摘要:

Earlier genetic studies on this stock of mice with an X-autosome translocation revealed that wild-type alleles of pink-eye and chinchilla of linkage group I have been translocated to the X. When the Xt was accompanied by an Xn, animals heterozygous for pp and cchcch showed variegated coat colors but the Xt alone led only to the wild-type coat color. The cytological investigation reported herein revealed the following information: 1. The translocation was non-reciprocal. About one third of the autosome representing linkage group I was transposed into the X, making the Xt about 20% longer than the Xn. 2. The autosomal insertion behaved as an integral part of the X, manifesting positive heteropyenosis when the X itself assumed this condition. 3. In the skin of animals with a variegated phenotype, the cc patches were apparently populated by cells containing a condensed Xt, while in wild-type patches from the same animal, the Xt was isopyenotic, behaving in the same manner as the euchromatic autosomes. These findings support Lyon’s hypothesis explaining the somatic variegation in Mus musculus due to X-autosome translocation (1961, 1962). The present study on skin cells of XtXn females has yielded convincing evidence that the mammalian female is indeed a natural mosai

ISSN:1424-8581    

DOI:10.1159/000129725

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

Cytogenetic studies of 77 individuals, including 13 mongols, in six families are described. Chromosomal abnormalities which are segregating include a 13–15/21 type translocation (three families), a 21/22 translocation (one family), and a deletion of the short arm of chromosome no. 21 (one family). Clinical, biographical, and karyological data are presented. Segregation ratios are discussed. Serological data for eight blood group loci are given in all families in a search for linkage of these markers with the mongol chromosom

ISSN:1424-8581    

DOI:10.1159/000129726

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

1. The chromosome complement of Ellobius lutescens (2 N = 17 in both sexes) is the simplest known for higher mammals. 2. The author has tried to apply the criteria proposed in the Denver System to six mitoses (three of each sex) obtained from the bone marrow of animals which had previously been treated with Colcemid. 3. The results are no more exact than those previously obtained by the author (Matthey, 1957) on material which had not been treated with Colcemid. 4. The results seem to some extent applicable to the group C chromosomes (autosomes 6–12 and the X) of the human karyotype and justify the scepticism of Patau (1961) concerning the possibility of individually identifying all human chromosomes. 5. The comparison of the long, despiralized mitotic chromosomes (1957 material) with the contracted ones shows that the contraction induced by colchicine does not modify the relative proportions of the chromosomes nor the value of the centromeric index. These findings are in contradiction with the conclusions of Sasaki (1960

ISSN:1424-8581    

DOI:10.1159/000129727

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

Chromosome Breakage is correlated with abnormal Polyploidy at Meiosis in man.

ISSN:1424-8581    

DOI:10.1159/000129728

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

A search for familial visible chromosome markers has been initiated among couples who have lost several children by spontaneous abortion. Because the great majority of genetically unbalanced offspring of translocation heterozygotcs die during intrauterine development, repeated spontaneous abortions of unknown etiology, intermittent with successful normal pregnancies, can suggest a reciprocal translocation in the genome of one of the parents. Among the first ten couples studied, one abnormal karyotype was found in the male of a young couple. His wife had lost two children in the third month of pregnancy and has now an apparently successful pregnancy in advanced stage. The abnormal karyotype contained a chromosome of the 21 to 22 group which had an extra chromatin piece, of undetermined origin, translocated to its short arm. This chromosome was also found in the man’s fathe

ISSN:1424-8581    

DOI:10.1159/000129729

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

Cultured blood cells of an 86-year-old healthy woman displayed a chromosomal mosaic. A large proportion of the cells exhibited an identical abnormal karyotype, most likely the result of a translocation between a number 2 chromosome and a long acrocentric. The mode of origin of the aberration, and possible similarities in the developmental pattern that this mosaicism shares with leukemias and Waldenström’s macroglobulinaemia are discuss

ISSN:1424-8581    

DOI:10.1159/000129730

出版商:S. Karger AG    

年代:1962

数据来源: Karger

摘要:

Generally, male and female heterogamety of amphibians and reptiles cannot be determined cytologically, as the X and Y or the Z and W appear morphologically identical. However, female heterogamety of the African water frog, Xenopus laevis, has been proven by the sex reversal experiments of Chang and Witschi. The present report describes the cytological identification of the sex chromosomes in this species. The Z-chromosome is the smallest element in the complement with a subterminal kinetochore, while the submediocentric W exceeds the largest autosome in size. Thus a distinct heteromorphism exists between the Z and W in this primitive anuran.

ISSN:1424-8581    

DOI:10.1159/000129731

出版商:S. Karger AG    

年代:1962

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129732

出版商:S. Karger AG    

年代:1962

数据来源: Karger