Kelleher M M, Berry D P, Kearney J F, McParland S, Buckley F, Purfield D C
1Animal & Grassland Research and Innovation Centre,Teagasc,Moorepark,Co. Cork,Ireland.
3Irish Cattle Breeding Federation,Bandon,Co. Cork,Ireland.
Animal. 2017 Jan;11(1):15-23. doi: 10.1017/S1751731116001099. Epub 2016 Jun 22.
Information on the genetic diversity and population structure of cattle breeds is useful when deciding the most optimal, for example, crossbreeding strategies to improve phenotypic performance by exploiting heterosis. The present study investigated the genetic diversity and population structure of the most prominent dairy and beef breeds used in Ireland. Illumina high-density genotypes (777 962 single nucleotide polymorphisms; SNPs) were available on 4623 purebred bulls from nine breeds; Angus (n=430), Belgian Blue (n=298), Charolais (n=893), Hereford (n=327), Holstein-Friesian (n=1261), Jersey (n=75), Limousin (n=943), Montbéliarde (n=33) and Simmental (n=363). Principal component analysis revealed that Angus, Hereford, and Jersey formed non-overlapping clusters, representing distinct populations. In contrast, overlapping clusters suggested geographical proximity of origin and genetic similarity between Limousin, Simmental and Montbéliarde and to a lesser extent between Holstein, Friesian and Belgian Blue. The observed SNP heterozygosity averaged across all loci was 0.379. The Belgian Blue had the greatest mean observed heterozygosity (HO=0.389) among individuals within breed while the Holstein-Friesian and Jersey populations had the lowest mean heterozygosity (HO=0.370 and 0.376, respectively). The correlation between the genomic-based and pedigree-based inbreeding coefficients was weak (r=0.171; P<0.001). Mean genomic inbreeding estimates were greatest for Jersey (0.173) and least for Hereford (0.051). The pair-wise breed fixation index (F st) ranged from 0.049 (Limousin and Charolais) to 0.165 (Hereford and Jersey). In conclusion, substantial genetic variation exists among breeds commercially used in Ireland. Thus custom-mating strategies would be successful in maximising the exploitation of heterosis in crossbreeding strategies.
在决定最优化的杂交策略（例如，通过利用杂种优势来提高表型性能）时，有关牛品种的遗传多样性和种群结构的信息非常有用。本研究调查了爱尔兰使用的最著名的奶牛和肉牛品种的遗传多样性和种群结构。对来自九个品种的4623头纯种公牛进行了Illumina高密度基因分型（777962个单核苷酸多态性；SNP）分析；这些品种包括安格斯牛（n = 430）、比利时蓝牛（n = 298）、夏洛莱牛（n = 893）、赫里福德牛（n = 327）、荷斯坦 - 弗里生牛（n = 1261）、泽西牛（n = 75）、利木赞牛（n = 943）、蒙贝利亚尔牛（n = 33）和西门塔尔牛（n = 363）。主成分分析表明，安格斯牛、赫里福德牛和泽西牛形成了不重叠的聚类，代表不同的种群。相比之下，重叠的聚类表明利木赞牛、西门塔尔牛和蒙贝利亚尔牛在地理起源上接近且遗传相似，在较小程度上荷斯坦牛、弗里生牛和比利时蓝牛也是如此。所有位点的平均观察到的SNP杂合度为0.379。在各品种内个体中，比利时蓝牛的平均观察到的杂合度最高（HO = 0.389），而荷斯坦 - 弗里生牛和泽西牛种群的平均杂合度最低（分别为HO = 0.370和0.376）。基于基因组的近亲繁殖系数与基于系谱的近亲繁殖系数之间的相关性较弱（r = 0.171；P < 0.001）。泽西牛的平均基因组近亲繁殖估计值最高（0.173），赫里福德牛的最低（0.051）。成对品种固定指数（Fst）范围从0.049（利木赞牛和夏洛莱牛）到0.165（赫里福德牛和泽西牛）。总之，爱尔兰商业使用的品种之间存在大量遗传变异。因此，定制交配策略将成功地在杂交策略中最大限度地利用杂种优势。
