Genomic variance partitioning of carcass and meat quality traits in Angus beef cattle

Hasan Baneh^1*Nikolay Elatkin²Laurent Gentzbittel¹

• ¹Skolkovo Institute of Science and Technology, Moscow, Russia
• ²LLC “Miratorg-Genetika”, Moscow, Russia

This study aimed to partition the genomic variance of carcass weight (CW), marbling score (MS), ribeye area (REA), and back fat thickness (BFT) traits in Angus beef cattle into components associated with minor allele frequency (MAF) bins, functional annotation classes, and chromosomes. The dataset included 6,511,978 (6.5 million) imputed whole genome sequence (WGS) SNPs for 13,241 Angus beef cattle. Genomic partitioning was performed using a multi-factor mixed linear analysis, modeling the random effects using multiple genomic relationship matrices (GRMs), either simultaneously (joint analysis) or separately (separate analysis). The estimated heritability (ℎ 2 ) for CW, MS, REA, and BFT, obtained from fitting all 6.5 million SNPs at once, was 0.22 ± 0.01, 0.25 ± 0.01, 0.35 ± 0.01, and 0.15 ± 0.01, respectively. The aggregate genetic variance components estimated by separate analysis were substantially larger than the estimated heritability, while the results of joint analysis for all subjects were very close to ℎ 2 estimates for all traits. A weak relationship was observed between chromosome length and its heritability (R 2 < 0.35). However, while intergenic and intronic variants significantly contributed to the genetic variation of the traits, the variance captured per SNP was considerably lower for these variants compared to genic variants, particularly exon variants.