我国家鸭品种资源遗传多样性保护等级分析

Conservation Priorities of Genetic Diversity in Chinese Indigenous Duck Breeds

本研究旨在分析我国地方鸭品种资源遗传多样性保护等级,为更好地制定我国地方鸭品种资源保护方案提供理论依据。采用28个微卫星标记计算我国24个地方鸭品种间DR遗传距离、基因流(Nm)、多态信息含量(PIC)和杂合度,并采用Weitzman和Caballero两种遗传多样性保护理论,分析各品种在遗传多样性最大化保护中的相对重要性。结果表明,28个微卫星座位的Ewens-Watterson检验均属选择中立性,各位点平均多态信息含量为0.494 4;三穗鸭(SS)的观察杂合度最高(0.864 8),大余鸭(DY)的观察杂合度最低(0.720 8),靖西大麻鸭(JXD)的多态信息含量最高(0.581 6),金定鸭(JD)的多态信息含量最低(0.434 7);四川麻鸭(SC)和汉中麻鸭(HZ)之间的遗传距离最远(0.425 7),基因流最小(0.471 1),广西小麻鸭(XL)和靖西大麻鸭之间的遗传距离最近(0.166 4),基因流最大(1.380 8)。Weitzman保护理论分析中,临武鸭(LW)、四川麻鸭(SC)、高邮鸭(GY)和北京鸭(BJ)的贡献率较高(>5.0%);Caballero保护理论分析中,绍兴鸭(SX)、四川麻鸭、巢湖鸭(CH)和兴义鸭(XY)具有较高的正贡献率(>0.2%),与Weitzman保护理论确定的等级顺序存在一定差异,主要原因是Weitzman保护理论没有考虑到品种内遗传多样性。在分析我国地方鸭品种资源遗传多样性保护等级时,应充分考虑品种间遗传多样性和品种内遗传多样性。绍兴鸭、四川麻鸭、巢湖鸭、兴义鸭、高邮鸭、临武鸭、汉中麻鸭、沔阳麻鸭(MY)、荆江麻鸭(JJ)、三穗鸭、恩施麻鸭(ES)、北京鸭、淮南麻鸭(HN)、云南麻鸭(YN)、攸县麻鸭(YX)、微山麻鸭(WS)16个品种对我国家鸭资源总体遗传多样性具有较高的贡献率,在品种资源保护中应当给予优先保护等级。

The objective of this study was to analyze conservation priorities of genetic diversity in Chinese indigenous duck breeds,and to supply a theoretical basis for better conservation programs.The DR genetic distance,gene flow,heterozygosity and polymorphism information content were measured by 28 microsatellite markers.Two conservation strategies,Weitzman and Caballero methods were used to assessed the conservation priorities of 24 Chinese indigenous duck breeds.The results showed that all the loci were neutral by Ewens-Watterson test,the mean PIC was 0.494 4.The SS and DY breeds respectively had the highest（0.864 8） and the least（0.720 8） observed heterozygosity.The JXD and JD breeds respectively had the highest（0.581 6） and the least（0.434 7） PIC.SC breeds had the farthest mean genetic distance（0.425 7） and the least gene flow（0.471 1） with HZ breeds,XL breeds had the nearest mean genetic distance（0.166 4） and the most gene flow（1.380 8） with JXD.The Weitzman method suggested that the most important breeds to be preserved are LW,SC,GY and BJ,their contribution rate to diversity were higher than 5%.The Caballero method suggested that SX,SC,CH and XY breeds had higher positive contributions to total diversity.The priority order of Caballero method had some difference from that of Weitzman,s.The reason was that the Weitzman method did not take into account the within-population genetic diversity.The full consideration to inter-populations genetic diversity and genetic diversity within populations should be given in the analysis of Chinese indigenous duck resources conservation levels.Sixteen breeds,including SX,SC,CH,XY,GY,LW,HZ,MY,JJ,SS,ES,BJ,HN,YN,YX and WS had higher contributions to overall genetic diversity of Chinese indigenous duck breeds,and should be given preferential protection levels.