摘要:

Three sibs with similar phenotypic abnormalities were found to have partial trisomy of chromosome 18 and a sizeable deficiency of one of the G chromosomes. The mother and her father as well as five other maternal relatives are carriers of a reciprocal translocation. A total of 35 individuals were tested. Viability in spite of a large deficiency may be explained by the distribution of heterochromatin and euchromatin in the acrocentric chromosome. The recovery of only one combination from adjacent segregation is probably the result of parallel orientation of a chain of four and/or early zygotic lethality. Blood grouping studies showed that the loci for Rh, MN, Duffy and Kidd are not situated on the deleted portion of the G chromosome involved.

ISSN:1424-8581    

DOI:10.1159/000129800

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

The pattern of terminal DNA synthesis of the sex chromosomes of the Syrian hamster was studied by means of tritiated-thymidine incorporation and autoradiography. In the female, an entire X-chromosome and the long arm of the other X-chromosome underwent late replication. In the male, one of the largest submetacentric chromosomes and the long arm of the X-chromosome underwent late replication. It was presumed that this uniquely late-replicating large submetacentric chromosome was the Y-chromosome. The pattern of late replication among the autosomes was similar in both sexes and included approximately half the smallest pair of median metacentric chromosomes and the short arms of many of the larger submetacentric chromosomes. The asynchronous duplication pattern of the sex chromosomes observed in the Syrian hamster bore a striking resemblance to that previously reported in established cell lines derived from the Chinese hamster. This similarity attests to the close taxonomic relationship of these two species and is not inconsistent with the hypothesis of polyploid evolution of the Syrian hamster.

ISSN:1424-8581    

DOI:10.1159/000129801

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

The authors of this paper report on a satellited large acrocentric chromosome showing abnormally lengthened short arms. This chromosome was found in a mongoloid child (GLD-Trisomy), her mother, and the dizygotic twin sister of the mother, both phenotypically normal. The chromosome abnormality may have originated from a duplication of the short arms or from insertion of a piece of another chromosome between the short arms and the satellites. Since the total length of this chromosome exceeds that of the other D’s, a pericentric inversion is improbable. Normal variability and structural heterozygosity coinciding with non-disjunction are discusse

ISSN:1424-8581    

DOI:10.1159/000129802

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

Studies of the pachytene stage of human meiosis in young adult males show that the principal nucleoli are associated with the terminal chromomeres of certain bivalents. These findings are reconcilable with earlier observations on the principal nucleolar chromosome on the basis of the association of bivalents by their nucleolus-forming regions. The pattern of multiple associations suggests that three long and two short bivalents are capable of forming terminal nucleoli. The evidence suggests that these five bivalents are the five pairs of satellited chromosomes in the human mitotic idiogram.

ISSN:1424-8581    

DOI:10.1159/000129803

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

A study of sex chromosome replication in euploid bovine cell cultures is presented. Both X chromosomes in the female replicate their DNA throughout most of the cell’s DNA synthetic period. However, one X (late X) continues its replication later than its homologue (early X). This late X is one of the last chromosomes in the complement to terminate replication. In the male, the DNA replication pattern of the X chromosome is like that of the early X in the female, while the Y chromosome begins its replication later than any chromosome in the complement (by two or more hours), and finishes replication just after the

ISSN:1424-8581    

DOI:10.1159/000129804

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

An improved technique for the preparation of meiotic chromosomes from human testicular biopsy specimens for microscopic examination is described. The results are exemplified by a description of the observations of the chromosomes at various stages of the first and second meiotic divisions in a normal male.

ISSN:1424-8581    

DOI:10.1159/000129805

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

A patient with Down’s syndrome was found to have a modal number of 46 with a trisomy 21 and a reciprocal translocation in the 13–15 group. Several members of his immediate family were phenotypically normal carriers of a similar reciprocal translocation in the 13–15 group. Extensive blood grouping studies gave the very tentative suggestion of a possible linkage between the Gm-locus and the translocation chrom

ISSN:1424-8581    

DOI:10.1159/000129806

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

Meiotic and mitotic chromosome counts conclusively established that an adult male mouse possessed 41 chromosomes. Karyotype analyses indicated that the extra chromosome was homologous to one of the smallest autosomes – probably chromosome number 16. The animal was phenotypically normal and was only detected by the fact that it was completely sterile. Spermatogenesis was normal until after meiotic metaphase I. Subsequently, few, if any, meiotic products could be identified. The trisomy was probably the result of triethylenemelamine-induced non-disjunction in a meiotic division of the fathe

ISSN:1424-8581    

DOI:10.1159/000129807

出版商:S. Karger AG    

年代:1964

数据来源: Karger

摘要:

The maturation division of oocytes has been studied in relation to estrus, and follicle diameter in gonadotropin-treated and untreated beef cattle. Injection of pregnant mare serum (PMS) gonadotropin had no effect on the pattern of maturation division of oocytes. The follicles reached full size shortly before the onset of estrus. During early estrus, all oocytes had nuclei of metaphase I; the maturation division rapidly progressed to metaphase II during late stages of estrus. Human chorionic gonadotropin (HCG) treatment which has been recognized to be effective for stimulating ovulation did not affect the pattern of maturation division of the oocytes. Degeneration of oocytes occurred in all stages of follicular maturation during and following estrus, irrespective of the follicle size.

ISSN:1424-8581    

DOI:10.1159/000129808

出版商:S. Karger AG    

年代:1964

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000129809

出版商:S. Karger AG    

年代:1964

数据来源: Karger