Association of variants in antibacterial TLR genes with reproductive traits in Czech Simmental cattle
Abstrakt
The Toll-like receptor functions are reflected in various phenotypic traits in addition to the immune response itself. Therefore, we tested the TLR gene diversity present in the Czech Simmental (Czech Red Pied) cattle population for association with not only the traits of infection resistance, but also with the female reproductive traits.
The starting bull set comprised 164 animals representing complete gene pool. Hybrid resequencing with Illumina X-Ten WGS and PacBio amplicon sequencing yielded 7 and 9 SNPs in the TLR4 and TLR5 genes, respectively.
The SNPs were validated with primer extension assays and characterized by the assignment to haplotypes and by function prediction. The breeding values for the reproductive traits, namely incidence of cystic ovaries, early reproductive disorders (ERD), calving ease, maternal calving ease, production longevity and calf vitality index were used for the association study.
Nominal P-values T (rs43578094) and g.10310T > G (rs8193072) in the reference AC000135.1 remained strictly associated with the index of ERD and maternal calving ease, respectively, at FDR C (rs8193060) was associated with as many as 4 traits. The permissive FDR interpretation for the TLR5 variants indicated associations with cyst incidence, ERD and maternal calving ease.
Positional matches with known QTLs for calving ease endorse the causative roles of TLR4 and TLR5. The findings are consistent with the known effects of TLR4 variation on reproduction in model species.
Consequently, the Bayesian inference supports the role of bovine TLR4 and TLR5 in the formation of female reproductive traits. However, additional experiments discriminating between different mechanisms of action are necessary.
The project was supported by the Institutional Research Concept MZE-RO0723 and by the grant QK22020280 of the Ministry of Agriculture of the CR.