In Cell Genomics, researchers at the University of Melbourne, the Centre for AgriBiosciences, and elsewhere consider cattle trait heritability linked to gene expression and RNA splicing patterns, demonstrating that regulatory genes appear to explain a significant proportion of the heritability of complex traits such as fertility and milk production in dairy cattle. After flagging apparent regulatory genes in a Cattle Genotype-Expression atlas, the team quantified the consequences of more than 4,700 expression quantitative trait loci or splicing QTLs across 16 tissue types in around 120,000 cattle, searching for ties to 37 complex traits like body size, fertility, temperament, milk production, and mastitis risk. Together, the results suggest just more than 69 percent of the heritability of complex traits could be explained by variants influencing nearby or distant expression or splicing. "Our analysis of large datasets in cattle demonstrates that both cis- and trans-regulatory variants significantly contribute to variation in complex traits," the authors report, noting that "with proper analysis and sufficient power, regulatory variants not only provide etiology behind the genome-to-phenome relationship but also are a powerful resource to directly map causal variants for mammalian complex traits."