[Effect of sperm genotype on the segregation of homologs in male mice, heterozygous for an aberrant chromosome 1]

Abstract

The aberrant chromosome 1 with two large homogeneously staining insertions was isolated from wild populations of Mus musculus. Specific features of aberrant chromosome were described elsewhere. These include preferential entry of the chromosome into the oocyte of heterozygous females, increased mortality of homozygotes, decreased fertility of homozygous females. The data obtained indicated that segregation of homologues in heterozygous females depended on which spermatozoon entered the oocyte, prior to the second meiotic division: meiotic drive is powerful when the spermatozoon bore the normal chromosome 1, and homologue segregation got normalized during MII when the spermatozoon bore the chromosome 1 with insertions. Experimental data are adduced and explanations offered for the phenomenon observed.