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SUMMARY:Experimental evolution reveals rapid streamlining of vitamin metab
 olism in chlamydomonas reinhardtii - Katherine Helliwell (Smith Group)
DTSTART:20140214T130000Z
DTEND:20140214T132500Z
UID:TALK49503@talks.cam.ac.uk
CONTACT:Dr Yoan Coudert
DESCRIPTION:Vitamins are essential components of all cells\, as they provi
 de cofactors for enzymes of central metabolism. Animals must obtain vitami
 ns from their diet\, but in fact a widespread and complex distribution of 
 vitamin auxotrophy exists across the whole tree of life. I will present re
 cent work investigating the evolutionary origins of vitamin dependence\, u
 sing an experimental evolution approach with the fast-growing vitamin B12-
 independent alga Chlamydomonas reinhardtii. We observe\, after fewer than 
 500 generations of growth in medium supplemented with vitamin B12 (1000 ng
 /L)\, the evolution of a B12-dependent clone that rapidly displaces its an
 cestor. Genetic characterisation of this line reveals that a type-II Gulli
 ver-related transposable element (GR-TE) has integrated into the B12-indep
 endent methionine synthase gene (METE). We have captured this transpositio
 n event in action\, and witness the origin of a new unitary pseudogene\, a
 nd its subsequent rise in frequency within the population. This selective 
 sweep is reproducible with as little as 200 ng/L vitamin B12. Our study ex
 hibits how loss of a superfluous gene can occur rapidly and in response to
  subtle environmental cues\, with significant consequences for eco-physiol
 ogical flexibility.
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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