Selection in the making: A Worldwide Survey of Haplotypic Diversity around a Causative Mutation in Porcine IGF2
Ana Ojeda 1, Lusheng Wang 2, Jun Ren 2, Antonella Angiolillo 3, In Cheol Cho 4, henry Soto 5, Clemente Lemus 6, Stanley Makuza 7, Josep M Folch 1 and Miguel Perez-Enciso 1*
1 Universidad Autónoma de Barcelona
2 Jiangxi Agricultural University
3 Università del Molise
4 National Institute of Subtropical Agriculture
5 Universidad de Costa Rica
6 Universidad de Nayarit
7 University of Zimbabwe
* To whom correspondence should be addressed. E-mail: miguel.perez{at}uab.es.
Submitted on November 7, 2007
Revised on January 8, 2008
Accepted on 9 January 2008
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Abstract |
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Domestic species allow us to study dramatic evolutionary changes at an accelerated rate due to the effectiveness of modern breeding techniques and the availability of breeds that have undergone distinct selection pressures. We present a worldwide survey of haplotype variability around a known causative mutation in porcine gene IGF2 that increases lean content. We genotyped 34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars. Although, the selective process had wiped out variability for at least 27 kb in the haplotypes carrying the mutation, there was no indication of an overall reduction in genetic variability of international vs. European local breeds. There was no evidence either of a reduction in variability caused by domestication. The haplotype structure and a plot of Tajima's D against the frequency of the causative mutation across breeds suggested a temporal pattern, where each breed corresponded to a different selective stage. This was observed comparing the haplotype NJ-trees of breeds that have undergone increasing selection pressures for leanness, e.g., European local breeds vs. Pietrain. These results anticipate that comparing current domestic breeds will decisively help to recover the genetic history of domestication and contemporary selective processes.
Key Words:
Domestication, IGF2, Pig, Selection footprint, genetic diversity
