Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Avenida Circunvalar # 16-20, Bogotá, Colombia.
Departamento de Ciencias Biológicas, Universidad de los Andes, Apartado, 4976, Bogotá, Colombia.
BMC Ecol Evol. 2022 Aug 2;22(1):95. doi: 10.1186/s12862-022-02047-0.
Metabolic activity and environmental energy are two of the most studied putative drivers of molecular evolutionary rates. Their extensive study, however, has resulted in mixed results and has rarely included the exploration of interactions among various factors impacting molecular evolutionary rates across large clades. Taking the diverse avian family Furnariidae as a case study, we examined the association between several estimates of molecular evolutionary rates with proxies of metabolic demands imposed by flight (wing loading and wing shape) and proxies of environmental energy across the geographic ranges of species (temperature and UV radiation).
We found weak evidence of a positive effect of environmental and morphological variables on mitochondrial substitution rates. Additionally, we found that temperature and UV radiation interact to explain molecular rates at nucleotide sites affected by selection and population size (non-synonymous substitutions), contrary to the expectation of their impact on sites associated with mutation rates (synonymous substitutions). We also found a negative interaction between wing shape (as described by the hand-wing index) and body mass explaining mitochondrial molecular rates, suggesting molecular signatures of positive selection or reduced population sizes in small-bodied species with greater flight activity.
Our results suggest that the demands of flight and environmental energy pose multiple evolutionary pressures on the genome either by driving mutation rates or via their association with natural selection or population size. Data from whole genomes and detailed physiology across taxa will bring a more complete picture of the impact of metabolism, population size, and the environment on avian genome evolution.
代谢活动和环境能量是研究最多的分子进化率的两个潜在驱动因素。然而，它们的广泛研究产生了混合的结果，很少包括探索影响大分支内分子进化率的各种因素之间的相互作用。以多样化的鸣禽家族灶鸟科为例，我们研究了几种分子进化率估计值与飞行所施加的代谢需求的代表物（翼负荷和翼型）以及物种地理分布范围内的环境能量代表物（温度和紫外线辐射）之间的关联。
我们发现环境和形态变量对线粒体替代率有微弱的正效应的证据。此外，我们发现温度和紫外线辐射相互作用，解释了受选择和种群大小影响的核苷酸位点的分子速率（非同义替换），这与它们对与突变率相关的位点（同义替换）的影响预期相反。我们还发现翼型（由手翼指数描述）和体重之间的负相互作用解释了线粒体分子速率，这表明在具有更大飞行活动的小体型物种中，存在着正选择或种群规模减小的分子特征。
我们的结果表明，飞行和环境能量的需求通过驱动突变率或通过与自然选择或种群大小的关联，对基因组施加了多种进化压力。来自整个基因组和详细生理数据的跨分类群数据将更全面地了解代谢、种群大小和环境对鸟类基因组进化的影响。
