摘要:

Methods to determine the proportion of variability manifested by a quantitative trait that is attributable to additive genetic effects are important tools for human population and statistical geneticists. Though traditional methods based on parent-offspring and sib-pair correlations have been well researched, they are being steadily supplanted or complemented by more powerful pedigree-based variance-component techniques. In this paper, a theoretical investigation of the relative efficiency and power of small (i.e., <10 members) variance-component pedigree designs for heritability estimation is undertaken. The information gain in adding sibs and generations to pedigrees is discussed. Sample size guidelines based on theoretical power functions are offered, as are directions for future research.

ISSN:0001-5652    

DOI:10.1159/000154106

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

A gene locus for autosomal dominant cerebellar ataxia (ADCA) has been found on chromosome 6p and named spinocerebellar ataxia 1. However, linkage exclusion from chromosome 6p and thus locus heterogeneity has been proven in Cuban ADCA, the largest known collective of ADCA patients, probably due to a founder effect. Two chromosomal regions were analyzed for linkage to Cuban ADCA: chromosome 4, since a pericentromeric inversion has been reported in a member of a European ADCA family, and chromosome 11q22-23, since it is known to contain the gene locus for ataxia teleangiectasia, the main autosomal recessive disorder of cerebellar degeneration. In neither region was evidence for linkage found.

ISSN:0001-5652    

DOI:10.1159/000154107

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Transferrin C subtypes were studied in 124 patients who were survivors of myocardial infarction and population controls to test the hypothesis that the TFC2 type is associated with an increased risk for myocardial infarction. The TFC2 type showed, however, only a marginal increase among the patients (p = 0.038), whereas the TF*C3 allele (p = 0.0004) and the types carrying the TFC3 variant, TFC3-1 and C3-2, displayed a highly significant increase (p = 0.0002).

ISSN:0001-5652    

DOI:10.1159/000154108

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

When an inconsistency occurs in a pedigree, it may not be apparent which individual(s) are causing it. Here, a statistical method is described which identifies individuals most likely to have caused an inconsistency. The method is based on the sum of squared deviations between two predictors of an individual’s genotypes: (1) that given an individual’s own phenotype, and (2) that given all phenotypes in the pedigree. Extreme deviations between the two arrays (measured in terms of a sum of squares) are interpreted as indicating an inconsistency. The method is applied to a pedigree with an inconsistency in which it is unclear who is causing the inconsiste

ISSN:0001-5652    

DOI:10.1159/000154109

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The p21Al/TaqI polymorphism was studied in 904 individuals in 23 African population groups, encompassing the Caucasoid, Negroid, Khoisan and Pygmy populations. The frequency of the polymorphism was higher than previously reported, with the rarer allele occurring at frequencies ranging up to 0.41. No distinct trends in population frequency were observed, suggesting that the polymorphism is of little value in anthropological population studies. The existence of several TaqI mutations, in both time and position within the repeat unit, is indicated.

ISSN:0001-5652    

DOI:10.1159/000154110

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

α2-HS-glycoprotein (AHSG) phenotypes were determinated in 506 unrelated autochthonous individuals from the Galician population (NW Spain) by means of isoelectric focusing followed by silver stain immunofixation. The phenotype frequency distribution fitted with the Hardy-Weinberg law. No evidence of intrapopulation heterogeneity was observed. The allele frequencies obtained were: AHSG* 1 = 0.7559 ± 0.013 and AHSG*2 = 0.2441 ± 0.013. Our findings lend support to the hypothesis of an AHSG gene frequency cline in European populations. Other population genetics’ considerations have also been discu

ISSN:0001-5652    

DOI:10.1159/000154111

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Genetic polymorphism of the epidermal growth factor (EGF) receptor gene following Taq I digestion was compared between samples of genomic DNA from glioma-derived cell lines and Caucasoid and Japanese subjects. The same three allelic forms of the EGF receptor gene, marked by variant fragments of approximately f 2.8, f 1.6 and f 0.8 kb in size were common to both ethnic groups and the 12.8- and 11.6-kb fragments were found in the glioma-derived cell line DNA. A further variant fragment of approximately 13.8 kb in size has been shown to be thus far restricted to the Japanese. These data suggest that most allelic forms of the EGF receptor gene recognized by Taq I restriction fragment length polymorphism have a long evolutionary history and probably do not predispose to development of malignant glioma.

ISSN:0001-5652    

DOI:10.1159/000154112

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Given the DNA fingerprints of two individuals with some bands being shared by both individuals, we define a new measure of the degree of similarity between the DNA profiles of two individuals. We use this measure to calculate the expected DNA similarity of two unrelated individuals of a randomly mating population; this similarity is due to chance only. Then, the expected similarity between two related individuals is obtained; this similarity is due to chance andrelatedness. From these results, the degree of similarity due to relatedness alone may be calculated.

ISSN:0001-5652    

DOI:10.1159/000154113

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Transferrin (TF) subtypes in blood serum were assessed by isoelectric focusing in 2,035 healthy unrelated individuals from populations in different regions of Eurasia and Africa. Considerable heterogeneity for TF subtypes was found between the populations studied. The data obtained were compared with those of other investigators.

ISSN:0001-5652    

DOI:10.1159/000154114

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Alterations in dopaminergic activity may play an important role in the pathogenesis of schizophrenia. The central effects of dopamine are mediated by at least five G protein-coupled receptors, Dl, D2, D3, D4 and D5. The Dl receptor maps to 5q35.1 and it identifies an Eco RI as well as a Taq I RFLP. In the present study we undertook a linkage analysis between the Dl receptor RFLPs and schizophrenia in 9 multigenerational families in which segregation of disease was consistent with autosomal dominant inheritance and reduced penetrance. Several flanking DNA markers were also analyzed as the Dl receptor RFLPs were relatively uninformative in our families. Pairwise analyses of schizophrenia and several flanking markers indicate that inheritability of this region is unlikely to be involved in the pathogenesis of schizophrenia in the 9 families studied.

ISSN:0001-5652    

DOI:10.1159/000154115

出版商:S. Karger AG    

年代:1993

数据来源: Karger