Suto Jun-ichi, Sekikawa Kenji
Department of Molecular Biology and Immunology, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
Pigment Cell Res. 2003 Aug;16(4):388-96. doi: 10.1034/j.1600-0749.2003.00060.x.
The dorsal fur in yellow F1 mice (F1-Ay) between C3H/HeJ and C57BL/6J-Ay is darker than that in C57BL/6J-Ay. Moreover, yellow F2 mice (F2-Ay) exhibit a wide spectrum of coat color phenotypes in terms of lightness and darkness. Quantitative trait locus (QTL) analysis on F2-Ay identified three significant modifier loci that accounted for darkening of the coat color on chromosomes 1 (Dmyaq1 and Dmyaq2) and 15 (Dmyaq3), and the C3H/HeJ allele at these loci increased the darkness. Because agouti F2 mice (F2-A) also exhibited a spectrum of coat color phenotypes, the question of whether these QTLs had any effects on F2-A was examined. Dmyaq1 and Dmyaq2 were shown to increase the darkness in F2-A, whereas Dmyaq3 did not. The results showed that Dmyaq1-Dmyaq3 were parts of determinants responsible for the sable (darker modification of yellow) coat color phenotype, and that Dmyaq1 and Dmyaq2 were parts of determinants responsible for the umbrous (darker modification of agouti) coat color phenotype. It is, thus, demonstrated that both the sable and the umbrous phenotypes resulted from multigenic contributions, and that they shared genetic bases, as had been implied for several decades.
C3H/HeJ与C57BL/6J-Ay杂交的黄色F1小鼠（F1-Ay）背部的毛比C57BL/6J-Ay的更黑。此外，黄色F2小鼠（F2-Ay）在毛色深浅方面表现出广泛的表型。对F2-Ay进行数量性状基因座（QTL）分析，确定了三个显著的修饰基因座，它们导致1号染色体（Dmyaq1和Dmyaq2）和15号染色体（Dmyaq3）上的毛色变深，这些基因座上的C3H/HeJ等位基因增加了毛色的深度。由于刺豚鼠色F2小鼠（F2-A）也表现出一系列毛色表型，因此研究了这些QTL对F2-A是否有任何影响。结果表明，Dmyaq1和Dmyaq2会使F2-A的毛色变深，而Dmyaq3则不会。结果表明，Dmyaq1-Dmyaq3是导致貂色（黄色的深色变异）毛色表型的决定因素的一部分，Dmyaq1和Dmyaq2是导致暗褐色（刺豚鼠色的深色变异）毛色表型的决定因素的一部分。因此，证明了貂色和暗褐色表型均由多基因作用产生，并且它们共享遗传基础，这一点已经被暗示了几十年。
