The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
Anim Genet. 2012 Oct;43(5):552-63. doi: 10.1111/j.1365-2052.2011.02296.x. Epub 2011 Dec 7.
The characterization of livestock genetic diversity can inform breed conservation initiatives. The genetic diversity and genetic structure were assessed in 685 individual genotypes sampled from 24 British chicken breeds. A total of 239 alleles were found across 30 microsatellite loci with a mean number of 7.97 alleles per locus. The breeds were highly differentiated, with an average F(ST) of 0.25, similar to that of European chicken breeds. The genetic diversity in British chicken breeds was comparable to that found in European chicken breeds, with an average number of alleles per locus of 3.59, ranging from 2.00 in Spanish to 4.40 in Maran, and an average expected heterozygosity of 0.49, ranging from 0.20 in Spanish to 0.62 in Araucana. However, the majority of breeds were not in Hardy-Weinberg Equilibrium, as indicated by heterozygote deficiency in the majority of breeds (average F(IS) of 0.20), with an average observed heterozygote frequency of 0.39, ranging from 0.15 in Spanish to 0.49 in Cochin. Individual-based clustering analyses revealed that most individuals clustered to breed origin. However, genetic subdivisions occurred in several breeds, and this was predominantly associated with flock supplier and occasionally by morphological type. The deficit of heterozygotes was likely owing to a Wahlund effect caused by sampling from different flocks, implying structure within breeds. It is proposed that gene flow amongst flocks within breeds should be enhanced to maintain the current levels of genetic diversity. Additionally, certain breeds had low levels of both genetic diversity and uniqueness. Consideration is required for the conservation and preservation of these potentially vulnerable breeds.
家畜遗传多样性的特征可以为品种保护计划提供信息。在 24 个英国鸡品种中，对 685 个个体基因型进行了遗传多样性和遗传结构评估。在 30 个微卫星位点中发现了 239 个等位基因，每个位点的平均等位基因数为 7.97。这些品种高度分化，平均 F（ST）为 0.25，与欧洲鸡品种相似。英国鸡品种的遗传多样性与欧洲鸡品种相当，每个位点的平均等位基因数为 3.59，范围从西班牙的 2.00 到马兰的 4.40，平均预期杂合度为 0.49，范围从西班牙的 0.20 到阿劳卡纳的 0.62。然而，大多数品种都没有处于哈迪-温伯格平衡状态，因为大多数品种都存在杂合子不足（平均 F（IS）为 0.20），平均观察到的杂合子频率为 0.39，范围从西班牙的 0.15 到科钦的 0.49。基于个体的聚类分析显示，大多数个体聚类到品种起源地。然而，在几个品种中发生了遗传细分，这主要与 flock supplier 有关，偶尔也与形态类型有关。杂合子不足可能是由于来自不同 flock 的抽样造成的 Wahlund 效应所致，暗示了品种内的结构。建议应加强品种内 flock 之间的基因流，以维持当前的遗传多样性水平。此外，某些品种的遗传多样性和独特性水平都较低。需要考虑保护和保存这些潜在脆弱的品种。
