NSF Postdoctoral Fellowship in Biology FY 2018

Ramirez Merce D, Amherst MA

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2018, Broadening Participation of Groups Under-represented in Biology. The fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. A fundamental goal in evolutionary biology is understanding how diversity in the form and function of organisms arises. Species differences in neural circuitry, i.e. wiring between neurons, are thought to be important for diversity in animal behavior. But the specific molecular changes that underlie divergence of neural circuits in different species is not known. This research aims to identify changes in gene expression within single neurons that cause divergent connectivity in the neural circuits underlying the swimming behaviors of two sea slug species. The neurons, neural circuits, and behaviors of these relatively simple animals are easily and directly comparable, making them uniquely suited to address this question. One way that neurons are connected is through direct electrical transmission mediated by structures called gap junctions, which are common to all nervous systems. This project investigates how species-specific patterns of connectivity arise, providing insight into the evolution of neural circuits underlying behavior. During this project, the Fellow will participate in multiple activities for broadening representation in biology, including mentoring students from underrepresented backgrounds, and creating an interactive, field observation based outreach module aimed at K-8 students from surrounding communities. The sea slugs Dendronotus iris and Melibe leonina are nudibranch molluscs that swim using an alternating homologous left-right motion. Furthermore, the neural circuits underlying this simple behavior are composed of homologous neurons, which are electrically coupled in species-specific patterns. The hypothesis being tested is that differences in expression of innexins in homologous neurons are responsible for the species differences in neural connectivity. The Fellow will learn a number of techniques to determine the role of innexins in species-specific patterning of electrical synapses, including single neuron RNA sequencing, single neuron quantitative real-time PCR, in situ hybridization and electrophysiology combined with RNAi and injection of synthetic mRNA. The outcomes of this project include more than 70 complete, single neuron transcriptomes with corresponding electrophysiological recordings, an innexin phylogeny, and in-situ hybridization to localize and compare innexin expression between neurons within the neural circuit for each species and between homologous neurons. The Fellow will also receive training in mentoring diverse students and directly mentor undergraduates in the lab as part of the STEM Ambassadors program at UMass. Finally, the Fellow will create a K-12 outreach module called "Wonder in a drop of water", where students from local schools will visit the UMass pond, explore invertebrate diversity using small portable microscopes to make field observations. This outreach module will be taught by 3rd year undergraduates from STEM Ambassadors, developing their own mentorship and leadership skills through outreach. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.