SCIENCE AT THE EDGE SEMINAR SERIES

Quantitative Biology & Modeling Seminar

Friday, 20 April 2012 at 11:30am

Room 1400 Biomedical and Physical Sciences Bldg.

Refreshments at 11:15

Speaker: Ehab Abouheif
         Department of Biology, McGill University

Title:   Parallel Evolution of a Gene Network in Sky Island Ant Populations
         is Contingent on Population History

Abstract:

The degree to which the repeatability of evolutionary outcomes is contingent
upon historical events is a central question in evolutionary biology. Although
this has been tested in microorganisms under controlled laboratory conditions,
little is known about its dynamic in wild populations. We therefore studied
independently evolving populations of the ant Monomorium emersoni on five
"Sky Islands," which are mountain ranges in Arizona that provide natural
laboratories for testing such ideas.  We combined ecological, morphological,
and population genetics with gene expression analyses to understand how the
gene network underlying wing development has evolved in parallel in the
different sky island populations. We show that these populations are evolving
independently in each sky island, where each exhibits frequency changes in an
alternative phenotype, winged and wingless queens, along a replicated
ecological gradient. We discovered that while some key genes in the network
show repeated adaptive changes reflecting an ancestral potential for wing
loss, other genes have evolved differences in their expression pattern
reflecting the historical context of population contacts as well as more
recent changes independent of population history. Therefore, evolutionary
trajectories of developmental gene networks may often be contingent on their
population history.