Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
Biol Lett. 2023 Jan;19(1):20220450. doi: 10.1098/rsbl.2022.0450. Epub 2023 Jan 25.
Our general understanding of the evolution of genome size (GS) is incomplete, and it has long been clear that GS does not reflect organismal complexity. Here, we assess the hypothesis that larger genomes may allow organisms to better cope with environmental variation. It is, for example, possible that genome expansion due to proliferation of transposable elements or gene duplications may affect the ability to regulate and fine-tune transcriptional profiles. We used 18 populations of the seed beetle , which differ in GS by up to 4.5%, and exposed adults and juveniles to environmental stress in a series of experiments where stage-specific fitness was assayed. We found that populations with larger genomes were indeed better buffered against environmental stress for adult, but not for juvenile, fitness. The genetic correlation across populations between GS and canalization of adult fitness is consistent with a role for natural selection in the evolution of GS.
我们对基因组大小（GS）进化的总体认识尚不完善，长期以来人们一直清楚地认识到，GS 并不反映生物的复杂性。在这里，我们评估了这样一种假设，即更大的基因组可能使生物体更好地应对环境变化。例如，由于转座元件或基因重复的增殖而导致的基因组扩张可能会影响调节和微调转录谱的能力。我们使用了种子象鼻虫的 18 个种群，它们的 GS 差异高达 4.5%，并在一系列实验中使成年和幼体暴露于环境压力下，在这些实验中测定了特定阶段的适应性。我们发现，GS 较大的种群确实对成年个体的适应性具有更好的缓冲作用，但对幼体的适应性没有影响。GS 与成年适应性 canalization 之间的遗传相关性表明，自然选择在 GS 的进化中发挥了作用。
