The initiation of metamorphosis as an ancient polyphenic trait and its role in metazoan life-cycle evolution.

摘要: Comparative genomics of representative basal metazoans leaves little doubt that the most recent common ancestor to all modern was morphogenetically complex. Here, we support this interpretation by demonstrating demosponge Amphimedon queenslandica has a biphasic pelagobenthic life cycle resembling present in wide range bilaterians and anthozoan cnidarians. The A. includes compulsory planktonic larval phase can end only once larva develops competence respond benthic signals induce settlement metamorphosis. temporal onset varies between individuals as revealed idiosyncratic responses inductive cues. Thus, with dispersing variable length appears be metazoan synapomorphy may viewed an ancestral polyphenic trait. Larvae particular age are subjected cue either maintain form or metamorphose into post-larval/juvenile form. Variance development dictates subset cohort will settle undergo metamorphosis at given time, which turn leads variation dispersal distance location settlement. Population divergence allopatric speciation likely outcomes conserved developmental