By Mark Prigg

PUBLISHED:13:57 EST, 12  November 2012| UPDATED:14:10 EST, 12 November 2012

Our intelligence and behaviour requires  optimal functioning of a large number of genes, which requires enormous  evolutionary pressures to maintain.

Now, in a provocative theory, a team from  Stanford University claim we are losing our intellectual and emotional  capabilities because the intricate web of genes which endows us with our brain  power is particularly vulnerable to mutations – and these mutations are not  being selected against our modern society because we no longer need intelligence  to survive.

But we shouldn’t lose any sleep over our  diminishing brain power – as by the time it becomes a real problem technology  will have found a solution making natural selection obsolete.

Researchers say be are becoming less intelligent because  we no longer need intelligence to survive

‘The development of our intellectual  abilities and the optimisation of thousands of intelligence genes probably  occurred in relatively non-verbal, dispersed groups of peoples before our  ancestors emerged from Africa,’ says Dr Gerald Crabtree, lead author of the  paper published today in Cell Press journal Trends in Genetics.

In this environment, intelligence was  critical for survival, and there was likely to be immense selective pressure  acting on the genes required for intellectual development, leading to a peak in  human intelligence.

But it was downhill from there on in as, from  that point, it’s likely that we began to slowly lose ground, the researchers  claim.

With the development of agriculture, came  urbanisation, which may have weakened the power of selection to weed out  mutations leading to intellectual disabilities.

Based on calculations of the frequency with  which deleterious mutations appear in the human genome and the assumption that  2,000 to 5,000 genes are required for intellectual ability, Dr Crabtree  estimates that within 3,000 years, about 120 generations, we have all sustained  two or more mutations harmful to our intellectual or emotional  stability.

Also, recent findings from neuroscience  suggest that genes involved in brain function are uniquely susceptible to  mutations.

Dr Crabtree argues that the combination of  less selective pressure and the large number of easily affected genes is eroding  our intellectual and emotional capabilities.

But the loss is quite slow, and judging by  society’s rapid pace of discovery and advancement, future technologies are bound  to reveal solutions to the problem, Dr Crabtree believes.

He said: ‘I think we will know each of the  millions of human mutations that can compromise our intellectual function and  how each of these mutations interact with each other and other processes as well  as environmental influences.

‘At that time, we may be able to magically  correct any mutation that has occurred in all cells of any organism at any  developmental stage.

‘Thus, the brutish process of natural  selection will be unnecessary.’

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Categories: . General Mutations, Counter Intuitive, Emerging, Hmmm?

Tags: Cell Press, Crabtree, Gene, Intelligence, Mutation, Natural selection, Stanford University, Trends (journals)