Skip to main content


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

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.


Aiyana Cyr

Aiyana graduated from the University of Connecticut in 2022 with a BS in Molecular and Cellular Biology and a minor in womens gender and sexualities studies. During her undergraduate education, Aiyana did several internships at Litron Laboratories and Pfizer designing genetic Toxicology assays to study dna damaging compounds. She also worked in the Giardina lab studying the dna damage response in colon cancer, specifically looking at 53BP1 mitotic stress bodies and differences in immune cell sequencing profiles in colon cancers diagnosed early vs late in life. Her research was presented at several poster sessions and she published one first author paper as well as a second author paper. She entered graduate school through the IGP program at Vanderbilt University and joined the lab of James Dewar in May of 2023.

When she is not in lab she enjoys activism regarding intersectional feminism and disability justice. She also enjoys reading, spending time with her service dog, crafting, and spending time with friends and family.


Nabil Saleh

Nabil graduated from University of Tennessee – Knoxville with a Bachelor’s of Science in Chemistry. He performed computational modeling for his Undergraduate Honor’s research under Dr. Robert Hinde. Before joining the IGP at Vanderbilt, Nabil worked the lab of Ann Richmond studying immunotherapies against Melanoma and Breast Cancer. Nabil has undertaken a variety of research projects, ranging from Organometallic chemical synthesis to translational research on Uveal Melanoma / Retinoblastoma. Nabil joined the Dewar lab as a graduate student in 2023.

Outside of lab, Nabil holds positions in Vanderbilt’s student leadership including President of the Honor Council and Graduate School Representative to the Appellate Review Board.


Research technicians

Obehi Ozua

Obehi graduated from Southwestern University with a B.S degree in Biochemistry in 2023. During her undergraduate years, she participated in a Research Experience for Undergraduates (REU) at Purdue University with the Tao Lab. Under the guidance of Dr. Tao, she worked on finding strategies to optimize their one-pot extracellular vesicle extraction method. Obehi joined the Dewar lab as a research technician in 2023.

In her free time, Obehi enjoys spending time with friends, watching movies and baking.


Lab Alumni

Name Position in lab Grad Year Current Position
Darren Heintzman Research Assistant 2019 PhD Candidate, Vanderbilt University Medical Center
Lillian Campos Post-doc 2022 Biotech
Tamar Kavlashvili Graduate student 2023 Post-doc, Sloan Kettering Institute
Stedman Stephens Research Assistant 2023 PhD Student, Vanderbilt University