DIVERSIFICATION AND ADAPTATION OF REPTILES AND AMPHIBIANS
Many of our projects investigate patterns of genomic and phenotypic differentiation across reptiles and amphibians with particular attention to comparative studies among species with similar ranges but different ecologies and habitat use. Our efforts to reconstruct geographic and genetic population histories focus on a number of taxa in North, Central, and South America.
We pair studies of rangewide genomic divergences among lineages with more fine-scale population genomic studies to address questions about the processes leading to local adaptation and population differentiation . We are particularly interested in how aspects of the landscape such as topographic complexity, naturally patchy or fragmented habitats, or intrinsic/extrinsic barriers to gene flow shape the distribution of genetic diversity in species with different degrees of habitat specialization.
SEXUAL SELECTION, MATING SYSTEMS, AND MATE CHOICE:
Reptiles and amphibians are highly diverse in mating system, making them an ideal group to examine the costs and benefits of mating strategies and choices. It is now feasible to establish reproductive success (via paternity genotyping) of large numbers of offspring, allowing us to accurately quantify the outcome of male-male competition and female choice (intra- and inter-sexual selection).
Our research has focused particularly on determining the ecological and evolutionary contexts for the evolution of alternative mating strategies, parental care, and identifying the determinants of reproductive fitness, especially in species with high variance in reproductive success. We use field experiments and behavioral observations coupled with laboratory studies for molecular assessment of paternity and maternity rates in natural populations. As is often the case in science, the complexity of mating systems and reproductive fitness has surprised us, underscoring the importance of exploring a variety of mating systems before drawing general conclusions about their evolution.
GENOMICS OF HOST-PATHOGEN INTERACTIONS
Amphibians are declining worldwide at an unprecedented rate, resulting in loss of biodiversity and serious consequences for ecosystems in which they play critical roles. Habitat loss, climate change, and emerging diseases contribute to these amphibian extinctions.
The chytrid fungus Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a disease that has been implicated in amphibian declines worldwide. Bd causes mortality in most species, but some are apparently resistant to the disease and thus may serve as reservoirs or vectors for movement of the pathogen to new populations. A number of projects in our lab focus on immunogenetic variation among species and/or populations, and the implications of that variation for susceptibility to chytridiomycosis.
A complementary interest in our lab focuses on the pathogen itself; Bd is widely distributed globally, and shows very different disease dynamics in different regions. We are testing hypotheses about the distribution and spread of Bd by using population genetic, phenotypic, and functional analyses of samples collected throughout the pathogen’s range.
CONSERVATION GENOMICS IN CHANGING LANDSCAPES
Our lab is interested in how anthropogenic habitat alteration impacts population persistence, population genetic diversity, and disease susceptibility in reptiles and amphibians. We are particularly interested in how habitat changes alter the genetic composition and connectivity among populations, how species-typical traits mitigate those effects, and how these types of information can be used to predict, and manage the impacts of continued anthropogenic change.