Elizabeth P. Derryberry, Ph.D. - US grants

This Major Research Instrumentation award funds the acquisition of a high-throughput capillary sequencer and related instrumentation to enhance research and educational programs at Tulane University and partner institutions in the greater New Orleans metropolitan area. The instrumentation will build on university and departmental strategic investments and major realignments in support of environmental research and educational initiatives. By providing cost effective high-throughput capacity for acquisition and analysis of locus-specific, multi-individual DNA sequence data and multilocus genotype data, the instrumentation will greatly expand shared-use genomics infrastructure available to university faculty, staff and students. The instrumentation will therefore meet steadily growing demands from expanding research and training programs emphasizing use of molecular techniques to address questions in ecology, evolutionary biology, and related environmental science disciplines.

Acquisition of a high-throughput DNA sequencer and supporting instrumentation will serve competitively funded research programs at Tulane University and partner HBCU institutions (Xavier University, Dillard University, Southern University at New Orleans) and institutions serving large minority populations (University of New Orleans). The instrumentation to be acquired includes an ABI3730xl DNA Analyzer with a computer control system and a Franek FT1-B3730X-DA uninterruptible power supply. This instrumentation will support a rapidly expanding user community, including core users undertaking studies on topics such as molecular phylogenetics of freshwater fish and Neotropical birds, the evolutionary ecology of plant-animal interactions, speciation genetics, microbial remediation of contaminants, and the development of genetic methods for environmental assessment.

Ready access to high-throughput capacity will accelerate the pace and scale of research and training at Tulane and partner institutions, which will immediately increase the number of faculty and investigators able to pursue leading-edge research. By helping bridge disciplinary research programs, particularly those in the biomedical and environmental sciences, it will support university-wide and cross-university initiatives to establish national research centers in New Orleans. Expanded capacity also will broaden opportunities for classroom and mentored research training in STEM fields, including NSF-funded programs intended to advance participation of underrepresented groups in environmental biology.

Darwin's finches of the Galápagos Islands stand as one of the most impressive examples of evolution. After colonizing the islands, a single ancestral finch species eventually diversified into 13 species of different sizes, bill shapes, and ecologies. The suboscine passerine birds exhibit a similar history, but their diversification was not limited to a small set of islands; instead they are found throughout South America, Central America, North America, and parts of the Old World. There are now 1,300 species that differ dramatically in body shape and size, feeding behavior, and nest architecture. The primary goal of this project is to use DNA sequences to reconstruct the evolutionary history of these species, and to use this model system to investigate why the tropics are so biologically diverse.

A vital component of this collaborative project between U.S. and Brazilian scientists is the research training it will provide. With fieldwork planned in Argentina, Chile, Costa Rica, Malaysia, Venezuela, and Viet Nam, young scientists from a diversity of countries will be exposed not only to a diversity of natural environments but will also interact and forge relationships with their international peers. By working together to reconstruct perhaps the most spectacular evolutionary radiations of birds in the world, the researchers will learn how evolution works on a continental scale while training a new generation of scientists.

Cities are recent environments for most organisms; yet little is known about the adaptations of species that persist in urban settings. A recent surge of interest in acoustic communication in urban contexts highlights a potential adaptation of birds to life in many different cities. These studies have raised several fundamental questions regarding this potential adaptation, which have global applications to studies of animal communication and mate selection. This proposal will address three of these fundamental questions: (1) how are birds adjusting their song to the urban environment?; (2) how has song urbanization affected signal information?; and (3) are urban songs adaptive? To address these questions, this study will employ behavioral, ecological and mechanistic modeling approaches, using an established NSF model organism for behavioral studies, white-crowned sparrows. Meeting the proposal's objectives will transform the state of understanding of urban-dependent selection on mating behaviors and, more broadly, the adaptations of species that persist in urban environments. There are several aspects of the proposed study that should yield broad impacts: (1) broad dissemination of research results through community organizations, local and national museum displays, media outlets, and development of learner-centered teaching modules, (2) research opportunities for students from demographic groups that are under-represented in the sciences, (3) development of a statistical software package for simulating bird song evolution, and a workshop to train scientists, educators, and students in its use, and (4) collaboration and sharing of data with the National Park Service Sound Division, which will help national parks local to this study as well as national parks nationwide with their sound management plans.

Hybridization, the breeding of two separate and distinct species, has the potential to merge two species into one when hybrids are fairly healthy, or keep the species separate when hybrids fare poorly. In western Panama, where the species ranges of the tropical shorebirds known as Northern Jacanas and Wattled Jacanas meet, they form a hybrid zone. Jacanas exhibit mating role reversal where females control access to mates by competing for territories encompassing a harem of males, and males provide all parental care. The unusual circumstance of hybridization between species with such a unique mating system offers a window into examining why and how species-specific boundaries to mating fail, from a female perspective. Genetic and experimental evidence suggests that differences in aggressive behavior between the species may explain patterns of hybridization. Females of the more aggressive species produce the majority of hybrid offspring. The proposed research employs techniques to assess the expression of genes to examine variation in aggressive behavior between the hybridizing species. This research addresses a fundamental question in ecology, evolution, and behavior what is the genetic basis of behavioral differences? This can 1) improve our understanding of the behavioral mechanisms important in species formation, and 2) provide insight into the genetic mechanisms underlying behavioral differences between males and females. Understanding of science and research will be communicated through workshops with local school aged children and ecotourists at the Panamanian field site.

Between recently diverged species, mating behavior can either impede or promote reproductive isolation. Theoretical and empirical evidence demonstrates this for female mate choice and male competition, but little is known about the relative roles of each. Female aggression has only recently been recognized as an adaptive behavior, and how its underlying mechanisms compare to those of males is not well understood. A key step towards understanding the evolutionary significance of the competitive phenotype in females is determining its underlying genomic mechanisms. The goal of the proposed research is to elucidate the molecular basis of the female competitive phenotype by identifying clusters of candidate genes whose differential expression is responsible for consistent variation in aggressive behavior. This study combines aggression assays with a transcriptomic approach to address this question in role reversed, hybridizing Northern Jacanas (Jacana spinosa)and Wattled Jacanas (J. jacana) in Central America. This project is novel with respect to understanding the mechanisms by which phenotypes change as role reversed species diverge, which could advance our understanding of how organisms respond and adapt to changing environmental selection. By identifying how the genes underlying aggression are differentially expressed between role reversed females and males, the proposed research will expand upon general principles in sexual selection theory that have been developed in well-known male-dominant systems. Furthermore, this project investigates the genetic underpinnings of complex behavioral traits in wild, free-living, non-model organisms, which is vital for understanding the evolution of ecologically relevant phenotypes under natural conditions.