Lack of potential mates has lead to sloppy gene control and risk of disease for humans

January 25, 2005

From Medical News Today and PLOS Biology 25 Jan 2005

Lack of potential mates has lead to “sloppy” gene control and risk of disease

for humans

Our evolutionary ancestors' lack of choice in the mating game has left modern

humans exposed to disease, according to new research published in the journal

PLOS Biology tomorrow (Tuesday 25 January 2005).

Key regions of our DNA, that control when genes are switched on and off, have

been altered by around 140,000 naturally-occurring mutations over the last six

million years, the researchers found.

This has left modern humans with ‘sloppy' gene control mechanisms which can make

us susceptible to diseases, or directly cause genetic diseases.

The researchers suggest that most of the ‘mildly harmful' mutations occurred at

a time when there was only a small population (10,000) of early Hominids, the

two legged primates that were to later evolve into both humans and chimpanzees.

Had there been more early Hominids, and hence a greater choice of mates, most of

these mutations would have been overridden by natural selection from a larger

pool of available DNA.

This contrasts dramatically with rats and mice which, because of their larger

ancestral population, have been able to maintain the integrity of their

regulatory sections of DNA.

The researchers, from the Universities of Bath, Edinburgh and Sussex, made the

finding after comparing control regions in human, rat, mouse and chimpanzee DNA.

After ‘unwinding' evolution using statistical techniques, they found that the

way our genes are switched on and off is much less carefully controlled in

humans and chimpanzees compared to other animals.

“We are used to viewing us as the pinnacle of evolution but seeing that rodents

control their genes much more precisely is somewhat sobering,” said Dr

Lercher from the University of Bath.

“As a species we have become used to the benefits of ever-increasing health care

and nutrition, but if what we found is still ongoing, then these improvements

might at some point be offset by the deterioration of our gene control regions.”

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