An ancient saga of ongoing genetic conflict is written in the DNA of most organisms, but it takes a unique kind of historian to read it. Harmit Malik, a geneticist, virologist, and evolutionary biologist, scours the genomes of humans and other animals to chronicle an endless genetic arms race between these organisms and their pathogens – and another within the organisms’ own genomes.
Malik grew up in a family of businesspeople and engineers in India and studied chemical engineering at the Indian Institute of Technology in Mumbai. But Richard Dawkins’s The Selfish Gene, which he read as an undergraduate, sparked a deep curiosity about molecular biology. Through his reading and informal meetings with a biotechnology professor, Malik learned enough to gain admittance to a graduate program in biology at the University of Rochester, where he studied selfish genes known as retrotransposons, which lurk in the genomes of plants and animals and try to insert copies of themselves elsewhere in their host’s DNA.
Malik has since broadened his research. As an HHMI Early Career Scientist at the Fred Hutchinson Cancer Research Center in Seattle, WA, he began exploring the record of viral evolution preserved in the genomes of host cells. Clues appeared in the forms of both viral genes that integrated into their hosts’ genomes and host genes that evolved as antiviral defense mechanisms. He helped launch the field of paleovirology, which traces these fossil-like records of ancient viruses in modern cells. Malik is now an HHMI investigator.
Malik’s work revealed that RNA viruses have existed for millions of years – far longer than predicted by scientists using earlier techniques. By tracing the genetic events that occurred over that long history, Malik is uncovering previously unknown antiviral strategies, mechanisms of immunity, and clues about autoimmune diseases.
Malik also studies the causes and consequences of genetic conflict within an individual genome. During the cell divisions that give rise to egg cells, a cell sorts its chromosomes into four daughter cells: a single oocyte that will become the egg and three smaller cells that soon degenerate. Thus, the chromosome that winds up in the egg is the evolutionary “winner.” Malik thinks competition for this position may have driven evolution at regions of DNA that attach to a cell’s chromosome-sorting machinery – even, perhaps, aiding speciation. It will take more interdisciplinary detective work – which Malik is pursuing as an HHMI investigator – to unravel the mystery.
Image: Stephen Brashear