Dana N, Megens H-J, Crooijmans R P M A, Hanotte O, Mwacharo J, Groenen M A M, van Arendonk J A M
Ethiopian Institute of Agricultural Research, PO Box 32, Debre Zeit, Ethiopia.Animal Breeding and Genomics Centre, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.International Livestock Research Institute, PO Box 30709, Nairobi, Kenya.School of Biology, The University of Nottingham, Nottingham, UK.
Anim Genet. 2011 Apr;42(2):125-33. doi: 10.1111/j.1365-2052.2010.02134.x. Epub 2010 Dec 10.
Understanding the complex origin of domesticated populations is of vital importance for understanding, preserving and exploiting breed genetic diversity. Here, we aim to assess Asian contributions to European traditional breeds and western commercial chickens for mitochondrial genetic diversity. To this end, a 365-bp fragment of the chicken mtDNA D-loop region of 16 Dutch fancy breeds (113 individuals) was surveyed, comprising almost the entire breed diversity of The Netherlands. We also sequenced the same fragment for 160 commercial birds representing all important commercial types from multiple commercial companies that together represent more than 50% of the worldwide commercial value. We identified 20 different haplotypes. The haplotypes clustered into five clades. The commonest clade (E-clade) supposedly originates from the Indian subcontinent. In addition, both in commercial chicken and Dutch fancy breeds, many haplotypes were found with a clear East Asian origin. However, the erratic occurrence of many different East Asian mitochondrial clades indicates that there were many independent instances where breeders used imported exotic chickens for enhancing local breeds. Nucleotide diversity and haplotype diversity analyses showed the influence of the introgression of East Asian chicken on genetic diversity. All populations that had haplotypes of multiple origin displayed high inferred diversity, as opposed to most populations that had only a single mitochondrial haplotype signature. Most fancy breeds were found to have a much lower within-population diversity compared to broilers and layers, although this is not the case for mitochondrial estimates in fancy breeds that have multiple origin haplotypes.
了解驯化种群的复杂起源对于理解、保护和利用品种遗传多样性至关重要。在此，我们旨在评估亚洲对欧洲传统品种和西方商业鸡线粒体遗传多样性的贡献。为此，我们对16个荷兰观赏品种（113只个体）的鸡线粒体DNA D-loop区域的一个365bp片段进行了调查，这些品种几乎涵盖了荷兰所有的品种多样性。我们还对代表多个商业公司所有重要商业类型的160只商业鸡的同一片段进行了测序，这些公司的商业价值合计占全球商业价值的50%以上。我们鉴定出20种不同的单倍型。这些单倍型聚为五个进化枝。最常见的进化枝（E进化枝）推测起源于印度次大陆。此外，在商业鸡和荷兰观赏品种中，都发现了许多具有明显东亚起源的单倍型。然而，许多不同的东亚线粒体进化枝的不规律出现表明，育种者在许多独立的情况下使用进口的外来鸡来改良本地品种。核苷酸多样性和单倍型多样性分析显示了东亚鸡基因渗入对遗传多样性的影响。所有具有多种起源单倍型的群体都显示出较高的推断多样性，这与大多数只有单一线粒体单倍型特征的群体形成对比。与肉鸡和蛋鸡相比，大多数观赏品种的群体内多样性要低得多，不过对于具有多种起源单倍型的观赏品种的线粒体估计并非如此。
