Longzhi Tan (postdoc)

Longzhi Tan (“Tan”) is a Postdoctoral Scholar in the Bioengineering department.  

Can you tell us about your Asian American heritage?

I was born in China and moved to the US in 2009 to attend MIT to study physics (and biology), then Harvard for my PhD in systems biology. I lived in Boston for 10 years and recently moved to California as a postdoc.  

What is your area of focus, and how did you gain interest in it?

My background is in physics, and I’ve always been fascinated by the physics of living organisms.  My research focuses on the 3D architecture of our genome -- the complicated 3D shape that exists in every cell and the physical properties that determine cellular functions -- and how it relates to autism, schizophrenia, and Alzheimer's.  There are 46 chromosomes packed into the nucleus of a human cell; these 6 billion bases (A, C, G, T) in a double helix would be 2 meters long if stretched to its full length, and must fold into a tiny volume. Using the technology I developed, we can see the genome (an organism's complete set of DNA) in 3D in a human cell for the first time.  This technology is based on biochemistry and computational algorithms rather than microscopy.  It works as follows: Imagine a large lecture hall where you want to map which student sits where.  Instead of measuring rows and seats directly, you can ask who the 4 people are who sit next to each student.  This provides the equivalent information from which you can deduce the actual seating arrangement.  Now imagine doing this mapping for each gene in a cell.  We are able to cut the genome into small pieces, while holding it in place, and then let them rejoin and “find their neighbors.”  In this way, we can read out each gene’s neighborhood in 3D and deduce their full 3D structure.

I started out studying the linear sequence of DNA -- in particular, the evolution of bacterial and human genomes -- for example, why East Asians have thicker hair.  I was interested in the fact that a string of DNA bases (A, C, G, T) determines so much of our body’s biological function. While doing my PhD at Harvard, I started developing biochemical methods and even researched the 3D genome behind our sense of smell (which has become a topic of interest for many people in this past year because of COVID).

Can you tell us about your involvement in BioE JEDI?

I joined the BioE Postdoc JEDI team this year and have enjoyed being part of the larger BioE JEDI mega team.  Ever since I came to Stanford, I have really liked the environment here.  I have found it to be culturally diverse and inclusive.  After spending the last few years here at Stanford, I felt like it was time to contribute to the inclusive welcoming environment that I love so much and from which I have benefited immensely.  In light of the recent events, I wanted to get more involved, both to educate myself and to help the community.  By helping the community in general, I feel that this will also benefit the postdoc community, which has a high percentage of international students.  I think it’s important to represent the postdoc group and promote justice, diversity, equity, and inclusion within our group.

What’s one thing that people might not know about you?

I do lots of graphic design.  I’ve done scientific illustrations for pre-print publications.  I’ve also been creating holiday cards every year for my previous lab at Harvard.  We would have themes each year (like Saturday Night Live, Star Wars, or Winter Olympics), and we would send these holiday cards to families of the lab and our collaborators around the world.  In this way, we were able to spread the diversity and joy of science.  Our Sabeti Lab cards were featured in the Boston Globe and Smithsonian Magazine!

What milestones in your life are of particular significance to you?

I became a parent last year, and it’s been a very different experience.  I’ve had to learn how to balance work and life better than before.  As a father, I like to find children’s science books that I can read to my daughter and to tell her stories about cells.  I don’t know what she thinks about these stories, but I hope that she may develop an interest in science when she is older!