Allan Wilson
Encyclopedia
Allan Charles Wilson was a pioneer in the use of molecular
approaches to understand evolution
ary change and reconstruct phylogenies, and a contributor to the study of human evolution
. 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. He is the only New Zealander to win the MacArthur Fellowship.
, 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 the University of Otago
. 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.
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 fossil
s, 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 chimpanzee
s, 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 marker
s for tracking human evolutionary history, he started to focus on mitochondrial DNA
(mtDNA) — gene
s 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 and Homo 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.
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.
After Wilson's death Charles Laird published some thoughts on his lost colleague and friend.
Molecular evolution
Molecular evolution is in part a process of evolution at the scale of DNA, RNA, and proteins. Molecular evolution emerged as a scientific field in the 1960s as researchers from molecular biology, evolutionary biology and population genetics sought to understand recent discoveries on the structure...
approaches to understand evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary change and reconstruct phylogenies, and a contributor to the study of human evolution
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...
. He was one of the most controversial figures in post-war biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
; his work attracted a great deal of attention both from within and outside the academic world. He is the only New Zealander to win the MacArthur Fellowship.
Early life and education
Allan Wilson was born in NgaruawahiaNgaruawahia
Ngāruawāhia is a town in the Waikato region of the North Island of New Zealand. It is located 20 km north-west of Hamilton at the confluence of the Waikato and Waipa Rivers...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and raised on a farm at Helvetia, Pukekohe
Pukekohe
Pukekohe is a town in the Auckland Region of the North Island of New Zealand. Located at the southern edge of the Auckland Region, it is approximately 50 kilometres south of Auckland City, between the southern shore of the Manukau Harbour and the mouth of the Waikato River. The hills of Pukekohe...
. He attended King's College
King's College, Auckland
King's College is an independent secondary school in New Zealand. It was originally a boys-only school but now also admits girls in the sixth and seventh forms . The school has strong links to the Anglican church; the Anglican Bishop of Auckland, and the Dean of Auckland are permanent members of...
in Auckland
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...
and excelled in maths and chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
. After school he gained a BSc from the University of Otago
University of Otago
The University of Otago in Dunedin is New Zealand's oldest university with over 22,000 students enrolled during 2010.The university has New Zealand's highest average research quality and in New Zealand is second only to the University of Auckland in the number of A rated academic researchers it...
. It was here as a Masters student that Wilson met Professor C.P. 'Mac' McMeekan, a New Zealand pioneer in animal science
Animal science
Animal Science is described as "studying the biology of animals that are under the control of mankind". Historically, the animals studied were farm animals, including livestock and horses, but courses available now look at a far broader area to include companion animals, for example dogs, cats and...
. He suggested that Wilson further his study in biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
instead of genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
.
In 1955 Wilson was invited to do his PhD at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
. 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
Arthur Pardee
Arthur Pardee is an American biochemist. One biographical portrait begins "Among the titans of science, Arthur Pardee is especially intriguing." There is hardly a field of molecular biology that is not affected by his work, which has advanced our understanding through theoretical predictions...
, and setting up one of the world's most creative biochemistry labs.
Career and scientific contributions
Allan Wilson first came to world attention when he published a paper titled Immunological Time-Scale For Human Evolution in Science magazineScience Magazine
Science Magazine was a half-hour television show produced by the Canadian Broadcasting Corporation from 1975 to 1979.The show was hosted by geneticist David Suzuki, who previously hosted the daytime youth programme Suzuki On Science...
in December 1967. Together with doctoral student Vincent Sarich
Vincent Sarich
- Biography :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...
, Wilson argued that the origins
Paleoanthropology
Paleoanthropology, which combines the disciplines of paleontology and physical anthropology, is the study of ancient humans as found in fossil hominid evidence such as petrifacted bones and footprints.-19th century:...
of the human species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
could be seen through, what he termed, a "molecular clock
Molecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...
". This was a way of dating, not from fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s, 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
Divergence
In vector calculus, divergence is a vector operator that measures the magnitude of a vector field's source or sink at a given point, in terms of a signed scalar. More technically, the divergence represents the volume density of the outward flux of a vector field from an infinitesimal volume around...
, given a certain rate of change.
When Wilson, with his then-student Mary-Claire King
Mary-Claire King
Mary-Claire King is an American human geneticist. She is a professor at the University of Washington, where she studies the genetics and interaction of genetics and environmental influences on human conditions such as HIV, lupus, inherited deafness, and also breast and ovarian cancer...
, and Sarich analysed and compared genetic material of humans and chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
s, 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
Mitochondrial Eve
In the field of human genetics, Mitochondrial Eve refers to the matrilineal "MRCA" . In other words, she was the woman from whom all living humans today descend, on their mother's side, and through the mothers of those mothers and so on, back until all lines converge on one person...
" hypothesis
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
. In his efforts to identify informative genetic marker
Genetic marker
A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify cells, individuals or species. It can be described as a variation that can be observed...
s for tracking human evolutionary history, he started to focus on mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
(mtDNA) — gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s that sit in the cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
, but not in the nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
, 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 and Homo erectus
Homo erectus
Homo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...
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
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
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
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
with Homo sapiens Neanderthals, in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
with Java Man
Java Man
Java Man is the name given to fossils discovered in 1891 at Trinil - Ngawi Regency on the banks of the Solo River in East Java, Indonesia, one of the first known specimens of Homo erectus...
, in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
with Peking Man
Peking Man
Peking Man , Homo erectus pekinensis, is an example of Homo erectus. A group of fossil specimens was discovered in 1923-27 during excavations at Zhoukoudian near Beijing , China...
. 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.
Legacy
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 sequencingDNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
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
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
creationists.
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…"
External links
- Allan Wilson Centre for Molecular Ecology and Evolution
- Background on Allan Wilson
- Work on human evolution
- "Allan Charles Wilson, Biochemistry; Molecular Biology: Berkeley", by Bruce N. AmesBruce AmesBruce Nathan Ames is an American biochemist. He is a professor of Biochemistry and Molecular Biology at the University of California, Berkeley, and a senior scientist at Children's Hospital Oakland Research Institute...
, Thomas H. JukesThomas H. JukesThomas Hughes Jukes was a British-American biologist known for his work in nutrition, molecular evolution, and for his public engagement with controversial scientific issues, including DDT, vitamin C and creationism...
, Vincent M. SarichVincent Sarich- Biography :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...
, David B. WakeDavid B. WakeDavid B. Wake is professor of integrative biology and former curator of herpetology of Museum of Vertebrate Zoology at the University of California, Berkeley. Wake is an internationally respected expert on species formation and has written widely on the subject...
in University of California: In Memoriam, 1991 - Guide to the Allan Wilson Papers at The Bancroft Library