Ph.D., Biology. Max Planck Institute for Developmental Biology, Tübingen, GermanyResearch Interests:
I am fascinated by how biological diversity and evolutionary novelty are generated in nature. As a cellular and developmental biologist, I study how development gets tweaked over evolutionary time, and I do this using an interdisciplinary approach. To minimize existing sampling biases in the evo-devo field and to gain fresh insights into biology, my approach has involved establishing and working with new, unconventional invertebrate model systems.
In the Extavour lab, my work primarily focuses on the evolution and development of reproductive and nervous systems. I study the developmental function evolution of an insect-specific gene called oskar. Almost four decades worth of work on oskar has focused on its role in the context of the germ line – it was known only as a germ line determinant that acts as a nucleator for germ plasm assembly in higher insects such as Drosophila (where this gene was first discovered). However, our lab has shown that oskar is not limited to higher insect genomes (as was previously believed), and is present even in basally-branching insects, albeit with a somatic role in nervous system development, and surprisingly no role in the germ line. I study this somatic role of oskar in adult neural functioning using the upcoming evo-devo model, the cricket Gryllus bimaculatus, that we have helped establish. This work elucidates how genes like oskar arise, and how genes and gene modules get co-opted for new developmental roles across evolutionary time scales in animals. In addition, I am also involved in molecular evolution studies on various Arthropod species that look at the role of male and female tissues on genome sequence evolution using a comparative genomics approach. Insights from these studies inform our understanding of how genomic complexity arises in animals.
Outside of the lab, I have served as a HGWISE mentor to 6 Harvard graduate women in STEM (2018-present), as an eLife Community Ambassador (2019-2020), and as a postdoc representative to 100+ postdocs at the Dept. of Organismic and evolutionary biology (2018-2020) at Harvard.Selected Publications:
Whittle, C.A., Kulkarni, A., Chung, N. and Extavour, C.G. (2021) Adaptation of codon and amino acid use for translational functions in highly expressed cricket genes. BMC Genomics, https://doi.org/10.1186/s12864-021-07411-w
Whittle, C.A., Kulkarni, A. and Extavour, C.G. (2020) Sex-biased genes expressed in the cricket brain evolve rapidly. bioRxiv, https://doi.org/10.1101/2020.07.07.192039.
Kulkarni A., Lopez DH and Extavour CG (2020) Shared Cell Biological Functions May Underlie Pleiotropy of Molecular Interactions in the Germ Lines and Nervous Systems of Animals. Front. Ecol. Evol. 8:215. doi: 10.3389/fevo.2020.00215
Whittle, C.A., Kulkarni, A. and Extavour, C.G. (2020) Absence of a faster-X effect in beetles (Tribolium, Coleoptera).G3: Genes, Genomes, Genetics, doi:10.1534/g3.120.401074
Whittle, C.A., Kulkarni, A. and Extavour, C.G. (2020) Evidence of multifaceted functions of codon usage in translation within the model beetle Tribolium castaneum. DNA Research, 26(6): 473-484
Kulkarni, A. and Extavour, C.G. (2019) Chapter 8: The Cricket Gryllus bimaculatus: Techniques for Quantitative and Functional Genetic Analyses of Cricket Biology. Results and Problems in Cell Differentiation, Volume 68: Evo-Devo: Non-model Species in Cell and Developmental Biology (edited by Waclaw Tworzydlo and Szczepan M. Bilinski), 68:183-216
Kulkarni, A. and Extavour, C.G. (2017) Convergent evolution of germ granule nucleators: a hypothesis. Stem Cell Research, 24: 188-194
Kulkarni A., Dyka A., Nemetschke L., Grant WN and Streit A. (2013) Parastrongyloides trichosuri suggests that XX/X0 sex determination is ancestral in Strongyloididae. Parasitology 140(14):1822-30
Kulkarni A., Holz A., Roedelsperger C., Harbecke D. and Streit A. (2015) Differential chromatin amplification and chromosome complements in the germ line of Strongyloididae (Nematoda). Chromosoma July 24, pp 1-12 * Cover Article *
Kulkarni A., Lightfoot J.W. and Streit A. (2015) Germline organization in Strongyloides nematodes reveals alternative differentiation and regulation mechanisms. Chromosoma 125(4): 725-45
Hunt V., Tsai I. J., Coghlan A., Reid A. J., Holroyd N., Foth B., Tracey A., Cotton J. A., Stanley E., Beasley H., Bennett H., Brooks K., Harsha B., Kajitani R., Kulkarni A., Harbecke D., Nagayasu E., Nichol S., Ogura Y., Quail M., Randle N., Ribeiro D., Sanchez-Flores A., Hayashi T., Itoh T., Denver D., Grant W.N., Lok J.B., Murayama H., Wastling J., Streit A., Kikuchi T., Viney M., Berriman M. (2016) The genomic basis of parasitism in the Strongyloides clade of nematodes. Nature Genetics48(3): 299-307