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SUMMARY:Unravelling the evolutionary forces that shape the B12 requirement
 s of algae - Katherine Helliwell\, Plant Metabolism
DTSTART:20121109T130000Z
DTEND:20121109T133000Z
UID:TALK40558@talks.cam.ac.uk
CONTACT:24938
DESCRIPTION:The distribution of vitamin B12 dependence in algae is sporadi
 c and there are several examples of closely-related species which differ i
 n their requirements for this vitamin. Such variable cofactor dependence r
 aises interesting evolutionary questions. Vitamin B12 is an essential cofa
 ctor for the vitamin B12 dependent isoform (METH). However\, the second is
 oform (METE) functions independently of vitamin B12. With the completion o
 f several algal genome projects\, a wealth of genomic information is now a
 vailable for representatives of key phylogenetic groups. Using this resour
 ce\, we have accumulated evidence which points to multiple losses METE as 
 being a key factor in the evolution of B12 dependence in algae. The discov
 ery of METE pseudogenes in the B12-dependent Chlorophycean species: Volvox
  carteri and Gonium pectorale\, captures this evolutionary transition in a
 ction. Moreover\, the repression of METE expression by B12 in the diverse 
 algae Chlamydomonas reinhardtii and Phaeodactylum tricornutum\, provides a
  mechanism for this to occur\, since prolonged repression of the gene by a
  reliable source of vitamin B12 could lead to the accumulation of mutation
 s\, and eventually the loss of METE entirely. During my talk I will provid
 e a summary of our most recent work that uses a variety of approaches to t
 ry to understand this process is more detail. Such insight would be highly
  valuable for our understanding of the interplay between genes and nutrien
 ts in algae\, which has important physiological and ecological consequence
 s.
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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