A morphological basis for path-dependent evolution of visual systems

• 成果类型: Article
• 署名作者: Varney, Rebecca M.; Speiser, Daniel I.; Cannon, Johanna T.; Aguilar, Morris A.; Eernisse, Douglas J.; Oakley, Todd H.
• 署名单位: University of California System; University of California Santa Barbara; University of South Carolina System; University of South Carolina Columbia; California State University System; California State University Fullerton
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11844
• DOI: 10.1126/science.adg2689
• 发表日期: 2024-03-01
• 页码: 983-987
• 关键词: chitons mollusca polyplacophora; aesthete canal morphology; historical contingency; protein evolution; fine-structure; fossil record; eye; ultrastructure; phylogeny; complex

摘要

Path dependence influences macroevolutionary predictability by constraining potential outcomes after critical evolutionary junctions. Although it has been demonstrated in laboratory experiments, path dependence is difficult to demonstrate in natural systems because of a lack of independent replicates. Here, we show that two types of distributed visual systems recently evolved twice within chitons, demonstrating rapid and path-dependent evolution of a complex trait. The type of visual system that a chiton lineage can evolve is constrained by the number of openings for sensory nerves in its shell plates. Lineages with more openings evolve visual systems with thousands of eyespots, whereas those with fewer openings evolve visual systems with hundreds of shell eyes. These macroevolutionary outcomes shaped by path dependence are both deterministic and stochastic because possibilities are restricted yet not entirely predictable.