DATING EVE
Page 1: Dating is never easy.

CASE STUDY IN MOLECULAR EVOLUTION NO. 3
Written by Harold B. White, Sept 1993, revised 1995 & 1997
C-647 BIOCHEMICAL EVOLUTION, FALL 2000

Allan Wilson
Allan C. Wilson
 Allan C. Wilson (1934-1991), perhaps the foremost molecular evolutionist in recent time (1-3), never shied from controversy. His lifelong interest in natural history and biological evolution gave him the uncanny ability to identify the unresolved, controversial issues of phylogeny and evolutionary theory that he and his associates could address with modern biochemical techniques (4-18). Repeatedly he confronted biologists and anthropologists with data that challenged their cherished models. For his work he received a MacArthur Foundation fellowship, dubbed the "Genius Award" because the recipients are often outstanding but unconventional thinkers from diverse fields (19). He was a member of the American Academy of Arts and Sciences and the Royal Society of London.
In 1987 Wilson and coworkers Rebecca Cahn and Mark Stoneking claimed they had evidence that the most recent maternal ancestor of all living humans was a woman living in Africa about 200,000 years ago (20). They based their conclusion on the analysis of restriction maps of mitochondrial DNA taken from 147 individuals representing different races and geographic origins. Their methods and results elaborated and supported earlier and continuing work in Cavalli-Sforza's laboratory (21,22). In typical journalistic fashion, the popular press immediately hyped this as the "Eve Hypothesis," "Garden of Eden Hypothesis," or the "Out-of-Africa Hypothesis."

In the subsequent years Wilson and his coworkers continued to collect data to test the "Eve Hypothesis." They sequenced particular segments of mitochondrial DNA from over 200 individuals (23,24), and their conclusions remained consistent. In addition, another group using restriction mapping of mitochondrial DNA from 3065 humans also concluded that humans had a recent origin in Africa although they refused to set a date (25). Thus, in 1991 when Allan Wilson died while being treated for leukemia, there seemed to be consistency in the results and growing support for his conclusions (26).

Focus Questions for Initial Group Discussion (Tuesday, 26 September)

What are the characteristics of mitochondrial DNA? (Size, structure, proteins and RNA's encoded, mode of inheritance (47), unusual properties, etc.)

Make a reasonable estimate (based on a rationale that you can explain to other groups) how long it has been since all the people in your group had a common ancestor. We will share the estimates and their basis before the end of class.

What would you want to know (learning issues) in order to evaluate the claims of Wilson and his challengers? Make a list of at least ten specific questions.

References
1. Jukes, T. & Zuckerkandl, E. (1991) "Remembering Allan Wilson," J. Mol. Evol. 33, ii.
2. Felsenstein, J. (1991) "Allan Charles Wilson (1934-1991)" Nature 353, 19.
3. Gibbons, A. (1991) "Systematics goes molecular" Science251, 872-874.
4. Wilson, A. C., Cahn, R. D. & Kaplan, N. O. (1963) "Functions of the two forms of lactate dehydrogenase in the breast muscle of birds" Nature 197, 331-334.
5. Kitto, G. B. & Wilson, A. C. (1966) "Evolution of malate dehydrogenase in birds" Science153, 1408-1410.
6. Sarich, V. M. & Wilson, A. C. (1967) "Immunological time scale for hominid evolution" Science158, 1200-1203.
7. Wallace D. G., Maxson, L. R. & Wilson, A. C. (1971) "Albumen evolution in frogs: A test of the evolutionary clock hypothesis" Proc. Natl. Acad. Sci. USA 68, 3127-3129.
8. Wilson, A. C., Mason, L. R. & Sarich, V. M. (1974) "Two types of molecular evolution. Evidence from studies of interspecific hybridization" Proc. Natl. Acad. Sci.71, 2843-2847.
9. King, M-C. & Wilson, A. C. (1975) "Evolution at two levels in humans and chimpanzees" Science188, 107-116 (see also commentary Science189, 446-447).
10. Wilson, A. C., Carlson, S. S. & White, T. J. (1977) "Biochemical evolution" Ann. Rev. Biochem. 46, 573-639.
11. Cherry. L. M., Case, S. M. & Wilson, A. C. (1978) "Frog perspective on the morphological difference between humans and chimpanzees" Science200, 209-211.
12. Ferris, S. D., Brown, W. M., Davidson, W. S. & Wilson, A. C. (1981) "Extensive polymorphism in the mitochondrial DNA of apes" Proc. Natl. Acad. Sci. USA 78, 6319-6323.
13. Brown, W. M., Prager, E. M., Wang, A. & Wilson, A. C. (1982) "Mitochondrial DNA sequences of primates: Tempo and mode of evolution" J. Mol. Evol. 18, 225-239.
14. Beverley, S. M. & Wilson, A. C. (1985) "Ancient origin for Hawaiian Drosophilinae inferred from protein comparisons" Proc. Natl. Acad. Sci. USA 82, 4753-4757.
15. Stewart, C-B., Shilling, J. W. & Wilson, A. C. (1987) "Adaptive evolution in the stomach lysozymes of foregut fermenters" Nature 330, 401-404 (commentary Nature330, 315).
16. Pääbo, S., Gifford, J. A. & Wilson, A. C. (1988) "Mitochondrial DNA sequences from a 7000-year-old brain" Nuc. Acid Res. 16, 9775-9787.
17. Prager, E. & Wilson, A. C. (1988) "Ancient origin of lactalbumin from lysozyme: Analysis of DNA and amino acid sequences" J. Mol. Evol. 27, 326-335.
18. Pääbo, S., Higuchi, R. G. & Wilson, A. C. (1989) "Ancient DNA and the polymerase chain reaction" J. Biol. Chem. 264, 9709-9712.
19. Brown, M. H. (1990) The Search for Eve, 357 pp, Harper & Row, Publishers, New York.
20. Cann, R. L., Stoneking, M. & Wilson, A. C. (1987) "Mitochondrial DNA and human evolution" Nature325, 31-36.
21. Johnson, M. J., Wallace, D. C., Ferris, S. D., Rattazzi, M. C. & Cavalli-Sforza, L. L. (1983) "Radiation of human mitochondrial DNA types analyzed by restriction endonuclease cleavage patterns"J. Mol. Evol. 19. 255-271.
22. Cavalli-Sforza, L. L., Manozzi, P., & Piazza, A. (1993) Demic expansions and human evolution. Science 259, 639- 646.
23. DiRienzo, A. & Wilson, A. C. (1991) "Branching pattern in the evolutionary tree for human mitochondrial DNA" Proc. Natl. Acad. Sci. USA 88, 1597-1601.
24. Vigilant, L., Stoneking, M., Harpending, H., Hawkes, K. & Wilson, A. C. (1991) "African populations in the evolution of human mitochondrial DNA" Science 253, 1503-1507.
25. Merriwether, D., Clark, A. G., Ballinger, S. W., Schurr, T. G., Soodyall, H., Jenkins, T., Sherry, S. T. & Wallace, D. C. (1991) "The structure of human mitochondrial DNA variation" J. Mol. Evol. 33, 543-555.
26. Angier, N. (1991) "New debate over humankind's ancestors" The New York Times, October 1, p. C1,6.
47. Awadalla, P., Eyre-Walker, A., and Smith, J. M. (1999) Linkage Disequilibrium and recombination in hominid mitochondrial DNA. Science 286, 2524 - 2525.

Page 2: Falling Out and Reconciliation

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Created 6 September 2000. Last updated 28 September 2000 by Hal White
Copyright 2000, Harold B. White, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716