Men
are different from women – they age faster for one thing, so why is that?
Clearly we need someone to blame, so who is it going to be, our mothers, or our
fathers? To get to the bottom of that we need an animal model, and the
same male/female divergence in aging occurs for many species.
The
latest attempt at unraveling the knotty problem is down to Camus et al in
Current biology (1, 2). They chose the humble fruit fly as their model. They
have the advantage that you can keep a lot of them very cheaply in a cage and
thy reproduce very rapidly. The latter asset means that it is possible to
follow the DNA mutations, if any, down through the generations.
Fruit
fly females live longer than their male counterparts, being energetic for
longer. Our cells generate the energy that they need to keep us happy and
content from the cellular mitochondrial power plants. As the paper points out,
our mitochondrial DNA, which is responsible for our mitochondria is only
inherited from our mothers.
The
concept is that mutations in the mitochondrial DNA will crop up periodically,
some of which will be good and some of which will be bad. Ultimately we believe
that good will triumph over bad, although it may take more than one attempt.
Now
we come to a selfish gene manifestation because mutations which effect females
adversely will be worked out of the system, but those that adversely effect
males only can survive and flourish if the inheritance is only through the
female and has no adverse effect on their survival.
Before
we lay too much blame at our mother’s door, we need to remember that aging is
effected by lots of other things such as our array of hormones, our brawling and
drinking habits as well as our love of the couch for football, beer and chips.
- M. F. Camus, D. J. Clancy and D.K. Dowling, Current Biology, 2012, dx.doi.org/10.1016/cub.2012.07.018
- http://www.bbc.co.uk/news/health-19093442
