[Triumf-seminars] TRIUMF Journal Club Seminar today at 12:00

Mon, 10 Apr 2006 05:00:04 -0700

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Date/Time: Mon 2006-04-10 at 12:00

Location:  MainOffice Boardroom

Speaker:   Richard H. Cyburt (TRIUMF)

Title:     Filling in the Gaps in Evolution

Abstract: "Study, in a First, Explains Evolution's Molecular Advance"
by Kenneth Chang, NY Times April 7, 2006

"Evolution of Hormone-Receptor Complexity by Molecular Exploitation"
by Jamie T. Bridgham, Sean M. Carroll, & Joseph W. Thornton
SCIENCE VOL 312 7 April 2006
www.science.org

According to Darwinian theory, complexity evolves by a stepwise process of elaboration and optimization under natural selection. Biological systems composed of tightly integrated parts seem to challenge this view, because it is not obvious how any element's function can be selected for unless the partners with which it interacts are already present. Here we demonstrate how an integrated molecular system—the specific functional interaction between the steroid hormone aldosterone and its partner the mineralocorticoid receptor—evolved by a stepwise Darwinian process. Using ancestral gene resurrection, we show that, long before the hormone evolved, the receptor's affinity for aldosterone was present as a structural by-product of its partnership with chemically similar, more ancient ligands. Introducing two amino acid changes into the ancestral sequence recapitulates the evolution of present-day receptor specificity. Our results indicate that tight interactions can evolve by molecular exploitation—recruitment of an older molecule, previously constrained for a different role, into a new functional complex.

"The fish that crawled out of the water"
NATURE online: 5 April 2006
doi:10.1038/news060403-7

Please bring your lunch, rumors, news and Journal Club ideas.  Check out more about Journal Club at
http://trshare.triumf.ca/~theoryweb/ttgjclub.html

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