Testing for beneficial reversal of dominance during salinity shifts in the invasive copepod Eurytemora affinis , and implications for the maintenance of genetic variation
Testing for beneficial reversal of dominance during salinity shifts in the invasive copepod Eurytemora affinis , and implications for the maintenance of genetic variation
复制标题
测试入侵桡足动物Eurytemora affinis在盐度变化过程中优势地位的有益逆转，以及对维持遗传变异的影响。
DOI：
10.1111/evo.12502
复制
发表时间：
2014
期刊：
影响因子：
3.3
通讯作者：
Lee, Carol Eunmi
中科院分区：
文献类型：
--
作者：
Posavi, Marijan;Gelembiuk, Gregory William;Larget, Bret;Lee, Carol Eunmi
在选择的基因座上保持遗传变异对环境变化下的适应具有深远的意义。在时空变化的生境中，非中性多态可以通过杂合子跨环境优势(边际超显性)来维持，这种优势可以通过有利的跨条件显性逆转而大大增加。我们测试了从咸水入侵到淡水入侵的Eurytemora affinis的耐盐性的显性逆转和边际优势。我们比较了由盐度和淡水自交系(盐度间的F1杂交)产生的F1后代的存活率相对于盐度内的F1，跨越三个盐度。我们发现了耐盐性中有利的显性逆转和边际超显性的证据。在支持优势逆转方面，盐度间F1与淡水F1和咸水F1在淡水条件下和咸水条件下的存活率没有差异。在支持边际优势的情况下，盐度间F1组合在盐度下的存活率显著高于淡水和咸水F1组合。我们的研究提供了一个罕见的经验例子，证明了与环境变化相关的主导地位的完全逆转是有益的。这一机制可能是维持耐盐性遗传变异的关键。亲缘种群，允许在栖息地入侵期间快速适应盐度变化。
Maintenance of genetic variation at loci under selection has profound implications for adaptation under environmental change. In temporally and spatially varying habitats, non-neutral polymorphism could be maintained by heterozygote advantage across environments (marginal overdominance), which could be greatly increased by beneficial reversal of dominance across conditions. We tested for reversal of dominance and marginal overdominance in salinity tolerance in the saltwater-to-freshwater invading copepodEurytemora affinis. We compared survival of F1 offspring generated by crossing saline and freshwater inbred lines (between-salinity F1 crosses) relative to within-salinity F1 crosses, across three salinities. We found evidence for both beneficial reversal of dominance and marginal overdominance in salinity tolerance. In support of reversal of dominance, survival of between-salinity F1 crosses was not different from that of freshwater F1 crosses under freshwater conditions and saltwater F1 crosses under saltwater conditions. In support of marginal overdominance, between-salinity F1 crosses exhibited significantly higher survival across salinities relative to both freshwater and saltwater F1 crosses. Our study provides a rare empirical example of complete beneficial reversal of dominance associated with environmental change. This mechanism might be crucial for maintaining genetic variation in salinity tolerance inE. affinispopulations, allowing rapid adaptation to salinity changes during habitat invasions.