[Effect study of white locus (I) on coat color inheritance in Chinese native pig breeds]

The classical White (I) locus is one of the important pig coat color hereditable loci,which is homologous to KIT gene. In this study,PCR-RFLP and PCR-SSCP analysis were commanded on the Intron 17 and 18 nucleotide sequences of KIT gene. The tested results showed that the substitution mutation (G-->A) of Intron 17 was found in white pigs, including Wuzhishan pigs (white), Landrace and Large White,and its genotype (AB) frequency was 1.1 and 0.8 respectively. The genotype frequency was uniformly 0 in the other native pig breeds. Similarly,the deleted mutation (AGTT) of Intron 18 was also found in the same white pigs,its genotype (,AA) frequency was 1.1 and 0.93 separately,while in the other native pig breeds was 0. Accordingly it was considered that KIT gene was an important factor regulating the white coat color genotype, and the classical I locus (KIT gene) was epistatic to the other genetic coat color loci. On the other hand,although the native pig breed Rongchang Pig is similar to Landrace and Large White in phenotype (white coat color), the mutation status found in them was absolutely distinct. So it is presumed that the coat color genetic system of Chinese native pig breeds was different from that of imported breeds.