Meeting Abstract
What drives diversification within island species? A variety of evolutionary processes structure intraspecific genetic diversity on islands: from selection to allopatry to population genetic processes such as drift– all potentially leading to unique evolutionary outcomes. However, we have an incomplete understanding of how these processes might work together or in conflict to drive the attenuation or acceleration of intraspecific divergence in widespread island reptiles. For a species experiencing allopatry and drift in one part of its range and differential ecological selection in another, we might expect multiple evolutionary trajectories to manifest simultaneously, with an important regulatory role to be played by gene flow. The lizard Anolis sagrei has the broadest distribution of any Caribbean anole, occurring on islands of all sizes from the northern Bahamas to the Central American mainland. Populations of A. sagrei experience vastly different ecological and selective pressures, and many are morphologically distinct. For instance, dewlap color (a sexual signal) and body size vary greatly, and some populations are as genetically divergent as full species at mitochondrial loci. We collected samples from across the range of A. sagrei, from the Bahamas to Cuba to the Swan Islands and on to the mainland. Using multilocus nuclear and mitochondrial genetic data we assessed range wide phylogeographic patterns in this species, focusing on macro-level patterns in intraspecific diversification. We further interpret our findings within the context of Caribbean Anolis speciation.
