You probably know about the BRCA1 gene and its link to breast cancer thanks to Angelina Jolie, but do you know about the woman who discovered it, Mary-Claire King? King was born in 1946 in Evanston, Illinois. She began her secondary education with her eye (and mind) on a career in math; following a degree in mathematics from Carleton College in Northfield, Minnesota, she began a PhD in statistics at the University of California, Berkeley. While there, she took a genetics class that so inspired her that she switched to Berkeley’s genetics program. She never gave up her love for math, however – instead she built an incredibly successful career upon applying mathematical modeling to biological questions.
In her PhD work, she compared the sequences of protein-coding genes for human and chimpanzee genes and found that the amino acid sequences of the proteins they produced were incredibly similar (99% identical). So why are humans and chimps so different? King proposed that evolution could be driven by changes in the expression of these genes through changes in regulatory DNA sequences, rather than changes in the coding sequences (later found to be true). She moved to Chile to teach after graduating in 1973, but a violent military coup led her to return to California, where she began a postdoctoral fellowship in cancer epidemiology and genetics at the University of California, San Francisco (UCSF) and then started as an assistant professor at UC Berkeley (where she was explicitly told she was only hired because of affirmative action).
At the time, cancer research was mainly focused on cancer-causing viruses, but King knew that breast cancer ran in certain families and believed that there must be a genetic cause in these cases. In order to collect more data on breast cancer inheritance, she convinced the National Cancer Institute (NCI) to add questions about family history of cancer to a survey they were conducting. Using this data, she developed a mathematical model that accounted for hereditary cases of breast cancer, but the responsible gene(s) were still unknown. After 17 years of hard work, King was able to map the gene, BRCA1. Women with BRCA1 mutations can have a significantly increased risk of developing breast or ovarian cancer, and King has worked hard to develop tools to cheaply screen for such mutations.
In addition to applying her mathematical & biological skills to evolution and cancer genomics, King has tackled humanitarian issues – developing mitochondrial DNA sequencing technology to help reunite families torn apart by war and identify soldiers’ remains. She moved to the University of Washington in 1995, where she is a Professor of Genome Sciences and Medicine. She received a Lasker Award in 2014 and a National Medal of Science in 2016 that recognized both her scientific and humanitarian achievements.