A single-nucleotide change underlies the genetic assimilation of a plastic trait

摘要: Genetic assimilation-the evolutionary process by which an environmentally induced phenotype is made constitutive-represents a fundamental concept in biology. Thought to reflect adaptive phenotypic plasticity, matricidal hatching nematodes triggered maternal nutrient deprivation allow for protection or resource provisioning of offspring. Here, we report natural Caenorhabditis elegans populations harboring genetic variants expressing derived state near-constitutive hatching. These exhibit single amino acid change (V530L) KCNL-1, small-conductance calcium-activated potassium channel subunit. This gain-of-function mutation causes strongly reducing the sensitivity environmental stimuli triggering egg-laying. We show that reestablishing canonical KCNL-1 protein isolates sufficient restore While highly deleterious constant food environments, V530L maintained under fluctuating availability. A point can therefore underlie assimilation-by either drift selection-of ancestrally plastic trait.