PDF(Pubmed)
Abstract：
Local chicken populations belonging to five villages in two geographically separated provinces of Sri Lanka were analyzed using 20 microsatellite markers to determine the genetic diversity of local chickens. Population genetic parameters were estimated separately for five populations based on geographic locations and for eight populations based on phenotypes, such as naked neck, long legged, crested or crown, frizzle feathered, Giriraj, commercial layer, crossbreds, and non-descript chicken. The analysis revealed that there was a high genetic diversity among local chickens with high number of unique alleles, mean number of alleles per locus (MNA), and total number of alleles per locus per population. A total of 185 microsatellite alleles were detected in 192 samples, indicating a high allelic diversity. The MNA ranged from 8.10 (non-descript village chicken) to 3.50 (Giriraj) among phenotypes and from 7.30 (Tabbowa) to 6.50 (Labunoruwa) among village populations. In phenotypic groups, positive inbreeding coefficient (F IS) values indicated the existence of population substructure with evidence of inbreeding. In commercial layers, a high expected heterozygosity He = 0.640 ± 0.042) and a negative F IS were observed. The positive F IS and high He estimates observed in village populations were due to the heterogeneity of samples, owing to free mating facilitated by communal feeding patterns. Highly admixed nature of phenotypes was explained as a result of rearing many phenotypes by households (58%) and interactions of chickens among neighboring households (53%). A weak substructure was evident due to the mating system, which disregarded the phenotypes. Based on genetic distances, crown chickens had the highest distance to other phenotypes, while the highest similarity was observed between non-descript village chickens and naked neck birds. The finding confirms the genetic wealth conserved within the populations as a result of the breeding system commonly practiced by chicken owners. Thus, the existing local chicken populations should be considered as a harbor of gene pool, which can be readily utilized in developing locally adapted and improved chicken breeds in the future.
摘要：
使用20个微卫星标记对斯里兰卡两个地理上分开的省份的五个村庄的当地鸡种群进行了分析，以确定当地鸡的遗传多样性。根据地理位置分别估算了5个种群的种群遗传参数,根据表型分别估算了8个种群的种群遗传参数,比如裸露的脖子，长腿,冠冕或冠冕，毛茸茸的羽毛，Giriraj,商业层，杂种,和不起眼的鸡肉。分析显示,本地鸡具有较高的遗传多样性,具有较高的独特等位基因,每个基因座的平均等位基因数（MNA），和每个种群每个基因座的等位基因总数。在192份样本中共检测到185个微卫星等位基因，表明等位基因多样性高。表型的MNA范围从8.10（非描述性乡村鸡）到3.50（Giriraj），村庄人口的MNA范围从7.30（Tabbowa）到6.50（Labunoruwa）。在表型组中，正近交系数（FIS）值表明存在种群亚结构，并有近交的证据。在商业层面，观察到高预期杂合性He=0.640±0.042）和负FIS。在村庄人口中观察到的正FIS和高He估计是由于样本的异质性，由于公共喂养方式促进了自由交配。表型的高度混合性质被解释为家庭饲养许多表型（58％）和邻近家庭之间鸡的相互作用（53％）的结果。由于交配系统，很明显有一个弱的子结构，忽略了表型。基于遗传距离,冠鸡与其他表型的距离最高，而在非描述的乡村鸡和裸颈鸟之间观察到最高的相似性。该发现证实了由于鸡主通常实行的育种系统而在种群中保留了遗传财富。因此，现有的当地鸡种群应被视为基因库的港湾，将来可以很容易地用于开发当地适应和改良的鸡肉品种。
