Genetic variability of two Italian indigenous chicken breeds inferred from microsatellite marker analysis

The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes.Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE.The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds.Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability.As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks. The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes. Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE. The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds. Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability. As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks.

本研究旨在利用国际通用微卫星位点（microsatellite loci）集（AVIANDIV-FAO），对意大利西北部皮埃蒙特地区的皮埃蒙特金发鸡（Bionda Piemontese）与萨尔扎诺白鸡（Bianca di Saluzzo）的遗传结构及遗传变异水平进行解析。本研究同时验证了该类群与商业品系及其他意大利家禽品种间的遗传差异，为保护计划的实施提供理论支撑。研究采用MolKin软件搭载的分析方法，评估了各鸡群对遗传变异的贡献度。分析过程中采用固定指数（fixation index）与雷诺遗传距离（Reynolds genetic distance）开展群体比较。借助STRUCTURE软件内置的聚类分析流程，估算出最优的群体划分数量。分子数据结果显示，当前的饲养管理模式可能阻碍了随机交配，进而导致各鸡群出现近交与遗传异质性。在此方面，皮埃蒙特金发鸡与萨尔扎诺白鸡呈现出群体亚结构，且相较于其他欧洲大陆家禽品种，它们与英国品种的遗传亲缘关系更近。皮埃蒙特金发鸡与萨尔扎诺白鸡属于等位基因数与期望杂合度均处于较高水平的欧洲家禽品种。皮埃蒙特本地鸡种与其他群体间存在显著的遗传分化。皮埃蒙特家禽不仅区别于商业品系与其他意大利本土品种，同时保留了较高水平的遗传变异。与其他地方品种（indigenous breeds）类似，皮埃蒙特金发鸡与萨尔扎诺白鸡未来有望为家禽产业带来创新性贡献。由于当前鸡群管理缺乏规范监管机制，因此采用集体化的计划性恢复方案至关重要。通过建立高效的种鸡替换交流机制与交配计划、加强育种者间的协作，是控制近交、缓解群体亚结构以及提升鸡群内遗传变异的有效途径。本研究旨在利用国际通用微卫星位点（microsatellite loci）集（AVIANDIV-FAO），对意大利西北部皮埃蒙特地区的皮埃蒙特金发鸡与萨尔扎诺白鸡的遗传结构及遗传变异水平进行解析。本研究同时验证了该类群与商业品系及其他意大利家禽品种间的遗传差异，为保护计划的实施提供理论支撑。研究采用MolKin软件搭载的分析方法，评估了各鸡群对遗传变异的贡献度。分析过程中采用固定指数与雷诺遗传距离开展群体比较。借助STRUCTURE软件内置的聚类分析流程，估算出最优的群体划分数量。分子数据结果显示，当前的饲养管理模式可能阻碍了随机交配，进而导致各鸡群出现近交与遗传异质性。在此方面，皮埃蒙特金发鸡与萨尔扎诺白鸡呈现出群体亚结构，且相较于其他欧洲大陆家禽品种，它们与英国品种的遗传亲缘关系更近。皮埃蒙特金发鸡与萨尔扎诺白鸡属于等位基因数与期望杂合度均处于较高水平的欧洲家禽品种。皮埃蒙特本地鸡种与其他群体间存在显著的遗传分化。皮埃蒙特家禽不仅区别于商业品系与其他意大利本土品种，同时保留了较高水平的遗传变异。与其他地方品种类似，皮埃蒙特金发鸡与萨尔扎诺白鸡未来有望为家禽产业带来创新性贡献。由于当前鸡群管理缺乏规范监管机制，因此采用集体化的计划性恢复方案至关重要。通过建立高效的种鸡替换交流机制与交配计划、加强育种者间的协作，是控制近交、缓解群体亚结构以及提升鸡群内遗传变异的有效途径。