Steve’s training has been broadly interdisciplinary, with study and mentorship in many fields of science. He studied mathematics and economics as an undergraduate at Stanford University, doing research on industrial organization. Steve began working in molecular neuroscience with Dr. Cori Bargmann in 1997 and received his PhD in neuroscience from UC San Francisco for that work in 2004. He trained as a postdoctoral fellow in human genetics and genomics with Dr. David Altshuler, where his work revealed how genes and genomic segments commonly vary in copy number from person to person. He started his own lab at Harvard Medical School in 2009. 

Steve and the scientists in his lab have developed many novel ways to use genomes and genome sequences to understand human biology and the molecular basis of disease. His lab has uncovered surprising ways in which genes and alleles shape risk of a variety of diseases – from schizophrenia to cardiovascular illness to cancer. 

Many of the discoveries from Steve’s lab have involved unexpected insights arising from new ways of analyzing genome sequences. For example, while studying DNA derived from people’s blood samples, his lab discovered a common pre-cancerous state in which blood stem cells have acquired somatic mutations and then clonally expanded, creating a reservoir of pre-cancerous cells that greatly increases risk of developing cancer later in life. His lab also discovered that the human genome replicates (copies itself) in ways that vary from person to person and are shaped by inherited genetic variation.