Identification of novel candidate genes for the inverted teat defect in sows using a genome-wide marker panel

Abstract

The number of functional teats is an important selection criterion in pig breeding. Inherited defects of the udder, such as the inverted teat, do have a considerable negative impact on the nursing ability of the sow. To investigate the genetic background of this defect and the number of functional teats in Swedish maternal lines, samples from 230 Yorkshire pigs were selected for genotyping using the PorcineSNP60K BeadChip (Illumina Inc.), each pig with at least one inverted teat was matched with one non-affected pig (fullsib or pairs with matching herd and gender). A genome-wide association study on these 230 pigs was performed using the two-step approach implemented in GenABEL using 46,652 single nucleotide polymorphisms across all autosomes and the X chromosome. A number of significant regions were identified for the inverted teat defect on chromosomes 2, 10, and 18. Many of the regions associated with the number of functional teats were located in the same or close regions, except two associated markers on the X chromosome and one on chromosome 3. We identified some of the regions on chromosomes previously reported in one linkage and one gene expression study. We conclude, despite being able to suggest new candidate genes, that further studies are needed to better understand the biologic background of the teat development. Despite the in-depth comparison of identified regions for the inverted teat defect done here, more studies are required to allow a clear identification of genetic regions relevant for this defect across many pig populations.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-016-0382-1) contains supplementary material, which is available to authorized users.

Enhancement of selectivity, 25-hydroxyvitamin D3 level, alkaline phosphatase activity and reproductive performance in gilts and primiparous sows using 14-epimer of 25-hydroxyvitamin D3

“…The heritability of this trait in gilts according to their study was 0.3 ( Long et al, 2010 ). Defect in the function of relaxin (a hormone expressed abundantly in developing mammary glands), and parathyroid hormones were identified as the major causes of inverted teat ( Chalkias et al, 2017 ; Sherwood, 2004 ). Though inverted teats can sometimes be redeemed by palpation between 5 and 6 months, or in some cases during early gestation, the inability to evert at early stage of reproduction could be a potential risk for mastitis ( Chalkias et al, 2013 ).…”

Genome-Wide Association Study Meta-Analysis Elucidates Genetic Structure and Identifies Candidate Genes of Teat Number Traits in Pigs

“…These traits collectively contribute to the overall reproductive performance and productivity of pigs [ 2 ]. The functional teat number in pigs serves as a critical indicator to assess sows’ lactation capacity and directly influences their offspring’s health and reproductive performance [ 3 ]. Teat number is characterized by low-to-medium heritability [ 4 ].…”

Genome-Wide Association Studies, Runs of Homozygosity Analysis, and Copy Number Variation Detection to Identify Reproduction-Related Genes in Bama Xiang Pigs

“…Litter size represents productivity levels per sow per year in pigs ( 21 ). Teat number is a proxy for lactation ability and, thus, is related to piglet mortality rates ( 22 ). Numerous researchers have focused on identifying SNPs, quantitative trait loci (QTLs), and candidate genes associated with litter size and teat number ( 23 – 25 ).…”