Evolution of a mouse Y chromosomal sequence flanked by highly repetitive elements

Abstract

Mammalian primary sex is determined by the presence or absence of the Y chromosome. However, little is known about the molecular processes through which the Y chromosome exerts its action. We applied recombinant DNA techniques to isolate mouse Y chromosomal fragments and described previously a clone designated as AC11 (Y. Nishioka and E. Lamothe. 1986. Genetics, 113: 417–432). To obtain information on DNA sequences that flank AC11, we screened a mouse genomic library for the presence of AC11-related sequences and isolated over 50 positive clones. In this report we describe clones ACC2 and ACC3, both of which contain highly repetitive elements. Using a male-specific portion of these clones, we compared DNA's isolated from mice (Mus musculus, M. hortulanus, M. spretus, M. cookii, M. pahari, and M. platythrix), rat, hamster, and guinea pig and obtained results that agree with the phylogenetic relationships deduced from morphological and biochemical studies. The male-specific accumulation of the related sequences was found only in M. musculus, M. hortulanus, and M. spretus. Key words: mouse, Y chromosome, repetitive sequence, genome evolution.