Novel harmful recessive haplotypes for reproductive traits in pigs.

Harmful recessive haplotypes for reproductive and fertility traits have previously been detected in cattle, but so far, no studies have been published for pigs. The aim of this study was to locate chromosomal regions with putative lethal haplotypes and estimate the effects of the identified haplotypes on reproductive traits in the Finnish Yorkshire pig breed. We used marker genotypes of 871 Finnish Yorkshire AI boars, genotyped with Illumina's PorcineSNP60 BeadChip. The analysed traits were number of stillborn piglets in first (NSB1) and later (NSB2) parities, total number of piglets born in first and later parities and piglet mortality between birth and weaning in first and later parities. A haplotype was claimed as a putative lethal if it was common in the population, but no homozygous animals were found. We detected altogether 26 putative lethal haplotypes, but only one haplotype on chromosome 8 (position 107.0-113.3 Mb) was significantly associated with traits NSB1 and NSB2. Three possible candidate genes were found in this chromosomal region: MAD2LI, FGF2 and ANXA5. Further analysis is needed to confirm the role of these genes on pig reproductive performance.