As many of you are probably aware of there is
an ongoing debate regarding the mechanism of mitochondrial DNA (mtDNA)
replication (see for instance Holt and Reyes, 2012).
The models were summarized well in a recent paper from Fonseca et al. in PlosOne
2014.
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| Fonseca MM et al. PlosOne 2014 |
They analyzed the base composition of the mtDNA
protein-coding genes (2500 mtDNAs) and found a clear bias, which correlated with the
direction of the control region. Based on this they concluded that the
strand-displacement model (SDM) or the ribonucleotides-incorporation throughout
the lagging strand model (RITOLS) is likely to be the replication mechanism
instead of the strand-coupled model (SCM).
Of course one can always hypothesize that the
SCM is specific for cell cultures (as in the original paper
describing this model) or is tissue specific. However, from the evolutionary
point of view the strand-displacement model seems to be the more important one.
Whether the single-strand DNA is covered by mtSSB or RNA remains to be seen.
