I am interested in the genetic basis of phenotypic evolution and especially in evolutionary innovations – that is, the origin of new morphological structures, developmental processes, and genetic regulatory circuits. Although true novelties are relatively rare, they ultimately shape all the complexity and diversity we see in nature – from geological nutrient cycles that support life to human sentience that occasionally distinguishes us from other animals. Projects in our lab seek to reconstruct the origin of innovations at all levels of biological organization, from new functional elements in the genome to new genetic pathways to entire new organs. I haven’t done an honest day of lab work in a long time (although I still torture flies sometimes), so I live vicariously through my labmates’ projects.
The sex comb is a morphological structure on the first leg of some Drosophila males that consists of modified mechanosensory bristles. It is a recent evolutionary innovation and plays an important role in courtship and mating. I am interested in the genetic and molecular mechanisms underlying the origin of morphologically different sex combs. Novel interactions between HOX and sex determination genes seem to play an important role in sex comb evolution. The HOX gene Scr is one of the key genes responsible for the origin of this new sex-specific structure. Right now I am working on a detailed functional dissection and comparative analysis of the regulatory elements of the Scr gene in multiple Drosophila species. This research will yield insight into how morphological innovation evolves.
In spite of a shared genome, males and females can differ dramatically in form, physiology, or behavior. To better understand how the sexes develop different phenotypes from a nearly identical set of genes, my research focuses on the molecular origin of sex-specific gene regulation. I study female-limited color polymorphisms in the Drosophila montium clade and the genetic changes that produce discrete color morphs in females. Characterizing the genetic mechanisms through which sex-specific gene regulation arises will elucidate how sexually dimorphic traits evolve.
I am interested in the mode and tempo of transcriptome evolution. Through comparative RNA-seq I am investigating the relative rates of regulatory change, gene duplication, de novo origination, and coding sequence change causing the evolution and turnover of tissue transcriptomes.
One of the most astounding mechanisms of evolutionary innovation is the ability for functional genes to evolve de novo from “inert” DNA sequence. However, such a change must be accompanied by the regulatory framework to co
ntrol the new gene’s expression. l study whether new regulatory sequence is driving the expression of de novo genes in Drosophila melanogaster.
I am interested in parsing out how males and females of the same species use the same genes to create vastly different phenotypes. To directly observe this, I am looking at how the D. melanogastersex differentiation pathway alternatively causes sex comb formation in males and suppresses this structure in females.
The accessory glands are secretory organs found in the reproductive system of Drosophila males, and are considered to be functionally equivalent to the human prostate. Only two cell types, the primary and secondary cells, secrete products into the lumen of this organ, which are then transferred to the female during mating. While much is known about the function of these proteins in the female post-mating, little is known about development of these glands in the first place. Currently, I am studying cell fate specification in the accessory glands, and working on projects related to testes function, sex brush/comb evolution, as well as evolution of the female reproductive system.
I am interested in the links between molecular evolution and phenotypic evolution. I study these questions in the speciesDrosophila prolongata, males of which have forelegs with pronounced expansion of chemosensory bristles and a dramatic increase in relative size. I am investigating the enhancer evolution responsible for gene expression changes that underlie the chemosensory bristle expansion, the gene expression and protein sequence changes of chemoreceptor genes in these bristles, and the cellular processes during development that produce larger relative leg size.
Yige Luo is currently a second year Ph.D. student in the Population Biology Program, at the University of California – Davis, working under the supervision of Professor Artyom Kopp. Before joining Kopp’s laboratory, he received his Bachelor Degree in the Biological Science at Peking University. He is broadly interested in the molecular genetics and the ecological implications underlying evolutionary innovations, specifically the chemical comm
unication system of the model organism Drosophila. He is now focusing on the pheromone production system, trying to unravel the gene network responsible for its differentiation between species and understand the selection forces working in nature. Pushing forward his own research project, he is currently in need of undergraduate assistants
Whether it is the brightly colored feathers of the male peacock or the horns of male dung beetles, scientists have long been intrigued by sexually dimorphic traits. However, the molecular mechanisms responsible for the origin of these sex specific traits are not well known. I am studying the role of transcription factor doublesex (dsx) in the origin and diversification of the sex combs of the Drosophila melanogaster and obscura species groups and the sex brush of the Drosophila immigrans species group. I will be joining Mark Rebeiz’s lab for a postdoctoral position in Winter of 2017.
Almost 90 percent of all insect species are holometabolous, meaning they undergo a complete metamorphosis from larvae to pupa to adult. This life history is a derived state — earlier branching insects are hemimetabolous, meaning they undergo only a partial metamorphosis between juvenile and adult forms. I’m interested in using hemimetabolous insects as a developmental biology model to understand how various aspects of holometabolous insects evolved. Specifically, I am studying the sexual differentiation pathway in hemimetablous insects to understand how the genetic regulation of sex evolved in holometabolous insects like the fruit fly, honey bee, and silk worm.