I read somewhere that chickens are sometimes hatched with teeth, as long-disused genes are switched back on by genetic mistakes. Nature is rather hopeless at managing DNA, so your genome is packed with "junk" including old genes that went wrong when we were plants. I was thinking about this because on Oxford Street today I was waiting to cross the road when I noticed a youth standing opposite me. He finished a bag of crisps and then threw the bag on the ground in a defiant manner, glaring around at the midday shoppers as if daring one of them to rebuke him for his exuberantly disgusting behaviour. In itself, not an unusual occurrence in the Zimbabwe of the North. But he looked decidedly Neanderthal to me, the spitting image of our pre-modern human cousins as depicted in museum displays around the world. I started to panic slightly. Suppose three generations of the welfare state has reduced evolutionary pressures for fitness, intelligence and other characteristics to the level below which they can no longer aid natural selection! It would explain a lot: as the old genes are randomly switched on, they are no longer selected away. This could explain why the general population is getting fatter and stupider and also provide an appropriate backdrop to celebrating the 200th anniversary of Charles Darwin's birth (which I am learning all about from the "In Our Time" podcasts even as I type). In hundred years or so, the population may well become largely Neanderthal again in Britain, and by then scientists will be able to clone wooly mammoths, so everyone will feel quite a home.
[posted with ecto]