The rate of mitochondrial mutagenesis is faster in mice than humans.

Published

Journal Article

We have investigated mitochondrial DNA (mtDNA) mutagenesis in the laboratory mouse. Using a nested PCR method for quantification, the absolute frequency, tissue distribution and rate of increase of mitochondrial deletion mutations was determined. Multiple deletions arise in brain, cardiac muscle and kidney tissues: deletions occur most frequently at regions of directly repeated mtDNA homology. Deletion frequencies rose by 2.5 x 10(5), 6300- and 4000-fold in heart, brain and kidney, respectively, between young and old mice. The rates of mtDNA mutation accumulation in mouse and human hearts are modeled well by exponential equations, with r-values of 0.96 and 0.97, and mutations rose much faster in mouse than human mtDNA per unit time. Thus, maintenance of the human mitochondrial genome is much better than that of mice, consistent with the higher rate and final extent of total DNA repair in humans than mice, that has been observed by others and consistent with the predictions of the disposable soma model of aging. A comparison of mtDNA mutagenesis from cardiocytes vs. whole heart tissue was undertaken. Deletion mutations were observed to be 100-fold lower in DNA prepared from isolated cardiocytes than from whole heart homogenates, consistent with a model of uneven mtDNA mutation accumulation.

Full Text

Duke Authors

Cited Authors

  • Wang, E; Wong, A; Cortopassi, G

Published Date

  • July 1997

Published In

Volume / Issue

  • 377 / 2

Start / End Page

  • 157 - 166

PubMed ID

  • 9247611

Pubmed Central ID

  • 9247611

Electronic International Standard Serial Number (EISSN)

  • 1873-135X

International Standard Serial Number (ISSN)

  • 0027-5107

Digital Object Identifier (DOI)

  • 10.1016/s0027-5107(97)00091-2

Language

  • eng