Uniparental propagation of mitochondrial DNA in mouse-human cell hybrids

The retention of the two parental mitochondrial DNAs has been investigated in a large number of mouse-human cell hybrids segregating either mouse or human chromosomes, by using a highly sensitive and specific method for detection of the DNA; the results have been correlated with the karyotype and isozyme marker pattern in the same hybrid lines. In all the hybrids examined, a consistent pattern was observed for the type of mitochondrial DNA retained: the mitochondrial DNA of the parent whose chromosomes were segregated from the nucleus was undetectable or present in marginal amounts. This was true also of hybrids containing a complete set of the segregating chromosomes in the total or a large fraction of the cell population.