mitochondrial DNA - all things bad?
Aubrey de Grey
ag24 at mole.bio.cam.ac.uk
Mon Nov 15 08:01:13 EST 1999
Doug Skrecky wrote:
> Mitochondrial DNA--all things bad?. [Review] [27 refs]
> Trends in Genetics. 15(3):91-3, 1999 Mar.
> The mitochondrial theory of ageing, however attractive in principle,
> is supported by very little hard evidence.
Yes, an excellent review (and I say that not just because I know the
authors well). It highlights the shortcomings (i.e. incompatibility
with existing data) of the simplistic mitochondrial theory of aging,
which is that we lose bioenergetic capacity due to having fewer and
fewer functional mitochondrial genomes. That theory has been history
for several years, in fact, and the somewhat frustrated tone of that
review is a reflection of the reluctance to abandon it that some who
should know better have shown. What the review doesn't cover is the
considerably greater difficulties facing the idea that mitochondrial
decline does NOT have much to do with aging. It does, however, note
in conclusion that:
"the argument that accumulation of mtDNA defects contributes to the
ageing process is unconvincing, unless one postulates a wholly
unprecedented 'dominant' effect of a small number of respiratory-
deficient cells. Although an interesting hypothesis has recently
proposed how such cells may cause a more global defect resulting
in tissue senescence, this hypothesis has yet to be tested
but modesty forbids me from elaborating.
Aubrey de Grey
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