遗传多样性的取样策略

Sampling strategy for genetic diversity

合理取样是生物多样性有效保护、利用和研究所面临的最基本问题 ,它在很大程度上受到植物自身的生物学特性、环境条件和取样目的的影响。遗传多样性的取样策略是指对一定地理分布范围内的生物个体取样时 ,使样本具有代表性和包含尽可能多的遗传变异的最佳取样方法 ,包括了取样数目 (一个给定区域的居群数和一个居群的个体数 )以及取样方式。包括“哈迪 温伯格平衡 (Hardy WeinbergEquilibrium)”定律在内的居群遗传学基本原理是研究取样策略的理论基础 ,在此基础上可以对居群内的取样个体数及应获取的居群数进行理论计算 ,同时还可以根据物种居群的遗传结构特点和环境条件的异质性来决定取样的方式。因此 ,应该依据研究对象本身的特点和取样的目的来确定某一特定区域的居群取样数 ,以及某一居群内的样本数及取样方式。

An appropriate sampling method not only serves as a prerequisite for conservation and utilization of biodiversity occurring in nature, but also affects the results of population genetic research. A strategic sampling method for genetic diversity can be defined as the optimum sampling method to achieve representation of the full genetic variation represented in a species or a population within a manageable number of samples. Therefore, strategic sampling must consider two factors: 1) the number of samples (including number of populations in a given area and number of individuals within a given population), and 2) the methods of sampling in relation to the genetic structure of the populations under consideration. The well-known Hardy-Weinberg Equilibrium and other principles of population genetics provide the theoretical bases of sampling strategy design. The theoretical models of sampling based on the Hardy-Weinberg Equilibrium offer a general guideline for the number of individuals to be sampled within a population and the number of populations to be sampled in a given region if there is no detailed genetic and environmental information available. Based on this, approximately 30 individuals from a population could be considered as a recommended size for collection under such conditions. When designing a sampling strategy, the biotic and abiotic factors that can influence the genetic diversity captured in the organisms under study should also be considered. The taxonomic status, life cycle, geographical distribution, breeding system, and environmental heterogeneity of a target species will significantly affect the pattern of genetic variation and consequently the design of sampling strategy. In general, the optimum sampling strategy should be designed on the basis of the biological features of the target species, environmental conditions, and objectives for conservation, utilization, or research.