“…There have been studies on chromosomal C-band patterns (Moriwaki et al, 1990), protein electrophoresis (Bonhomme et al, 1984;Boursot et al, 1989;Miyashita et al ,1985), and DNA RFLP (Ferris et al, 1983a(Ferris et al, , 1983bRedi et al, 1990;Suzuki et al, 1986;Yonekawa et al, 1981). Historically, because of the rather conservative morphology of mice, the definition of subspecies is largely based on the combinations of allele frequencies at many nuclear DNA loci (Bonhomme et al, 1984).…”