Kinetic effects of temperature on rates of genetic divergence and speciation

doi:10.1073/pnas.0603587103

Kinetic effects of temperature on rates of genetic divergence and speciation

*National Center for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, CA 93101;
^‡Department of Zoology, University of Florida, Gainesville, FL 32611;
^§Bauer Center for Genomics Research, Harvard University, Boston, MA 02138; and
^¶Department of Biology, University of New Mexico, Albuquerque, NM 87131

Contributed by James H. Brown, May 2, 2006

Abstract

Latitudinal gradients of biodiversity and macroevolutionary dynamics are prominent yet poorly understood. We derive a model that quantifies the role of kinetic energy in generating biodiversity. The model predicts that rates of genetic divergence and speciation are both governed by metabolic rate and therefore show the same exponential temperature dependence (activation energy of ≈0.65 eV; 1 eV = 1.602 × 10⁻¹⁹ J). Predictions are supported by global datasets from planktonic foraminifera for rates of DNA evolution and speciation spanning 30 million years. As predicted by the model, rates of speciation increase toward the tropics even after controlling for the greater ocean coverage at tropical latitudes. Our model and results indicate that individual metabolic rate is a primary determinant of evolutionary rates: ≈10¹³ J of energy flux per gram of tissue generates one substitution per nucleotide in the nuclear genome, and ≈10²³ J of energy flux per population generates a new species of foraminifera.

Footnotes

^†To whom correspondence may be addressed. E-mail: drewa{at}nceas.ucsb.edu or jhbrown{at}unm.edu
Author contributions: A.P.A., J.F.G., and J.H.B. designed research; A.P.A. and J.F.G. performed research; A.P.A. and V.M.S. contributed new reagents/analytic tools; A.P.A. analyzed data; and A.P.A., J.F.G., V.M.S., and J.H.B. wrote the paper.
Conflict of interest statement: No conflicts declared.
Abbreviations:

Abbreviations:

CI,

confidence interval;

FO,

first occurrence;

Ma,

mega-annum;

SSU rDNA,

small subunit rRNA-encoding DNA.
Freely available online through the PNAS open access option.