Origin of intelligence and mental illness linked to ancient genetic accident
December 4, 2012
Like mice, humans with mutations in the DLG2 gene made significantly more errors than healthy control subjects in tests of visual discrimination acquisition and cognitive flexibility (credit: J. Nithianantharajah et al/Nature Neuroscience)
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, 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 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.
Mice and humans share limitations of higher mental functions’
This animal’s descendants benefited from these extra genes, leading to behaviorally sophisticated vertebrates — including humans.
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 behavioral tests with information from the genetic codes of various species to work out when different behaviors evolved.
They found that higher mental functions in humans and mice were controlled by the same genes.
Genetic causes of brain disorders
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.
The study was funded by the Wellcome Trust, the Medical Research Council and European Union.
Comments (11)
by Bri
What was the accident? Was it a two car pile up? I’ve heard rumors that sponges have protosynapsis, but don’t ask them about it. Jokes aside, I didn’t think that DNA was conserved for such a long time period. At 550 million years ago, that Chordate vertebrate was definitely qt the base of the tree. Now I can see a human kicking back with a touch screen, but I’d love to see the mouse reaching out to touch a choice. We’ll forget about the chordate vertebrate taking that test.
by Gorden Russell
“…a simple invertebrate animal living in the sea 500 million years ago experienced a “genetic accident…”
I do wish that they were more specific in describing this animal. So was it a flatworm or a roundworm? Was it segmented? C’mon, inquiring minds want to know.
by Editor
Good question. It was a vertebrate at the base of the chordate evolutionary tree (http://en.wikipedia.org/wiki/Chordate) 550 million years ago, per Ref. 1 (Jess Nithianantharajah et al., Synaptic scaffold evolution generated components of vertebrate cognitive complexity, Nature Neuroscience, 2012, DOI: 10.1038/nn.3276)
by eldras
Ho! That’s well answered!
Anecdotally there has often said to be a link between mental illness and brilliance: many ‘geniuses’ have close relations with mental illness.
Until the great calculators arrive we cant do good enough brain simulations…which are vast…to know what;s going on from atoms up. It may be humanly impossible to – although it might be possible in abstractions, but coming machine intelligences could do it all quite quickly, including producing by 3D print the one off gene therapy pill to cure any mutations.
Definitely a case for the quantum archaeology grid!
by Mr.X
“Anecdotally there has often said to be a link between mental illness and brilliance: many ‘geniuses’ have close relations with mental illness.”
Excuse me sir, but could you please define the term “urban legend” for me!?Or, more fittingly, the word “myth.” Thanks in advance.
“including producing by 3D print the one off gene therapy pill to cure any mutations.”
Not talking about the usefulness of such a pill, “curing” ANY mutations, this presupposes that such a thing can be brought into the physical form of a pill.Why not just building a pill that can do everything, instead!?
Have a nice day.
by Jerry
While there hasn’t been any extensive study done for intelligence that I’m aware of, creativity seems to have a link with mental illness. Here’s a new study http://www.huffingtonpost.com/2012/10/17/creativity-mental-illness-bipolar-disorder_n_1972391.html
by Mr.X
@Jerry: Thanks for your link.
by Bri
@Eldras: check out Steve Jobs biography.. Definitely a few loose screws!
by Mr.X
@Bri: He believed in things that are similiar to your beliefs:)
by David Nollmeyer
Musing Overman. I believe the first land animal was a scorpion. Hence a shrimp that crawled on land. I run into one every few months here near the Salton Sea which is below sea level now.
by Jerry
Great, now you made me want to re-watch the ‘Walking with …’ series!