Genetic analysis of tumorigenesis: IV. chromosome reduction and marker segregation in progeny clones from Chinese hamster cell hybrids

1979 ◽  
Vol 5 (4) ◽  
pp. 491-502 ◽  
Author(s):  
Ruth Sager ◽  
Patricia E. Kovac
Keyword(s):  
Genetic Analysis ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Cell Hybrids

Segregation of recessive phenotypes in somatic cell hybrids: role of mitotic recombination, gene inactivation, and chromosome nondisjunction

1981 ◽  
Vol 1 (4) ◽  
pp. 336-346
Author(s):  
C E Campbell ◽  
R G Worton
Keyword(s):  
Somatic Cell ◽  
Chinese Hamster ◽  
Mitotic Recombination ◽  
Chinese Hamster Cell ◽  
Gene Inactivation ◽  
Chromosome Loss ◽  
Resistance Locus ◽  
Chromosome 2 ◽  
Somatic Cell Hybrids ◽  
Cell Hybrids

Somatic cell hybrids heterozygous at the emetine resistance locus (emtr/emt+) or the chromate resistance locus (chrr/chr+) are known to segregate the recessive drug resistance phenotype at high frequency. We have examined mechanisms of segregation in Chinese hamster cell hybrids heterozygous at these two loci, both of which map to the long arm of Chinese hamster chromosome 2. To follow the fate of chromosomal arms through the segregation process, our hybrids were also heterozygous at the mtx (methotrexate resistance) locus on the short arm of chromosome 2 and carried cytogenetically marked chromosomes with either a short-arm deletion (2p-) or a long-arm addition (2q+). Karyotype and phenotype analysis of emetine- or chromate-resistant segregants from such hybrids allowed us to distinguish four potential segregation mechanisms: (i) loss of the emt+- or chr+-bearing chromosome; (ii) mitotic recombination between the centromere and the emt or chr loci, giving rise to homozygous resistant segregants; (iii) inactivation of the emt+ or chr+ alleles; and (iv) loss of the emt+- or chr+-bearing chromosome with duplication of the homologous chromosome carrying the emtr or chrr allele. Of 48 independent segregants examined, only 9 (20%) arose by simple chromosome loss. Two segregants (4%) were consistent with a gene inactivation mechanism, but because of their rarity, other mechanisms such as mutation or submicroscopic deletion could not be excluded. Twenty-one segregants (44%) arose by either mitotic recombination or chromosome loss and duplication; the two mechanisms were not distinguishable in that experiment. Finally, in hybrids allowing these two mechanisms to be distinguished, 15 segregants (31%) arose by chromosome loss and duplication, and none arose by mitotic recombination.

Changes in the cell cycle during culture of mouse-Chinese hamster cell hybrids

1980 ◽  
Vol 102 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Jennifer A. Marshall Graves ◽  
Kenneth W. Koschel
Keyword(s):  
Cell Cycle ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Cell Hybrids
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