Well Assembled Snake Genomes – A Foundation for Understanding Many Things about Snakes We Wanted to

Castoe, Todd A. todd.castoe@uta.edu Schield, Drew R. Perry, Blair W. Adams, Richard H. Department of Biology University of Texas at Arlington Arlington, Texas, USA

Card, Daren C. Department of Biology University of Texas at Arlington Arlington, Texas, USA Department of Organismic and Evolutionary Biology Museum of Comparative Zoology Harvard University Cambridge, Massachusetts, USA

Hales, Nicole M. Nikolakis, Zachary L. Orton, Richard W. Pasquesi, Giulia I. M. Department of Biology University of Texas at Arlington Arlington, Texas, USA

Meik, Jesse M. Department of Biological Sciences Tarleton State University Stephenville, Texas, USA

Smith, Cara F. Mackessy, Stephen P. School of Biological Sciences University of Northern Colorado Greeley, Colorado, USA

In many ways, genomes represent a nexus of biological context for understanding the evolutionary mechanisms that shape organisms. To date, the relatively poor quality of available snake genomes has prevented a detailed understanding of many basic biological features of snakes. Here, through a series of vignettes, we illustrate how a new and well-assembled rattlesnake genome provides a foundation for fundamentally increasing our ability to address diverse longstanding questions about the biology and evolution of snakes, and rattlesnakes specifically. First, we provide evidence that squamate genomes may function remarkably differently from those of mammals. Second, we demonstrate substantial progress towards understanding the origins of venom, and molecular mechanisms responsible for its precise regulation. Third, we show how new genomic resources may fundamentally increase our ability to understand patterns of speciation, reproductive isolation, and hybridization in rattlesnakes.