Genetic differentiation between laboratory lines of the musk shrew (Suncus murinus, Insectivora) based on restriction endonuclease cleavage patterns of mitochondrial DNA.

The cleavage patterns of mitochondrial DNA (mtDNA) by 17 restriction endonucleases were compared between eight lines of musk shrews derived from different wild-caught stocks. Enzymatic digestion by BamHI, PvuII, XbaI, and XhoI showed a cleavage pattern common to all lines that were from five Japanese islands (Nag, Ize, OKI, TKU, and Tr), Bangladesh (BAN), Sri Lanka (SRI), and Java (Bog), and every line lacked cleavage sites for SalI and SmaI. Different cleavage patterns were detected by the remaining 11 enzymes. Within the BAN line, the presence of at least two types of mtDNAs was proved by six enzymes and was not contradictory to the maternal pedigrees going up to the wild ancestors of the stock. More than 30 cleavage sites of the shrew mtDNA were mapped by double-digestion methods. Nucleotide diversities of mtDNA were calculated from these maps and were estimated to be less than 0.5% among Japanese and Bog lines but to be 3.8% between BAN and the other seven lines and 2.3% within the BAN line. These results indicate that BAN shrews differentiate from the other lines to the intersubspecific extent reported in mice previously.