Salmenkova E A
Genetika. 2008 Jul;44(7):874-84.
Introductions of alien species (populations) acquired a global scale, becoming a major factor of environmental change. Population-genetic and ecological studies of these species promote understanding of evolutionary change and mechanisms of adaptation of the species introduced into a novel environment. This knowledge is of interest also with regard to conservation biology in connection with restoring endangered or extinct populations. The transplanted populations are subject to the founder effect and gene drift, which entails loss of genetic variation, inbreeding depression, and reduction of fitness of the introduced species. However, the decrease in the quantitative variability (additive genetic variance, which is directly affected by selection) prove to be significantly less than the loss in neutral molecular genetic variation. Maintenance of genetic variation at the level providing establishment of the invasive species requires a high number of introduced individuals and multiple introductions from different populations of the species. Introductions are accompanied by hybridization and genetic introgression of the invader with the indigenous species, which augments the variability and viability of the former, but are extremely deleterious to the latter. Adaptive changes of morphological and ecological traits and the formation of the population-genetic structure in the new area occur very rapidly. The allied genetic divergence of the introduced population from the donor one may be directly or indirectly associated with the adaptation processes. Transplantation of anadromous salmonid species among hatcheries undertaken to increase the population numbers (i.e., introductions within the natural range) were of low efficiency owing to conservative local adaptations and low fitness of the transplanted fish. However, sometimes these transplantations were successful, if they involved geographically close populations with common origin and common evolutionary history. Numerous studies yield negative genetic, ecological, and ecosystemic effects of introduction of alien species and populations, which should be taken into account when planning transplantations.
外来物种（种群）的引入已具有全球规模，成为环境变化的一个主要因素。对这些物种进行种群遗传学和生态学研究，有助于理解进化变化以及引入新环境的物种的适应机制。这方面的知识对于与恢复濒危或灭绝种群相关的保护生物学也具有重要意义。被移植的种群会受到奠基者效应和基因漂变的影响，这会导致遗传变异丧失、近亲繁殖衰退以及引入物种适应性降低。然而，数量变异性（直接受选择影响的加性遗传方差）的减少被证明明显小于中性分子遗传变异的损失。要在能确保入侵物种立足的水平上维持遗传变异，需要引入大量个体并从该物种的不同种群进行多次引入。引入过程伴随着入侵者与本地物种的杂交和基因渗入，这增加了前者的变异性和生存能力，但对后者极为有害。形态和生态特征的适应性变化以及新区域种群遗传结构的形成非常迅速。引入种群与供体种群之间的相关遗传分化可能直接或间接与适应过程有关。为增加种群数量而在孵化场之间移植溯河产卵鲑科鱼类物种（即在自然分布范围内进行引入），由于当地适应性保守以及移植鱼类适应性低，效率很低。然而，如果涉及地理上相近、起源相同且具有共同进化历史的种群，这些移植有时会取得成功。大量研究表明引入外来物种和种群会产生负面的遗传、生态和生态系统影响，在规划移植时应予以考虑。
