PRESIDENTIAL LECTURE SERIES  
2003
 
presents
 

Professor Ronald S. Burton
Professor and Director
Marine Biology Research Division Scripps Institution of Oceanography University of California, San Diego
La Jolla, CA 92093-0202

Ronald S. Burton is Professor of Marine Biology and Director of the Marine Biology Research Division at Scripps Institution of Oceanography at the University of California, San Diego. He received his Ph.D. from Stanford University in 1981 and has held faculty positions at the University of Pennsylvania and the University of Houston before arriving at SIO in 1992. He has published over 50 papers focusing on the integration of evolutionary studies across disciplines of biology, from molecular genetics to evolutionary ecology. Of particular interest are the molecular mechanisms underlying the formation of new biological species.

LECTURE

"Why F2 Hybrids are Weak: The Molecular Basis of Coadaptation"

Tuesday, November 4th
3.45 pm

Florida International University (FIU)
Wertheim Conservatory
11200 SW 8th Street, Miami, FL

(Enter FIU through SW 107th Avenue and SW 16th Street)

Arrive early.
Seating is on a first-come, first-serve basis.
  When populations of organisms genetically diverge (whether due to geographic isolation or agricultural practices), first generation hybrids often show growth and productivity greater than the parental strains. This hybrid vigor (the basis of much of modern agriculture), however, gives way to hybrid breakdown (reduced productivity) in later generations. Why are F2 hybrids weak? What genetic interactions lead to reduced performance? Starting with the hypothesis that reduced performance might reflect reduced efficiency in energy production, we have focused our investigations on genes functioning in mitochondrial metabolism in populations of a small marine crustacean, the copepod Tigriopus californicus. Geographically isolated populations of this species show extensive differentiation in mitochondrial gene sequences. Since energy production requires interaction between proteins encoded in both nuclear and mitochondial genomes, we have studied enzyme activities of hybrids having their nuclear genome from one population but their mitochondrial genome from a different population. Such hybrids show reduced enzyme activity, apparently due to the lack of coevolution between the genomes of isolated populations. Experiments at the whole organism level confirm that certain inter-population gene combinations have low fitness, but fitness is also strongly tied to environmental conditions.