In the broadest terms, I am interested in whence new biological functions arise and how they evolve. My works approaches these questions at the molecular level through the study of recently evolved, or young, genes.
Young genes are defined as loci that came into being within the last few million years and therefore are only present in a particular subset of species within a given taxonomic group. Most of these young genes arose through some kind of duplication mechanism, by which an extra copy of an already existing gene is generated. The recent origin of these genes makes them excellent candidates for the study of how new biological phenomena arise and evolve since the molecular signatures and functional consequences of their evolution have not yet been totally obscured by the long march of geological time. Furthermore, since young genes are only present in a few species of a given genus, this creates opportunities to use comparative methods to detect differences between closely related species that either do or do not have the new loci. Most of our work in Manyuan Long’s laboratory focuses on these young genes in the fruit fly genus Drosophila because of the wealth of experimental and computational tools available in this group.
The majority of my graduate study has focused on a recently arisen Drosophila gene called Zeus. The Zeus gene arose via a type of duplication called a retroposition approximately 5 million years ago on the lineage leading to Drosophila melanogaster, the classic model organism, and its closest relatives. Thus far, we have discovered that after a period of very rapid molecular evolution, Zeus acquired crucial roles in the development and function of the male reproductive system in fruit flies. Furthermore, at the molecular level, Zeus seems to be acting as some sort of regulatory protein, interacting with a large network of genes across the genome. The study of this gene has therefore opened up new possibilities to shed light on precisely how a new gene, after its initial origination, integrates into a network of gene-gene interactions to influence the phenotype of an organism. My ongoing work uses a genome-wide approach to map this network of Zeus targets not only in Drosophila melanogaster, but also in its sister species, Drosophila simulans. These experiments will thus allow us to understand the tempo and extent to which these functional gene networks evolve over relatively short timescales. I am also working on mapping the targets of Zeus’s parent gene, Caf40, in order to gain insights into how Zeus’s function has diverged and become unique since its origination.