What’s got zebrafish in a Twist? - Louis Balas
One of the many wonders of biology is the immense biodiversity of the natural world. Anyone can walk outside right now and encounter all different forms of life: large arching trees, shiny armored bugs, furry four-legged creatures, soaring birds, and microscopic critters invisible to the naked eye. What encodes for this biodiversity? What mechanisms at the cellular and molecular level cause indeterminate single-celled zygotes to develop into drastically different organisms?
My fascination with these questions led me to pursue an undergraduate honors thesis with the Medeiros Lab, where I am attempting to help us understand how vertebrates evolved to obtain neural crest cells. This novel cell type is a key player in the development of the head skeleton – a key differentiator between vertebrates and invertebrates.
We think that the recruitment of a family of genes called Twist genes to the neural crest cell developmental program in ancestral vertebrates played a key role in the innovation of the vertebrate head skeleton. However, how twist genes were recruited to this developmental program is not understood. My project investigates how mutations in non-coding DNA regulators (cis-regulatory elements) of Twist genes may have facilitated the recruitment of Twist genes to the zebrafish neural crest. To do this, I am computationally identifying these cis-regulatory elements and testing their influence on neural crest development with transgenic reporter assays.
It is my hope that this project can give us insight into how novel cell-types emerge, further define the logic of cis-regulatory sequences, and refine the use of transgenic tools for cis-regulatory sequence identification. As a senior in MCDB who is interested in EBIO and molecular biology, pursuing this honors thesis project has served as a way for me to investigate my passions and develop key technical and soft skills essential for the endeavoring researcher.
