崂山奶山羊分子系谱的构建及家系遗传特征分析

Construction of Molecular Genealogy and Analysis of Family Genetic Characteristics in Laoshan Dairy Goat

【目的】通过微卫星DNA标记技术对已知系谱记录的试验群体构建分子系谱,验证崂山奶山羊与原有系谱记录的一致性,探讨影响亲权鉴定的因素,摸清家系的遗传特征,为群体的保种和遗传管理提供科学依据。【方法】从25个微卫星DNA标记中筛选出12个高多态性的遗传标记,对已知系谱记录的212只崂山奶山羊,利用Cervus vs 2.0软件进行亲权分析,利用Pedigraph vs 2.2软件构建试验群体的分子系谱,利用Molkin vs 3.0、MEGA4和GeneClass2软件对所构建家系的遗传特征及系统发育关系进行分析。用SPSS vs 16软件对每个位点的排除概率(EP)与多态信息含量(PIC)、期望杂合度(He)、观察杂合度(Ho)、等位基因数(K)等多态性参数的相关性进行分析,分析不同位点数及信息来源对亲权鉴定准确性的影响。【结果】12个微卫星DNA遗传标记的多态信息含量均为高度多态(PIC≥0.5),平均为0.687,平均等位基因数为5.75个,期望杂合度平均为0.730;在父本已知的基础上进行母子亲权鉴定,置信度在95%以上的累积排除概率为0.9998,最终从80个候选母亲、祖母中找出了115个后裔的母亲、祖母,发现3个个体与原有系谱记录不相符,符合度达到98.58%,构建了2个以父系为基础的家系及群体分子系谱图。排除概率与PIC相关系数最大(0.99以上),与K相关系数最小(0.67)。使用8个位点可使CEP2达到99.73%以上。【结论】所选12个微卫星标记可用于崂山奶山羊试验群体的亲权鉴定及分子系谱构建;所构建家系具有较好的遗传基础,家系间及家系内具有较高的遗传变异。

[Objective] The molecular genealogy of population known pedigree records in Laoshan Dairy Goat was constructed by using microsatellite DNA markers technology to verify the consistency with the known pedigree records, identify the factors affecting paternity testing, ascertain the genetic characteristics of family and provide a scientific basis for the conservation and genetic management of the groups. [Method] Twelve microsatellite markers with high polymorphism were selected from 25 ones for 212 Laoshan Dairy Goat with known pedigree records, parentage were analyzed with Cervus vs 2.0, molecular genealogy was built with Pedigraph vs 2.2, the genetic characteristics and phylogenesis of family were analysed with Molkin vs 3.0, MEGA4 and GeneClass2. The correlation coefficient between the exclusion probability（EP） per locus and PIC, He, 11o, K was analyzed with SPSS vs 16, and the effect of different locus and information source on the accuracy of paternity testing was analysed, also. [ Result ] Twelve highly polymorphic microsatellite DNA markers were selected from 25 ones in Laoshan Dairy Goat, the mean PIC value is 0.687, the mean number of allele is 5.75, the mean expected heterozygosity is 0.730. The two-parents combined exclusion probability is 0.9998 on the confidence level of 95%. The biological mother or grandmother of 115 offsprings were found from 80 candidate parents, 3 individuals were not accorded with the known pedigree records, the conincidence rate is 98.58%. The molecular genealogy was constructed on the basis of paternal strains. The correlation coefficient between the exclusion probability and the PIC is the biggest （0.99）, and K with the smallest correlation coefficient （0.67）. The CEP2 is more than 99.73% with 8 microsatellite loci. [ Conclusion] Twelve microsatellite loci can be used for analysis of paternity or construct molecular genealogy in Laoshan Dairy Goat group. The built families have a good genetic basis, and a high genetic diversity within each family or among families.