摘要:

A computer algorithm for numerical evaluation of the statistical power of an exact test of Hardy-Weinberg genotypic proportions (HWP), developed here, indicates that the power is dependent on the number of segregating alleles as well as allele frequencies. While low levels of departure from the null hypothesis are difficult to detect from single-locus data, should such deviation be due to population substructuring, multiple loci, at each of which the number of segregating alleles is large (as seen with hypervariable loci), may easily detect even low levels of departure from HWP. Undetected small levels of departure may still provide conservative’ estimates of genotype frequencies from allele frequency data, following the current practice in forensic genetic

ISSN:0001-5652    

DOI:10.1159/000154181

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Haptoglobin subtypes were analysed by isoelectric focusing in four populations from Colombia, England, Nigeria, and India. There is a wide range of variation of allele frequencies in these four populations: HP*1S = 15–28%, HP*1F = 5–19%, HP*2FS = 54–79%. With the exception of the English, and the Spanish-speaking population of Colombia, all interpopulation comparisons showed significant heterogeneity. There is an extreme variation for the HP*1F allele in different populations, and a possible geographical cline of the HP*2FS allele increasing from west to east. The data presented here suggest that HP subtypes provide a useful anthropogenetic marker for racial differenti

ISSN:0001-5652    

DOI:10.1159/000154182

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Screening for phenylthiocarbamide (PTC) taste insensitivity was performed and PTC taste threshold values using 13 solutions were obtained for 102 newly detected male diabetics and 103 male non-diabetics aged 21–40 years. The study revealed a significant difference in taste sensitivity to the bitterness of PTC crystals between the diabetics and non-diabetics, the former being less sensitive than the latter (16.7 vs. 6.8%

ISSN:0001-5652    

DOI:10.1159/000154183

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Genetic polymorphism of orosomucoid (ORM1) was studied by isoelectric focusing in 3,817 conscripts and blood donors from the counties of Norrbotten and Västerbotten in northern Sweden. The individuals were distributed according to place of birth into 23 subpopulations. There was a significant heterogeneity between the 23 subpopulations with respect to the allele frequencies (p = 1.10–8). The ORM1*2 allele varied between 27 and 46%, and a clineal variation was observed with decreasing ORM1*2 allele frequencies in the northern direction. Significant correlations were found between the frequencies of the ORM1 alleles and previously studied Finnish and Saamish marker genes. The geographical variation of ORM1 alleles was in close agreement with the pattern expected from the known mixture of Finns, Saamis, and Swedes in northern Sweden and further underlines the impact of ethnic heterogeneity on the genetic differentiation of the north Swedish populati

ISSN:0001-5652    

DOI:10.1159/000154184

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The study of 230 diabetic mothers along with their newborn babies has shown that foetal macrosomia is associated with two specific genomic sites: phosphoglucomutase locus 1 (PGM1)-Rhesus blood group (Rh) linkage group (chromosome 1) and HindIII restriction fragment length polymorphism (RFLP) linked to insulin-like growth factor 1 (IGF1) (chromosome 12). In PGM12-1 mothers carrying the E allele, there is a proportion of 8.7% of macrosomic newborns as compared with 39.6% in mothers with other genotypes. The relationship between the maternal PGM1 RhE genotype and neonatal macrosomia does not depend on the type of diabetes. The proportion of macrosomic infants is much lower among newborns carrying the IGF1HS allele of the HindIII RFLP linked to IGF1 (20%) than among IGF1F/IGF1HF newborns (55%).

ISSN:0001-5652    

DOI:10.1159/000154185

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

A rare variant of 6q11+ heteromorphism was found in a fetus and the mother during amniocentesis. The G- and Q-banding and DA/DAPI stain were negative. The C-banding was positive and the C-banded segment was 3-fold longer in the variant than in its homologue. Neither of the C-banded regions of chromosomes 6 decondensed when exposed to distamycin A or 5-azacytidine. A DNA replication study indicated that the C-banded variant was late replicating. The lateral asymmetry observed in the 6q11 variant after one replication cycle in 5-bromodeoxyuridine may result from an unequal interstrand distribution of thymidine in the repetitive DNA. Fluorescent in situ hybridization using a chromosome-6-specific α-satellite probe (D6Z1) demonstrated hybridization signals on the centromere of chromosome 6. The 6q11 variant showed a signal which was 3-fold larger than its homologue. These results indicate that the 6q11 variant is an amplification of a chromosome-6-specific α repeat, and the size of the hybridization signal correlates with the size of the laterally asymmetric and C-banded regio

ISSN:0001-5652    

DOI:10.1159/000154186

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The affected sib-pair method can be applied to investigate linkage between a marker locus and a disease. Several statistics have been proposed to test if the observed pattern of marker alleles shared identically by descent (ibd) is compatible with the null hypothesis of no linkage. Here, we consider different optimality criteria for sib-pair linkage tests. While for recessive inherited diseases the mean test is found to be uniformly (in θ) most powerful, it can also be shown that, irrespective of the mode of inheritance, the mean test is the locally optimal test.

ISSN:0001-5652    

DOI:10.1159/000154187

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

It is believed that the main advantage of affected sib-pair tests is that their application requires no information about the underlying genetic mechanism of the disease. However, here it is proved that the mean test, which can be considered the most prominent of the affected sib-pair tests, is equivalent to lod score analysis for an assumed recessive mode of inheritance, irrespective of the true mode of the disease. Further relationships of certain sib-pair tests and lod score analysis under specific assumed genetic modes are investigated.

ISSN:0001-5652    

DOI:10.1159/000154188

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Segregation analysis provides a genetic model of disease based upon morbid risks in age-specific classes, from which the model derives genotype-specific morbid risks. In the absence of disease-specific mortality each morbid risk is a cumulative incidence (age-specific penetrance). If disease-specific mortality reduces the number of affected in the older classes, the morbid risk is less than the corresponding penetrance. When counselling individuals with a family history of disease, their genetic risk is a function of penetrances, which can be calculated from morbid risks. We have applied this method to breast, ovarian and colorectal cancer.

ISSN:0001-5652    

DOI:10.1159/000154189

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Cystic fibrosis (CF) is the most common severe autosomal recessive disorder in the Caucasian population. Beside the major mutation ΔF508, which accounts for approximately 68% of all CF chromosomes, more than 350 different point mutations leading to this disease have been detected and communicated to the ‘Cystic Fibrosis Genetic Analysis Consortium’. As these mutation are scattered about the whole CFTR gene we used denaturing gradient gel electrophoresis as a rapid method for screening a large number of CF patients for point mutations in the CFTR e

ISSN:0001-5652    

DOI:10.1159/000154190

出版商:S. Karger AG    

年代:1994

数据来源: Karger