Frankham Richard
Key Centre for Biodiversity and Bioresources, Department of Biological Sciences, Macquarie University, NSW 2109, Australia.
Mol Ecol. 2008 Jan;17(1):325-33. doi: 10.1111/j.1365-294X.2007.03399.x.
As wild environments are often inhospitable, many species have to be captive-bred to save them from extinction. In captivity, species adapt genetically to the captive environment and these genetic adaptations are overwhelmingly deleterious when populations are returned to wild environments. I review empirical evidence on (i) the genetic basis of adaptive changes in captivity, (ii) factors affecting the extent of genetic adaptation to captivity, and (iii) means for minimizing its deleterious impacts. Genetic adaptation to captivity is primarily due to rare alleles that in the wild were deleterious and partially recessive. The extent of adaptation to captivity depends upon selection intensity, genetic diversity, effective population size and number of generation in captivity, as predicted by quantitative genetic theory. Minimizing generations in captivity provides a highly effective means for minimizing genetic adaptation to captivity, but is not a practical option for most animal species. Population fragmentation and crossing replicate captive populations provide practical means for minimizing the deleterious effects of genetic adaptation to captivity upon populations reintroduced into the wild. Surprisingly, equalization of family sizes reduces the rate of genetic adaptation, but not the deleterious impacts upon reintroduced populations. Genetic adaptation to captivity is expected to have major effects on reintroduction success for species that have spent many generations in captivity. This issue deserves a much higher priority than it is currently receiving.
由于野生环境往往不适宜生存，许多物种不得不进行圈养繁殖以避免灭绝。在圈养环境中，物种会在基因上适应圈养环境，而当这些种群回归野生环境时，这些基因适应绝大多数都是有害的。我回顾了关于以下方面的实证证据：（i）圈养环境中适应性变化的遗传基础，（ii）影响对圈养环境遗传适应程度的因素，以及（iii）将其有害影响降至最低的方法。对圈养环境的遗传适应主要归因于野生环境中有害且部分隐性的稀有等位基因。正如数量遗传学理论所预测的，对圈养环境的适应程度取决于选择强度、遗传多样性、有效种群大小以及圈养代数。尽量减少圈养代数是将对圈养环境的遗传适应降至最低的一种非常有效的方法，但对大多数动物物种来说并非实际可行的选择。种群碎片化和杂交复制圈养种群为尽量减少对圈养环境的遗传适应对重新引入野生环境的种群产生的有害影响提供了切实可行的方法。令人惊讶的是，使家庭规模均等化会降低遗传适应的速度，但不会减少对重新引入种群的有害影响。对于在圈养环境中度过许多代的物种而言，对圈养环境的遗传适应预计会对重新引入的成功率产生重大影响。这个问题理应得到比目前更高的优先级。
