Origin of Human Intelligence --"Linked to a Genetic Accident 500 Million Years Ago"

Researchers have identified the moment in history 500 million years ago that provided our ability to learn complex skills, analyze situations and have flexibility in the way in which we think. According to Professor Seth Grant of the University of Edinburgh, who led the new research, intelligence in humans developed as the result of an increase in the number of brain genes in our evolutionary ancestors: a simple invertebrate animal living in the sea 500 million years ago experienced a “genetic accident,” which resulted in extra copies of these genes being made.

The research team studied the mental abilities of mice and humans, using comparative tasks that involved identifying objects on touch-screen computers. They then combined results of these behavioral tests with information from the genetic codes of various species to work out when different behaviors evolved and discovered 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 behaviors is more mental illness,” said Professor Grant.

“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,” said John Williams, Head of Neuroscience and Mental Health at the Wellcome Trust, one of the study funders.

The researchers had previously shown that more than 100 childhood and adult brain diseases are caused by gene mutations.“We can now apply genetics and behavioral testing to help patients with these diseases”, said Dr Tim Bussey from Cambridge University, which was also involved in the study.

Journal reference: Jess Nithianantharajah et al., Synaptic scaffold evolution generated components of vertebrate cognitive complexity, Nature Neuroscience, 2012, DOI: 10.1038/nn.3276

Source: The Daily Galaxy via the Wellcome Trust, University of Edinburgh