Jenkins N L, Sgrò C M, Hoffmann A A
School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia.
EXS. 1997;83:79-96. doi: 10.1007/978-3-0348-8882-0_5.
We have started to test the effects of environmental extremes on the expression of genetic variation for traits likely to be under selection in natural populations. We have shown that field heritability may be high for stress response traits in contrast to morphological traits, which tend to show lower levels of heritable variation in nature compared with the laboratory. Selection for increased stress resistance can lead to a number of other evolutionary changes, and these may underlie trade-offs between favourable and stressful environments. Temperature extremes can have a marked influence on the heritability of life history traits. Heritabilities for fecundity can be high when parental flies are reared at low temperatures and under field conditions. The expression of genetic variation for development time is somewhat more complex when temperature extremes are considered. Populations at species margins may be ideal for studying the effects of environmental stress on evolution.
我们已开始测试极端环境对自然种群中可能处于选择之下的性状的遗传变异表达的影响。我们已经表明，与形态性状相比，应激反应性状的田间遗传力可能较高，形态性状在自然环境中与实验室环境相比往往表现出较低水平的遗传变异。选择增强抗逆性可能会导致许多其他进化变化，而这些变化可能是有利环境与应激环境之间权衡的基础。极端温度会对生活史性状的遗传力产生显著影响。当亲代果蝇在低温和田间条件下饲养时，繁殖力的遗传力可能较高。考虑极端温度时，发育时间的遗传变异表达则更为复杂。物种边缘的种群可能是研究环境应激对进化影响的理想对象。
