Department of Biology

Lab

Myers Hall 100
812-855-7773
Ledón-Rettig Lab website

Awards

Indiana University Provost's Travel Award for Women in Science, 2015
NSF Postdoctoral Research Fellowship, 2011-2014
NSF Graduate Research Fellowship, 2006-2009
University Merit Scholarship, UNC Chapel Hill, 2005-2006

Research

Historically, there has been much thought as to how an individual's environment and ecology (e.g., its resources, competitors, predators and symbionts) influence them, both developmentally and evolutionarily, to produce adaptive traits. However, it is still unclear how—and in what situations—the environment plays a creative role in phenotypic evolution. Thus, my research goals are driven by these two questions:

1. How do environmental and endogenous signals interact to generate novel phenotypic variation? and
2. What are the ecological and evolutionary consequences of this variation?

To answer these questions, I use wealth of approaches and a diversity of animal systems including nematodes, beetles and frogs. For instance, spadefoot toads (which are, in fact, frogs) are an excellent system for understanding the role of cryptic genetic variation in adaptation. Organisms may harbor a considerable amount of genetic variation that is, under typical environmental conditions, hidden from selection (i.e., cryptic genetic variation). Under certain conditions, this genetic variation becomes phenotypically expressed, creating fitness variation among individuals in a population. If, by chance, any of this variation improves an organism's viability in the inducing environment, and they recurrently experience this environment, then genetic modifiers that favor the expression of such variation will increase in the population (i.e., genetic accommodation). My research with spadefoot toads seeks to understand how cryptic genetic variation accumulates, when it is released, mechanisms that mediate its expression, and how it is selected to yield adaptive and sometimes novel traits.

Other environment factors that may influence the fitness of individuals include closely associated species. Most animals exist in species partnerships (symbioses) such that their health is fundamentally multi-organismal in nature. However, it is intrinsically hard to characterize how symbiotic interactions influence both developmental and evolutionary change. I have developed a convenient system—dung beetles and their associated nematodes—to characterize symbiotic interactions at a genetic level. Dung beetles create developmental chambers that are rich with other organisms (e.g., bacteria and fungi) that can influence the fitness of their offspring. Interestingly, mother dung beetles also transmit a nematode to these developmental chambers that helps their offspring grow and suffer less mortality. Using manipulative experiments, I am sequencing the bacterial and fungal communities of these brood balls to determine if, and how the nematodes are modifying the developmental conditions of their host's offspring. Further, I am comparing different populations of beetles that have different, recent, evolutionary histories with antihelminthic drugs in order to determine how host adapt, or fail to adapt, to the loss of their symbionts. By revealing the genetic underpinnings of this "interspecific epistasis," this research will enhance our understanding of how species partnerships influence organismal development and evolution, an unaddressed yet critical question in biology.

My research benefits greatly from the many resources available at Indiana University, in particular the Center for Genomics and Bioinformatics, which has allowed me to include transcriptomic and metagenomics approaches into my research. Further, I benefit from close colleagues who are interested in evolutionary developmental biology (evo-devo), ecology, behavior, systematics and evolution.

Other research interests of mine are:

• How sex, tissue identity and environmental conditions interact to create phenotypic variation
• The role of environment-dependent epigenetic variation in local adaptation, and how we can use molecular tools to assess this variation in natural populations

Research areas

Behavior
Ecology
Evolution