Meeting Abstract

S10-1.1  Monday, Jan. 7  Evolutionary origins of an animal light interaction tool-kit OAKLEY, Todd H; UCSB oakley@lifesci.ucsb.edu

Eye evolution is touted as a prime example of deep homology, whereby novel structures arise – sometimes convergently – by modification of homologous regulatory circuits that draw upon a common genetic tool kit. What is this genetic tool kit, how common is it, and when and how did its components originate? Here I discuss a light interaction toolkit (LIT) of genes and examine its evolution. LIT genes variously function in sensing, blocking, bending, and reflecting light or in developmental processes to specify cells and organs that interact with light. First, I highlight that LIT genes are often used in cells outside of eyes, for example, in dispersed photoreceptors and in light-producing organs. While some genes like opsin have very ancient origins and conserved light interaction function, several LIT genes have recent origins and/or newly function in light interaction. Light interaction genes indicate that while deep homology is a galvanizing concept of the genomic era that is valid in some instances, we must take care not to over-generalize and miss the rich variation of the evolutionary process.