Chromosome segregation from cell hybrids. III. Segregation is independent of spindle constitution.

Hamster beta-tubulin (detected as a mutant subunit that confers Colcemid resistance) is either not expressed or is underexpressed in Chinese hamster-mouse somatic cell hybrids. This selectivity of tubulin expression suggests that a uniparental mouse spindle might preferentially engage mouse chromosomes and lead to loss of hamster chromosomes. However, the repression of hamster tubulin was found to have no bearing on the direction of chromosome segregation occurring in eight hybrids studied, some of which segregated predominantly mouse and other hamster chromosomes.