ISSN:1424-8581    

DOI:10.1159/000131505

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Simultaneous Q- and R-type banding patterns in human chromosomes have been achieved by staining with chromomycin A3. Some peculiarities of these patterns as compared to the patterns induced by other fluorochromes are described. The resolution power of this technique in analyzing structural rearrangements of human chromosomes is discussed.

ISSN:1424-8581    

DOI:10.1159/000131506

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The similarity of chromosomes and the mode by which differences occurred in the chromosomes of the species comprising the genus Mesocricetus, M. auratus (2n = 44), two “cryptic” species of M. brandti (2n = 44 and 2n = 42) and M. newtoni (2n = 38) were determined. Most of the autosomes and the sex chromosomes have either complete or partial G-band correspondence and thus provide definitive evidence for the taxonomic relationship of these species. The karyotypic differences occurred primarily as a result of deletion of sex chromosome heterochromatin and of autosomal translocations that frequently involved chromosomes with heterochromatic short arms or chromosomes bearing NOR’s. Only one Robertsonian centric fusion occurred. Despite the conservatism of arrangement of the genetic material, the chromosomal distribution of heterochromatin diverged during the evolution of these species. M. brandti and newtoni each have a metacentric chromosome with a common long arm matching a submetacentric M. auratus autosome, but a short arm corresponding to two different M. auratus chromosomes. These translocations are crucial for explaining the direction of chromosomal evolution of these species and indicate that M. auratus was the common ancestral species and that M. brandti and newtoni subsequently evolved independ

ISSN:1424-8581    

DOI:10.1159/000131507

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Growth rates were investigated in long-term lymphoblastoid cell lines derived from normal individuals and patients with ataxia telangiectasia (AT R). By a cell doubling method, sister chromatid exchanges, and autoradiography, the AT R cells showed a significantly longer total generation time. Autoradiography demonstrated that the difference in cell cycle was due to a specific lengthening of the S period in the AT R lymphoblasts.

ISSN:1424-8581    

DOI:10.1159/000131508

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The genomic location of rDNA in the rabbit was determined by in situ hybridization with 125I-labeled ribosomal RNA (rRNA). The results demonstrate the presence of rRNA genes on chromosomes 13, 16, and 20, all of which have secondary constrictions, and on the telomere of the long arm of 21. The number of genes, as assessed by grain counts, was not equally distributed among the chromosomes. Chromosome 20 had the most copies and along with 13 and 16 carried significantly more genes than 21.

ISSN:1424-8581    

DOI:10.1159/000131509

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The G-, C-, and Q-banding and NOR patterns of the chromosomes of Miopithecus talapoin are described. G-banding patterns are compared with those of Macaca mulatta and Cercopithecus aethiops which show large homoeologies.

ISSN:1424-8581    

DOI:10.1159/000131510

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The induction of cytotoxicity, growth inhibition, specific locus mutations, and cytological alterations such as micronuclei, chromosome/chromatid aberrations, and sister chromatid exchanges by 5-bromodeoxyuridine (BudR) in Chinese hamster ovary cells was determined. BudR shows concentration-dependent increases in cytological alterations over the range of 5–500 µM, but it is mutagenic only at concentrations greater than 50 µM.

ISSN:1424-8581    

DOI:10.1159/000131511

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The Giemsa-banded karyotype of the chacma baboon, Papio ursinus, was shown to be identical to that of Papio hamadryas. Comparison of G-banded P. ursinus (PUR) chromosomes with those of man (HSA) showed close morphological homoeology between PUR and HSA chromosomes 5, 8, 12, 19, and X, and partial homology for seven other PUR and HSA chromosomes. PUR 10 showed a striking resemblance to HSA 15 and 22 and was the only Papio chromosome containing a nucleolar organizer region (NOR). This baboon chromosome, therefore, shows genetic homoeology with human acrocentrics for at least 18S and 28S rRNA gene loci. It is postulated that HSA 15 and 22 originated from the fission of a larger submetacentric chromosome in a lower primate.

ISSN:1424-8581    

DOI:10.1159/000131512

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Chromosome banding patterns of Lepus saxatilis, 2n = 48, and Pronolagus rupestris, 2n = 42, are presented. Comparison of G-banded karyotypes allows the identification of similar elements in both species. The karyotype of P. rupestris differs from that of L. saxatilis by the presence of three fusions in the former. Comparative studies with the fusion products of Oryctolagus cuniculus indicate that fusion and not fission is the major factor in chromosomal evolution of these leporids. The chromosomal conservatism of the hares is compared to the karyotypic variability of the rabbits and possible causes are discussed.

ISSN:1424-8581    

DOI:10.1159/000131513

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The karyotypes of six killer whales were studied by banding techniques. A striking accumulation of C-heterochromatin has occurred in the Orcinus karyotype. The four telocentric pairs characteristic of the 2n = 44 cetacean karyotypes have become masked due to the accumulation of heterochromatin in the short arms. Conspicuous C-band polymorphism occurred in the materials studied, rendering each specimen karyotypically unique. Owing to the amount and variation of C-heterochromatin in the Orcinus karyotype, access to C-banded karyotypes was essential for the evaluation of the G-band pattern. The G-band pattern of Orcinus was found to be closely similar to that of Stenella. The results indicate an evolution of the Orcinus karyotype from the karyotypes characterizing other delphinids.

ISSN:1424-8581    

DOI:10.1159/000131514

出版商:S. Karger AG    

年代:1980

数据来源: Karger