摘要:

SummaryThe X‐linked gene,MIC5, encodes a human cell‐surface antigen, R1. We have assignedMIC5to the region betweenHPRTandG6PDon the long arm of the X chromosome. Regional localization was based on the pattern of reactivity of the R1 monoclonal antibody with human‐rodent somatic cell hybrids which contained different fragments of the human X chrom

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00861.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryFamilies segregating forPEPDhave been investigated for linkage betweenPEPDandCYP1. The results provide evidence for close linkage betweenPEPDandCYP1in males.

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00862.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryTwo hybrid cell lines, whose only human material was a portion of the X translocated on to a mouse chromosome, have been characterized by cytogenetics,in situhybridization and Southern blotting. In one hybrid (HORL911R8B) the region Xpter to Xq2(2–4) was identified. In the other (PIP) the single human fragment was found to contain sequences from two separate X chromosomal regions (corresponding approximately to Xp11.4–Xp22.1 and Xq26–Xqter). These two hybrids in combination with a third (WAG 8) retaining Xqter to Xp21 as a human X‐autosome translocation chromosome, form a mapping panel for rapid subregional assignments to the human X chromosome. This mapping panel has been used to provide information about the order of DNA sequences derived from the X chromosome and to provide an assignment for an anonymous DNA segment, M201γ, to Xp11.

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00863.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryWe report data on diagnoses made on amniotic fluid specimens from 1977 to 1984 as reported to the New York State Chromosome Registry. The rate of allde novo(presumed mutant) abnormalities was about 2 per 1000 in about 61000 fetuses in which results are unlikely to be biased by the reason for amniocentesis (except for maternal age). This includes about 0·5 per 1000de novomarkers, about 0·5 per 1000 otherde novounbalanced, and about 1·0 per 1000de novobalanced rearrangements. In about 55000 fetuses in which rates of inherited abnormalities could be evaluated without apparent bias, the rate of all inherited rearrangement was about 2·9 per 1000. This includes about 0·3 per 1000 inherited markers, about 0·2 per 1000 other inherited unbalanced rearrangements, and about 2·4 per 1000 inherited balanced abnormalities. Only mutant markers showed a clear association with maternal age (37·6±2·7 in 24 casesv. 35·8±3·6 in controls). Inherited markers did not exhibit this trend (35·8±2·0 in 12 casesv. 36·4±2·8 in controls). Paternal age does not appear to account for the association. Among abnormalities of known origin, the ratio of mutant to inherited cases is for markers 64:36, for other unbalanced rearrangements 73:27, and for all balanced abnormalities 29:71. In a subgroup of about 55000 fetuses, of 263 total abnormalities there were 8 instances of apparent true somatic mosaics (5 mutant and 3 of unknown origin but almost certainly mutant). There were also 20 instances of markers in which presumptive somatic loss had resulted in mosaicism (10 mutant, 6 of unknown origin and 4 inherited) and 13 other instances of mosaicism associated with apparent somatic loss (9 mutant, 3 of unknown origin, and 1 inherited). The sex ratio (Y to non‐Y karyotypes) for all abnormalities detected was 228:210 (1·09), not different from controls. Only deletions (5:14) and ‘other’ unbalanced rearrangements (5:13) exhibited a suggestive deviation from this trend. The rates of mutant chromosome rearrangements reported from 1977 to 1983 showed no apparent time cluster, with the possible exception of a peak of markers in 1977, a trend that may be due to higher maternal age in this year. Among fetuses studied because of maternal exposure to putative mutagens there was a non‐significant excess of mutants (2·9–5·7 per 1000v. 1·7–2·2 per 1000) and a borderline significant excess of inherited rearrangements (8·6–11·5 per 1000v. 2·6–3·1 per 1000). The latter effect, if not due to chance, may be due to effects on segregation. Fetuses studied because of known or suspected fetal pathology were excluded from most of the analyses above. In those ascertained because of known or suspect fetal pathology, a group defined conservatively to diminish bias in the remainder, the rate of unbalanced abnormalities was notably higher than in the reference groups. For mutants the rate was 1·8–2·4 per 1000v0·8–1·1 per 1000 in controls and for inherited unbalanced abnormalities the rate was 1·2–1·8 per 1000v0·3–0·7 per 1000 in controls. For balanced abnormalities by contrast, the rates of mutants were 0·6–1·2 per 1000v0·9–1·1 per 1000 in controls, and of inherited abnormalities 3·6–4·2 per 1000v2·2–2·4 per 1000 in controls. Because of increasing use of serum alpha‐fetoprotein screening and early ultrasound screening of pregnancies, it is likely that in the future it will be increasingly difficult to derive unbiased rates of unbalanced abnormalities at amniocentesis, even after adjustment for maternal age. Balanced abnormalities may prove mor

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00864.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryRecent molecular analysis has proved the hypothesis that parts of the human sex chromosomes are homologous and can recombine in male meiosis. The biological consequences of this recombination have been investigated by considering the joint effect of neutral mutation and random genetic drift on a locus that is closely linked to the non‐homologous segments of the sex chromosomes, but which recombines with them in an appreciable frequency. Our model predicts that, in the absence of selection, allelic differentiation between genes carried on the X and on the Y chromosomes will develop only if the recombination rate is of the same order of magnitude as the mutation rate or smaller.Similarly, a mutation favourable in males but disadvantageous in females will increase in frequency on the Y chromosomes, while remaining rare on the X chromosomes, only if the recombination rate is smaller than the fitness advantage of the mutation.The X and Y chromosomes are, thus, not expected to show any genetic differentiation for almost all of their homologous parts. Divergence will occur only for loci thatveryrarely recombine between the sex chromosome

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00865.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryData on the gene frequencies of four blood groups and six polymorphic erythrocyte enzymes were collected in a small population of the Northern Apennines (municipality of Zeri, Tuscany, Italy), whose civic records are available from 1866 on. Starting from the assumption that the mean gene frequencies of large populations of the neighbouring regions may represent a good estimate of the frequencies of the ‘mother population’ of the isolate, an observed value of the standardized (‘Wahlund’) variance of gene frequencies was computed and found to be 0·0131. The expected value of the same variance, due to random drift, has been computed on the basis of an evaluation of the immigration to the isolate, drawn from the marriage register of the municipality: this value wa

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00866.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe affected sib methods, which are used to make inferences about the genetic components of HLA associated diseases, have many underlying assumptions which may not always be realistic. These include no selective disadvantage of affected individuals, little or no recombination between the marker loci and the ‘disease’ locus, a single panmictic population, Mendelian segregation of the disease locus alleles and random distribution of individuals over environments. The effects of breaking these assumptions have been investigated. We have explicitly derived the haplotype sharing identity by descent (IBD) expectations for the cases of selection against affected individuals and recombination between the HLA marker loci and the ‘disease’ predisposing locus for affected sib trios (as was previously done for affected sib pairs). We have also derived, for both affected sib pairs and trios, the haplotype sharing expectations for non‐random mating (positive assortative), admixture, meiotic drive (of disease allele carrying haplotypes), and a random versus shared environmental component for sibs. In order to assess the sensitivity of the affected sib methods to perturbations in the assumptions, the expectation spaces of haplotype sharing in affected sib pairs and sib trios under the single diallelic locus model with varying penetrances and allele frequencies are fully described. The effects on haplotype sharing and subsequent disease parameter estimation are different for each of the factors we have considered. The affected sib methods are found to be robust in many s

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00867.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1987.tb00868.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY