ISSN:1424-8581    

DOI:10.1159/000131648

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

G- and C-banded karyotypes from 9 previously unstudied species of Peromyscus are described and compared to the 9 species described in the literature. Additional new data are presented for P. eremicus. A hypothetical evolutionary tree for the 18 species was constructed based on the assumption that, where possible, shared chromosomal rearrangements became established in a common ancestor. A minimum of 60 chromosomal rearrangements (34 heterochromatic additions and 26 pericentric inversions) were needed to construct the most parsimonious tree. Seven of the 18 species have heterochromatin in noncentromeric areas. Three times as many inversions have been identified in the 11 largest pairs as have been observed in the 12 smallest pairs. Peromyscine rodents are characterized by a pattern of chromosomal variation quite distinct from that described for other rodent genera, such as Sigmodon and Mus. Karyotypic orthoselection in rodents appears to be relatively common in closely related species.

ISSN:1424-8581    

DOI:10.1159/000131649

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Elevated frequencies of spontaneous chromosome breakage and hypersensitivity to radiation induced chromosome damage are characteristic findings in cultured lymphocytes and skin fibroblasts of patients with ataxia telangiectasia (AT). To determine whether long-term AT lymphoblastoid cells (B-lymphocytes) which do not express spontaneous chromosomal instability, exhibit increased chromosomal radiation sensitivity, four AT lymphoblastoid cell lines were exposed to various doses of 250 kVp X-rays during G2. At doses of 25 and 50 rad, the AT cells exhibited a 2–3 fold increase in radiation damage relative to that observed in B-cell lines or PHA stimulated lymphocytes from normal donors, while at 100 rad, the AT cells demonstrated approximately 1.5 times more lesions. These findings suggest that the genetic (or other) factors responsible for increased chromosomal radiation sensitivity in AT lymphocytes and fibroblasts also operate in long-term lymphoblastoid AT cell

ISSN:1424-8581    

DOI:10.1159/000131650

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Intraspecies somatic cell hybrids of BALB/c mouse 3T3 and SV40-transformed embryonic fibroblast (SVT2) cells were analyzed for transformation-associated properties and their tumorigenic potential in nude mice. In confirmation of our earlier findings, hybrids expressing the viral T-antigen were not suppressed for the ability to clone in medium with 1% serum. In contrast, division rate in medium with 1% or 10% serum, anchorage independence, cytochalasin-sensitive growth control, and tumorigenicity were suppressed noncoordinately, and the extent of suppression varied from one hybrid to another. Suppression was not simply determined by the increased chromosome content of the hybrid cells, nor was suppression correlated with rearrangements of the integrated viral sequence (Sager et al., 1981a, b). Similar results were found in cytoplasmic transferants expressing T-antigen. Four independent transferants and subclones derived from them varied in the extent of suppression of anchorage independence and tumorigenicity. In both hybrids and transferants, a low serum requirement for clonal growth apparantly was determined solely by expression of SV40 T-antigen, but other transformation properties, as well as tumorigenicity, appeared to require multiple changes in the cellular genome for their expression. These changes must occur during or after viral integration, since they are not expressed in uninfected 3T3 cells.

ISSN:1424-8581    

DOI:10.1159/000131651

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

A total 23 enzymatic markers were analyzed in cell hybrids obtained between Cebus capucinus (CCA) fibroblasts and a Chinese hamster cell line. The following markers, or syntenic groups, could be localized in CCA chromosomes homologous to human chromosomes or chromosome segments: PGD-ENOl-PGMl, MDH1, IDH1, PGM2, PGM3-ME1, AK3, TPI-LDHB-PEPB, GPI, and SODl. The following syntenic groups were observed but could not be localized: GUK1-FH and MPI-PKM2. The following loci could not be localized with full confidence: LDHA, NP, PEPD, ITP, and PGK.

ISSN:1424-8581    

DOI:10.1159/000131652

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131653

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

R banding of porcine chromosomes by chromomycin A3 plus distamycin A and DAPI (DA-DAPI) revealed two distinct types of heterochromatin: The GC-rich centromeric heterochromatin of the biarmed autosomes (Nos. 1–12) and of the X chromosome exhibited bright chromomycin A3 fluorescence, while the heterochromatin of the acrocentric chromosomes (Nos. 13–18) stained brightly by DA-DAPI. The latter also fluoresced brightly when stained by D 287/170. In addition, significant fluorescent polymorphism was observed among both acrocentric and metacentric chromoso

ISSN:1424-8581    

DOI:10.1159/000131664

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131654

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131655

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000131647

出版商:S. Karger AG    

年代:1981

数据来源: Karger