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SUMMARY:Molecular perspectives of adaptations to challenges of polar envir
 onment - C-H Christina Cheng (University of Illinois)
DTSTART:20100705T133000Z
DTEND:20100705T143000Z
UID:TALK25390@talks.cam.ac.uk
CONTACT:Michael Thorne
DESCRIPTION:The survival challenges faced by endemic ectothermic\norganism
 s of the perennially frigid Antarctic marine\nenvironment are well appreci
 ated. The Antarctic\nnotothenioid fishes must contend with two exacting\ne
 nvironmental modalities - freezing seawater and high\nmarine oxygenation. 
 Underlying their cold-adaptive\nphysiologies are genomic and gene expressi
 on changes\ncrafted by millennia of these environmental selection\nforces.
  Nuclear gene expression changes are seen in\nhighly augmented transcripti
 on of a set of protein gene\nfamilies that operate in protein biosynthesis
 \, protein\nfolding and degradation\, anti-oxidation\, anti-apoptosis\,\ni
 nnate immunity\, and others\, all of recognizable functional importance in
  mitigating stresses in the cold during notothenioid life histories. Many 
 of these gene families have substantially expanded through gene duplicatio
 n\, providing large gene dosages for the observed transcriptional augmenta
 tions. The mitochondrial genome in Antarctic notothenioids and its role in
  mitochondrial energy production capacity are much less studied. We recent
 ly discovered a major mtDNA rearrangement that resulted in the translocati
 on of the gene encoding the ND6 subunit of mt Complex I to the mt Control 
 Region\, as well as detected positive selection operating on the ND6 prote
 in sequence. This highlights the importance of including the mt genome and
  mt proteins (mt and nuclear encoded) in evaluating mitochondrial capaciti
 es of Antarctic notothenioid in face of temperature and oxygenation change
 s in both evolutionary and short-term contexts. The growing body of genomi
 c and gene expression data for Antarctic notothenioids provide\ninformativ
 e entry points to experimental investigations\nof their cold-adaptive phen
 otypes (and thermal limits) at\nhigher level of biological organizations.\
 n
LOCATION:British Antarctic Survey\, Room 330B
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