Genomic analyses and biological validation of candidate genes for rectal temperature as an indicator of heat stress in Holstein cattle

Abstract

Heat stress is a major cause of welfare issues and economic losses to the worldwide dairy cattle industry. Genetic selection for heat tolerance has a great potential to positively affect the dairy industry, as the gains are permanent and cumulative over generations. Rectal temperature (RT) is hypothesized to be a good indicator trait of heat tolerance. Therefore, this study investigated the genetic architecture of RT by estimating genetic parameters, performing genome-wide association studies, and biologically validating potential candidate genes identified to be related to RT in Holstein cattle. A total of 33,013 RT records from 7,598 cows were used in this study. In addition, 1,114 cows were genotyped using the Illumina 150K Bovine BeadChip (Illumina, San Diego, CA). Rectal temperature measurements taken in the morning (AMRT) and in the afternoon (PMRT) are moderately heritable traits, with estimates of 0.09 ± 0.02 and 0.04 ± 0.01, respectively. These 2 traits are also highly genetically correlated (r = 0.90 ± 0.08). A total of 10 SNPs (located on BTA3, BTA4, BTA8, BTA13, BTA14, and BTA29) were found to be significantly associated with AMRT and PMRT. Subsequently, gene expression analyses were performed to validate the key functional genes identified (SPAG17, FAM107B, TSNARE1, RALYL, and PHRF1). This was done through in vitro exposure of peripheral blood mononuclear cells (PBMC) to different temperatures (37°C, 39°C, and 42°C). The relative mRNA expression of 2 genes, FAM107B and PHRF1, significantly changed between the control and heat stressed PBMC. In summary, RT is heritable, and enough genetic variability exists to enable genetic improvement of heat tolerance in Holstein cattle. Important genomic regions were identified and biologically validated; FAM107B and PHRF1 are the main candidate genes identified to influence heat stress response in dairy cattle.

Signature selection analysis reveals candidate genes associated with production traits in Iranian sheep breeds

“…This gene plays a role in heat-shock induction [ 47 ]. A recent genome-wide association study in Holstein cattle has shown that the FAM107B gene is strongly associated with heat stress response in dairy cattle [ 48 ]. Also, USP43 (ubiquitin specific peptidase 43, Chr.…”

Genome-wide associations for heat stress response suggest potential candidate genes underlying milk fatty acid composition in dairy cattle

“…TSNARE1 and TRAPPC9 are described as candidate genes for milk production (Jiang et al, 2014(Jiang et al, , 2019Shabalina, 2021) and FA (Freitas et al, 2020) in Holstein dairy cattle. TSNARE1 plays a role in intracellular protein transport and synaptic vesicle exocytosis (Luo et al, 2021). Luo et al (2021) .…”

“…TSNARE1 plays a role in intracellular protein transport and synaptic vesicle exocytosis (Luo et al, 2021). Luo et al (2021) . Previous studies demonstrated that heat stress reduces the antioxidant body capacity, with detrimental effects on immune functions (Zhang et al, 2014;Dahl et al, 2020).…”

Weighted single-step GWAS and RNA sequencing reveals key candidate genes associated with physiological indicators of heat stress in Holstein cattle

“…Genome-wide association studies (GWAS) are used to discover genomic regions associated with phenotypes of interest [ 11 ], and consequently, biological processes in which they are involved in. For instance, Luo et al [ 12 ] identified candidate genes related to RT by using single-SNP regression GWAS. Subsequently, gene expression analyses were performed to validate the key functional genes identified [ 12 ].…”