Original Article

Heredity (2010) 105, 274–281; doi:10.1038/hdy.2009.191; published online 24 February 2010

Artificial selection of the melanocortin receptor 1 gene in Chinese domestic pigs during domestication

J Li1,2, H Yang2, J-r Li3, H-p Li3, T Ning1,2, X-R Pan1, P Shi2 and Y-P Zhang1,2

  1. 1Laboratory for Conservation and Utilization of Bio-resources & Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
  2. 2State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
  3. 3Department of Computational Genomics, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China

Correspondence: Professor Y-P Zhang, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 Jiaochangdong ST, Yunnan, Kunming 650223, China. E-mail: zhangyp@mail.kiz.ac.cn; Professor P Shi, E-mail: ship@mail.kiz.ac.cn

Received 5 July 2009; Revised 1 November 2009; Accepted 21 December 2009; Published online 24 February 2010.

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Abstract

Black coat colour is common in Chinese indigenous domestic pigs, but not among their wild ancestors, and it is thus presumed to be a ‘domestication trait.’ To determine whether artificial interference contributes to morphological diversification, we examined nucleotide variation from 157 Chinese domestic pigs and 40 wild boars in the melanocortin receptor 1 (MC1R) gene, which has a key role in the coat pigmentation of Sus scrofa. Compared with a pseudogene GPIP, our results showed that the joint effects of demography and selection have resulted in markedly low genetic diversity of MC1R in Chinese domestic pigs. Coalescent simulation and selection tests further suggest that the fixation of two non-synonymous substitutions associated with black colour is the result of artificial selection. In contrast, a much higher genetic diversity and only a single non-synonymous substitution were found among the wild boars, suggesting a strong functional constraint. Moreover, our conclusion is consistent with the preference for black colour in the ancient Chinese sacrificial culture. This case provides an interesting example of a molecular evaluation of artificial livestock selection and its associated cultural impact in ancient China.

Keywords:

coat colour; domestic animal; population genetics; evolution