An age old problem?

January's Sci Bar was delivered by Dr Joao Pedro De Magalhaes from the University of Liverpool's Institute of Integrative Biology. The topic was close to the hearts (perhaps literally) of everyone in the audience, which was, as usual, a full house. Bob Roach thanked Joao (following a group discussion on consensus pronunciation), as Pedro, for agreeing by return of email to turn up so close to New Year. The aim of the talk was to explore what could be learned from comparing the genetics of ageing in man and in a wide range of organisms, from whales and mice, to the simpler eukaryotes: Baker's yeast and Caenorhabditis elegans. In addition Joao discussed the types of genes that seemed to be associated with longevity. In keeping with the influence of epigenetics in contemporary clinical and behavioural research, there was a discussion of the environmental factors, including diet, that might influence life-span.

Using examples drawn from a wide spectrum of evolutionary examples, Joao began with a statement of the central dogma of Molecular Biology, originally proposed by Francis Crick: DNA makes RNA makes protein. It was in this context that he explained how mutations in the genome could give rise to proteins of modified function, which in turn could potentially influence life-span. What was striking from one of Joao's slides, was the "investment" that simple model organisms make in age-related processes. For example, out of around 6 000 genes, the simple unicellular yeast has over 800 genes linked in some way to life-span. Clearly, many of these genes will provide essential functions that impact upon ageing, but are probably there to provide other key roles in general growth and reproduction of yeast. And what of the role of non-coding RNAs in these mechanisms?

The gene associated with the maintenance of the tips of chromosomes, or telomeres, was also discussed as an important factor in cellular aging, with Dolly the Sheep owing its early onset ageing characteristics being partly a result of a dysfunctional telomerase activity. Companies like Geron in California who focus on understanding the genetic factors influencing life-span, seem to provide "wealthy" citizens the opportunity to extend life and in particular the quality of life at an advanced age.

There were two issues raised in the presentation that seemed to capture the audience's attention. The first was a study of the correlation between height and life expectancy and the second was the explanation behind the exceptional longevity of whales. The gene encoding the growth hormone receptor in both mice and men, when mutated can supply a form of "resistance" to cancer and diseases in general and indirectly promotes life-span. Whilst the speaker acknowledged that the sample size and its restricted nature (a self contained US community), made extrapolation questionable; the trend was intriguingly clear in the particular sample  tested.
 
The Bowhead whale has proved a rich seem of longevity related research but, suggestions about the age estimates are not easy to verify; notwithstanding old harpoon scars! However, the superb, online resource provided by Joao and his colleagues is surely the way forward for unlocking teh potential of comparative genomics in improving the quality of life as the mean life-span of humans slowly increases!

You can find access to the Bowhead Whale Genome Project here.