DeAssis J B, DeLaat D M, Peixoto M G C D, Bergmann J A G, Fonseca C G, Carvalho M R S
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
Genet Mol Res. 2009 Dec 23;8(4):1519-24. doi: 10.4238/vol8-4gmr647.
One hundred and fifteen unrelated Mangalarga Marchador horses were sampled from three geographically distinct regions of Minas Gerais State, Brazil (South, Southeast, and Northeast) and tested for 10 microsatellite loci. Genetic diversity and population structure parameters were estimated with ARLEQUIN 3.0, CERVUS 2.0, POPGENE 1.31, GENEPOP on the web, STRUCTURE 2.0, and SPAGEDI 1.2 software packages. Under Hardy-Weinberg assumptions, seven markers were at equilibrium (LEX014, LEX017, LEX019, SGCV23, TKY321, VHL20, and VIASH39), while two (ASB3 and LEX031) presented significant homozygote excess. Seventy-four alleles were identified in these nine markers, with a mean of 8.22 alleles. Mean heterozygosity was 0.637 and polymorphism information content was 0.662. Markers ASB3, LEX019, SGCV23, TKY321, and VHL20 were highly informative (PIC >0.7) and may be useful for eventual expansion of parentage test panels. The F(ST) value (0.0562) indicated relatively little geographical structure. However, based on a Bayesian-based cluster analysis under a three-cluster model, 94% of the 115 individuals were correctly assigned to the subpopulations from where they were sampled. Mean pairwise f was relatively high (0.11), and in spite of the efforts towards non-consanguineous sampling, 1% of the pairs of individuals shared over 50% of the alleles. These results strongly suggest that the population is genetically structured. Under a conservation genetics approach, two strategies are recommended: avoidance of crosses between highly endogamic individuals and stimulation of crosses between individuals from those regions for which low genetic flow was identified.
从巴西米纳斯吉拉斯州三个地理上不同的地区（南部、东南部和东北部）采集了115匹无亲缘关系的曼加拉尔加马查多马，并对10个微卫星位点进行了检测。使用ARLEQUIN 3.0、CERVUS 2.0、POPGENE 1.31、在线GENEPOP、STRUCTURE 2.0和SPAGEDI 1.2软件包估计了遗传多样性和种群结构参数。在哈迪-温伯格假设下，7个标记处于平衡状态（LEX014、LEX017、LEX019、SGCV23、TKY321、VHL20和VIASH39），而2个（ASB3和LEX031）表现出显著的纯合子过剩。在这9个标记中鉴定出74个等位基因，平均每个标记有8.22个等位基因。平均杂合度为0.637，多态性信息含量为0.662。标记ASB3、LEX019、SGCV23、TKY321和VHL20具有高度信息性（PIC>0.7），可能有助于最终扩大亲权鉴定面板。F(ST)值（0.0562）表明地理结构相对较小。然而，基于三聚类模型的贝叶斯聚类分析，115个个体中有94%被正确分配到它们所采样的亚种群中。平均成对f相对较高（0.11），尽管努力进行非近亲采样，但仍有1%的个体对共享超过50%的等位基因。这些结果强烈表明该种群具有遗传结构。在保护遗传学方法下，建议采取两种策略：避免高度近亲个体之间的杂交，并促进那些鉴定出低基因流区域的个体之间的杂交。
