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Friday, August 12, 2005

Genetics, Disease and Peak Oil: The Race to the Bottom

Does modern medical science encourage the spread of weaknesses in the human population?

It is no secret that modern medicine has allowed many people to survive diseases and conditions that might otherwise have killed them. Does this mean that the genes for these conditions, like diabetes for example, are spreading in the population?

If the genes for potentially lethal conditions have persisted in the human species up to this point, then that indicates that they aren’t totally reliant on medical science. For example, any gene that produces a condition after the prime reproductive age is unlikely to be restrained in any significant way. So the genes for cancers of different types, for example, are prevalent in humans.

But there are many commonplace conditions, carried as recessive alleles, which would, in a less beneficent age, have done away with people before they were able to breed. Allowing those that inherit two copies of a destructive allele to survive only marginally adds to the reproductive success of that particular gene.

Many expectant parents in the western world carry out genetic screening to determine whether their offspring carry genes that will potentially require lifelong treatment, so that they can decide whether to terminate the pregnancy, so you could argue that medical science is helping to eliminate the transmission of certain undesirable genes.

But are any genes being actively reinforced? In other words, what are the selection pressures on the human species that are driving our evolution? We can say one thing for sure – life in much of the world today is less physically demanding than it was in our species’ early history. We do not have to chase down our prey, we do not necessarily have to have good eyesight, and many of us have such ready access to food that we are at risk of killing ourselves by overeating rather than starving.

Are we getting smarter then? It would be extremely difficult to find evidence that intelligent people are more reproductively successful. In fact, you could argue that an intelligent person might look at the state of life on earth and wonder whether it is a good idea to reproduce.

We are adapting to our environment, but that environment is not one of relentless competition, but rather one of comparative ease. We are living in the heyday of an energy glut, the like of which will never be seen again. We have adapted to this by developing technologies and techniques that support more and more of us through the use of fossil fuel derivatives to grow food, produce medicines and allow transportation.

And this ever burgeoning population does support a larger proportion of people with congenital defects that would have killed them in days gone by, but these may in fact be immaterial in the short run.

Rather than being flung into a situation where we are again tracking antelope on the steppes, we are more likely to face a threat that has always menaced human populations. Microbes.

As I write H5N1 has been found in another Asian country. It is by no means certain that this particular virus will cross the species barrier completely and begin human-to-human transmission. But if it doesn’t, eventually a virus will evolve that does.

In today’s hyper-connected world a virus with the right characteristics of lethality, mode of transmission and incubation period could easily engulf the world, leaving a huge numbers of deaths in its wake.

Viruses have a much more terrifying potential for the human species than the quirks of genetic variability, which would be weeded out by a more strenuous environment. We live under the pretence that we are immune to the ravages of the plague cycle. But nothing could be further from the truth. If anything we have become more susceptible.

One caveat does obtain to this argument however. If we fall off the cliff of energy decline, then we may in fact avoid being caught up in a worldwide pandemic. It is probably more likely that as medicines become less available, air travel less common and people more malnourished, that less widespread but more locally devastating epidemics will predominate.

Look out below! The race to the bottom has started!

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