Department of Animal Science and Resources, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan.
Exp Anim. 2013;62(1):25-34. doi: 10.1538/expanim.62.25.
There are many coat colors in the laboratory mouse, Mus musculus. On the basis of traditional genetics, there are four loci, A-D, related to coat color expressions. As shown by previous studies, Japanese wild mice have gray backs and white bellies and are assumed to carry the A(w) allele at the A (agouti) locus, which is dominant over any other alleles. However, we collected Japanese wild mice from central Honshu with black coats. To understand this black coat expression, we performed cross experiments concerning the four loci using wild-caught mice and DBA/2 laboratory mice from the standpoint of traditional genetics. The offspring of the current crosses showed the wild type, the blackish type, and the intermediate type from some combinations of parents. Considering the coat colors of the offspring, we did not obtain any evidence that the Japanese wild mice always carry the A(w) allele at the A locus. Furthermore, we were not able to explain the current coat color expressions using the traditional logic with regard to the A-D loci and concluded that it is possible for another locus (loci) to be related to the coat color expressions. On the other hand, skull characteristics and external body measurements of the captured wild mice were fundamentally different from those of DBA/2 and offspring from captured wild mice and DBA/2 combinations. Thus, we concluded that the Japanese wild mice had original criteria from a morphological viewpoint.
实验室小鼠（Mus musculus）有许多毛色。根据传统遗传学，有四个与毛色表达相关的基因座 A-D。之前的研究表明，日本野生小鼠背部为灰色，腹部为白色，被认为携带 A（agouti）基因座的 A(w)等位基因，该等位基因对其他任何等位基因均为显性。然而，我们从本州中部收集到的日本野生小鼠却是黑色的。为了理解这种黑色的毛色表达，我们从传统遗传学的角度，使用野生捕获的老鼠和 DBA/2 实验室老鼠进行了四个基因座的交叉实验。当前杂交的后代表现出野生型、黑褐色型和中间型，这取决于父母的某些组合。考虑到后代的毛色，我们没有任何证据表明日本野生小鼠总是在 A 基因座携带 A(w)等位基因。此外，我们无法用传统的 A-D 基因座逻辑来解释当前的毛色表达，得出了另一个基因座（或多个基因座）可能与毛色表达有关的结论。另一方面，捕获的野生小鼠的头骨特征和外部身体测量值与 DBA/2 以及捕获的野生小鼠和 DBA/2 组合的后代有根本的不同。因此，我们得出结论，从形态学的角度来看，日本野生小鼠有其原始的标准。
