摘要:

AbstractUnlike inbreeding, population subdivision affects different genotypes differently for multiple alleles, so that the simple relationship between inbreeding and subdivision for two alleles no longer holds for all genotypes. In this communication, the detailed effects of subdivision have been studied for three alleles with results easily generalized to any number of alleles. Then an average effect of subdivision is proposed. This average effect of subdivision is found to play the same role as the inbreeding coefficient for multiple alleles, so that the overall relationship between inbreeding and subdivision may be reestablished again. In the final section, we discuss the relationship of the genetic result with measures of association of square contingency tables arising from epidemiological, social studies, educational and psychological studies.

ISSN:0741-0395    

DOI:10.1002/gepi.1370080102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractAlthough coeliac disease (CD) is strongly associated with the HLA alleles B8 and DR3, the genetic basis of this illness remains obscure. Recent studies show that at least two unlinked loci are involved. Most studies agree on recessivity at the HLA‐unlinked locus but differ with respect to dominance or recessivity at the HLA‐linked disease susceptibility locus.To address this controversy, we examined the association of CD with HLA in 39 families from the West of Ireland. Previous studies have shown that the prevalence of CD and the frequencies of the HLA antigens associated with it are higher in this population than in most others. Analysis of the data revealed a significant excess of concordant sib‐pairs with two HLA haplotypes in common and an excess of discordant pairs with no haplotype in common. Chi‐square tests confirmed a highly significant association between HLA‐B8 and CD. Both heterozygotes and homozygotes for B8 had a significantly increased risk of CD. The risk for homozygotes was slightly higher than for heterozygotes, although not significantly so. The segregation ratio for disease occurrence among sibs of probands was estimated to be 0.185 when neither parent is affected. We estimated a gene frequency of 0.003 for the disease allele (C) at the HLA‐linked locus and of 0.648 for the disease allele (d) at the HLA‐unlinked locus. Assuming that CCdd homozygotes are always affected and that only carriers of C who are homozygous dd can be affected, the disease was found to be completely penetrant in Ccdd heterozygotes. These results support dominance at the HLA‐linked locus conferring susceptibility to CD. Possible reasons for the discrepancy between the West of Ireland and other population

ISSN:0741-0395    

DOI:10.1002/gepi.1370080103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe use of patterned covariance matrices in forming pedigree‐based mixed models for quantitative traits is discussed. It is suggested that patterned covariance matrix models provide intuitive, theoretically appealing, and flexible genetic modeling devices for pedigree data. It is suggested further that the very great computational burden assumed in the implementation of covariance matrix‐dependent mixed models can be overcome through the use of recent architectural breakthroughs in computing machinery. A brief and nontechnical overview of these architectures is offered, as are numerical and timing studies on various aspects of their use in evaluating mixed models. As the kinds of computers discussed in this paper are becoming more prevalent and easier to access and use, it is emphasized that it behooves geneticists to consider their use to combat needless approximation and time constraints necessitated by smaller, scalar computation oriented, machi

ISSN:0741-0395    

DOI:10.1002/gepi.1370080104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ascertainment of probands according to place of residence in hospitals or in the community has enabled our sampling to be representative of whole subpopulations of patients. Probands from psychiatric hospitals are characterized by biased clinical parameters. Our sampling procedure provides important preliminary results which appear to be contradictory to those produced by conventional sampling methods.

ISSN:0741-0395    

DOI:10.1002/gepi.1370080105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA probabilistic sample representative of the adult population of Rio Grande do Sul, Brazil, was studied to estimate the genetic and nongenetic determinants of blood pressure. Four thousand five hundred and sixty‐five individuals, 20 to 74 years old, from 2050 households, were examined. The genetic determination of the SBP (systolic blood pressure) and DBP (diastolic blood pressure) was evaluated in 557 families extracted from this sample. The analysis was performed first with no adjustments for other influencing factors, and then adjusting for the effects of the two significant covariates, age and Quetelel's index, identified through a multiple stepwise regression analysis with nine independent variables. Higher heritability estimates were obtained for DBP (raw data: 0.40; residuals: 0.45) than for SBP (raw data: 0.22; residuals: 0.26). The significant correlation coefficients varied from 0.13 (for father–offspring raw data, total sample), to 0.36 (for siblings, adjusted data, untreated sample). Slight differences were observed between the total and pharmacologically untreated samples in relation to correlation and heritability estima

ISSN:0741-0395    

DOI:10.1002/gepi.1370080106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0741-0395    

DOI:10.1002/gepi.1370080101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY