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Tatum Simonson, PhD

Tatum Simonson, PhD 
Associate Professor and John B. West Endowed Chair in Respiratory Physiology
Division of Pulmonary, Critical Care, and Sleep Medicine, UC San Diego School of Medicine
Principal Investigator
UCSD Profile
Dr. Simonson applies integrative physiological genomics approaches to understand systems-level responses to environmental stress in diverse populations. Her research provides evidence for genetic adaptations to high altitude and associations among these factors, molecular functions, and physiological traits. In addition to her research in the highlands of Tibet and Peru, her team studies natural variation in human responses to environmental challenges and aims to understand the contributions of genetic and epigenetic factors to variation in hypoxia-related disease states (e.g., altitude illness, sleep apnea, and cardiometabolic diseases). These and related interdisciplinary efforts are coordinated through the recently developed Center for Physiological Genomics of Low Oxygen at UC San Diego.  


Esteban Moya, PhD
Project Scientist
Esteban is a Project Scientist interested in physiological responses to hypoxia in animal models and human populations living at high altitudes. He obtained his Ph.D. in Physiological Sciences at the P. Universidad Católica de Chile studying the carotid body, cardiorespiratory, and oxidative responses in an animal model of obstructive sleep apnea. Currently, his interests include understanding the consequences of sustained hypoxia on the neuroplasticity occurring in the neurons and glial cells of the brainstem areas that control the ventilation in rodents. As well as the genetic and physiological basis for the control of breathing in human populations living at high altitudes.

James Hall, PhD
Assistant Project Scientist
Dr. James Hall is an Assistant Project Scientist interested in elucidating the mechanisms underlying the interactions between genomes, environment, and phenotypes in high altitude populations.  His research focuses on the importance of the integration of multidisciplinary research to elucidate the mechanisms of complex systems.  He received a PhD in Biochemistry and Molecular Biology in 2014 from UC Riverside while working in the laboratory of Dr. Russ Hille on the structure and function of molybdenum-containing enzymes.  Dr. Hall was then recruited to UC San Diego in 2015 as a postdoctoral scholar and UC San Diego Institutional Research and Academic Career Development Award (IRACDA) Fellow in the Department of Chemistry and Biochemistry working within the laboratory of Dr. Susan Taylor on multimolecular signaling complexes containing protein kinase A (PKA). In 2020 he joined the lab of Dr. Simonson where he has been actively involved in research regarding structural biochemistry and understanding the functional roles of hypoxia-adaptive genetic variants identified through whole-genome sequence analyses. UCSD Profile

Ana Sánchez-Azofra, M.D.
Postdoctoral Research Fellow
Dr. Sánchez-Azofra is a Research Fellow at UCSD. The aim of her current Fellowship is to further deepen our knowledge of the physiological consequences of the superposition of intermittent and sustained hypoxia in animal and human models. Ana completed her training as a medical doctor at the University of the Basque Country in Spain, and her fellowship as a pulmonologist and sleep doctor in the Autonomous University of Madrid, Spain. In 2020, Dr. Sánchez-Azofra was granted an award by the prestigious Alfonso Martin Escudero Foundation to participate with the laboratory of Prof. Malhotra, who has a close collaboration with Prof. Simonson. Her research with Prof. Malhotra and Prof. Simonson aims to determine new biomarkers of inflammation, oxidative stress, metabolomics, and transcriptomics in patients with the COPD-OSA overlap syndrome. UCSD Profile

Katie A. O’Brien, PhD.
Marie Sklodowska -Curie Global Research Fellow
Katie is a Marie Sklodowska-Curie Global Research Fellow based between the University of Cambridge and UCSD. The aim of her current Fellowship is to characterise the high-altitude metabolic phenotype driven by unique Andean genetics. She completed her doctorate in 2017 on metabolic profile changes and effects of dietary nitrate supplementation in hypoxia at King’s College London under the supervision of Prof. Stephen Harridge.  During this time, she was a scientific investigator on the Xtreme Everest 2 research expedition. Following this, she worked as a postdoctoral researcher investigating drug induced mitochondrial toxicity in the context of hypoxia in the group of Dr Andrew Murray at the University of Cambridge and in collaboration with GlaxoSmithKline and AstraZeneca. 

James J. Yu
Ph.D. Student, Biomedical Sciences Graduate Program
James is a PhD student interested in identifying genetic, metabolic, and physiological variation in high-altitude populations that are adaptive in hypoxic (both chronic and intermittent) environments. He is interested in utilizing techniques and tools such as CRISPR, metabolomics, and hypoxic ventilatory response to investigate variation within these populations. He graduated from Duke University in 2016 and serves as a Medevac pilot and Platoon Leader in the Army Reserves. In his free time, he enjoys rock climbing and surfing.

Wanjun Gu
Research Data Analyst
Wanjun graduated from UC San Diego with majors in Chemical Engineering and Economics. He is interested in hypoxia physiology and population genomics. He is currently doing genomic, transcriptomic, and metabolomic analysis on Tibetans, Han Chinese, and Andeans. UCSD Profile


Elijah Lawrence
Postgraduate Research Assistant
Eli graduated cum laude from UCSD with a BS in Biochemistry and Cellular Biology. With his interests vested in molecular biology and human physiology, he has dedicated his college career to research and clinical work. He has been a part of the Simonson Lab for over four years and plans to continue his research in a clinical context as he pursues admittance into a variety of MD/Ph.D. programs. His ultimate goal is to contribute to the world of healthcare through both the study and practice of medicine as both a physician and a scientist. UCSD Profile

Mitchell Kong
Ph.D. Student, Department of Bioengineering

Mitchell is a Ph.D. student interested in identifying genetic mutations found in populations living in extreme conditions and linking those mutations to adaptive phenotypes. He seeks to apply engineering techniques to develop ways to maintain biological function despite environmental stress. Mitchell graduated from UCSD in 2020 with a B.S. in Bioengineering.

Caroline Gaeta
Graduate Research Assistant
Caroline graduated from UC San Diego (UCSD) in 2020 with a major in Human Biology. She is currently a Biology Master’s student in the BS/MS Program at UCSD. Her research focuses on hypoxia, Chronic Mountain Sickness, and epigenetics modifications such as DNA methylation. After graduating from her Master’s program, Caroline plans to apply for dental school in the hopes of becoming an orthodontist in the future. Outside of academia, Caroline enjoys baking, traveling, and spending time with her cat and two dogs. 

Mikael Fakhoury
Graduate Research Assistant
Mikael is a Biology Masters student and graduated in 2020 as a Human Biology major. He is interested in studying the inflammatory response involved in Chronic Mountain Sickness and intermittent hypoxia. After he obtains his Master’s in Biology, Mikael plans to continue onto medical school. Outside of academia, Mikael is an advisor for Global Medical Training at UC San Diego and enjoys helping the less fortunate in his community and abroad. His interests include hiking, rock climbing, and overall adventure. During the pandemic, he has focused on working out, reading, and overall self-care.

Zhijian Zhang
Graduate Research Assistant
Jack is interested in both the biological and computational components of cellular hypoxia as well as adaptations in genomics of high altitude populations and how these physiological and genetic changes affect their lives. In addition, he hopes to learn more about how current bioinformatics tools can contribute to the discovery of new knowledge in regards to cellular hypoxia. Outside of lab and classes, he enjoys playing the cello.

Jennifer Reeves
Undergraduate Research Assistant
Jennifer is a Human Biology major interested in physiological and genetic aspects of hypoxia with a focus on recurring biological pathways and how certain mutations induce phenotypic variation in high altitude populations. Outside of academia and personal endeavors, she enjoys cooking, boxing, and traveling. 

Marco Bauk
Undergraduate Research Assistant
Marco is a fourth-year Human Biology major interested in the physiological responses to hypoxia in high-altitude populations. He is narrowing his focus on whether certain functional variants of endothelin receptor genes are associated with specific medical conditions in Andean populations. Marco occupies his free time with water polo, ship restoration on the USS Midway, and sailing. 

Jeevan Singh
Undergraduate Research Assistant
Jeevan is a third-year Human Biology major with a minor in Chemistry. He is interested in investigating the body’s response to hypoxia at the molecular level and understanding how variation between populations can be used to advance precision medicine. His current research focuses on investigating functional variants of genes related to the Andean response to hypoxia using gene-editing technology. Outside the lab, Jeevan is a safety officer for the UCSD club lacrosse team and a member of AED. After graduating from UCSD, he plans to attend medical school. A San Diego native, Jeevan enjoys spending his free time playing lacrosse, mountain biking, and surfing. 

Santiago Fassardi
4th Year Undergraduate Research Assistant
Sago is a fourth-year Molecular Biology major. He is interested in studying the relationship between cancer and hypoxia in high-altitude populations at the genome and transcriptome levels. Outside of the lab, Sago enjoys reading about history, playing basketball, and walks on the beach.

Maianh Phan 
Undergraduate Research Assistant 
Maianh is a 4th-year Physiology and Neuroscience major interested in the comparative physiology of high altitude hypoxia. She is currently investigating the effects of hypoxia on Tibetan sheep and its relation with hypoxic effects on humans. After graduating, she will be in pursuit of obtaining a master's degree through UCSD’s BS/MS program and later planning on applying to medical school. Aside from academics, she enjoys spending time with her two dogs and is a proud member of the UCSD Kendo Team. 

Andrew Lin
Undergraduate Research Assistant
Andrew is a second-year student majoring in Human Biology and minoring in Math. He is interested in the different physiological responses to hypoxia across populations/living conditions and is currently exploring the field before focusing on a specific area of study. His passions include hugging his dog (Ollie), cooking, and working out.

Lab Alumni

Postdoctoral Fellows
Erica Heinrich, PhD   
Michael Tift, PhD
Pablo Catalan Serra, MD

Postgraduate Students
Robby Boparai
Jason Pan
Chang Han
William Wegeng
Adam Zhao
Medical Students
Lu Wu
Jeremy Sieker

Undergraduate Students
Christina Blaul
Matea Djokic
Gigi Yip
Sama Alpatty 
Dean Tan
Kevin Lin  
Chetan Potu         
Madison Calder                                            
Anh Bui

High School Students
Catie Boehmer 
Sarah Espinoza
Ian Xu

Lab Support


  Phoebe and Dudley


  Milou and Toto



Congratulations to Caroline Gaeta on getting into the UC San Francisco Post-Bac Denistry Program! (August 2021)

Congratulations to James Hall on becoming an Assistant Project Scientist! (July 2021)

Congratulations to Mitchell Kong on receiving fundings from the NIH Genetics Training Program! (September 2021)

Congratulations to Mitchell Kong on passing the PhD qualifying exam! (July 2021)

Congratulations to Caroline Gaeta on her completing her BS/MS Thesis Defense! (June 2021)

Congradulations to Sylas Eckhart on getting into the UC San Diego STARS Program! (June 2021)

Congratulations to Zhijian Zhang on getting into the UC San Diego Post-Bac Medical School Program! (June 2021)

Congratulations to Mitchell Kong on receiving an Honorable Mention by NSF GRFP! (March 2021)


Congratulations to Katie O'Brien on receiving the Marie Curie Global Fellowship! (October 2020)

Congratulations to James Yu on receiving the NDSEG Fellowship! (September 2020)

Congratulations to James Hall on receiving fundings from the NIH T32 in Respiratory Physiology! (July 2020)

Congratulations to James Yu on receiving an Honorable Mention by NSF GRFP! (March 2020)

----Before 2020----

Congratulations to Sago Fassardi on getting into UC San Diego BS/MS program in Biology!

Congratulations to Ian Xu on getting into University of Pennsylvania for undergraduate studies with a major in Bioengineering!

Congratulations to Chang Han on getting into Yale PhD in Biostatistics!

Congratulations to Jason Jialei Pan on getting into Stanford MS in Environmental Engineering!

Congratulations to Eli Lawrence on his Palomar Pathmaker Internship!

Congratulations to Eli Lawrence, Ledell Family Undergraduate Research Scholarship AND Chancellor's Research Excellence Scholarships (CRES) 2017 Recipient! 
Congratulations to Christina Blaul, Ledell Family Undergraduate Research Scholarship Recipient 2018! 

​Congratulations to Wanjun Gu, University of Tokyo Research Internship Program 2018 Recipient!

Congratulations to Christina Blaul, recipient of the Society for Advancement of Chicanos/Hispanics and Native Americans in Science Travel Award!

Congratulations and farewell to previous postdoctoral fellow Erica Heinrich, who has accepted an Assistant Professor position at the University of California, Riverside School of Medicine!

Congratulations and farewell to previous postdoctoral fellow Mike Tift, who has accepted an Assistant Professor position at the University of North Carolina, Wilmington!