Sarich and his PhD advisor, Allan Wilson, used molecular data to estimate that humans and chimpanzees have a common ancestor just four to five million years ago.
Born in Chicago, he received a bachelor of science in chemistry from Illinois Institute of Technology and his masters and doctorate in anthropology from University of California, Berkeley, where he was supervised by Sherwood Washburn.
As a doctoral student, and along with his PhD supervisor Allan Wilson, Sarich measured the strength of immunological cross-reactions of blood serum albumin between pairs of creatures, including humans and African apes (chimpanzees and gorillas).
For this, Sarich and Wilson used the most well-established fossil evidence (In particular: no primates of modern aspect had been found prior to the K-T boundary, ~65 million years ago) to calibrate the tree's branch points.
This work on a variety of molecules (and confirmed by modern DNA differences) consistently suggested a recent (~5 million year old) common ancestry with the African apes (chimpanzees and gorillas).
[7] In 1994, Sarich was a signatory of a collective statement titled Mainstream Science on Intelligence,[8] written by Linda Gottfredson and published in the Wall Street Journal.
[7] In an interview with The New York Times, Sarich agreed with his critics, who stated that there was little or no scientific basis for his claims about homosexuality, or on the relationship that he was then teaching of brain size to intelligence.