Over the last years, high-throughput technologies have providedthe opportunity to explore the genomes of livestock speciesto identify regions influencing traits of economicinterest. Genome wide association studies (GWAS) have beenwidely used to disentangle the genetic variation in complexphenotypes, such as milk production traits in sheep. Thestudy presented here investigated the possible association ofgenome-wide SNPs and breeding values for milk productiontraits in the Valle del Belice sheep. The studied populationconsisted of a total of 481 ewes belonging to 9 half-sib familieswith available records for milk yield (MY), protein and fat percentage (P% and F%, respectively). All animals weregenotyped for 54,241 SNPs, using the Illumina OvineSNP50KGenotyping BeadChip. During quality control, SNPs withminor allele frequency (MAF)<5%, call rate <95% and outof Hardy Weinberg Equilibrium (HWE) p<.001, were excludedfrom the analysis. In addition, sheep that missed more than5% of genotypes were also removed. Finally, after quality control,39,110 SNPs and 469 individuals were available for theGWAS. Univariate animal models were used to estimate variancecomponents and breeding values for MY, P% and F%.The genome-wide association using mixed model and regression-genomic control approach as implemented in GenABELwas used. P-values of 5105 were considered as significantassociations. Heritability estimates for MY, P% and F%was 0.21, 0.34, and 0.39 respectively. In total, nine significantSNPs on six different Ovis aries chromosomes (Oar) (Oar1:rs402356478; Oar2: rs406142196 and rs426814658; Oar3:rs399070200; Oar10: rs406329083 and rs405825255; Oar20:rs398454547; Oar24: rs405426757 and rs412849969) associatedwith MY, P% and F% were identified. All significant detectedSNPs were within or close to known ovine genes. In particular,one SNP associated with P% was found within the alphalactalbumin(LALBA) gene on OAR3, which is a functionaland positional candidate underlying this association, and oneSNP associated with MY was found near the cyclic AMPresponsiveelement-binding protein (CREB1) on OAR2, agene associated to genesis and secretion of milk, developmentof mammary glands and circadian rhythms. Genomic regionsfound to be significantly associated with milk productiontraits in this study will further contribute to the identificationof the genes regulating those traits in dairy sheep.
|Numero di pagine||2|
|Stato di pubblicazione||Published - 2017|