Mitochondrial DNA and recombination

Bio-student

Does mtDNA recombine? I've tried doing my own research but I'm getting very mixed responses, from the evidence being strongly against it, right up to it being a well-known phenomenon in yeast. any insight please?

SW VandeCarr

mtDNA recombination is known to occur in yeast, plants, fungi and even some invertebrates. There is evidence of occurrence of inter-molecular heterologous mtDNA recombination in mammals including humans according to the linked article, based in part on experiments with human hybrid cells.

http://hmg.oxfordjournals.org/conten....full.pdf+html

mack_10

I would have thought this extremely unlikely

In mammals all the mitochondrial is from the maternal mitochondria there is nothing for it to recombine with

SW VandeCarr

I don't know how mtDNA repair or replication would be related to the fact that mtDNA is determined by the maternal line. On the other hand, the paper I cited was in human hybrid cells under experimental conditions, so I don't believe natural mtDNA repair by recombination has been established in humans. Here's a paper discussing the finding of possible intermediates of mtDNA repair by recombination in human heart muscle.

http://www.nature.com/embor/journal/.../embor288.html

mack_10

http://www.nature.com/embor/journal/.../embor288.html

sounds more like an artefact than proof

madcat8000

It depends entirely on the situation. In higher animals it is exceedingly rare because in most cases there are safeguards to prevent maternal and paternal mitochondria from mixing for various good reasons. However in yeasts and some other single celled eukaryotes, they are known to fuse under both natural and experimental conditions and so mt-recombination is more common. Basicly it dose happen where ever there is a mixed inheritance. http://www.nature.com/hdy/journal/v9.../6800572a.html

SW VandeCarr

This paper discusses three possible mechanisms for non-clonal inheritance in human mtDNA: paternal leakage, nuclear pseudogenes and heteroplasmy. The last is a very rare condition in humans.

http://www.springerlink.com/content/...1/fulltext.pdf

This paper summarizes the evidence for mtDNA recombination in animals as of 2004.

http://mbe.oxfordjournals.org/content/22/4/925.full.pdf

wedris

In 1992, i found evidence of resolved Holliday junctions in rat mtDNA by PCR across the 16 bp direct repeat. If not an artifact, this at the least would argue for intramolecular recombination producing sub-plasmid minicircles and the reverse. Maybe this would account for the unusually robust maintenance of mtDNA sequence integrity over the long lifetime of mammals in a hostile (respiratory) environement. No one was interested.

Ryan_m_b

Welcome to PF wedris. This post is quite old (9 months) and the OP has been answered. Nether the less feel free to start a new thread regarding mitochondrial DNA. Please note though that as per the PF rules personal theories are not allowed so if you would like to talk about your work you should provide some publications to support it.

http://www.physicsforums.com/showthread.php?t=414380