# Genetic Links between Reproductive Traits and Amino Acid Pairwise Distances of Swine Leukocyte Antigen Alleles among Mating Partners in Microminipigs

## TL;DR

This study shows that greater genetic differences in certain immune-related genes between pig mates lead to better reproductive outcomes like larger litters and healthier piglets.

## Contribution

The study expands on prior findings by linking SLA allele dissimilarity to multiple reproductive traits in inbred microminipigs.

## Key findings

- Greater amino acid distances in SLA-1 and DQB1 alleles correlate with larger litter sizes and more live piglets.
- Higher SLA-2 allele dissimilarity is associated with fewer pre-weaning deaths.
- SLA allele differences may serve as genetic markers for improved breeding outcomes.

## Abstract

Previously, we found that a greater dissimilarity in swine leukocyte antigen (SLA) class I and class II alleles between mating partners resulted in increased farrowing rates in a highly inbred population of Microminipigs (MMPs). In this follow-up study, we have analyzed the effects of dissimilarity in SLA alleles between mating partners for seven different reproductive traits, including litter size and the number of stillborn and live or dead weaned piglets. We determined the relationships among reproductive traits within each mating event and the amino acid distances of SLA alleles as markers of diversity between mating partners. Our results indicate that mating partners with greater amino acid pairwise genetic distances in the SLA-1 class I gene or DQB1 class II gene alleles were associated with significantly larger litter sizes and higher numbers of live piglets at birth and weaning. Also, partners with greater pairwise distances in the SLA-2 class I gene alleles exhibited fewer pre-weaning deaths. These findings suggest that the dissimilarity in SLA class I and class II alleles between mating partners may affect not only farrowing rates but also other key reproductive traits such as litter size and improved piglet survival rates. Consequently, SLA alleles could serve as valuable genetic markers for selecting mating partners in breeding programs and for conducting epistatic studies on various reproductive traits in MMPs.