Revelando a arquitetura genômica do intervalo de partos em bovinos da raça nelore.

Abstract

Studies using phenotypes and pedigree show little additive genetic variability for CI. However, there are still no studies that aggregate the genotypes in this evaluation in Nellore cattle. The addition of genotypes will allow evaluating the genomic architecture of this complex and important trait. Thus, the objective was to estimate the heritability based on genomic data, to carry out a GWAS and functional study for CI in the Nelore breed. The data analyzed were provided by Katayama farms, with 12,599 pedigree records, 7,778 CI phenotypes and 3,836 animals genotyped with an Illumina 50k chip. Molecular markers contained in the autosomal chromosomes and in the X chromosome were used in the analyses. To carry out the quality control of the genotypic data and association analyzes, the packages of the BLUPF90 family were used, adopting the Single-step genomic best linear unbiased predictor method. The genomic significance level was 2.55 x 10-05, but significant SNPs at the chromosomal level were also evaluated. The mean CI was approximately 450.3 days, with a standard deviation of 134.1 days and a total range of 270 to 730 days. The environmental and genetic variances were 8986.6 and 369.20, respectively, with a heritability of approximately 0.04 ± 0.04. GWAS analysis generated p-values that resulted in a genomic inflation factor (lambda) of 1.08. The only SNP (rs136725686) significant at the genomic level (P = 1.532587e-06) was located on chromosome 13. Another 19 SNPs were significant at the chromosomal level, which are distributed on chromosomes 1, 2, 3, 6, 10, 13, 14, 17, 18, 22 and 26. In the region of these SNPs, 32 genes were found, among which we highlight LYZL4, TEC, RAD21, SLC38A7, GOT2, CLPX, CCK, LMO4, NFATC2, SLC51B, TXK, BCAR3, UTP23, MTFMT, FOXP1 and TRAK1 as relevant, as they were previously linked to factors that can affect reproduction.