Vincent M. Sarich
and Allan C. Wilson

"Immunological time scale for hominid evolution"

Science 158, 1967, p. 1200-1203.

Sarich and Wilson's analysis of immunological evidence allowed them to propose "that if, man and Old World monkeys shared a common ancestor 30 million years ago, then man and apes shared a common ancestor no more than 5 million years ago, upsetting the contemporary view that human's common ancestor was Ramapithecus, a 13 million year old. This challenge to paleontological opinion purely on the basis of biochemistry of living species was for sometime either ridiculed or ignored, but is now fairly well accepted."

From: Unpubilshed biographical sketch of Dr. Vincent Sarich