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 million years 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.

中文翻译：

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副生藤壶的生态负荷和平衡选择。

橡子藤壶成虫在其周围生境的各个空间尺度上都经历了环境异质性，这就提出了一个问题，即面对强烈的少年散布和死亡，如何保持对高环境变异性的适应性。在这里，我们显示了藤壶基因组中4％的基因在整个物种范围内经历了平衡选择。这些基因中有许多在太平洋和大西洋之间的200万年的进化过程中都保持着突变。这些基因参与离子调节，疼痛承受和耐热性，这些功能在高度可变的生态系统中至关重要。数据还显示，在跨北极交汇处和最后一次冰川作用的驱动下，盆地内部和盆地之间的人口结构复杂。大西洋与太平洋人口之间的差异很大，