Department of Biology

Lab

Myers Hall 100
(812) 855-8821
Ragsdale Lab website

Awards

Alexander von Humboldt Fellowship, 2011-2013
Erasmus Mundus Scholar, 2010

Research

My research focuses on the role of developmental mechanisms in the evolution and diversification of form, using nematode worms as a tractable laboratory model. Nematodes lead virtually every lifestyle known to animals and include microbivores, omnivores, predators, and parasites of insects, vertebrates, and plants. The diversity of nematode mouthparts bears testament to this remarkable ability to specialize. I seek to unravel the mechanisms underlying such morphological diversification by integrating developmental biology, genetics, population genetics, phylogenetics, and natural history.

My lab uses the nematode Pristionchus pacificus as a reference point and central model, and focus is on the genetic basis of developmental plasticity (polyphenism) in its mouthparts. After an irreversible decision in larval development, the nematodes assume one of two distinct feeding-forms. This dimorphism involves an evolutionary novelty of the adult stage: teeth, which enable predatory feeding on other nematodes.

The ability to produce different phenotypes from a single genotype is increasingly considered as a facilitator of novelty and diversity. Using the sophisticated analytical toolkit available for P. pacificus, I study the mouth plasticity to identify the genetic program for executing a morphological novelty and to understand the significance of such a program in evolution.

A few goals of this research include:

1. A detailed genetic understanding of the regulation of developmental plasticity;
2. To know how regulators of plasticity diverge to produce new phenotypes;
3. To use a polyphenism as an inroad to discover the genes that build morphological novelties.

In research funded by the National Science Foundation, my lab is using forward genetics to reconstruct the genetic pathway for a polyphenism switch and revealing how this switch has appeared and changed across lineages. Furthermore, we are using inference-based and reverse genetics approaches to understand the evolution of "plasticity genes" and their targets. In summary, my lab combines developmental genetics with comparative and phylogenetic approaches to understand the mechanisms and evolution of developmental responses to the environment.

Research Areas

Developmental Mechanisms and Regulation in Eukaryotic Systems
Evolution
Genomics and Bioinformatics