Department of Biology
Student Project Ideas
These pages include scientific ideas that supplement my own research interests. I provide a short summary and a few references but students are encouraged to propose independent ideas.
- Genetic Basis for Maternal Behavior in A. burtoni * (several projects)
- Natural vs. Environmental Sex-Role Reversal among Julidochromis species * (several projects)
- Identification of Rapidly Evolving Cichlid Genes with hCGH *
- Proof of Principle for hCGH using Drosophila melanogaster (related to project 3)
- Sex Determination in African Cichlids
- Data Imputation with cDNA Microarray Data
- Assortitive Mating by Cichlid Populations
- Blue fish / Yellow fish
- Bioinformatics (several projects available)
- Genomic Resources for Cichlids - complete 2006 Robby Kunkle
(* indicates ongoing projects that are a main focus in our research)
Student Project Idea 2
Natural vs. Environmental Sex-Role Reversal among Julidochromis species.
NIH - Funded Project
The complex social behaviors (gender-roles) that we are studying 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. This is a large research project intended to provide an integrated understanding of the mechanisms by which both genes and the environment can influence gender biased behaviors. We will quantify and characterize behavioral reversals, correlate these measures with hormone levels and construct a covariance network that includes multi-level phenotype data from gene expression, hormones, and behavior in order to contrast the enivornmental and geneitc influences on behavior. This project will require the co-ordianted efforts on multiple student project.
There are three main aims described below. Each aim will assess the relative
influence of genetic and environmental factors at different levels of
the phenotype. Each aim (behavior (aim1), hormones (aim2) and gene expression
(aim3)) will utilize the following three gender bias paradigms.
Paradigm 1 Natural pair-bonded males and females of a conventional gender biased species, J. transcriptus
Paradigm 2 Pair-bonded male and female J. transcriptus under manipulation of the social environment to induce "gender-bias reversal."
Paradigm 3 Natural pair-bonded males and females of a "gender-bias reversed" species, J. marlieri. The robust reversal of gender roles is clearly under genetic influence of this species' genome and represents a model for an extreme variation within a population.
Aim 1 To use calculated behavioral indices of gender-bias for males and females under conventional, environmental reversal and genetic reversal to compare the phenotype details as altered by reversal.
With a universal ethogram, including multiple gender biased behaviors, I will quantify male and female behavior in three paradigms outlined above. The relative level of specific behaviors will determine an index of parental care, territory defense, aggression, and submission. Because these animals exhibit a monogamous bi-parental strategy, we expect that each sex will demonstrate components of each index regardless of the paradigm but that the exact profile of that index will reflect the gender bias. The indices will then be compared between paradigms to test the hypothesis that environmental and genetic reversals of sex-role are fundamentally different at the level of behavioral phenotype.
Aim 2 To determine if steroid hormone levels are altered
to the same degree by genetic and environmental gender-role reversal.
I will measure physical traits related to condition and reproduction as well as circulating levels of three related steroid hormones (Testosterone, 11KT, Estrogen) for males and females under the three paradigms described above. Hormone levels and physical traits from individuals of the same sex within a single paradigm will be correlated with the behavioral indices (aim1) in order to determine which behaviors are most tightly coupled to physiological measures. This correlation analysis will test the hypothesis that changes in the physiological measures for an individual are correlated with different changes in behavior indices of that individual depending on the mode of the reversal (genetic vs. environmental).
Aim 3 - To construct gene networks of co-expression
based on covariance with behavioral and physiological measures in each
of the three gender-role paradigms. The network modulation induced
by environmental gender-role reversal will be contrasted with that induced
by genetic gender-role reversal.
Beyond the direct identification of subsets of genes that co-regulated according to gender role independently of sex, microarray data will also be interrogated at the level of the individual. This approach will capitalize upon individual variation within a sex and within a paradigm. I will structure the gene expression variation among individuals according to strength and direction of correlation with the individual behavioral indices (aim 1), physical factors (aim 1) or hormone titers (aim 2). This systems level analysis will be used to build a network of gene interactions for each sex in each gender bias paradigm. These networks will then be evaluated for genes, or groups of genes, whose expression underlies specific aspects of the higher order phenotypes. Bioinformatic integration of these networks with gene annotations can be used to identify functional modules that are affected by either environmental or genetic factors and identify mechanism of gender biased behavior.
- Awata, S., Kohda, M. (2004) Parental roles and the amount of care in a Bi-parental substrate brooding cichlid: the effect of size differences within pairs. Behaviour 141, 1135-1149.
- Barlow, G.W. Lee, J.S.R, (2005) Sex-reversed dominance and agression in the cichlid fish Julidochromis marlieri. Ann Zol. Fenici 42.
Aspects of the Project:
Create a universal "ethogram" for different Julidochromis species
Manipulate social environment to determine if sex-role behavior is plastic in all Julidochromis species.
Little is known about the hormone levels throughout the reproductive cycle of these species.
Use cDNA microarrays to analyze gene expression in the brains of males vs females both within and between species.