Genetic determinants of pig birth weight variability

Abstract

BackgroundPiglet birth weight variability, a trait also known as the within-litter homogeneity of birth weight, reflects the sow’s prolificacy, because it is positively genetically correlated with preweaning mortality but negatively correlated with the mean growth of piglets during sucking. In addition, the maternal additive genetic variance and heritability has been found exist for this trait, thus, reduction in the variability of piglet birth weight to improve the sow prolificacy is possible by selective breeding.ResultsWe performed a genome wide association study (GWAS) in 82 sows with extreme standard deviation of birth weights within the first parity to identify significant SNPs, and finally 266 genome-wide significant SNPs (p < 0.01) were identified. These SNPs were mainly enriched on chromosome 7, 1, 13, 14, 15 and 18. We further scanned genes of the top 50 SNPs with the lowest p values and found some genes involved in plasma glucose homeostasis (GLP1R) and lipid metabolism as well as maternal-fetal lipid transport (AACS, APOB, OSBPL10 and LRP1B) which may contribute to the birth weight variability trait.ConclusionsBirth weight variability trait has a low heritability. It is not easy to get significant signal by GWAS using small sample size. Herein, we identified some candidate chromosome regions especially chromosome 7 and suggested five genes which may provide some information for the further study.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0309-6) contains supplementary material, which is available to authorized users.

Genetics and genomics of uniformity and resilience in livestock and aquaculture species: A review

“…Estimates of residual variance per animal were used as response variables by Mulder, Crump, et al (2013) and deregressed EBVs (dEBVs) were used by Sell-Kubiak, Duijvesteijn, et al (2015) to identify genomic regions associated with variability of somatic cell score (SCS) in dairy cattle and litter size in pigs, respectively. Wang, Liu, Deng, Yu, and Li (2016), Wang et al (2017) and Wolc et al (2012) used phenotypic standard deviation and CV of BW in pigs and egg weight in chickens, respectively, as response variables in traditional linear models. This range of response variables is partly due to problems in getting a proper measure of residual variance per genotype (see also the discussion on statistical models to estimate genetic variation in residual variance), but also partly because genotypic and phenotypic information may be available on different animals.…”

The papers presented at 7th Young Scientists School “Systems Biology and Bioinformatics” (SBB’15): Introductory Note

“…Additionally, there a basic science related vibe in this study as it may provide some mechanistic explanation to relative success of intrauterine competition of the fetuses in species with larger size of litter [5].…”

Genome-Wide Association Study and Fine Mapping Reveals Candidate Genes for Birth Weight of Yorkshire and Landrace Pigs

“…With the widespread use of customized single nucleotide polymorphism (SNP) arrays, an increasing number of potential markers have been identified by genome-wide association study (GWAS). Wang X. et al (2016) found over two hundred SNPs associated with birth weight by using first parity sows whose offspring had extreme birth weights; Zhang et al (2018) identified 17 genomic regions associated with birth weight; Wang et al (2017) found 12 SNPs that were significantly associated with piglet uniformity; and 27 differentially selected regions associated with the birth weight of piglets were detected by Zhang et al (2014). However, a birth weight GWAS of Large white pigs by Wang et al (2018) was unable to determine any significant loci.…”