Identification of selection footprints on the X chromosome in pig

PLoS One. 2014 Apr 16;9(4):e94911. doi: 10.1371/journal.pone.0094911. eCollection 2014.

Abstract

Identifying footprints of selection can provide a straightforward insight into the mechanism of artificial selection and further dig out the causal genes related to important traits. In this study, three between-population and two within-population approaches, the Cross Population Extend Haplotype Homozygosity Test (XPEHH), the Cross Population Composite Likelihood Ratio (XPCLR), the F-statistics (Fst), the Integrated Haplotype Score (iHS) and the Tajima's D, were implemented to detect the selection footprints on the X chromosome in three pig breeds using Illumina Porcine60K SNP chip. In the detection of selection footprints using between-population methods, 11, 11 and 7 potential selection regions with length of 15.62 Mb, 12.32 Mb and 9.38 Mb were identified in Landrace, Chinese Songliao and Yorkshire by XPEHH, respectively, and 16, 13 and 17 potential selection regions with length of 15.20 Mb, 13.00 Mb and 19.21 Mb by XPCLR, 4, 2 and 4 potential selection regions with length of 3.20 Mb, 1.60 Mb and 3.20 Mb by Fst. For within-population methods, 7, 10 and 9 potential selection regions with length of 8.12 Mb, 8.40 Mb and 9.99 Mb were identified in Landrace, Chinese Songliao and Yorkshire by iHS, and 4, 3 and 2 potential selection regions with length of 3.20 Mb, 2.40 Mb and 1.60 Mb by Tajima's D. Moreover, the selection regions from different methods were partly overlapped, especially the regions around 22∼25 Mb were detected under selection in Landrace and Yorkshire while no selection in Chinese Songliao by all three between-population methods. Only quite few overlap of selection regions identified by between-population and within-population methods were found. Bioinformatics analysis showed that the genes relevant with meat quality, reproduction and immune were found in potential selection regions. In addition, three out of five significant SNPs associated with hematological traits reported in our genome-wide association study were harbored in potential selection regions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Animals
  • Breeding / methods*
  • Chromosomes, Mammalian / genetics*
  • Female
  • Gene Frequency
  • Genome-Wide Association Study / methods
  • Genotype
  • Haplotypes
  • Male
  • Meat / standards
  • Polymorphism, Single Nucleotide
  • Selection, Genetic*
  • Swine / genetics*
  • X Chromosome / genetics*

Grants and funding

This work was supported by National Natural Science Foundation of China (31272418), the earmarked fund for CARS-36, Ministry of Education of China, Program for Changjiang Scholar and Innovation Research Team in University (Grant No. IRT1191), and the open project of Key Laboratory of Pig, Ministry of Agriculture (13405), which will pay the publication fee. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.