Genome-wide association analysis highlights genomic regions and genes potentially associated with anestrus in crossbred gilts.

Abstract

Anestrus, an infertility condition that affects several animal' species, is characterized by failing to display estrus. In pig production, it leads to the culling of 5 to 15% of the replacement gilts, resulting in significant losses impairing the swine female longevity. Despite that, little is known about the genetic mechanisms involved with anestrus in pigs. Hence, this study evaluated cyclic and non-cyclic F1 Landrace × Large White gilts to identify genomic regions associated with failure to display pubertal estrus through a genome-wide association study (GWAS), highlighting possible candidate genes involved with this condition in swine. Tissue samples were collected at 219.8 ± 4.7 days of age and genotyped with the PorcineSNP50 BeadChip from Illumina. In the GWAS, a SNP in the EML4 gene located on chromosome 3 (SSC3) was moderately associated with anestrus. The other 14 SNPs suggestively associated with anestrus were identified on SSCs 1, 3, 6, 7, 9 and 15. Investigating the regions close to those SNPs, new candidate genes for anestrus occurrence, such as EML4, DST, SRTB, MEAF, PHF1, PPMIB and PREPL, including 11 lncRNAs and a snoRNA were identified. Therefore, our study highlighted novel genetic mechanisms involved with the failure to display pubertal estrus in pigs, contributing to unraveling the genetic architecture of anestrus in pigs and other species. The use of genomic methodologies is a promising tool to help the early identification of gilts with potential reproductive problems associated with anestrus.