My current research is focused on three aspects of evolutionary biology. Broadly, these topics are genetic architecture, hybridization, and adaptation. Genetic architecture is the number of genetic loci controlling a trait, the interactions between those loci, and their position within a species genome. Hybridization is the interbreeding of distinct species or evolutionary lineages. Adaptation is the mechanism by which species become better suited to their environment over many generations. I am interested in the interplay between these three subjects within the greater context of biological invasions. Currently, I am developing models to explain how the genetic architecture governing adaptive traits influences the dynamics of hybridization between native and introduced species. I am applying these models to contemporary invasions on islands in order to investigate how the ecological and evolutionary consequences of the process of island colonization may promote hybrid invasions.
My empirical work aims to test the predictions generated by my models. As such, I am investigating potential cases of hybridization between native and invasive plant species in the Galápagos archipelago. Why the Galápagos? The Galápagos consists of many isolated islands which are themselves isolated from continental South America. Galápagos therefore offers an ideal natural laboratory to study evolutionary processes within varying ecological contexts. In addition, roughly a third of all native plant genera in the Galápagos also contain at least one introduced species. The potential for hybridization between such species is therefore considerable. I am investigating hybridization in one such genus: Psidium (guava). In Galápagos, there occurs a native and invasive species of guava on the inhabited islands of San Cristobal, Santa Cruz, Isabela, and Floreana. The ranges of these species overlap at intermediate altitudes, and it is in these regions of secondary contact that I seek out hybrid populations. Specifically, I use a battery of morphological characteristics such as leaf dimensions, architecture, and fruit and flower dimensions in order to identify potential hybrids, and then use genomic sequencing to scan for signals of hybridization and adaptation. Ultimately, I seek to determine whether or not hybridization contributed to the successful invasion of introduced Psidium guajava.
Leaf comparison. From left to right: 1. guayabillo (Psidium galapageium) native to Galápagos, 2. potential hybrid individual (Psidium sp.), 3. common guava (Psidium guajava) invasive in Galápagos.
Fruit & Seed comparison. From left to right: 1. guayabillo (Psidium galapageium) native to Galápagos, 2. potential hybrid individual (Psidium sp.), 3. common guava (Psidium guajava) invasive in Galápagos.