Research Overview

What does theoretical population genetics could tell us about the major features of evolution?

Since 1961, a main concern of mine has been to learn what theoretical population genetics could tell us about the major features of evolution; features, for example, that one could detect from the fossil record. The only interesting thing in my Ph.D. dissertation was a demonstration that “fair meiosis,” whereby each gamete of an individual heterozygous at a locus had equal chance of inheriting either allele at that locus, expressed the common interest of the autosomal genome. The reason for this is that if an allele spreads an unfavorable phenotype by “biasing meiosis in its favor” — insuring that most sperm in heterozygotes carry that allele rather than its “fair” alternative — selection favors mutants at unlinked loci that restore the fairness of meiosis because they are less likely to inherit the phenotypic defect. Fair meiosis ensures that alleles spread only if they benefit their bearers.

For animals living in stable groups, when does selection favor the good of the group rather than individuals that are promoting their own advantage?

Also, I have been interested in when, for animals living in stable groups, selection would favor the good of the group rather than individuals best at promoting their own advantage to the group’s detriment. These groups cannot exchange migrants, which would allow individuals that benefited by trashing their own group to “infect” other groups, like hit-and-run criminals. As some major transitions transform groups of individuals into tightly knit individuals in their own right, this showed how population genetics could reveal circumstances favoring a major transition. This is one example of where I asked a question which I could only answer decades later. This happens to me all the time.

How does natural selection among individuals lead to interdependence among species and among different ecological communities?

Through evolution, competitive natural selection on individuals and species gives rise to the extraordinary diversity and independence of tropical ecosystems. One route to better understanding how interdependence evolves is to compare and contrast natural ecosystems with human economies. Another is to compare island and mainland ecosystems.

Why are there so many kinds of tropical trees?

In the tropics, where there is no winter, diseases and plant-eating insects are active all year round. As a result, pest pressure is intense, far more so than in the temperate zone. Indeed, young tropical leaves are much more heavily eaten, despite being much more poisonous, than hardwood tree leaves in the temperate zone. Therefore, each species of tree is kept rare enough by its specialized pests and pathogens to make room for many others.

How do sociality and mutualism evolve?

Cooperation within and between species evolves if all partners spread their genes better by cooperating. Almost always, this requires behaviors that effectively suppress or prevent cheating (benefitting from others’ efforts without contributing to the common good), rendering it unprofitable.

What characteristics favor ecosystem productivity and diversity?

As Darwin already knew, large, tropical landmasses, with a great variety of habitats, which are intermittently connected to other such continents, shelter the most productive and diverse ecosystems. Competition is most intense there, such continents offer the greatest opportunity for interdependence between ecosystems, and the most openings for rare specialists.

Education

B.A., Mathematics, Princeton University, 1962.

Ph.D., Biology, Yale University, 1966.

Selected Publications

EG Leigh, Jr. 2017. Cooperation, Evolution of. Reference Module in Life Sciences, Elsevier. Doi:10.1016/B978-0-12-809633-8.02340-2.

EG Leigh, Jr. 2014. Historical Biogeography of the Isthmus of Panama. Biological Reviews 89: 148-172. doi: 10.1111/brv.12048 

G. J. Vermeij & EG Leigh, Jr. 2011. Natural and human economies compared. Ecosphere 2(4):art 39 doi 10.1890/ES1100004.1

EG Leigh, Jr. 2010. The group selection controversy. Journal of Evolutionary Biology 23: 6-19.

EG Leigh, Jr. 2010. The evolution of mutualism. Journal of Evolutionary Biology 23: 2507-2528.

EG Leigh, Jr. 2008. Tropical forest ecology: sterile or virgin for theoreticians? pp. 121-144 in W. P. Carson and S. Schnitzer, eds. Tropical Forest Community Ecology. Wiley-Blackwell.

EG Leigh, Jr., A. Hladik, CM Hladik, A. Jolly. 2007. The biogeography of large islands, or how does the size of the ecological theater affect the evolutionary play? Revue d'Ecologie 62: 105-168.

EG Leigh, Jr. 2007. Neutral theory: a historical perspective. Journal of Evolutionary Biology 20: 2075-2091.

EG Leigh, Jr. 1991. Genes, bees & ecosystems: the evolution of a common interest among individuals. Trends in Ecology and Evolution 6: 257-262.

EG Leigh, Jr., RT Paine, JF Quinn & TH Suchanek. 1987. Wave energy and intertidal productivity. Proc. Nat. Acad. Sci. 84: 1314-1318.

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