AUTHOR=Tian Ran , Guo Han , Jin Zhihong , Zhang Fan , Zhao Junpeng , Seim Inge 

TITLE=Molecular evolution of vision-related genes may contribute to marsupial photic niche adaptations

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2022.982073

DOI=10.3389/fevo.2022.982073

ISSN=2296-701X

ABSTRACT=<p>Vision plays an essential role in the life of many animals. While most mammals are night-active (nocturnal), many have adapted to novel light environments. This includes diurnal (day-active) and crepuscular (twilight-active) species. Here, we used integrative approaches to investigate the molecular evolution of 112 vision-related genes across 19 genomes representing most marsupial orders. We found that four genes (<italic>GUCA1B</italic>, <italic>GUCY2F</italic>, <italic>RGR</italic>, and <italic>SWS2</italic>) involved in retinal phototransduction likely became functionally redundant in the ancestor of marsupials, a group of largely obligate nocturnal mammals. We also show evidence of rapid evolution and positive selection of bright-light vision genes in the common ancestor of <italic>Macropus</italic> (kangaroos, wallaroos, and wallabies). <italic>Macropus</italic>-specific amino acid substitutions in opsin genes (<italic>LWS</italic> and <italic>SWS1</italic>), in particular, may be an adaptation for crepuscular vision in this genus via opsin spectral sensitivity tuning. Our study set the stage for functional genetics studies and provides a stepping stone to future research efforts that fully capture the visual repertoire of marsupials.</p>