Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Linking Darwinian mechanisms with the evolution of form

Marty Kreitman

University of Chicago, USA

Abstract

As early as the 1960’s, prior to elucidation of genome structure, eukaryotic gene regulation, or the mechanisms controlling development, R. Britten and E. Davidson had compiled enough evidence indicating to them that the evolution of the multi-cellular body plan occurred through changes in the circuitry regulating development rather than through the adaptive substitution of point changes in proteins. But twenty years earlier, C.H. Waddington had already proposed his theory of canalization, a mechanism by which robust developmental pathways could suppress phenotypic (and genetic) variability, and give rise to an abundant classes of “hidden” variation upon which Darwinian selection can act when called upon. More recently, evolutionary studies of cis-regulatory modules ¬– the functional unit of gene expression control – have revealed surprisingly rapid structural evolution of their functional elements, even when there is strong evolutionary constraint on gene expression. Adaptive morphological evolution has also been traced to evolutionary changes in CRM’s, on the one hand reinforcing the Britten and Davidson belief that changes in gene regulation are paramount to evolutionary change, but also elevating Darwinian mechanisms involving the accumulation of mutational changes of small effect on the other. Here I attempt to sort through both the dialectical and empirical evidence supporting these opposing views. I also describe our current work on variation and evolution in pattern formation in Drosophila, a system I believe will allow resolution of the molecular basis for Darwinian selection acting on phenotypic variation filtered through developmental processes and pathways.

Marty Kreitman

University of Chicago, USA

Biography

Marty Kreitman is currently Professor of Ecology and Evolution at the University of Chicago. He received Ph.D in 1983 at Harvard University in the laboratories of Richard Lewontin and Walter Gilbert. He was one of pioneers in experimental molecular population genetics to test natural selection at the DNA sequence level and developed widely used statistical methods to detect selection.