Presenter : Ryan Loker
Mentor : Ingo Braasch
Major : Biology
Poster 26
Indian Hedgehog(IHH) is a signaling molecule that acts in several important developmental processes in vertebrates including gut, vascular, and skeletal development. Duplicated(paralogous) copies of the ihh gene have been retained in the teleost fish lineage, ihha and ihhb, following the teleost genome duplication(TGD). The mechanisms of evolution following a whole genome duplication are not completely understood, but one possible reason that ihh and many other duplicates remain in the teleost genomes is
that each paralog carries out essential sub-functions of the ancestral pre-duplication gene, following the Duplication-Degeneration-Complementation(DDC) model. Investigation of this mechanism requires characterization of the regulatory elements controlling expression of ihh genes in teleosts as well as the ancestral state, which can be represented using spotted gar(Lepisosteus oculatus), a member of a sister group to teleosts with an unduplicated genome. Here, we use a comparative genomics approach to compare the ge- nomes of several teleosts and gar in order to identify ancestral conserved non-coding elements(CNE) representing possible regulatory elements, and test their functionality in vivo using transgenic reporter constructs in zebrafish(Danio rerio). In addition to the insight of the evolutionary mechanisms, characterizing enhancers of ihha and ihhb will provide an opportunity to further characterize the role of these genes in developmental pathways, which are commonly conserved throughout vertebrates including humans.