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Principle Investigator

James Dewar

James carried out his undergraduate studies at the University of Bath, England, and graduated in 2007 with First Class Honours in Molecular and Cellular Biology. He received his PhD in 2011 in yeast genetics from Newcastle University, England, before undertaking post-doctoral training in Johannes Walter’s lab at Harvard Medical School, where he became a Charles A. King Trust Fellow. In 2016, James joined the Vanderbilt Faculty as an Assistant Professor of Biochemistry. Since joining Vanderbilt, James has been a recipient of a Joe and Dorothy Brown Foundation award for research into healthy aging and is an American Cancer Society Research Scholar.

Outside of the lab, James is a devoted parent, low-key audiophile, and podcast addict.


Science Twitter Handle: @JamesMDewar


Graduate students

Tamar (‘Tata’) Kavlashvili

Tata graduated from the University of Iowa in 2017 with her Bachelor of Science with Honors in Cell and Developmental Biology and Clinical & Translational Science certificate. At Iowa, she carried out undergraduate research on a research fellowship for 3 years with Dr. Shujie Yang at Carver College of Medicine. She studied epigenetic regulation of progesterone receptor expression and its signaling in gynecologic cancers. As an undergraduate she published 2 articles and presented her research at 2 international conferences. In 2017, Tata joined the Vanderbilt IGP program and in 2018 joined the department of biochemistry as a graduate student in the Dewar Lab.

In her free time, Tata likes to ski when she gets a chance and run or bike when she doesn’t. She also enjoys cooking, hiking, drinking matcha lattes and spending time with her friends.


Sabrina Van Ravenstein

Sabrina graduated The University of Texas at Austin with a Bachelors degree in Biology Honors (B.S.A.) in 2018. While studying, she worked part-time as an Undergraduate Research Assistant for Dr. Kevin Dalby under the guidance of Dr. Tamer Kaoud for 3 years. In the Dalby lab she worked on small-molecule inhibitors for MAP kinases. In 2018, Sabrina joined the Vanderbilt IGP program and then joined the Dewar Lab in April of 2019. She currently works on the mechanisms of how topoisomerases and topoisomerase-targeting drugs affect DNA replication termination.

Outside of the lab, Sabrina can be spotted browsing the local farmer’s markets, baking sourdough, or trying to min-max her D&D character.

Science Twitter Handle: @sabrinadoessci1


Emma Vontalge

Emma graduated with honors from Iowa State University in 2020 with a degree in Biochemistry. During her time at Iowa State, Emma was an undergraduate researcher in the Sashital Lab where she developed an inducible protein dimerization tool using the CRISPR-Cas protein Cas6. Emma came to Vanderbilt through the IGP program and joined the Dewar lab in May 2021.

During her free time Emma enjoys working out, spending time with friends and family, exploring Nashville, and scrapbooking!


Sara Conwell

Sara received her B.A. from Vanderbilt University in 2020, double majoring in Molecular & Cellular Biology and Medicine, Health, & Society. During her undergraduate years, Sara worked as an undergrad. researcher in Dr. Katherine Friedman’s lab where she studied mechanisms of telomere maintenance and telomerase regulation. In 2020, Sara continued her studies at Vanderbilt, entering the Vanderbilt Interdisciplinary Graduate Program (IGP). Upon completion of her first year, Sara joined the Dewar Lab where she currently studies mechanisms of replication restart.

When she is not in lab, Sara likes to spend time with family and friends, explore new areas of Nashville, and watch trashy reality tv.


Steven Dahmen

Steven graduated from the University of California, Santa Cruz with a Bachelors degree in Biochemistry and Molecular Biology (B.S.) in 2020. He worked as an Undergraduate researcher for Dr. Camilla Forsberg under the guidance of Donna Poscablo for 1 and a half years. In the Forsberg Lab, Steven worked on characterizing a novel population of age-specific platelets in mice. In September of 2020, Steven joined the Zinkel lab at Vanderbilt University as a Research Assistant 1. In 2021, Steven joined the Vanderbilt IGP program and then joined the Dewar lab in 2022.

During his free time, Steven likes to play video games, play with his dog Sox, or enjoy the outdoors looking for new ant queens.


Research assistants

Stedman Stephens

Stedman graduated from Freed-Hardeman University (FHU) in Henderson, TN with a B.S in Biology with Honors. At FHU, he worked under the guidance of Dr. Caleb Kersey with bacteria P. carotovorum which causes root rot in vegetables. Stedman worked with mutant variants of P. carotovorum to understand how mutations in various areas caused hyper virulence. Stedman joined the Dewar Lab as a research assistant and currently investigates telomere function.


Lab Alumni


Name Position in lab Grad Year Current Position
Darren Heintzman Research Assistant 2019 PhD Candidate, Molecular Pathology and Immunology, Vanderbilt University Medical Center
Lillian Campos Post-doc 2022 Senior Scientist, Proof Diagnostics