257W Poster - Population Genetics
Wednesday June 08, 9:15 PM - 10:00 PM

Authors:
Amanda Clark; Tonia Schwartz

Affiliation: Auburn University

Keywords:
Population history

The “island rule” is the worldwide phenomenon of rapid evolution of dwarfism and gigantism on islands. It is unknown to what degree convergence in insular body size is accompanied by convergence at the level of genetics, physiology, and/or life-history traits. We have identified three reptile species—two snakes and one lizard—on the California Channel Islands that have independently evolved insular dwarfism relative to mainland southern California. Island populations of all three reptiles have smaller body size, smaller relative head size, and lower blood glucose relative to mainland populations, though with some variation by sex and year. We further this investigation at the genomic level, presenting a chromosome-level genome assembly for the gopher snake (Pituophis catenifer) and whole genome population sequencing across two mainland and two island locations to characterize the genomic divergence across the landscape and specifically in candidate functional genetic pathways. Our data support a single colonization event, with population-level divergence (F^ST) estimates between mainland and island sites. Additional results on historical demography of California gopher snakes will be presented and discussed in the context of our ultimate goal—to understand the mechanisms of convergence across the ecology, life-history, physiology, and genetic networks.