Allan Wilson



Allan Wilson (1934–1991) was a pioneer in the use of molecular approaches to understand evolutionary change and reconstruct phylogenies. He was one of the most controversial figures in post-war biology; his work attracted a great deal of attention both from within, and outside, the academic world.

Allan Wilson was born in Ngaruawahia, New Zealand, and raised on a farm at Helvetia, Pukekohe. He attended King's College in Auckland and excelled in maths and chemistry. After school he gained a BSc from Otago University. It was here as a Masters student that Wilson met Professor C.P. 'Mac' McMeekan, a New Zealand pioneer in animal science. He suggested that Wilson further his study in biochemistry instead of genetics.

In 1955 Wilson was invited to do his PhD at the University of California, Berkeley. At the time the family thought Allan would only be gone two years; instead he stayed at Berkeley for 35 years, gaining his PhD in 1961 under the direction of Arthur Pardee, and setting up one of the world's most creative biochemistry labs and turning ideas of evolution on their ear.

Allan Wilson first came to world attention when he published a paper titled Immunological Time-Scale For Human Evolution in Science magazine in December 1967. Together with doctoral student Vincent Sarich, Wilson argued that the origins of the human species could be seen through, what he termed, a "molecular clock". This was a way of dating, not from fossils, but from the genetic mutations that had accumulated since they parted from a common ancestor. The molecular clock estimated the length of time from divergence, given a certain rate of change.

When Wilson, with his then-student Mary-Claire King, and Sarich analysed and compared genetic material of humans and chimpanzees, they found the material to be 99 percent identical. From King's work, using the 'molecular clock' reasoning (bigger differences equate to greater time since their last common ancestor) Wilson deduced that the earliest proto-hominids evolved only five million years ago. Most contemporary anthropologists, who favoured a date of around 25 million years, dismissed his work as absurd.

In the early 1980s, as his findings for the age of the proto-humans were starting to be more widely accepted, Wilson again dropped a bombshell on traditional anthropological thinking with his best known work with Rebecca Cann and Mark Stoneking on the so-called "Mitochondrial Eve" hypothesis. In his efforts to identify informative genetic markers for tracking human evolutionary history, he started to focus on mitochondrial DNA (mtDNA) - genes that sit in the cell, but not in the nucleus, and are passed from mother to child. This DNA material is important because it mutates quickly, thus making it easy to plot changes over relatively short time spans. By comparing differences in the mtDNA Wilson believed it was possible to estimate the time, and the place, modern humans first evolved. With his discovery that human mtDNA is genetically much less diverse than chimpanzee mtDNA, he concluded that modern human races had diverged recently from a single population while older human species such as Neandertal, Java erectus and Pekin erectus had become extinct. He and his team compared mtDNA in people of different racial backgrounds and concluded that all modern humans evolved from one 'lucky mother' in Africa about 150,000 years ago.

This finding was as, if not more, controversial than his 1967 findings. Accepted thinking had various human groups evolving from different ancestors, over a million years in separate geographic regions, but at basically the same rate around the world. In Europe with Homo sapiens Neanderthals, in Indonesia with Java Man, in China with Peking Man. Again, as in the 1960s, many palaeontologists rejected Wilson's conclusions; fossil scientists were unfamiliar with biochemistry and trusted their own data more than molecular data. It took 20 years to convince palaeontologists of the value of Wilson's theory, but when they did, it married their science with that of genetics.

Wilson's success can at least partially be attributed to his willingness to adopt new molecular techniques at the earliest stages of their development. For instance, he was one of the first scientists to apply DNA sequencing and PCR to the study of evolution. Throughout the course of his career, Wilson trained more than 200 graduate students and post-docs in molecular evolutionary biology. Indeed, his laboratory was a virtual obligatory passage point for anyone wishing to do empirical work in the field of molecular evolution in the 1970s and 1980s.

His investigations into the origins of humanity through biochemistry were revolutionary, yet at the time of his death in July 1991, while undergoing treatment for leukaemia, he was still a controversial figure. His theories on the evolution and age of modern humans still flew in the face of some anthropological thinking of the time, not to mention inciting anger from American creationists.

One of the great innovators of science, New Zealander Allan Wilson revolutionised the study of human evolution. He was short listed for the Nobel Prize and is the only New Zealander to win the prestigious MacArthur Fellowship. Allan Wilson's scientific achievements are nothing short of profoundly significant.

After Wilson's death Charles Laird published some thoughts on his lost colleague and friend.

"'I have wondered about the parts of his personality that were so unusual even among first-rate scientists - his courage, his openness, his ability to focus on a problem and not let go, his special vision to see the final experiment and not to get distracted by intermediate ones and the details in between…'"