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PubMed1996

Genetic variation in "first" male effects on egg laying and remating by female Drosophila melanogaster.

Male Drosophila melanogaster from lines artificially selected to have divergent life histories were tested to determine if they differed in their effects on female reproductive behavior. During the first 5 days after mating, males from short-generation populations caused females to lay eggs at a faster rate than did males from long-generation populations. This faster oviposition rate resulted in greater numbers of adult progeny produced by short-generation males. During the period 6-21 days after mating, long-generation males fathered more adult progeny. Females that were first mated to short-generation males were more likely to remate than were females first mated to long-generation males. Rematings were interrupted in order to prevent transfer of second-male accessory fluid and sperm. Females that were first mated to long-generation males produced more progeny after interrupted matings than did females that were first mated to short-generation males.

Animals↗
PubMed1991

Genetic variation in Arizona Mexican Americans: estimation and interpretation of admixture proportions.

Mexican Americans are a numerous and fast growing ethnic population in the United States. Yet little is known about their genetic structure. Since they are a hybrid, it is of interest to identify their parental populations and to estimate the relative contributions of these groups. This information is relevant to historical, biomedical, and evolutionary concerns. New genetic typings on 730 Arizona Mexican Americans for the HLA-A, HLA-B, ABO, Rh, MNSs, Duffy, Kidd, and Kell loci are presented here and they are used to estimate ancestral contributions. We considered both a dihybrid model with Amerindians and Spaniards as proposed ancestors, and a trihybrid model with Amerindians, Spaniards, and Africans as proposed ancestors. A modified weighted least squares method that allows for linkage disequilibrium was used to estimate ancestral contributions for each model. The following admixture estimates were obtained: Amerindian, 0.29 +/- 0.04; Spaniard, 0.68 +/- 0.05; and African, 0.03 +/- 0.02. The interpretation of these results with respect to Amerindian and Spanish ancestry is straightforward. African ancestry is strongly supported by the presence of a marker of African descent, Fy, despite the fact that the standard error of the estimate is as large as the estimated admixture proportion. An evaluation of the sensitivity of these results to a number of variables is presented: 1) our choices of ancestral allele frequencies, 2) the possibility of selection at HLA and the blood groups, and 3) genetic drift in Mexican Americans.

Africa↗
PubMed1993

A comparison of genetic variation in two sibling species pairs of haplodiploid insects.

Sibling species pairs of sweat bees (Halictus confusus and H. tumulorum) and pine sawflies (Neodiprion pratti and N. maurus) were surveyed for genetic variability using enzyme electrophoresis. Levels of heterozygosity were found to be within the ranges earlier recorded for Hymenoptera. Expected heterozygosities were not significantly higher in the sawflies than in the sweat bees. Estimates of genetic identity between the sibling species were not lower than those generally found for diplodiploid insect species: no evidence was found for an increased rate of evolution in these haplodiploids. Genetic identity data among populations of H. confusus and between Halictus species were within the range expected for conspecific populations and sibling species, respectively. In Neodiprion all genetic distances were low but the two populations of N. pratti had similar genetic distances as each did to N. maurus, indicating the necessity for further systematic studies of the genus.

Animals↗
PubMed2003

Common genetic variation in a basal promoter element alters DDAH2 expression in endothelial cells.

Synthesis of the vasodilator nitric oxide (NO) can be inhibited by the endogenous methylarginines L-NMMA and ADMA. ADMA is elevated in a number of cardiovascular disorders in which NO availability is reduced. Elimination of ADMA from the body occurs primarily by enzymatic breakdown through the action of DDAH, of which two isoforms exist, DDAH1 and DDAH2. In this study we have identified a core promoter region of the DDAH2 gene, and transcription factor sites that play an important role in the regulation of DDAH2 expression. Using PCR-SSCP analysis we also identified six common polymorphisms. One of these polymorphisms (an insertion/deletion at position -871) within the core promoter element influenced basal transcription. The discovery of a functional polymorphism within the DDAH2 promoter suggests that there may be common, individual differences in the ability to metabolise ADMA in vivo, that in turn, might underlie susceptibility to cardiovascular disease.

Amidohydrolases↗
PubMed1972

Genetic variation in human erythrocyte acetylcholinesterase.

