2003 Balzan Prize for Genetics and Evolution
Wen-Hsiung Li has made many fundamental contributions to molecular evolution. He has developed and applied mathematical techniques to a very wide range of problems and his methods are amongst the most generally used in the field.
With the explosion of DNA sequence data since the 1980s, Wen-Hsiung Li has been the architect of methods for inferring evolutionary relationships from comparison of DNA sequences.
He was particularly influential in establishing methods for estimating the degree of accuracy of evolutionary trees and the statistical confidence that can be placed in them.
One key to the interpretation of DNA data is the assumption that changes in DNA data take place at a constant rate through evolutionary time (the so-called molecular clock). This assumption is used to pinpoint the time of divergence of lineages.
Wen-Hsiung Li was the first to show, in the 1980s, that the clock runs at a speed dependent on generation time: the shorter the generation, the faster the clock. So the clock runs five times as fast in rats and mice as in monkeys and man. This discovery has led to a better understanding of divergence times in evolution.
Wen-Hsiung Li has also been influential in showing that the mutation rate in males is higher than that in females. He has demonstrated this for higher primates including humans as well as for rodents.
With the appearance of data from the Human Genome Project, Wen-Hsiung Li and his colleagues have turned their attention to the analysis of the detailed structure of the human genome, including the detection of non-functional DNA embedded within coding regions.
Wen-Hsiung Li has, in addition to his own pioneering research, played a central role in educating others in the field of Molecular Evolution. His books are regarded as definitive in the field.