The new findings thus indicate that the differences appear to lie outside the protein-coding genes in what has been labelled as "junk DNA", which was thought to have no function and which constitutes the majority of our DNA.
“This suggests that the basis for the human brain’s evolution are genetic mechanisms that are probably a lot more complex than previously thought, as it was supposed that the answer was in those two per cent of the genetic DNA. Our results indicate that what has been significant for the brain’s development is instead perhaps hidden in the overlooked 98 per cent, which appears to be important. This is a surprising finding.”
The stem cell technique used by the researchers in Lund is revolutionary and has enabled this type of research. The technique was recognised by the 2012 Nobel Prize in Physiology or Medicine. It was the Japanese researcher Shinya Yamanaka who discovered that specialised cells can be reprogrammed and developed into all types of body tissue. And in the Lund researchers’ case, into brain cells. Without this technique, it would not have been possible to study the differences between humans and chimpanzees using ethically defensible methods.
Why did the researchers want to investigate the difference between humans andchimpanzees?
“I believe that the brain is the key to understanding what it is that makes humans human. How did it come about that humans can use their brain in such a way that they can build societies, educate their children and develop advanced technology? It is fascinating!”
Johan Jakobsson believes that in the future the new findings may also contribute to genetically-based answers to questions about psychiatric disorders, such as schizophrenia, a disorder that appears to be unique to humans.
“But there is a long way to go before we reach that point, as instead of carrying out further research on the two per cent of coded DNA, we may now be forced to delve deeper into all 100 per cent – a considerably more complicated task for research”, he concludes.