ISSN:1424-8581    

DOI:10.1159/000130431

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Previous studies have suggested that the microchromosomes of birds may contain a distinct type of DNA termed heavy shoulder DNA. To examine whether a similar relationship might hold for the microchromosomes in snakes, Boa constrictor, Cieiia occipitolutea, and Liophis miliaris were examined. Although these possess 20, 36, and 0 microchromosomes respectively, only Boa constrictor had significant amounts of heavy shoulder DNA.

ISSN:1424-8581    

DOI:10.1159/000130432

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The cells of two ascitic effusions from human cancers of the ovary were analyzed by the fluorescence and Giemsa banding techniques. The normal chromosomes still present in the cancer cells were identified, and several chromosomes which appeared normal with the conventional techniques were found to be rearranged ones. In the rearranged chromosomes it was possible to identify chromosome material which appeared preferentially lost. The sequence of events leading to the formation of many new chromosomes were deletions, inversions, and translocations. Both ascites showed, in all cells, a relative constancy in the ratio of normal to new chromosomes, and this suggests that not all the possible combinations of normal and abnormal chromosomes can occur. In one of the ascites, six different rearrangements have been found in several cells, all involving the long arm of chromosome No. 1.

ISSN:1424-8581    

DOI:10.1159/000130433

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Cytogenetic analyses of 11,950 lymphocyte metaphases from 122 cultures from 10 control men and 17,759 lymphocyte metaphases from 183 cultures from 21 control women have shown: (1) variations in breakage frequencies in consecutive cultures from the same person, (2) variations in average breakages among cultures from different people, (3) greater variability in breakages in cultures from women than in cultures from men, and (4) differences in average breakage frequencies in cultures obtained at different times of the year.

ISSN:1424-8581    

DOI:10.1159/000130434

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A 46, XYq+, r(B) karyotype was observed in a four-month-old boy with cri du chat syndrome. The ring was identified as a No. 5 on the basis of both G-staining and quinacrine fluorescence. The break points were located at bands 5ρl5 and 5q35, i.e., his karyotype was 46, XYq+ , r(5)(pl5q35). The loss of chromosome material was estimated to be about 5.5% of a normal No. 5 chromosome. The father also had a Yq+ chromosome

ISSN:1424-8581    

DOI:10.1159/000130435

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Two males with apparently identical rings of chromosome 7 and very different phenotypic features are presented. Patient 1 is severely retarded, has short stature, microcephaly, craniosynostosis, unilateral proptosis, ptosis, and microcornea, small phallus, first-degree hypospadias, and undescended testes. Patient 2 is of normal intelligence, and his only abnormalities are short stature and a small head. Study of lymphocytes at metaphase showed the same proportion of cells with the ring, 46, XY, r(7), and those without a ring, 45, XY,-7, in each case. Quinacrine fluorescence and Giemsa banding techniques showed all the bands of chromosome 7 to be present, suggesting little material missing as a result of ring formation. A similar degree of instability of the ring in each case was indicated by the frequency of abnormal cells at anaphase and telophase.

ISSN:1424-8581    

DOI:10.1159/000130436

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

It has been reported that the Y chromosome consistently assumes a peripheral location in metaphase cells. Analysis of two normal males and an XYY individual revealed no evidence to support this contention.

ISSN:1424-8581    

DOI:10.1159/000130437

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A male individual with two fluorescent Y-chromatin bodies in a buccal smear taken from him and 46 chromosomes in his dividing lymphocytes was shown by banding techniques to carry a Y/22 translocation.

ISSN:1424-8581    

DOI:10.1159/000130438

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A sterile male mouse with absence of the normal X-Y chromosome association at meiotic metaphase I is described. The X and Y chromosomes were seen together in the sex vesicle at pachytene, but they became separated soon after this stage. No secondary spermatocytes were found in air-dried testicular chromosome preparations, and no spermatozoa were seen in the epididymes. The mitotic chromosomes of the sterile mouse were normal. The father and a fertile brother of the sterile male had a higher-than-normal proportion of spermatocytes with failure of X-Y chromosome association at metaphase I. The ratios of the length of the X to the length of the Y chromosome in the sterile male, the fertile brother, and a chromosomally normal male of the same stock were not significantly different. Seventeen other tested sibs of the sterile male proved to be fully fertile. The mating in which the sterile male was found gave small litters with an excess of males (31 males:14 females). Some possible causes of the sterility are discussed.

ISSN:1424-8581    

DOI:10.1159/000130439

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Oocytes were obtained from C57BL/6J and ICR female mice ranging in age from six weeks to 15 months. Both strains demonstrated a significant increase in univalents and a significant decrease in chiasma frequencies at metaphase I with age. Strain differences were observed with respect to the specific type of univalent formation and the regression of chiasma frequency on age. Univalent formation was nonrandom and involved small chromosomes predominantly. Although the percentage of oocytes possessing univalents increased significantly with age, the vast majority possessed only one pair of univalents.

ISSN:1424-8581    

DOI:10.1159/000130440

出版商:S. Karger AG    

年代:1973

数据来源: Karger