ISSN:1424-8581    

DOI:10.1159/000130742

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A number of salt solutions were tested for their ability to replace 2 × SSC in the production of C-bands with the so-called CT technique. Those containing monovalent cations, except for the ones with Ag+ ions, were capable of inducing C-bands in Ba(OH)2-pretreated human chromosomes. Cesium cations were the most effective in this respect. In contrast to the effect of the monovalent cations studied, di- or polyvalent cations (and Ag+ cations) were incapable of producing C-bands, but appeared to stabilize the Ba(OH)2-induced reverse-banding pattern. This stabilizing effect was obtainable with relatively low cation concentrations and persisted even when C-band-producing cations were present at the same time. The experiments clearly show that the cations present during salt incubations, generally used in the CT- and several other banding methods, can exert a pronounced influence on chromosome behavior

ISSN:1424-8581    

DOI:10.1159/000130743

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The distribution of the break points of sister chromatid exchanges (SCE) was compared with that of chromosome aberrations in Bloom’s syndrome by using differential sister chromatid staining and banding techniques. A comparison was made of the distribution in chromosomes 1, 2, and 3, since the exact identification of other chromosomes is difficult with the differential sister-chromatid staining technique. It was shown that SCE and chromosome breaks do not necessarily correlate as to location. Some chromosome break points, e.g., 1q21, lp36, 2q31, 3ql2, and 3pl3, were common with those of SCE, whereas others (at 1pl3, 2pll, 2qll, and 3qll) showed little or no SCE. SCE breaks were not observed in the centromeric regions. In addition, the SCE frequency was examined in Bloom’s syndrome cells with and without chromosome aberrations, and no significant differences of SCE frequency were observed between cells with chromatid- or chromosome-type of aberrations and those with normal complements. Banding analyses indicated a nonrandom distribution of chromosome breaks in the lymphocytes and marrow cells of the Bloom’s syndrome pa

ISSN:1424-8581    

DOI:10.1159/000130744

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In this paper, we present an analysis of the sex chromosomes of four hamster species after application of different staining techniques. The mitotic X chromosomes show a striking similarity in G-banding pattern but rather great differences in their C-banding patterns. A presumably homologous euchromatic segment that exhibits two distinct G-bands appears in the X chromosome of each species. The Y chromosome of Cricetus cricetus is in contrast to those of the other species, because it reveals a relatively well-differentiated G- and C-banding pattern. Inmeiotic metaphase I, interstitial chiasmata can be found in the sex bivalents ofCricetus cricetus and Cricetulus griseus, whereas the gonosomes of Mesocricetusauratus and Phodopus sungorus sungorus are terminally associated. The regionsthat are involved in pairing or association are always heterochromatic.

ISSN:1424-8581    

DOI:10.1159/000130745

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

It is generally accepted that at least some Y chromosomes in human mature sperm heads are represented in preparations by fluorescent F-bodies. From data consisting solely of F-body scorings and the visually estimated size of sperm heads from normal donors, a quantitative model is developed which permits simultaneous estimation of six parameters representing biological factors (the proportions of ploidy classes and of their sex-chromosome complements) and biassing factors (not all Y chromosomes represented by F-bodies, not all F-bodies representing Y chromosomes, and error in scoring ploidy from visual size). The analysis is statistically adequate and succeeds in predicting a variety of independently validated phenomena. The work may be regarded as a contribution to the integration of qualitative and quantitative evidence in the study of F-bodies. In all, 21,700 one-headed spermatozoa from 12 donors were scored. A mean of 54 % spermatozoa lacking F-bodies was subject to a standard deviation between donors of 4.8, over and above binomial error. Analysis yielded the following estimates: 83.3 % of diploid spermatozoa are XY, the remainder XX and YY in assumed equal number (this information assists analysis of the origin of embryonic triploidy); 2.4 % of spermatozoa are diploid (this estimate does not compete in accuracy with direct estimates from DNA absorbance); only 83 % of Y chromosomes are represented by F-bodies; 7 % of haploid heads and 14 % of diploids contain one or more “adventitious bodies” indistinguishable from true F-bodies. The visually scored head sizes “Small” and “Medium” correspond approximately with haploidy and diploidy; nearly all haploids are scored as Small, and 72% of the Medium are diploid. F-bodies are not thought at present to give a useful basis for estimating the presumably low incidence of sex-chromosome aneuploidy and nondisjunction. No such estimate has been attempted. The problem is overshadowed by not fully understood complicating factors of greater magnitude, which now appear to be a major subject of enquiry. Some implications and possible future developments ar

ISSN:1424-8581    

DOI:10.1159/000130746

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Chromosome studies in a male and female bushbuck (Tragelaphus scriptus) are described. The male has a diploid chromosome number of one fewer than the female, and a Y-to-autosome fusion. The configuration of a quadrivalent observed in meiotic preparations from the male confirmed the presence of a fusion between a Y chromosome and an autosome. All other members of the tragelaphine tribe so far studied chromosomally show the presence of a Y-to-autosome fusion. It is postulated that the fusion observed in all present-day species of the tribe studied to date arose as a single event in a common ancestor.

ISSN:1424-8581    

DOI:10.1159/000130747

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000130748

出版商:S. Karger AG    

年代:1977

数据来源: Karger