[2] She studies the interaction of genetics and environmental influences and their effects on human conditions such as breast and ovarian cancer, inherited deafness, schizophrenia,[3] HIV, systemic lupus erythematosus and rheumatoid arthritis.
In 1984, in Argentina, she began working in identifying children who had been stolen from their families and adopted illegally under the military dictatorship during the Dirty War (1976–1983).
[7] King received her undergraduate degree in mathematics (cum laude) from Carleton College, Phi Beta Kappa, in 1967.
She says: "The single most effective thing we did was on the day after the US invaded Cambodia, we got out our suit jackets and shirtwaist dresses – not clothes that any of us had worn since coming to Berkeley – and went to the synagogues and churches and by the end of Sunday we had 30,000 letters opposing the action.
[11][12] She spent a year doing consumer advocacy work for Ralph Nader, investigating pesticide use and its effects on farm workers.
[14] In her doctoral work at Berkeley, King demonstrated through comparative protein analysis that chimpanzees and humans were 99% genetically identical.
[19] King accepted a postdoctoral position at the University of California, San Francisco (UCSF), to work with Nicholas L. Petrakis.
[22] Nonetheless, the search for the breast cancer susceptibility gene was moving forward with firm steps in King's lab and accelerating in the mid-1980s.
The idea was that early cases might be more likely to reflect a genetic component, in contrast to sporadic mutations that might occur at any age or even accrue over time.
In September 1994, Myriad Genetics published a paper on the positional cloning of the sequence after a highly publicized "race" by groups of scientists.
The researchers studied women of Ashkenazi Jewish ancestry in New York, a group that was known to have a very high incidence of breast cancer (up to an 80% risk by age 70, compared with 12% in the general population).
[35][22] King also worked on a project studying the mutations of genes linked to breast cancer inheritance in Nigerian women between March 1998 and 2014.
King's team decided to do this research on the grounds that more people die in Nigeria from triple negative breast cancer that is diagnosed at a later stage than other, more educated regions of the world, such as Europe or America.
At the finish of this study, King's team was still unsure of the reason for such high levels of Triple-negative breast cancer, since many of the people diagnosed were not showing mutations in the BRCA1 gene.
Her study supported the idea that genomic sequencing could be useful as a tool to help detect gene mutations early and be proactive in letting those who have high risks for breast cancer know ahead of time.
Hereditary deafness is common among some Palestinian and Israeli communities, providing good study populations to understand the genetics of this condition.
King's collaboration with scientists in Israel and Palestine has resolved the complex web of different genes and varying modes of transmission for this common phenotype among many kindreds in the communities in that region.
In collaboration with other scientists including Judith L. Rapoport, Jonathan Sebat, and Deborah L. Levy, she has discovered evidence that suggests that schizophrenia may be linked to the presence of genetic mutations called copy number variations (CNVs) in pathways involved in neural development.
Most had been born to women in prison who had been persecuted as political dissidents and were later "disappeared" by the Argentine military dictatorship during the eight-year "Dirty War" from 1976 to 1983.
King's technique, using mitochondrial DNA and human leukocyte antigen serotyping genetic markers from dental samples, proved invaluable.