The pedigree rate of sequence divergence in the XXXX mitochondrial genome: there is a difference between phylogenetic and pedigree rates.

@entity1 @entity3054 @entity17054
We have extended our previous analysis of the pedigree rate of control-region divergence in the @entity1 mitochondrial genome. One new germline mutation in the mitochondrial DNA (mtDNA) control region was detected among 185 transmission events (generations) from five @entity3054 ( @entity3054 ) pedigrees. Pooling the @entity3054 pedigree analyses yields a control-region divergence rate of 1.0 mutation/bp/10(6) years ( @entity17054 ). When the results from eight published studies that used a similar approach were pooled with the @entity3054 pedigree studies, totaling >2,600 transmission events, a pedigree divergence rate of 0.95 mutations/bp/ @entity17054 for the control region was obtained with a 99.5% confidence interval of 0.53-1.57. Taken together, the cumulative results support the original conclusion that the pedigree divergence rate for the control region is approximately 10-fold higher than that obtained with phylogenetic analyses. There is no evidence that any one factor explains this discrepancy, and the possible roles of mutational hotspots (rate heterogeneity), selection, and random genetic drift and the limitations of phylogenetic approaches to deal with high levels of homoplasy are discussed. In addition, we have extended our pedigree analysis of divergence in the mtDNA coding region. Finally, divergence of complete mtDNA sequences was analyzed in two tissues, white blood cells and skeletal muscle, from each of 17 individuals. In three of these individuals, there were four instances in which an mtDNA mutation was found in one tissue but not in the other. These results are discussed in terms of the occurrence of somatic mtDNA mutations.
