variable number of tandem repeat (VNTR) polymorp…