A method for solubilization of human erythrocyte membranes was developed and used to survey 70 unselected human blood samples for isozymic variation of stromal acetylcholinesterase. Three variants were observed. Pedigrees of families studied by this method indicated that this variation represented the phenotypic expression of two codominant alleles at a single locus.

Acetylcholinesterase↗
PubMed1997

Antigenic and genetic variations among Japanese encephalitis virus strains belonging to genotype 1.

Hyperimmune antisera against four Japanese encephalitis (JE) virus strains, ThCMAr4492 and ThCMAr6793 from Thailand and Nakayama and JaGAr01 from Japan, were used to analyze the antigenic relationships among 12 Thai strains belonging to genotype 1, and two Japanese strains and one Chinese strain belonging to genotype 3. The antiserum for ThCMAr6793 significantly neutralized nine of the 12 Thai strains, none of which was significantly neutralized by antisera for the Nakayama and JaGAr01 strains. The antiserum for ThCMAr4492 neutralized only its homologous strain; therefore, ThCMAr4492 was antigenically different from all other strains. Two Thai strains (Subin and KE-093/83) were significantly less neutralized by all four of the antisera tested. In the deduced amino-acid sequence of the E protein, the 12 Thai strains revealed 100 to 98.2% identity among them and 90.0 to 98.8% identity with the published strains, respectively. Among significant amino-acid substitutions, three residues at positions E-222, E-327 and E-366 were shared by all of the Thai strains, whereas residues at E-89, E-123, E-131, E-178, E-293, E-351 and E-373 seemed to be strain-specific. The amino acids at positions E-178, E-327, E-351, E-373 and E-366 are found either in the peptides with functional T-helper cell epitopes or in the ectodomain of the E protein of other flaviviruses. These amino acids may therefore be responsible for determining the antigenic heterogeneity of these strains.

Amino Acid Sequence↗
PubMed2006

CYP2D6 genetic variation in healthy adults and psychiatric African-American subjects: implications for clinical practice and genetic testing.

Limited information is available on the frequency of the many CYP2D6 alleles found in African-Americans. DNA was isolated and genetic testing was performed on samples from 222 African-Americans, healthy controls (n=131), and psychiatric patients (n=91). Each DNA was tested for CYP2D6 alleles *2, *3, *4, *5, *6, *7, *8, *9, *10, *11, *14, *15, *17, *18, *19, *20, *25, *26, *29, *30, *31, *35, *36, *37, *40, *41 and *43 and 8 multiple copy alleles (*1xn, *2xn, *4xn, *41xn, *2Lxn, *17xn, *35xn and *10xn) using the AmpliChip CYP450 prototype microarray assay, along with allele-specific-PCR and PCR restriction fragment length polymorphism methods. No significant difference was noted between controls and psychiatric patients in any CYP2D6 allele frequencies. Three subjects were genotyped as poor metabolizers (1.4%; 0.0-2.9%, 95% confidence intervals (CI)), and 10 were classified as ultrarapid metabolizers (4.5%; 1.8-7.2%, 95% CI). A new CYP2D6 allele (*58) and two new duplicated CYP2D6 alleles (*17xn and *2Lxn) not previously reported were also identified. The frequency of the CYP2D6 overexpression in African-Americans may represent a greater therapeutic challenge than its deficiency based on these results. The most common alleles found in African-Americans including CYP2D6*1, *17 and *41 need to be investigated more closely for race-specific allelic variations and the mechanism responsible for differences in allele function more closely examined. The diversity of CYP2D6 alleles suggests that nucleotide arrays or similar methods are needed to efficiently test for the most prominent/relevant CYP2D6 alleles in humans.

Adolescent↗
PubMed2005

Polymorphism of the adrenergic receptor alpha 2a -1291C>G genetic variation and clozapine-induced weight gain.

Weight gain, leading to further morbidity and poor treatment compliance, is a common consequence of treatment with clozapine. The substantial interindividual and interracial differences in drug-induced weight gain suggest that genetic factors may be important. Several studies showed that alpha-2, adrenoceptor may related to feeding behavior with rat or lipolytic activity of human adipocyte tissue, they are related to body weight change. In the study, we try to test the possible relation of clozapine-induced weight gain and adrenergic receptor alpha 2a -1291C>G genetic polymorphism in a long term follow up (14.0 +/- 6.2 months). Our results show the genotype GG (8.45 +/- 7.2 Kg) with higher mean body weight gain than genotype CC (2.79 +/- 6.1 Kg) (p = 0.023). The finding identify a genetic factor associated with clozapine-induced weight gain in schizophrenic patients.

