摘要:

G-banding, C-banding, and silver staining techniques were used to analyze the chromosomes of Trichomys apereoides. In a sample of 22 specimens the diploid number was 2n = 30, with several pairs of biarmed chromosomes and a large metacentric (pair 1) with a secondary constriction, or nucleolar organizing region (NOR), in the short arm. One male had a heteromorphic pair 1, with only one NOR-bearing homolog. C-bands showed constitutive heterochromatin in the centromeric region of almost all autosomes. The X has a large block in the proximal region and an interstitial small band in the long arm. The Y is totally heterochromatic. One heteromorphic female with an increased C-band block in one of the X chromosomes was observed. The Y is a small submetacentric; one male showed a metacentric Y, resulting probably from a pericentric inversion. The sexual bivalent and the synaptonemal complexes of all autosomal bivalents were revealed by silver staining in pachytene cells.

ISSN:1424-8581    

DOI:10.1159/000131755

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

We have combined the recently developed monoclonal antibody techniques and an experimental protocol for the definition of chromosome-specific cell surface antigens in order to produce a monoclonal antibody, Rl, which recognizes an X-linked human cell surface antigen.

ISSN:1424-8581    

DOI:10.1159/000131756

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

The karyotype of Microcebus murinus (MIM) (Lemuridae) is considered by Dutrillaux (1979) as the closest to the karyotype ancestral to all primates. A large number of homoeologies exists between the banding patterns of MIM chromosomes and those of man (HSA). We report a comparison of the gene maps of these two species which confirms most of these homoeologies. Fifteen cell hybrids were obtained by fusing MIM fibroblasts and an HPRT- Chinese hamster cell line. Twenty-seven enzyme markers were investigated. The following assignments were demonstrated: NP to chromosome MIM 2, homoeologous to HSA 14; the syntenic group PGD—ENOl—PGMl to MIM 3, homoeologous to HSA lp; LDHA to MIM 5, homoeologous to HSA 11; ME1 to MIM 6, homoeologous to HSA 6; the syntenic group LDHB—CS—PEPB—EN02—TPI to MIM 7, homoeologous to HSA 12; the syntenic group AK1—AK3 to MIM 10, which we considered to be homoeologous to HSA 9 (we do not consider MIM 9 to be homoeologous to HSA 9, as does Dutrillaux, 1979); GOT1 to MIM 15, homoeologous to HSA 10; the syntenic group HPRT—G6PD—PGK—GLA to MIM X. Synteny dissociation in three hybrids suggests closer linkage between G6PD and HPRT than between PGK—GLA and HPRT. Three syntenic groups, known in man, were confirmed in MIM but could not be assigned with full confidence: ACPI—MDH1 , MPI—PKM2, andPEPD—GPL GUK1 and PEPC, known to be syntenic in man, were found to be asyntenic in MIM and could not be assigned. PGM2 and SOD1 could not be assigned. A comparison of these gene assignments with those known in Cebus capucinus showed a remarkable homoeology for six chr

ISSN:1424-8581    

DOI:10.1159/000131757

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

A 5-year-old male with mild mental retardation showed a chromosomal rearrangement involving duplication of part of 2q (2q33.3→2qter) in 70% of metaphases from peripheral blood; the remaining 30% of cells had a rearrangement of chromosome 2 in the form of a ring, viz., r(2)(2p25.2→2q33.2). Both configurations appeared to be missing a tiny portion of 2p (p25.3→pter). All metaphases examined from cultured skin fibroblasts from the child had the abnormal rod configuration of chromosome 2; none had the ring. The pattern of the 2q duplication/2p deletion in the rod is that expected if there were an inversion in a No. 2 in one of the parents. Q-, G-, and R-banding studies, however, revealed both parents to be chromosomally normal. Furthermore, the finding of an inversion would not explain the origin of the ring. The most probable explanation is that neither parent is mosaic for an inversion, but that the rod and ring configurations arose simultaneously from a de novo, prezygotic or early zygotic exchange in a No. 2, either between complementary DNA strands in Gl or by intrachromosomal exchange in S or G2. Differential selection against cells with the ring chromosome in blood and skin probably occurred during subsequent embryological development. Cytoplasmic malate dehydrogenase (MDH1) was excluded from the terminal band of 2p (i.e., 2p25.3) by deletion ma

ISSN:1424-8581    

DOI:10.1159/000131758

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

During the five years of a cytogenetic study on spontaneous abortions in Hawaii there have been significant increases in the frequencies of triploidy of maternal origin and trisomy 16, a significant decrease in sex chromosome monosomy, and variation without trend in the frequency of tetraploidy. Attempts to explain these results in terms of technical factors or changes in maternal and gestational age have been unsuccessful, as have preliminary attempts to identify viral, pharmacological, or other causes. Apparently the etiology of chromosomal abnormality is variable over a few years even in a stable population. Research to identify these causes is continuing on the supposition that variable risks can be reduced.

ISSN:1424-8581    

DOI:10.1159/000131759

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

Using a method of chromosome preparation which yielded pachytene spermatocytes with exceptionally well spread bivalents, we undertook detailed chromomere analysis of each of the 22 autosomal bivalents stained with orcein or quinacrine. A maximum of 442 chromomeres were recognized and mapped at mid-pachytene. The chromomere maps of pachytene chromosomes presented here corresponded well with the high resolution banding maps of somatic chromosomes at the 850 band stage described in the International System for Human Cytogenetic Nomenclature (ISCN, 1981). Our observations of other features of the pachytene chromosomes, such as the parameres, also agree well with previous reports.

ISSN:1424-8581    

DOI:10.1159/000131760

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

The frequency of background or spontaneous sister chromatid exchanges (SCE) was estimated in young and old rat and mouse bone marrow cell populations by exposing these cells to increasing concentrations of bromodeoxyuridine (BrdU). At the lowest levels of BrdU where SCE could be accurately assessed, there was no significant difference in background SCE between young and old cell populations. Extrapolation to zero BrdU concentration yielded SCE frequencies of approximately 1.0 SCE/cell/cell cycle in both mouse and rat cells.

ISSN:1424-8581    

DOI:10.1159/000131761

出版商:S. Karger AG    

年代:1982

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131762

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

Twenty-eight hybrid clones with different mink chromosomes were derived from the fusion of Chinese hamster and American mink (Mustela vison) cells. This set of clones made it possible to assign the mink genes for isocitrate dehydrogenase-1 (soluble) to chromosome 4, for isocitrate dehydrogenase-2 (mitochondrial) to chromosome 10, for glutathione reductase to chromosome 6, and for phosphoglycerate kinase-1 to the X chromosome.

ISSN:1424-8581    

DOI:10.1159/000131763

出版商:S. Karger AG    

年代:1982

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131764

出版商:S. Karger AG    

年代:1982

数据来源: Karger