Inferring the Process of Human–Chimpanzee Speciation

K Ryo Takahasi, RIKEN, Yokohama, Japan
Hideki Innan, Graduate University for Advanced Studies, Hayama, Japan

Published online: May 2008

DOI: 10.1002/9780470015902.a0020833

By examining deoxyribonucleic acid (DNA) sequence data from closely related species, we may gain insights into the genetic mechanism and process leading to the formation of new species. Recently, several interesting hypotheses have been proposed independently that maintain a complex mode of speciation of humans and chimpanzees, but at present, there does not seem to be any compelling evidence to support this provoking scenario.

Keywords: coalescent; genome; human evolution; hybridization; speciation

Figure 1. Illustrations of three speciation models: (a) instantaneous speciation model, which posits a sudden loss of gene flow at t=Ts; (b) prolonged gene flow model, which posits a gradual formation of isolating barriers to gene flow before t=Ts and (c) hybridization model, which involves a period of admixture following temporal isolation during TIe<t<TIs.
Figure 2. The probability density distributions of TMRCA under the three speciation models. For each model, the distribution is derived by setting Ts=1. The thick line represents the distribution under the null model of instantaneous speciation. The dashed line is for the prolonged gene flow model, and the grey line is for the hybridization model with TIs=3 and TIe=1.2. The three situations correspond to Figure 1a, b and c, respectively.
Figure 3. Genealogical trees showing (HC)G and H(CG) relationships, presented by solid and grey lines, respectively. Only the mutations that occurred on the internal branch between the first coalescent event and the MRCA of the three species (represented by circles) are useful in resolving the tri-species relationship.
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 References
    Barton NH (2006) Evolutionary biology: how did the human species form? Current Biology 16: R647–R650.
    Hey J (2003) Speciation and inversions: chimps and humans. BioEssays 25: 825–828.
    Innan H and Watanabe H (2006) The effect of gene flow on the coalescent time in the human–chimpanzee ancestral population. Molecular Biology and Evolution 23: 1040–1047.
    Lu J, Li W-H and Wu C-I (2003) Comment on “Chromosomal speciation and molecular divergence – accelerated evolution in rearranged chromosomes”. Science 302: 988b.
    Navarro A and Barton NH (2003) Chromosomal speciation and molecular divergence – accelerated evolution in rearranged chromosomes. Science 300: 321–324.
    Osada N and Wu C-I (2005) Inferring the mode of speciation from genomic data: a study of the great apes. Genetics 169: 259–264.
    Patterson N, Richter DJ, Gnerre S, Lander ES and Reich D (2006) Genetic evidence for complex speciation of humans and chimpanzees. Nature 441: 1103–1108.
    Rieseberg LH (2001) Chromosomal rearrangements and speciation. Trends in Ecology and Evolution 16: 351–358.
    Takahata N, Satta Y and Klein J (1995) Divergence time and population size in the lineage leading to modern humans. Theoretical Population Biology 48: 198–221.
    Wu C-I and Ting C-T (2004) Genes and speciation. Nature Reviews Genetics 5: 114–122.
 Further Reading
    Chen F-C and Li W-H (2001) Genomic divergences between humans and other hominoids and the effective population size of the common ancestor of humans and chimpanzees. American Journal of Human Genetics 68: 444–456.
    book Coyne JA and Orr HA (2004) Speciation. Sunderland, MA: Sinaur Associates, Inc.
    book Klein J and Takahata N (2002) Where Do We Come From? Berlin: Springer.
    Navarro A and Barton NH (2003) Accumulating postzygotic isolation genes in parapatry: a new twist on chromosomal speciation. Evolution 57: 447–459.
    Wu C-I (2001) The genic view of the process of speciation. Journal of Evolutionary Biology 14: 851–865.

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Human Evolution | Evolution of Species
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Article Title: Inferring the Process of Human–Chimpanzee Speciation
 
How to Cite close
Takahasi, K Ryo, and Innan, Hideki(May 2008) Inferring the Process of Human–Chimpanzee Speciation. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0020833]