- 期刊
微衛星標記應用於季新鴨之遺傳結構及其類緣關係之探討
Study on genetic structure and phylogeny in Chihsin duck using microsatellite markers
摘要
北京鴨（Duck, Anas platyrhynchos）最初於民國40至50年代引進現在的行政院農業委員會畜產試驗所，持續進行毛色、體重及受精持續性等選拔，此品系於民國110年命名為季新鴨。然因季新鴨為閉鎖族群，族群數量小，其基因頻率及遺傳歧異度易受選拔、配種策略影響，應定期進行遺傳監測，故本研究之目的即為分析季新鴨之遺傳變異資訊，並了解其與其他鴨種的類緣關係。本研究使用分布於5個染色體上共11組篩選自褐色菜鴨的微衛星標記進行分析，結果顯示，季新鴨整體遺傳變異略低於民間北京鴨品系，交替基因數略低於保種菜鴨及北京鴨與褐色菜鴨的合成品系等各家鴨品系，但高於選育白色菜鴨，有效交替基因數則與前述品系大致相當，此結果可能由季新鴨族群不大，加上長期選拔所造成，但不同標記間近交指數差異甚大，顯示此族群目前應尚無嚴重近親衰退之虞。類緣關係樹結果顯示，季新鴨與民間北京鴨遺傳距離最近，但與其他品種（系），包括民間北京鴨，皆未形成明確分支。本研究中季新鴨跟兩民間北京鴨品系的pairwise F_(ST)分別為0.1582及0.1873，雖接近品種層級最低之pairwise F_(ST)，但綜合類緣關係樹及STRUCTURE分析結果，季新鴨與兩民間北京鴨品系的遺傳分化程度應仍為品系層級。後續將以本研究建立遺傳變異結果作為基準，供定期進行季新鴨遺傳監測，另遺傳結構分析的結果亦可提供於此品系推廣至產業時配種、選育參考。
並列摘要
Pekin duck was first introduced into the Livestock Research Institute in Taiwan in the 1950s and 1960s and continuously selected for feather color, weight, and duration of fertility. The novel line was named Chihsin Duck (CH) in 2021. However, because CH are a closed population with a small population size, their allele frequencies and genetic diversity were easily affected by selection and breeding strategies, and should be monitored regularly. Therefore, the purposes of this study were to establish the genetic variation information of CH and to investigate the phylogeny with other duck species. In this study, a total of 11 microsatellite markers selected from the brown Tsaiya duck were used for analysis. The results showed the genetic variations in CH were slightly lower than that of the industrial Pekin duck lines (BPs). The average number of alleles in CH was slightly lower than that of germplasm-persevered Tsaiya ducks and the synthetic line between Pekin duck and brown Tsaiya duck, but higher than the selected white Tsaiya duck. The number of effective alleles was roughly in the same level as that of the aforementioned lines. It may be due to the small population of CH and the long-term selection, resulting in the aforementioned results. However, the values of within-population inbreeding coefficient in different markers were very different, so there should be no serious inbreeding depression in CH at present. The results of the phylogenetic tree showed that CH hed the shortest genetic distance with BPs, but it did not form any robust branch between CH with any other breeds (lines), including the BPs. In this study, the pairwise F_(ST) of CH and BPs were 0.1582 and 0.1873, respectively, which were close to the pairwise F_(ST) at the lowest breed level. However, the genetic differentiation relationship between CH and BPs should still be close to the line level based on the results of the phylogenetic tree and STRUCTURE. In the future, the genetic variation results analyzed in this study would be used as a reference to regular genetic monitoring. In addition, the results of genetic structure analysis could also be applied to mating and breeding programs when this line was promoted to industry.