My name is Gayani Senevirathne. I am currently a Helen Hay Whitney postdoctoral scholar at Harvard University, in Capellini Lab. For my postdoctoral work, I am studying the underlying genetic and morphological patterns that gave rise to the unique morphology of the human pelvis. I use single-cell sequencing techniques (visium spatial transcriptomics, single-cell RNA and ATAC-sequencing) and integrative methods to understand in depth how the human pelvic girdle develops.

My research interests have always focused on understanding evolutionary novelties. Both as an undergraduate and as a Ph.D candidate, I focused on identifying novel patterns and processes during vertebrate development. As an undergraduate at the University of Peradeniya, Sri Lanka, I studied and compared the patterns of skeletal ontogeny in frog lineages across an island (Sri Lanka) and mainland (India) habitats. I analyzed a series of tadpoles of different evolutionary lineages (differentially stained for bone and cartilage) across developmental stages to observe the skeletal ontogeny and ossification patterns correlated with their habitat changes. I was also involved in fieldwork across the Sri Lankan and Indian subcontinent to identify new frog lineages.

I joined Professor Neil Shubin’s lab at the University of Chicago as a Ph.D candidate in 2016 to integrate genetics and cutting-edge techniques to study the underlying changes in evolutionary novelties. Anurans (frogs and toads) possess a unique body plan. The urostyle, one such structure that is unique to the frog body type, is a composite skeletal structure formed at the onset of metamorphosis. I developed a nearly complete developmental series from free-living larvae through metamorphs of Xenopus tropicalis, and studied the ontogeny of the urostyle, adapting clearing and staining techniques, histology, immunohistology, cell proliferation, and cell death. Following documentation of morphological changes, I identified genes and gene- regulatory pathways responsible for formation of the urostyle using RNA- seq and ATAC-seq approaches, respectively. Since formation of the urostyle coincides with metamorphosis, I also looked at the possible role of thyroid hormone in controlling formation of this structure, both morphologically and genetically, which helped me narrow down the genes directly regulated by the hormone. Finally, I tested the function of two candidate genes in development of the urostyle by using a functional assay (generating knockout animals). Through my dissertation work, I highlighted how the changes to an underlying ancestral gene regulatory network would eventually alter the phenotype and genotype, giving rise to an evolutionary novelty. This is one of the first detailed demonstrations of how regulatory developmental modulations underlie novelty.

After my PhD, I joined Capellini Lab as a postdoctoral scholar in 2021 to study the evolution of human bipedalism. The human pelvis is composed of four subelements (the ilium, pubis, ischium, and acetabulum), each quite different in morphology yet critical for human walking/ running and childbirth. I carried out single-cell(sc) multiomics and spatial transcriptomics to look at gene expression and chromatin accessibility at a single-cell resolution across the developing human pelvis.