Research

The evolution of eyes and light detection

Eyes have evolved independently numerous times, resulting in remarkable diversity in animals. Invertebrates in particular have extraordinary diversity in eye types, eye morphology, and color vision. Yet, the genes and expression patterns driving visual system evolution outside of model bilaterians remains largely unexplored. We use a multidisciplinary approach to investigate the molecular mechanisms underlying eye evolution in non-model invertebrates. This research will inform us about the conservation of genetic material between distantly related animals and the mechanisms leading to specialized tissues.

Previous Research: Phototransduction in Lepidoptera

Using Lepidoptera (moths and butterflies) we addressed the questions: 1) how representative is the Drosophila phototransduction  cascade for other insects? and 2) how similar are the cascades of diurnal butterflies and nocturnal moths? We found that between Lepidoptera and Drosophila, phototransduction genes were evolving by gene gain and loss. Within Lepidoptera, moths and butterflies had different cascades adapted to their light environments that were driven by differences in gene expression.

 

Ongoing research: The evolution of phototransduction cascades using Cnidaria

Cnidaria the group that encompasses jellyfish, sea anemones, and corals is sister to Bilateria thus studies in this group can inform us  about the evolution of genomes and gene function. Cnidarians use opsins for light detection,  and have evolved eyes multiple times independently. The incredibly regenerative Hydra, that lacks eyes but has light sensing behavior, has 45 opsin genes many of which may be evolving by tandem duplications. Our lab is interested in characterizing the opsins in cnidarians and investigating their functions.

Areas of interest:

  • How are opsin genes evolving across the Cnidaria phylum?
  • Where are opsins expressed? Which opsins are light sensing?
  • What are the gene regulatory networks for opsins?
  • How similar are the  phototransduction cascades across species?
  • Is there are ancestral phototransduction or sensory  cascade?

The evolution of regeneration and understanding regeneration competency

Tissue regeneration is a fascinating phenomenon in animals. regeneration competency, or the ability to regenerate varies widely between species and even cell types. Studies on tissue regeneration inform us about the healing process, cell fate regulation, and signaling pathways active in tissue healing and regrowth. Yet, the cellular composition and genetics controlling normal tissue development and regeneration remains unknown.  We use expression, regulation, and single cell genomics to investigate the regeneration program in Cnidaria, a sister group to Bilateria. This work will tell us to what extent the same genes and transcription factors are activated during development and regeneration. Comparing the regeneration programs between Cnidaria and early Bilateria will improve our understanding of the conservation and differences in transcription factors used and the gene networks regulating regeneration.

Regeneration in Hydra 

Hydra have an incredible regenerative ability, being able to regenerate head and foot when bisected, and to form polyps from cell aggregates. In Dr. Mortazavi’s lab, I collaborated with Dr. Rabi Murad to compare gene expression and cis-regulation of regenerating Hydra heads to developing heads during asexual budding. We found that gene expression trajectories were different with expression being much more dynamic during regeneration.
Ongoing research: Regeneration in Cnidaria
Our lab seeks to characterize the cellular and molecular mechanisms of eye regeneration  and development across species.
Areas of interest:
  • how similar is regeneration to development?
  • which  pathways are active during regeneration and when are they active?
  • what is the  crosstalk between different developmental pathways? is crosstalk conserved?
  • what are the cellular and genetic features that determine regeneration competency?
  • what are the roles of transposable elements in regeneration?