Saturday, August 11, 2007

Evolution's greatest mistakes

There's an interesting article in New Scientist magazine this week on Evolution's greatest mistakes. The article covers seven areas of human biology where evolution has made the best of a bad job, and where it would be hard to argue that any 'intelligent' design has been going on. Unfortunately reading the article requires a subscription to the magazine so from a Berkeley website you may, or may not, be able to read it here. But if not, in the interest of academic debate and in the spirit of fair use, I copy an extract below.

A particularly interesting topic for this class is the discussion of mitochondrial DNA. Bottom line: If you wanted to build humans to last, mitochondria are the last place you'd put DNA.

'Inside every one of our cells are dozens of little sacs called mitochondria, in which sugars are "burned" to produce the energy that powers the cells. The process also produces highly damaging molecules called free radicals, so the interior of a mitochondrion is hardly the safest place for vital DNA - and yet it is home to the genes for 13 crucial mitochondrial proteins.

It's a crazy design: like keeping the repair manual for a steam engine by the furnace, where it inevitably becomes charred and unreadable. The slow loss of function as mutations accumulate in mitochondrial DNA may be the main cause of ageing and, some believe, of many age-related diseases, from diabetes to Alzheimer's.

The DNA is there because of our evolutionary history. Mitochondria are the remnants of a once independent bacterium that formed a symbiotic alliance with our cells around 2 billion years ago. Over time, many of the bacterium's original genes have been lost or jumped to the cell nucleus, but human mitochondria still retain 13 genes.

Anti-ageing research is already exploring ways of moving the remaining genes to the safety of the nucleus. It will not be easy. The 13 genes cannot simply be moved to the nuclear genome, because then the 13 proteins will be made outside the mitochondria where they are needed. A solution might be to get the mRNA recipes for proteins delivered to the mitochondria, so the genes reside in the nucleus but the proteins are still made inside the mitochondria.'

This time last year: the very depressing Eastern Garbage Patch



At 2:14 PM, Anonymous Anonymous said...

This is a pretty interesting case against the idea that humans were built to last, but I don't think that's an integral criterium for most intelligent design theories. If they use the bible to support anything, it does say something along the lines of God stating outright that he won't allow man to live more than 120 years. The repercussions of DNA being stored in mitochondria doesn't serve as evidence against ID in that light.

At 1:23 AM, Anonymous Garden seating said...

There are many who believe that the body is a design that can live for many hundreds of years and there have been accounts of such people, is there a mutation where individuals in the past have been born with these genes in another place, it makes us wonder if the 'body clock' is there by design or by accident.

At 1:33 AM, Anonymous B&Q said...

Having the ability to control aging is a dangerous thing, I know this is just research but if through gene manipulation it was possible the population increase would be unsustainable, we would quickly over populate the planet, this is for some the territory of god and maybe we should not pursue this path.

At 5:37 AM, Anonymous asda car insurance said...

I agree that we should not try to manipulate genes, something could and probably would go drastically wrong, we are sometimes a little arogant with out scientific knowledge and it is a dangerous attitude to have, we should let nature takes its course.


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