Multi-trait genome wide association meta-analysis of body weight, carcase composition and eating quality traits in Australian sheep

Abstract

<p>The objective of this study was to perform a multi-trait meta-analysis of summary statistics of a single-trait genome-wide association study (GWAS) on 10 body weight, carcase composition and eating quality traits in Australian sheep. Meta-analysis was performed based on an approximate chisquared test according to estimated SNP effects and their associated standard errors obtained in a single-trait GWAS. Single-trait association testing was based on single-marker regression analysis in linear mixed models using imputed whole genome sequence data and between 2,707 and 135,022 adjusted phenotypes across the traits studied. Meta-analysis showed higher power of QTL detection compared to single trait GWAS, it confirmed the highly significant QTL regions in single-trait GWAS and revealed numerous pleiotropic QTLs on chromosomes 1, 3, 6, 8, 11, 16 and 18, affecting two or more traits. In total meta-analysis showed 4,823 SNPs in strong association with at least one trait (<i>-Log P≥6.0</i>) but did not show any new highly significant QTL regions across the traits. </p>