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Ved Brat, S.; Verma, R.S.; Dosik, H.
doi: 10.1159/000131381pmid: 509990
The identification, morphology, and banding pattern of the chromosomes of the Indian muntjac (Muntiacus muntjak) are described. A diagrammatic representation of the banding pattern as revealed by various techniques is presented following the nomenclature suggested by Paris Conference (1971) for human chromosomes. The Y<sub>2</sub> chromosome and the neck of the X chromosome are late replicating based on observations made with the use of a bromodeoxyuridine plus Giemsa technique. Most of the G-bands are early replicating, contrary to earlier findings based on autoradiography.
Walker, L.I.; Spotorno, A.E.; Fernández-Donoso, R.
doi: 10.1159/000131382pmid: 509991
The assumption of simple fusion in a group showing a constant number of chromosome arms was tested by comparison of the G-band patterns of chromosomes of three Phyllotis species. The karyotypes, each of which has 40 chromosome arms, have a 2n of 38, 38, and 40 and are made up of mostly metacentric chromosomes. Operational concepts describing the amount of matching in G-band patterns are proposed, separating chromosomes or arms into those with total correspondence, partial correspondence, or unique cases. Seven chromosomes and 21 arms out of the total were identical in the three species, denoting a conservation of whole-arm band sequences in this group. A greater number of identical arms than of identical chromosomes was observed, giving some support to the simple fusion hypothesis. An unexpected chromosomal divergence was detected, including chromosomal variation in the C-banded sex chromosomes.
Lin, M.S.; Oizumi, J.; Ng, W.G.; Alfi, O.S.; Donnell, G.N.
doi: 10.1159/000131383pmid: 509992
Somatic cell hybrids between mouse and human cells containing two different reciprocal translocations involving human chromosome 1, 46, X, t(l;X)(ql2;q26) and 47, XX, + 21, t(l;17)(p32;pl3), were studied for the expression of human uridine diphosphate galactose 4-epimerase (UDPGal 4-epimerase, E.C. 5.1.3.2) by starch-gel electrophoresis. Analysis of the hybrid clones for the expression of the enzyme and the presence of the translocation chromosome 1 has permitted the assignment of the gene for human UDPGal 4-epimerase to the pter→p32 region of chromosome 1.
doi: 10.1159/000131384pmid: 116803
The karyotypes of five species of Malagasy lemurs are described and compared with those of 12 previously studied species or subspecies. Based on these studies, phylogenetic relationships among nearly all the species of Cheirogaleidae and Lemuridae are proposed. The karyotype of the common ancestor is identical or very similar to that of Microcebus. Nearly 60 chromosomal changes, including five intrachromosomal rearrangements of the X chromosome, have been detected during the evolution of these two families. The possible evolutionary role of the different chromosomal rearrangements is discussed.
Wang, H.S.; Niewczas, V.; de S. Nazareth, H.R.; Hamerton, J.L.
doi: 10.1159/000131385pmid: 509993
A cytological analysis of 26 polyethylene glycol (PEG) induced human/hamster hybrid lines has shown that such lines are similar to inactivated Sendai virus (ISV) induced hybrids in respect to stability, retention of specific chromosomes, and cell selection. The evolution of stable hybrid cell lines carrying variable human chromosome complements depends upon a balance being established between the retained human and hamster genomes. This balance is a result of random loss of human and hamster chromosomes followed by selection of the fittest stem lines. A major mechanism of chromosome loss may be fragmentation and elimination of acentric fragments. Twelve of the 26 lines had stabilized by the 30th passage, an incidence similar to that found with ISV-induced hybrids studied in this laboratory. Thus, PEG may be considered to be an ideal chemical for inducing somatic cell hybrids for genetic analysis.
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