Ed. Ladoukakis et E. Zouros, Direct evidence for homologous recombination in mussel (Mytilus galloprovincialis) mitochondrial DNA, MOL BIOL EV, 18(7), 2001, pp. 1168-1175
The: assumption that animal mitochondrial DNA (mtDNA) does not undergo homo
logous recombination is based on indirect evidence, yet it has had an impor
tant influence on our understanding of mtDNA repair and mutation accumulati
on land thus mitochondrial disease and aging) and on biohistorical inferenc
es made from population data. Recently, several studies have suggested reco
mbination in primate mtDNA on the basis of patterns of frequency distributi
on and linkage associations of mtDNA mutations in human populations, but ot
hers have failed to produce similar evidence, Here, we provide direct evide
nce for homologous mtDNA recombination in mussels, where heteroplasmy is th
e rule in males. Our results indicate a high rate of mtDNA recombination. C
oupled with the observation that mammalian mitochondria contain the enzymes
needed for the catalysis of homologous recombination, these, findings sugg
est that animal mtDNA molecules may recombine regularly and that the extent
to which. this generates: new haplotypes may depend only on the frequency
of biparental inheritance of the mitochondrial genome. This, generalization
must, however, await evidence from animal species with typical maternal mt
DNA inheritance.