Cooperative Research Centre for Beef Genetic Technologies, University of New England, Armidale, New South Wales 2351, Australia.
J Anim Sci. 2012 May;90(5):1398-410. doi: 10.2527/jas.2011-4410. Epub 2011 Nov 18.
The genetics of reproduction is poorly understood because the heritabilities of traits currently recorded are low. To elucidate the genetics underlying reproduction in beef cattle, we performed a genome-wide association study using the bovine SNP50 chip in 2 tropically adapted beef cattle breeds, Brahman and Tropical Composite. Here we present the results for 3 female reproduction traits: 1) age at puberty, defined as age in days at first observed corpus luteum (CL) after frequent ovarian ultrasound scans (AGECL); 2) the postpartum anestrous interval, measured as the number of days from calving to first ovulation postpartum (first rebreeding interval, PPAI); and 3) the occurrence of the first postpartum ovulation before weaning in the first rebreeding period (PW), defined from PPAI. In addition, correlated traits such as BW, height, serum IGF1 concentration, condition score, and fatness were also examined. In the Brahman and Tropical Composite cattle, 169 [false positive rate (FPR) = 0.262] and 84 (FPR = 0.581) SNP, respectively, were significant (P < 0.001) for AGECL. In Brahman, 41% of these significant markers mapped to a single chromosomal region on BTA14. In Tropical Composites, 16% of these significant markers were located on BTA5. For PPAI, 66 (FPR = 0.67) and 113 (FPR = 0.432) SNP were significant (P < 0.001) in Brahman and Tropical Composite, respectively, whereas for PW, 68 (FPR = 0.64) and 113 (FPR = 0.432) SNP were significant (P < 0.01). In Tropical Composites, the largest concentration of PPAI markers were located on BTA5 [19% (PPAI) and 23% (PW)], and BTA16 [17% (PPAI) and 18% (PW)]. In Brahman cattle, the largest concentration of markers for postpartum anestrus was located on BTA3 (14% for PPAI and PW) and BTA14 (17% PPAI). Very few of the significant markers for female reproduction traits for the Brahman and Tropical Composite breeds were located in the same chromosomal regions. However, fatness and BW traits as well as serum IGF1 concentration were found to be associated with similar genome regions within and between breeds. Clusters of SNP associated with multiple traits were located on BTA14 in Brahman and BTA5 in Tropical Composites.
繁殖的遗传学理解甚少，因为目前记录的特征的遗传力较低。为了阐明肉牛繁殖的遗传基础，我们使用热带适应的肉牛品种婆罗门牛和热带复合牛的牛 SNP50 芯片进行了全基因组关联研究。在这里，我们介绍了 3 个雌性繁殖性状的结果：1）初情期年龄，定义为频繁进行卵巢超声扫描后首次观察到黄体（CL）的天数（AGECL）；2）产后乏情间隔，测量从产犊到产后首次排卵的天数（首次再配种间隔，PPAI）；3）在第一次再配种期间断奶前的第一次产后排卵（PW），定义为 PPAI。此外，还检查了 BW、身高、血清 IGF1 浓度、体况评分和脂肪等相关性状。在婆罗门牛和热带复合牛中，分别有 169 个（错误发现率（FPR）=0.262）和 84 个（FPR=0.581）SNP 对 AGECL 具有显著意义（P＜0.001）。在婆罗门牛中，41%的这些显著标记物映射到 BTA14 上的单个染色体区域。在热带复合牛中，16%的这些显著标记物位于 BTA5 上。对于 PPAI，婆罗门牛和热带复合牛分别有 66 个（FPR=0.67）和 113 个（FPR=0.432）SNP 具有显著意义（P＜0.001），而对于 PW，婆罗门牛和热带复合牛分别有 68 个（FPR=0.64）和 113 个（FPR=0.432）SNP 具有显著意义（P＜0.01）。在热带复合牛中，PPAI 标记物的最大浓度位于 BTA5[19%（PPAI）和 23%（PW）]和 BTA16[17%（PPAI）和 18%（PW）]。在婆罗门牛中，产后乏情的最大标记物浓度位于 BTA3（PPAI 和 PW 均为 14%）和 BTA14（PPAI 为 17%）。婆罗门牛和热带复合牛的雌性繁殖性状的显著标记物很少位于同一染色体区域。然而，脂肪和 BW 性状以及血清 IGF1 浓度被发现与品种内和品种间的相似基因组区域相关。与多个性状相关的 SNP 簇位于婆罗门牛的 BTA14 和热带复合牛的 BTA5 上。
