Journal of Experimental Zoology Part B Molecular and Developmental Evolution, Journal Year: 2025, Volume and Issue: unknown

Published: April 9, 2025

ABSTRACT Shells, spicules, and chaetae are diverse among extant extinct spiralians such as mollusks, annelids, or brachiopods. These hard parts serve different functions, but their formation process evolutionary interrelationships still contentious. We investigated the expression of evolutionarily conserved transcription factor encoding genes well structural chitin synthase ferritin in cells giving rise to shells spicules aculiferans, i.e. polyplacophoran Acanthochitona fascicularis neomeniomorph Wirenia argentea , conchiferan cephalopod Xipholeptos notoides scaphopod Antalis entalis . Polyplacophorans neomeniomorphs express hox1 (only neomeniomorphs), goosecoid grainyhead chitin‐synthase spicules. Grainyhead notch delta zic expressed shell fields spicule‐bearing cells. In conchiferans, (scaphopods cephalopods), (scaphopods) fields. Ferritin is a gene that has been shown be gastropod field; however, it not by studied species. Our study shows all candidate epithelia give shells, revealing close relationship between contrast, field appears innovation. Building on previous research involving brachiopod annelid chaetal sacs, our results suggest may have predated molluscan homologous chaetae. If this were true, then mollusks would secondarily lost

Language: Английский