Adult↗
PubMed2003

Genetic variation in the promoter region of the basic fibroblast growth factor gene.

Basic fibroblast growth factor (bFGF) is a member of the fibroblast growth factor family that possess broad mitogenic and cell survival activities and is involved in a variety of biological processes. We investigated possible genetic polymorphism in the promoter and 5' flanking region of the bFGF gene. Polymorphism was analysed by means of heteroduplex analysis, fragments with altered mobility were sequenced. Three novel substitutions (-553T/A, -834T/A and -921C/G) were identified in the promoter region. Allele frequencies in a sample of healthy Caucasian subjects (n=126) were determined by polymerase chain reactions followed by restriction analyses with specific endonucleases. The frequencies of the mutated alleles (-553A, -834A and -921G) were 0.04, 0.05 and 0.14, respectively. Newly identified variants in the bFGF gene promoter appear to be common polymorphisms in the Czech population.

5' Flanking Region↗
PubMed1996

Genetic variation in bilirubin UPD-glucuronosyltransferase gene promoter and Gilbert's syndrome.

BACKGROUND: The genetic basis of Gilbert's syndrome is ill-defined. This common mild hyperbilirubinaemia sometimes presents as an intermittent jaundice. A reduced hepatic bilirubin UPD- glucuronosyltransferase (UGT) is associated with this syndrome. We have examined variation in the gene encoding the UGT1*1 enzyme and serum bilirubin levels in a Scottish population. METHODS: Blood was collected from 12 patients with confirmed or suspected Gilbert's syndrome, from 6 members of a family with 4 Gilbert members, and from 77 non-smoking, alcohol-free, drug-free volunteers recruited from the staff of a teaching hospital in Dundee. Polymerase chain reaction amplification was used to examine sequence variation of the promoter upstream of the UGT1*1 exon I. Genotypes were assigned as follows: 6/6 (homozygous for a common allele bearing the sequence [TA](6)TAA), 7/7 (homozygous for a rarer allele with the sequence [TA](7)TAA), and 6/7 (heterozygous with one of each allele). FINDINGS: Individuals in the population with the 7/7 genotype had significantly higher bilirubin concentrations than those who had the 6/7 or 6/6 genotype. 14 volunteers underwent a 24 h fasting test to see if they had Gilbert's syndrome, and all four positives had the 7/7 genotype. One confirmed Gilbert's patient, two recurrent jaundice patients (with suspected Gilbert's syndrome), and nine clinically diagnosed cases had the 7/7 genotype. Segregation of the 7/7 genotype with the Gilbert phenotype was also demonstrated in the family with four affected members. The frequency of the 7/7 genotype in this eastern Scottish population was 10-13%. INTERPRETATION: In a healthy population there was an association between variation in bilirubin concentration and a mutation within the gene encoding the enzyme bilirubin UGT. This and other findings suggest the existence of a mild and a more severe form of Gilbert's syndrome, depending on whether the gene defect lies in the promoter sequence upstream of UGT1*I exon I, as here (mild), or in the coding sequence (severe) of the gene.

Adult↗
PubMed2004

Association of late-onset Alzheimer's disease with genetic variation in multiple members of the GAPD gene family.

Although several genes have been implicated in the development of the early-onset autosomal dominant form of Alzheimer's disease (AD), the genetics of late-onset AD (LOAD) is complex. Loci on several chromosomes have been linked to the disease, but so far only the apolipoprotein E gene has been consistently shown to be a risk factor. We have performed a large-scale single-nucleotide polymorphism (SNP)-based association study, across the region of linkage on chromosome 12, in multiple case-control series totaling 1,089 LOAD patients and 1,196 control subjects and report association with SNPs in the glyceraldehyde-3-phosphate dehydrogenase (GAPD) gene. Subsequent analysis of GAPD paralogs on other chromosomes demonstrated association with two other paralogs. A significant association between LOAD and a compound genotype of the three GAPD genes was observed in all three sample sets. Individually, these SNPs make differential contributions to disease risk in each of the casecontrol series, suggesting that variants in functionally similar genes may account for series-to-series heterogeneity of disease risk. Our observations raise the possibility that GAPD genes are AD risk factors, a hypothesis that is consistent with the role of GAPD in neuronal apoptosis.

Age of Onset↗