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Department of Biology

Renn Lab

Fish 'N Chips: Comparative Functional Genomics in African Cichlid Fishes. The evolution of behavior.

Research Interests

Come visit my lab and I will tell you all about our research interests.

I work in both the field and the lab in order to study the evolution of behavior and also the role of behavior in evolution. We use modern genomic techniques in a comparative approach to reveal modularity of gene expression that underlies the modularity of behavioral phenotypes.

          Current Research at Reed College

Molecular modules of aggression; maternal behavior in the African cichlid Astatotilapia burtoni Abstract funded by NSF BIO-Neural Systems.

While aggressive, territorial, socially regulated dominance behavior in the males of this species has been a long standing and fruitful model for the mechanistic study of mechanisms underlying complex behavior, few studies have investigated female behavior. This is, in part, due to the fact that the labstock females, collected in 1977 do not show many interesting social behaviors. However, a recently collected wild stock of this same species exhibits a rich repertoire of aggressive and maternal behaviors. I aim to use this model to uncover molecular, hormonal and genetic mechanisms responsible for these behaviors and the differences between the two stocks.

Mechanisms for Environmental and Genetic Reversal of Gender Biased Beahvior Project Description funded by NIH - NIGMS through the R15 AREA program.

The great influence of sex on the brain is undeniable at the level of neuroanatomy, neurochemistry, brain function, and even behavior. The proposed systems level research integrates data from behavioral, physiological and molecular level in order to contrast mechanisms by which genes and the environment influence gender-biased behaviors and identify neuroanatomical sites important for the regulation of these behaviors. I use an animal model (cichlid fish) to study complex social behaviors that are directly relevant to the broad range of normal sex-related differences in human social behaviors as well as psychiatric conditions that show both genetic and environmental components. We rely primarily upon two species of the genus Julidochromis, one that exhibits conventional sex-role behavior and one that exhibits characteristics of s

ex-role reversal. Furthermore, by manipulating the relative size ratio between males and females these species can be induced to switch gender biased behaviors. This allows us to investigate the molecular and hormonal mechanism that orchestate these behaviors.

Identification of rapidly evolving genes among Tanganyikan cichlids using heterologous Comparative Genomic Hybridization (hCGH). Project Summary -- Funded by M.J. Murdock Charitable Trust; Life Sciences Award)

I am proposing to use our cDNA microarray as tool to look for rapidly evolving genes among the various cichlid species.  This is different than the "traditional use" of a cDNA microarray in which you isolate RNA and hybridize that to the array in order to measure relative level of gene expression.  In the proposed experiments I will be labeling genomic DNA from 2 different species and competitively hybridizing that to the array (one will always be the species from which the array was made, A. burtoni). If the two species have exactly the same genomic sequence for a gene (represented by a single spot on the array) then one would expect to find a 1:1 ratio of fluorescent signal (equal hybridization strength).  But if the gene in one animal is highly diverged the hybridization ratio will be highly biased toward the species from which the array was made.  Conversly if the gene has been duplicated in the other species (referred to as the "heterologous species") then the hybridization ratio will be biased toward that species.  This array work will be validated through Quantitative PCR and gene cloning for sequence analysis.

 

           Past Research (still continued)

Natural Sex-role reversal among species of the genus Julidochromis: behavior, and ecology. (proposal funded in part by A.C.A.)

Molecular basis of socially regulated male aggressive behavior in the established A. burtoni model species. (video excerpt from The Body Changers; National Geographic) -- Manuscript in press --

Molecular basis of experimentally induced sex-role behavior in females of the established A. burtoni model species. (recent poster) -- Manuscript in Prep
-- In collaboration with Eleanor Fraser (Harvard student, senior thesis)

hCGH technique proof of principle using several sequenced species of Drosophila in order to understand the relationship between hybridization ratio and characteristics of genomic divergence. -- Manuscript in Prep
-- In collaboration with Rob Kulathinal (Fly Base)

Molecular mechanisms of genetic (natural) and environmental (temperature) sex differentiation in the aquaculture tilapia cichlid species. (J.E.B. funded proposal t o H. Lequang) -- Manuscript in Prep
-- In collaboration with Hao Lequang, Helena D'Cotta and JF Baroiller (CIRAD)

Sex Determination in African Cichlids: Genetic, or Environmental (social regulation) ?
-- In collaboration with Jasmine Christell Dowell (Harvard Student, HCRP project)

 

Acknowledgements: 

I am grateful for the support of my former advisor and current collaborator Hans Hofmann as well as other members of that lab, Nadia Aubin-Horth, Daphne Soares, Nina Duftner, Jonah Larkins-Ford, as well as the students who worked in the lab. These projects have been funded by Reed College, NSF, NIH, WISC, ACA, JEB and the Bauer Center.