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SUMMARY:The 2nd Annual Sir John Walker Lecture: &quot\;Bioenergetic constr
 aints on the evolution of cells&quot\; - Dr Nick Lane\, University College
  London
DTSTART:20141124T163000Z
DTEND:20141124T173000Z
UID:TALK54815@talks.cam.ac.uk
CONTACT:Penny Peck
DESCRIPTION:Chemiosmotic coupling is as universal as the genetic code\, ye
 t its origins are poorly understood. I will show how natural proton gradie
 nts could have driven the emergence of cells in hydrothermal vents. Prokar
 yotes are then constrained by membrane bioenergetics. Despite their bioche
 mical virtuosity\, neither bacteria nor archaea show any tendency to evolv
 e complex eukaryotic traits or large genomes. All complex life on Earth is
  eukaryotic\, and all eukaryotes share a common ancestor that was already 
 a complex cell\, with a nucleus\, dynamic cytoskeleton\, meiotic sex\, etc
 . Eukaryotes arose in a rare endosymbiosis between two prokaryotes\, which
  broke the energetic constraints on prokaryotes through the evolution of m
 itochondria. Loss of almost all mitochondrial genes produced an extreme ge
 nomic asymmetry\, in which tiny mitochondrial genomes support\, energetica
 lly\, a massive nuclear genome\, giving eukaryotes 3-5 orders of magnitude
  more energy per gene than prokaryotes. The requirement for endosymbiosis 
 radically altered selection on eukaryotes\, potentially explaining the evo
 lution of deeply conserved traits including two sexes\, germline\, apoptos
 is\, speciation\, ageing and disease. 
LOCATION:Max Perutz Lecture Theatre\, MRC LMB
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