# Genome-Wide Association Study of Body Mass Index in a Commercial Landrace × Yorkshire Crossbred Pig Population

## TL;DR

This study identifies genetic markers linked to body mass index in pigs, offering insights for breeding healthier herds and potentially informing human obesity research.

## Contribution

The study provides new genetic markers and validates carcass-based BMI as a reliable trait for pig breeding.

## Key findings

- BMI in pigs is heritable with moderate-to-high heritability estimates of 0.55 and 0.47 for BMI-S and BMI-O.
- 17 genome-wide significant SNPs were identified, including rs81382440 and rs80898583, linked to fat metabolism and growth.
- Carcass-based BMI improves phenotypic accuracy for breeding and offers insights into lipid deposition and body conformation.

## Abstract

We analyzed the DNA of 439 Landrace × Yorkshire crossbred commercial pigs and pinpointed specific genetic markers strongly associated with Body Mass Index (BMI). We demonstrated that BMI is a heritable trait and that calculating it based on carcass straight length (CSL) is more reliable for breeding. Several of the implicated genes are known to influence fat metabolism and growth. Our findings enhance the understanding of the genetic architecture governing pig body structure. The identified markers can assist breeders in efficiently selecting animals with superior conformation, promoting healthier herds and potentially improving meat quality, while this work may offer comparative insights into human obesity research.

The Body Mass Index (BMI), integrating body weight and length, is a widely used metric for obesity assessment in humans. As pigs serve as crucial biomedical models, the application of BMI in swine and its genetic basis remain poorly explored. This study aimed to investigate the genetic architecture of pig BMI and compare two carcass-based BMI metrics (BMI-S and BMI-O) for breeding applicability. A total of 439 Landrace × Yorkshire crossbred pigs were genotyped with a 50 K SNP chip; heritability was estimated via a mixed linear model, and genome-wide association study (GWAS) was performed using the BLINK model. BMI-S and BMI-O exhibited moderate-to-high heritability of 0.55 and 0.47, respectively, with 17 genome-wide significant SNPs detected—including the top associated SNP rs81382440 on chromosome 4 and rs80898583 on chromosome 7. Key candidate genes (GPHN, ADAM33, KCNH8, PDCD4) and 5 SNP-trait associations validated in PigQTLdb were linked to lipid/energy metabolism and muscle development. Carcass-based BMI improved phenotypic accuracy, and our findings provide core genetic markers and a theoretical basis for molecular breeding of pig body conformation and lipid deposition traits.