摘要:

Pedigree analyses of five families in which a form of spinocerebellar ataxia (SCA1) is present have been used to obtain additional information on the location of SCA1 on chromosome 6. Recombination rates with HLA and glyoxalase I (GLO) suggest that the order is HLA-GLO-SCA1. There was no evidence for linkage of pepsinogen isozyme-5 (PG) either to HLA or GLO.

ISSN:1424-8581    

DOI:10.1159/000131524

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

A ring 12 chromosome was found in a male child with minor phenotypic alterations. No obvious loss of chromosome material was detected. Since there is no other case of a ring 12 in the literature, it was not possible to determine whether the phenotype was due to (invisible) terminal deletions or to karyotypic variation. In lymphocyte cultures 9% of the cells had either no or two rings, but the patient’s RBC had normal activities of the enzymes lactate dehydrogenase B and peptidase B, whose loci are located on the proximal portions of 12p and 12q, respectively. Dicentric rings were found in 37 cells, and all had two active centromeres, in contrast with the relatively frequent finding of latent centromeres in translocated dicentric autosomes. Two latent centromeres were found in one tricentric “rod-shaped” open ring 12, probably derived from a tetracentric ring. It is postulated that latent centromeres are rare in ring chromosomes because, if consistent suppression of centromeres in excess of one took place at each duplication, rings with four, eight, or more centromeres would be formed rather frequently, which is not the

ISSN:1424-8581    

DOI:10.1159/000131525

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Giant oocytes and zygotes twice the normal size from the Chinese hamster were studied embryologically and cytogenetically in order to clarify their significance as a cause of digynic triploidy. There were 6 (0.62%) giant eggs among 973 primary oocytes, 5 (1.37%) among 365 secondary oocytes from mature follicles missing ovulation, 3 (0.44%) among 677 secondary oocytes from oviducts, 4 (0.45%) among 886 one-cell zygotes, and 3 (0.49%) among 608 two-cell zygotes. The results indicated that follicles containing a giant oocyte might have a tendency to miss ovulation. But once ovulated, the giant eggs were fertilized normally and developed normally. uclear and chromosomal aspects were studied in 6 primary and 18 secondary oocytes, and 6 one-cell and 5 two-cell zygotes. There were mononuclear and binuclear giant oocytes, but the latter state was rarely maintained to metaphase II. The primary oocytes showed a diploid number of bivalents (22 tetrads) with normal chiasma configuration, and the secondary oocytes had 22 dyads with normal features, indicating normal segregation. The one-cell zygotes exhibited one set of diploid female pronuclear chromosomes and one set of haploid male pronuclear chromosomes in the late prophase. The two-cell zygotes were all digynic triploids; the tail of a fertilizing spermatozoon was attached. There were five XXX and six XXY giant triploids, giving a ratio of 1:1, as expected. t was suggested that the nuclear-cytoplasmic ratio of giant triploid eggs may be more favorable at least for preimplantation development than that of any other type of triploidy. Giant diploid oocytes may be an important source of human digynic triploids, in spite of the prevailing view from studies of marker chromosomes that suppression of first polar body extrusion is the predominant cause.

ISSN:1424-8581    

DOI:10.1159/000131526

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The segregation of the chromosome 22 markers AC02, ARSA, and NAGA was studied in somatic cell hybrid clones. These hybrids were isolated following fusion of Chinese hamster (E36 or a3) cells with leucocytes of donors carrying an (X;22) or (1;22) translocation. The results suggest the assignment of ARSA and NAGA to the region 22q13→22qter and of AC02 to the region 22q11→22

ISSN:1424-8581    

DOI:10.1159/000131527

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Mice were force-fed ethyl alcohol at different doses, administration rates, and durations during pregnancy. A tablet of 5-bromodeoxyuridine (BrdU) was implanted sub-cutaneously in the animals between the 16th and 18th day of gestation. Twenty-one hours later, the animals were killed, the fetuses removed, and the fetal liver cells treated to exhibit sister chromatid exchanges (SCE’s). The following conclusions were drawn: Ingestion of alcohol by pregnant mice induced SCE’s in the liver cells of their fetuses. The number of exchanges in the fetal cells was directly proportional to the amount of alcohol consumed by the dam in the period when BrdU was present in her blood. (3) The induction of exchanges above control level was due entirely to alcohol ingestion and was independent of exposure to BrdU, any other drug, or any dietary deficiency. There is an association between maternal alcohol consuption during pregnancy and birth defects, both in children and in experimental animals (Hansen et al., 1976; for review of animal experiments, see Sandor and Elias, 1968; Green, 1974; Warner and Rosett, 1975). While there is no direct evidence to date that any of these defects result from chromosomal damage,

ISSN:1424-8581    

DOI:10.1159/000131528

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

An auxotrophic mutant, GAT-, derived from the Chinese hamster cell line CHO-K1 and exhibiting multiple growth requirements for glycine, adenine, and thymidine, has been shown to be deficient in one of the folate-dependent enzymes, folylpolyglutamate synthetase (FPGS). This mutant was fused with normal human lymphocytes and human lymphoblasts and 41 GAT + primary hybrid clones were isolated in medium lacking glycine, adenine, and thymidine. In addition, 71 secondary clones were isolated after growth of four primary hybrid clones in enriched medium, which allows losing the complementing human chromosome without losing cell viability. Analysis of human isozyme markers in the 112 primary and secondary clones established a syntenic relationship between the GAT marker and AK1, an isozyme marker for human chromosome 9. Enzyme studies of the parental and hybrid cells not only showed restored enzyme activities of FPGS in the hybrids, but also demonstrated that several enzyme characteristics of FPGS in the hybrids are consistent with those of the human enzyme. Thus, it is concluded that the human gene coding for the enzyme FPGS which complements the auxotrophic mutant GAT- in the CHO-K1 cells can be assigned to human chromosome 9. This assignment provides an additional selective marker for mammalian cell genetic analysis in which human chromosome 9 can be selectively and stably retained in the cell hybrids.

ISSN:1424-8581    

DOI:10.1159/000131529

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Using the protein A rosette technique, it was found that the gene for polledness (P) in goats is associated with the presence of H-Y antigen on the cell surface of cultured fibroblasts. Two XX intersex goats (PIP) were found to be H-Y+, and one heterozygous (P/+) normal XX female was also found to express H-Y antigen at a low level. The expression of H-Y antigen by intersex goats was found to be lower than that of normal XY males. The statistical analysis suggests that animals of the same genotype and sex might differ in the density of H-Y antigen on their cell surface, which might explain the variability in primary sex determination among intersex goats. The association between the gene for sex reversal and H-Y antigen is discussed in relation to the location of the H-Y gene(s).

ISSN:1424-8581    

DOI:10.1159/000131530

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Purified fetal mouse germ cell preparations have been analyzed for the presence of a heterochromatic X chromosome at cell division. A single large heterochromatic chromosome is found in oogonia stage germ cells, but such a chromosome is not present in 16-day fetal oocytes. These results support the idea that mitotic stage germ cells are subject to X-chromosome inactivation and that they go through a reactivation step at meiosis.

ISSN:1424-8581    

DOI:10.1159/000131531

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131532

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131533

出版商:S. Karger AG    

年代:1980

数据来源: Karger