Genome-Wide Association Analysis Identifies the Gene Affecting Coat Color and Birth Weight in Simmental × Holstein.

Coat color and birth weight, as easily selected traits in cattle, play important roles in cattle breeding. Therefore, we carried out a genome-wide association study on birth weight and coat color to identify loci or potential linkage regions in 233 Simmental × Holstein crossbred beef cattle. The results revealed that nine SNPs were significantly associated with coat color (, , , , , , , , and ), and these were in , , , , and on BTA5. Interestingly, , , , , and showed strong linkage disequilibrium ( > 0.8) and were significantly associated with coat color. Notably, and were located in the gene ( = 2.22 × 10). Among the five significant SNPs associated with coat color, the birth weight of heterozygous individuals (AB) was greater than that of homozygous individuals (AA). Notably, the birth weight of heterozygous individuals with and genotypes was significantly greater than that of homozygous individuals (0.01 < < 0.05). Interestingly, the two loci were homozygous in black/white individuals and heterozygous in gray/white individuals, and the birth weight of heterozygous brown/white individuals (43.82 ± 5.25 kg) was greater than that of homozygous individuals (42.58 ± 3.09 kg). The birth weight of calves with the parental color (41.95 ± 3.53 kg) was significantly lower than that of calves with a non-parental color (43.54 ± 4.78 kg) ( < 0.05), and the birth weight of gray/white individuals (49.40 ± 7.11 kg) was the highest. Overall, appears to be a candidate gene affecting coat color in cattle, and coat color may have a selective effect on birth weight. This study provides a foundation for the breeding of beef cattle through GWAS for coat color and birth weight.