摘要:

The distribution of chromosome breaks induced by streptonigrin (SN) and X-ray in chromosomes Nos. 1, 2, and 3 of cultured human leukocytes was investigated. In all chromosomes tested, the breaks caused by X-ray were randomly distributed both among and within the chromosomes in proportion to their relative lengths. SN, however, produced significant non-random distributions of breaks in chromosomes No. 1 and No. 2. The pericentric regions of chromosomes No. 1 and No. 2, as well as the secondary constriction area in the long arm of No. 1, seemed highly susceptible to breakage. Although SN produced significantly fewer breaks than expected in chromosome No. 3, these breaks were randomly distributed along its length. The telomere regions of all chromosomes and the short arm of chromosome No. 2 appeared to be relatively resistant to the action of SN.

ISSN:1424-8581    

DOI:10.1159/000129786

出版商:S. Karger AG    

年代:1963

数据来源: Karger

摘要:

A main karyotype of 48/XXYY was found in a mentally defective male patient with clinical signs of Klinefelter’s syndrome. 3.4% of the cells were XXY, thetefore the patient is thought to be an XXYY/XXY mosaic. The interpretation of the extra chromosome as a Y seems most likely, but some other possibilities are also discusse

ISSN:1424-8581    

DOI:10.1159/000129787

出版商:S. Karger AG    

年代:1963

数据来源: Karger

摘要:

1) In a previous paper published in 1963, the author showed that in a population of Mus minutoides musculoides found in Bangui, Republic of Central Africa, there were individuals with 30, 31, 32, 33 and 34 chromosomes forming a polymorphic Robertsonian system. The present study shows that M. m. minutoides (Cape Province) and M. m. bellus (Tanganika) have 36 and 30 chromosomes respectively. The subspecies names are provisional since the difference in the chromosome complements of three forms is so great that interbreeding appears to be impossible even though they cannot be distinguished according to the methods of typological taxonomy. From the cytological standpoint we have three different species, respectively designated by the letters A (M. m. musculoides), B (M. m. bellus) and C (M. m. minutoides). Group bujo-triton: Three males of M. triton (Tanganika) were analysed and again found to form a polymorphic Robertsonian system with 20, 21 and 22 chromosomes. Two females have 21 chromosomes but their chromosome constitution does not agree with those of the males. Here we are dealing with another polymorphic system whose origin implicates complicated and numerous translocations. The sex chromosomes of M. m. minutoides are of the same type as those of M. musculus. In M. m. bellus they are like those of M. m. musculoides where it is probable that a translocation of both sex chromosomes onto a pair of autosomes has occurred (Matthey, 1957, 1958, 1963). The X of M. triton is big and sub-metacentric, the Y acrocentric and relatively small. he existence of at least two polymorphic systems (M. minutoides and M. triton) and of different chromosome complements found in the forms A, B and C seems to be linked with very active processes of transformation and partially explains the difficulties met by systematists in the study of pigmy-mice.

ISSN:1424-8581    

DOI:10.1159/000129788

出版商:S. Karger AG    

年代:1963

数据来源: Karger

摘要:

The presence of Barr bodies was investigated in cells of a fibroblast culture, which consisted mainly of diploid cells with two X-chromosomes and triploid cells with three X-chromosomes in approximately equal numbers. Out of a total of 1000 cells, 487 cells contained a single Barr body and 64 contained two Barr bodies. By measuring the DNA contents of interphase nuclei in arbitrary values using an integrating mícrodensitometer it could be shown that some of the nuclei containing two Barr bodies were triploid, while the rest were more highly polyploid. It is concluded that for a given number of X-chromosomes, triploid cells may contain the same number of Barr bodies as diploid cells

ISSN:1424-8581    

DOI:10.1159/000129789

出版商:S. Karger AG    

年代:1963

数据来源: Karger

摘要:

The testes of three marmoset monkeys in whom a percentage of marrow cells was found to be derived from a female co-twin were studied. In two of the animals some XX mitoses of presumed spermatogonial origin were present. After delineation of the XY bivalent in first meiotic metaphases, some cells were found in two animals in which no XY bivalent could be identified. These findings are interpreted to support the suggestion by Ohno et al. (1962), that germ cells occasionally reach the circulation of mammalian embryos and may be distributed to the gonads of co-twins.

ISSN:1424-8581    

DOI:10.1159/000129790

出版商:S. Karger AG    

年代:1963

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129791

出版商:S. Karger AG    

年代:1963

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129792

出版商:S. Karger AG    

年代:1963

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129793

出版商:S. Karger AG    

年代:1963

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129785

出版商:S. Karger AG    

年代:1963

数据来源: Karger