Genome-wide detection of selection signatures in Chinese indigenous Laiwu pigs revealed candidate genes regulating fat deposition in muscle

Minhui Chen,Ying Wu,Jian-Feng Liu,Yanping Wang,Jiying Wang,Jinluan Fu

doi:10.1186/s12863-018-0622-y

Minhui Chen, Ying Wu + Show 4 more

Open Access

https://doi.org/10.1186/s12863-018-0622-y

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Abstract

BackgroundCurrently, genome-wide scans for positive selection signatures in commercial breed have been investigated. However, few studies have focused on selection footprints of indigenous breeds. Laiwu pig is an invaluable Chinese indigenous pig breed with extremely high proportion of intramuscular fat (IMF), and an excellent model to detect footprint as the result of natural and artificial selection for fat deposition in muscle.ResultIn this study, based on GeneSeek Genomic profiler Porcine HD data, three complementary methods, FST, iHS (integrated haplotype homozygosity score) and CLR (composite likelihood ratio), were implemented to detect selection signatures in the whole genome of Laiwu pigs. Totally, 175 candidate selected regions were obtained by at least two of the three methods, which covered 43.75 Mb genomic regions and corresponded to 1.79% of the genome sequence. Gene annotation of the selected regions revealed a list of functionally important genes for feed intake and fat deposition, reproduction, and immune response. Especially, in accordance to the phenotypic features of Laiwu pigs, among the candidate genes, we identified several genes, NPY1R, NPY5R, PIK3R1 and JAKMIP1, involved in the actions of two sets of neurons, which are central regulators in maintaining the balance between food intake and energy expenditure.ConclusionsOur results identified a number of regions showing signatures of selection, as well as a list of functionally candidate genes with potential effect on phenotypic traits, especially fat deposition in muscle. Our findings provide insights into the mechanisms of artificial selection of fat deposition and further facilitate follow-up functional studies.

Highlights

Genome-wide scans for positive selection signatures in commercial breed have been investigated
Our results identified a number of regions showing signatures of selection, as well as a list of functionally candidate genes with potential effect on phenotypic traits, especially fat deposition in muscle
Our findings provide insights into the mechanisms of artificial selection of fat deposition and further facilitate follow-up functional studies

Summary

Introduction

Genome-wide scans for positive selection signatures in commercial breed have been investigated. Domestic animals have been subjected to a series of strong artificial selection to meet the demand of humans, such as growth rate, body size, muscle composition and reproduction. These processes of selection have left signatures, such as reduced genetic diversity and long haplotypes, in the genomes of domestic animals. (integrated haplotype homozygosity score) [5] and CLR (composite likelihood ratio) [6] Based on these methods, genome-wide scans for signatures of diversifying selection have been successfully applied to domestic animals [7,8,9]. A good example is the CMS (composite of multiple signals) method [11], which combines iHS, XP-EHH (cross population extended haplotype homozygosity), FST, ΔDAF and ΔiHH

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