Scientists pinpoint origin of intelligence

Scientists have discovered for the first time how humans - and other mammals - have evolved to have intelligence.

Researchers have identified the moment in history when the genes that enabled us to think and reason evolved.

This point 500 million years ago provided our ability to learn complex skills, analyse situations and have flexibility in the way in which we think.

One of the greatest scientific problems is to explain how intelligence and complex behaviours arose during evolution.

Professor Seth Grant

Professor of Molecular Neuroscience, University of Edinburgh

Origins of intelligence linked to brain disease

The research also shows a direct link between the evolution of behaviour and the origins of brain diseases.

Scientists believe that the same genes that improved our mental capacity are also responsible for a number of brain disorders.

Their study is detailed in two papers in Nature Neuroscience

Evolutionary ancestors

The study shows that intelligence in humans developed as the result of an increase in the number of brain genes in our evolutionary ancestors.

The researchers suggest that a simple invertebrate animal living in the sea 500 million years ago experienced a ‘genetic accident’.

This resulted in extra copies of these genes being made.

This animal’s descendants benefited from these extra genes, leading to behaviourally sophisticated vertebrates - including humans.

Important genes

The research team studied the mental abilities of mice and humans, using comparative tasks that involved identifying objects on touch-screen computers.

Researchers then combined results of these behavioural tests with information from the genetic codes of various species to work out when different behaviours evolved.

They found that higher mental functions in humans and mice were controlled by the same genes.

The study also showed that when these genes were mutated or damaged, they impaired higher mental functions.

Our work shows that the price of higher intelligence and more complex behaviours is more mental illness.

Professor Seth Grant

Professor of Molecular Neuroscience, University of Edinburgh

The researchers had previously shown that more than 100 childhood and adult brain diseases are caused by gene mutations.

The study was funded by the Wellcome Trust, the Medical Research Council and European Union.

This ground breaking work has implications for how we understand the emergence of psychiatric disorders and will offer new avenues for the development of new treatments,”

John Williams,

Head of Neuroscience and Mental Health at the Wellcome Trust


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