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SUMMARY:A battle of dominance: should mitochondrial DNA be selfless or sel
 fish?  - Hansong Ma (Gurdon Institute)
DTSTART:20170315T173000Z
DTEND:20170315T193000Z
UID:TALK71381@talks.cam.ac.uk
CONTACT:Clara Sidor
DESCRIPTION:Mitochondrial DNA (mtDNA) is a maternally-inherited genome tha
 t encodes important\nsubunits of the respiratory chain. Given that there a
 re multiple copies of mtDNA\nwithin each cell\, pathogenic mutations often
  arise among thousands of wild-type\ngenomes. Selectivity in transmission 
 of functional versus pathogenic genomes in\nsomatic cells impacts expressi
 on of disease phenotype. While selective\ntransmission in germline governs
  the heritance of mtDNA mutations into progeny\,\nand thus its evolution. 
 However\, what influences the competition of co-existing\nmitochondrial ge
 nomes is not yet clear.\n\nRecently\, we have developed Drosophila as a po
 werful model for mtDNA studies. This\nhelped to resolve two types of selec
 tion that influence the competition between\nmitochondrial genomes: 1) a p
 urifying selection where the genome providing more\nfunction always takes 
 over. This selection plays an essential role in keeping the\nfunctional in
 tegrity of mtDNA during evolution\; 2) a selfish selection where a\nbully 
 genome gain over a wimpy genome if it replicates or transmits better (i.e.
 \nindependent of function). This selection allows different mutations that
  enhance\nreplication to accumulate in different female lineages\, thus en
 hancing mtDNA\ndiversity.  For an individual\, when the gains in one selec
 tion are balanced by\nlosses in the other\, both genomes are maintained in
  a stable ratio for many\ngenerations. We have established such a line in 
 Drosophila that stably carries two\nmitochondrial genomes\, one that benef
 its from a selection for function and one\nwith a replicative advantage. C
 urrently\, we are performing a deficiency genetic\nscreen to identify nucl
 ear regions/genes whose genetic dose influence the stable\nbalance of thes
 e mitochondrial genomes\, in order to identify nuclear genes\nimpacting th
 e selective transmission of mtDNA.  
LOCATION:Gurdon Institute Tea Room
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