Department of Ecology and Evolutionary Biology, Brown University, Providence, RI.
Center for Computational Molecular Biology, Brown University, Providence, RI.
Mol Biol Evol. 2021 Jan 23;38(2):676-685. doi: 10.1093/molbev/msaa227.
Acorn barnacle adults experience environmental heterogeneity at various spatial scales of their circumboreal habitat, raising the question of how adaptation to high environmental variability is maintained in the face of strong juvenile dispersal and mortality. Here, we show that 4% of genes in the barnacle genome experience balancing selection across the entire range of the species. Many of these genes harbor mutations maintained across 2 My of evolution between the Pacific and Atlantic oceans. These genes are involved in ion regulation, pain reception, and heat tolerance, functions which are essential in highly variable ecosystems. The data also reveal complex population structure within and between basins, driven by the trans-Arctic interchange and the last glaciation. Divergence between Atlantic and Pacific populations is high, foreshadowing the onset of allopatric speciation, and suggesting that balancing selection is strong enough to maintain functional variation for millions of years in the face of complex demography.
橡果藤壶成虫在其环北极栖息地的不同空间尺度上经历着环境异质性，这就提出了一个问题，即在幼体强扩散和死亡率的情况下，如何保持对高环境变异性的适应。在这里，我们表明，在该物种的整个范围内，有 4%的藤壶基因组基因经历着平衡选择。这些基因中的许多都携带着在太平洋和大西洋之间 200 万年的进化过程中保持下来的突变。这些基因参与离子调节、疼痛感知和耐热性，这些功能在高度可变的生态系统中是必不可少的。数据还揭示了内部和之间的复杂群体结构，这是由跨北极交换和最后一次冰川作用驱动的。大西洋和太平洋种群之间的分化很高，预示着异域物种形成的开始，并表明平衡选择足以在复杂的人口统计学条件下维持数百万年的功能变异。
