Distinct cold tolerance traits independently vary across genotypes in Drosophila melanogaster
Distinct cold tolerance traits independently vary across genotypes in Drosophila melanogaster
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DOI：
10.1111/evo.14025
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发表时间：
2020-06-10
期刊：
影响因子：
3.3
通讯作者：
Teets, Nicholas M.
中科院分区：
文献类型：
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作者：
Garcia, Mark J.;Littler, Aerianna S.;Teets, Nicholas M.
耐寒性，即科普低温胁迫的能力，是在热变环境中的关键适应。个体的耐寒性包括几个性状，包括生长和活动的最低温度，在严寒中生存的能力，以及在寒冷消退后恢复正常功能的能力。在不同的物种中，这些特征是相关的，这表明它们是由共同的进化过程或可能共同的生理机制塑造的。然而，在何种程度上耐冷性状及其相关机制的群体内的协变尚未进行评估。我们测量了五个耐寒性特征-临界热最低限度，寒冷昏迷恢复，短期和长期的耐寒性，以及冷诱导的运动行为的变化，以及冷诱导的表达的两个基因可能在耐寒性（热休克蛋白70和霜冻）-在12个线的黑腹果蝇来自一个单一的人口。我们观察到显着的遗传变异在所有性状，但很少有跨基因型相关，这些相关性是性别特异性的。此外，冷诱导的基因表达因基因型而异，但没有证据支持我们的假设，即耐寒品系将具有更高的基线表达或诱导应激基因。这些结果表明，耐寒性状具有独特的机制，并具有独立进化的能力。
Cold tolerance, the ability to cope with low temperature stress, is a critical adaptation in thermally variable environments. An individual's cold tolerance comprises several traits including minimum temperatures for growth and activity, ability to survive severe cold, and ability to resume normal function after cold subsides. Across species, these traits are correlated, suggesting they were shaped by shared evolutionary processes or possibly share physiological mechanisms. However, the extent to which cold tolerance traits and their associated mechanisms covary within populations has not been assessed. We measured five cold tolerance traits-critical thermal minimum, chill coma recovery, short- and long-term cold tolerance, and cold-induced changes in locomotor behavior-along with cold-induced expression of two genes with possible roles in cold tolerance (heat shock protein 70 and frost)-across 12 lines of Drosophila melanogaster derived from a single population. We observed significant genetic variation in all traits, but few were correlated across genotypes, and these correlations were sex-specific. Further, cold-induced gene expression varied by genotype, but there was no evidence supporting our hypothesis that cold-hardy lines would have either higher baseline expression or induction of stress genes. These results suggest cold tolerance traits possess unique mechanisms and have the capacity to evolve independently.