Sergei Mirkin (born September 29, 1956) is a Russian-American biologist who studies genome instability mediated by repetitive DNA during DNA replication and transcription. He is a professor of Genetics and Molecular Biology and holds the White Family Chair in Biology at Tufts University. Early life and education Mirkin was born in Moscow, Russia. He attended Moscow State University, where he earned both a Bachelor of Science and a Master of Science degree in Genetics in 1978. Mirkin went on to pursue a PhD in Molecular Biology at the Russian Academy of Sciences’ Institute of Molecular Genetics. His PhD was under the supervision of Roman B. Khesin, a molecular biologist and Mirkin later described his formative years in the Khesin lab in his essay, “Thinking of R.B. Khesin”. By studying conditionally lethal mutants of DNA gyrase, he established a fundamental interplay between DNA supercoiling and transcription in E. coli. Career and research Mirkin conducted his postdoctoral studies at the Institute of Molecular Genetics with Maxim Frank-Kamenetskii, a biophysicist. This work culminated with the discovery of the three-stranded H-DNA structure. Mirkin moved to the US as a Fogarty International Fellow in 1989 and joined the faculty of the Department of Genetics at University of Illinois Chicago (UIC) in 1990. He worked at UIC until 2006 rising to the rank of Professor of Biochemistry and Molecular Genetics. In 2007, he joined Tufts University as a professor and the White Family Chair in Biology. Mirkin’s major contributions to science include discovering of the first multi-stranded DNA structure (H-DNA); detection of dynamic non-B DNA structures, including DNA cruciforms and triplexes in vivo; establishing that structure-prone DNA repeats stall DNA replication driving their expansions that are responsible for numerous hereditary diseases in humans; and unraveling the mechanisms and consequences of transcription-replication collisions in vivo. The Mirkin lab continues studying genome structure and function from two perspectives: the mechanisms responsible for the instability of DNA repeats implicated in human disease, the role of transcription-replication collisions in genome instability and the mechanisms of genome instability mediated at interstitial telomeric sequences. Selected publications Mirkin SM, Lyamichev VI, Drushlyak KN, Dobrynin VN, Filippov SA, Frank-Kamenetskii MD (1987) DNA H form requires a homopurine-homopyrimidine mirror repeat. Nature 330: 495-497. Dayn A, Malkhosyan S, Mirkin SM (1992) Transcriptionally driven cruciform formation in vivo. Nucleic Acids Res. 20: 5991-5997. Samadashwily GM, Dayn A, Mirkin SM (1993) Suicidal nucleotide sequences for DNA polymerization. EMBO