Abstract In Mexico, since 2010 the Asociacion Mexicana de Criadores de Ganado Caprino de Registro has been undertaking annual national genetic evaluations for the Boer and Nubian goat breeds. Mexican pedigree goat farmers are concerned with maintaining a reasonable high genetic diversity and a low level of inbreeding without loss of genetic gain. This study aimed to assess the genetic diversity and to describe the population structure of the Boer and Nubian goat breeds in Mexico using pedigree analyses to support the development of strategies for breeding programs. Herdbook information collected between 1994–2017 for Boer and from 1991 to 2017 for Nubian were utilized. The information included pedigree records on 18,947 animals for Boer (141 flocks) and 13,744 animals for Nubian (99 flocks). The effective number of founders ( f e ) were 504 and 203, and the effective number of ancestors ( f a ) were 253 and 88, for Boer and Nubian, respectively. The ratio f a / f e was 0.50 for Boer and 0.43 for Nubian, indicating the existence of population bottlenecks. The average inbreeding and relatedness coefficients were 1.02 and 0.28 % for Boer and, 1.39 and 1.04 % for Nubian. The number of most influential ancestors that explained 50 % of the genetic diversity in the population were 109 for Boer and 38 for Nubian. The average generation interval estimated through the four gametic paths was 3.27 ± 0.03 yr for Boer and 4.63 ± 0.06 yr for Nubian. Realized effective population size, computed from the individual increase in inbreeding, was 61.3 ± 24.5 for Boer and 69.3 ± 22.8 for Nubian (kids born from 2013 to 2017 were considered as the reference population for both breeds). The average equivalent completed generations, as a measure of pedigree completeness, were 2.02 for Boer and 2.88 for Nubian. The pedigree completeness index increased over time for both breeds. The results revealed the loss of genetic diversity and the presence of genetic bottlenecks for both populations. The study of the genetic diversity on these populations must continue to prevent the decrease in genetic progress and genetic variability. Additionally, a mating policy that simultaneously allows low levels of inbreeding, high levels of genetic diversity and maximum genetic progress, must be designed.

中文翻译：

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墨西哥波尔山羊和努比亚山羊的遗传多样性和种群结构

摘要 在墨西哥，自 2010 年以来，Asociacion Mexicana de Criadores de Ganado Caprino de Registro 一直在对波尔山羊和努比亚山羊品种进行年度国家遗传评估。墨西哥血统山羊养殖者关心在不损失遗传增益的情况下保持合理的高遗传多样性和低水平的近亲繁殖。本研究旨在评估遗传多样性，并使用谱系分析来描述墨西哥波尔山羊和努比亚山羊品种的种群结构，以支持育种计划策略的制定。使用了 1994 年至 2017 年间为布尔人和 1991 年至 2017 年间为努比亚人收集的牧群信息。这些信息包括波尔的 18,947 只动物（141 只鸡群）和努比亚动物的 13,744 只动物（99 只鸡群）的系谱记录。布尔人和努比亚人的有效创始人人数（fe）分别为504人和203人，有效祖先人数（fa）分别为253人和88人。fa / fe 比值布尔人为 0.50，努比亚人为 0.43，说明存在人口瓶颈。波尔人的平均近亲繁殖和亲缘关系系数分别为 1.02 和 0.28 %，努比亚人为 1.39 和 1.04 %。解释人口中 50% 遗传多样性的最有影响力的祖先数量是布尔人 109 人和努比亚人 38 人。通过四个配子路径估计的平均世代间隔为布尔人 3.27 ± 0.03 年，努比亚人为 4.63 ± 0.06 年。根据近亲繁殖的个体增加计算，实现的有效种群大小为 Boer 61.3 ± 24.5 和 69.3 ± 22。努比亚为 8（2013 年至 2017 年出生的孩子被视为两个品种的参考人群）。作为谱系完整性的衡量标准，平均等效完整世代为 Boer 为 2.02，Nubian 为 2.88。两个品种的谱系完整性指数都随着时间的推移而增加。结果揭示了两个种群的遗传多样性丧失和遗传瓶颈的存在。对这些种群的遗传多样性的研究必须继续防止遗传进展和遗传变异的减少。此外，必须设计一种同时允许低水平近交、高水平遗传多样性和最大遗传进展的交配政策。88 为努比亚。两个品种的谱系完整性指数都随着时间的推移而增加。结果揭示了两个种群的遗传多样性丧失和遗传瓶颈的存在。对这些种群的遗传多样性的研究必须继续防止遗传进展和遗传变异的减少。此外，必须设计一种同时允许低水平近交、高水平遗传多样性和最大遗传进展的交配政策。88 为努比亚。两个品种的谱系完整性指数都随着时间的推移而增加。结果揭示了两个种群的遗传多样性丧失和遗传瓶颈的存在。对这些种群的遗传多样性的研究必须继续防止遗传进展和遗传变异的减少。此外，必须设计一种同时允许低水平近交、高水平遗传多样性和最大遗传进展的交配政策。