Evolution of Gene Regulation and the Origin of Pregnancy in Mammals

Friday seminar by: Günter P. Wagner

Abstract

 

The evolution of organismal complexity is, to a large part, based on the evolution of differential gene regulation. Hence the population genetic and molecular processes that lead to the origin of novel expression patterns are the core of the evolutionary developmental biology. We investigate these processes in the context of the evolution of placentation in mammals, specifically the evolution of the endometrial stromal cell (ESC). The ESC is the maternal cell type that forms the maternal-fetal interface. In short we find that there are two types of unconventional genetic changes involved in the evolution of the ESC gene regulatory network: 1) novel cis-regulatory elements, and 2) adaptive changes in the functional properties of transcription factor proteins. These findings contradict the current paradigm of developmental evolution which assumes a conserved developmental “toolset” (i.e. the protein functions do not change) and cis-regulation evolves through the modification of ancestral CREs. It is thus likely that innovation and adaptation may be based on different kinds of genetic changes. Innovations are facilitated by transposable elements and induce changes in the transcription factor proteins, while most of adaptive modifications of development are based on modifications of existing CREs.

Günter P. Wagner
Yale University

Published Feb. 6, 2012 2:57 PM