We are broadly interested in genomic and epigenomic studies of regulatory evolution. We have built up expertise in evolutionary epigenomics, and we study diverse systems to pursue specific research questions. Here are some of our current research interests.
Comparative Genomics and Epigenetics of Human Brains:
The human brain is a fascinating example with numerous occurrences of evolutionary innovation at multiple levels: the unprecedented expansion of its size, the histological and structural remodeling, the molecular level changes such as gene and protein expression profiles. How did human brains achieve such dramatic evolutionary changes in a relatively short geological time is a long-standing question for many evolutionary biologists. In addition, it is becoming clear that some human specific phenotypic traits and disorders can be better understood by elucidating their evolutionary origins. We study the genomic and epigenomic modifications of human brains during evolution, and how they impacted specific traits and regulatory modules in brains. We recently completed a study of DNA methylation changes along human brain evolution. We are also interested in how epigenetic marks regulate and/or propagate traits such as cognition, neuropsychiatric disorder, and plasticity of human brains. Our current research includes epigenetic analysis of brains from schizophrenia patients.
Ecological and Evolutionary Epigenomics:
Epigenetic mechanisms are widespread throughout the tree of life, but its components and how each component interact with each other vary greatly across different taxa. For example, genomic patterns of DNA methylation in invertebrate animals differ greatly from those of vertebrates. We investigate variation of epigenetic regulation across the genome and among species, and functional consequences of such variation. A major focus of our current research is to investigate how DNA methylation changes in response to system-wide perturbation (such as disease or ecological changes), and to understand the implications of such changes at the phenotypic level.
Linking Genomes and Phenotypes:
In collaboration with Dr. Donna Maney at Emory University, we are investigating how a prevalent chromosomal polymorphism in the white-throated sparrow (Zonotrichia albicollis) leads to two distinctive phenotypes. In this species, social behavior and plumage morph has been affected by an inversion polymorphism on chromosome 2. Individuals homozygous and heterozygous for this inversion exhibit contrasting patterns of behavior at many levels, including response to aggression, parental care, and extra-pair copulations. Because it predicts social behaviors, the inversion represents a powerful tool for understanding how genetic sequence encodes complex phenotypes. In collaboration with Dr. Maney’s lab, we are investigating genetic differences between the inverted and non-inverted chromosomes and how we can connect the genotypic differences to phenotypes. The long-term goal of this research is to understand how naturally occurring, heritable changes in genetic sequence have large, downstream effects on complex behavioral phenotypes.