Serrano Magdalena, Calvo Jorge H, Martínez Marta, Marcos-Carcavilla Ane, Cuevas Javier, González Carmen, Jurado Juan J, de Tejada Paloma Díez
Departamento de Mejora Genética Animal, INIA, 28080 Madrid, Spain.
BMC Genet. 2009 Sep 29;10:61. doi: 10.1186/1471-2156-10-61.
Assessing genetic biodiversity and population structure of minor breeds through the information provided by neutral molecular markers, allows determination of their extinction risk and to design strategies for their management and conservation. Analysis of microsatellite loci is known to be highly informative in the reconstruction of the historical processes underlying the evolution and differentiation of animal populations. Guadarrama goat is a threatened Spanish breed which actual census (2008) consists of 3057 females and 203 males distributed in 22 populations more or less isolated. The aim of this work is to study the genetic status of this breed through the analysis of molecular data from 10 microsatellites typed in historic and actual live animals.
The mean expected heterozygosity across loci within populations ranged from 0.62 to 0.77. Genetic differentiation measures were moderate, with a mean FST of 0.074, GST of 0.081 and RST of 0.085. Percentages of variation among and within populations were 7.5 and 92.5, respectively. Bayesian clustering analyses pointed out a population subdivision in 16 clusters, however, no correlation between geographical distances and genetic differences was found. Management factors such as the limited exchange of animals between farmers (estimated gene flow Nm = 3.08) mostly due to sanitary and social constraints could be the major causes affecting Guadarrama goat population subdivision.
Genetic diversity measures revealed a good status of biodiversity in the Guadarrama goat breed. Since diseases are the first cause affecting the census in this breed, population subdivision would be an advantage for its conservation. However, to maintain private alleles present at low frequencies in such small populations minimizing the inbreeding rate, it would necessitate some mating designs of animals carrying such alleles among populations. The systematic use of molecular markers will facilitate the comprehensive management of these populations, which in combination with the actual breeding program to increase milk yield, will constitute a good strategy to preserve the breed.
通过中性分子标记提供的信息评估小型品种的遗传生物多样性和种群结构，有助于确定其灭绝风险，并设计管理和保护策略。已知微卫星位点分析在重建动物种群进化和分化的历史过程中具有很高的信息量。瓜达拉马山羊是一种濒危的西班牙品种，2008年实际普查显示，共有3057只母羊和203只公羊分布在22个或多或少隔离的种群中。本研究的目的是通过分析历史和现存活体动物的10个微卫星分子数据，研究该品种的遗传状况。
各群体内各基因座的平均期望杂合度在0.62至0.77之间。遗传分化程度中等，平均FST为0.074，GST为0.081，RST为0.085。群体间和群体内的变异百分比分别为7.5%和92.5%。贝叶斯聚类分析指出该种群可分为16个簇，然而，未发现地理距离与遗传差异之间存在相关性。管理因素，如农民之间动物交换有限（估计基因流Nm = 3.08）主要是由于卫生和社会限制，可能是影响瓜达拉马山羊种群细分的主要原因。
遗传多样性测量结果显示瓜达拉马山羊品种的生物多样性状况良好。由于疾病是影响该品种普查数量的首要原因，种群细分对其保护将是一个优势。然而，为了在如此小的种群中维持低频存在的私有等位基因，同时尽量降低近亲繁殖率，有必要在种群间对携带此类等位基因的动物进行一些交配设计。系统使用分子标记将有助于对这些种群进行全面管理，这与目前提高产奶量的育种计划相结合，将是保护该品种的一个良好策略。
