Dinosaurs were nervous rex

A GENETIC link between dinosaurs and humans could provide the key to developing a treatment for depression, according to Scots scientists.

Experts have discovered that the component in human DNA which triggers depression also existed in prehistoric beasts – and would have helped determine their moods.

Using cutting-edge technology, scientists at Aberdeen University have identified the genetic "switches" they believe turn off and on genes that control our behaviour and moods.

The switches, also known as "enhancers", have remained unchanged in human genes for hundreds of millions of years. Scientist were able to make the link between humans and dinosaurs by examining the DNA structures of other species of animals and birds.

They believe the enhancers may hold the key to unlocking the causes of depression and explain why some people develop the illness while others, with a similar genetic make-up, do not.

Although the enhancers are found in every animal alive today, their location has remained a mystery until now.

Dr Alasdair MacKenzie, senior lecturer at Aberdeen University, who is leading the study, said: "It appears the switch that drives the gene (which causes depression] seems to have controlled feelings of fear and anxiety in our ancestors 300 million years ago.

"The difference is that, originally, it was part of our survival system. The pathology of this gene now is people suffer these same feelings of fear and anxiety when they don't need them."

The cells containing these genes are found in the amygdala – located deep within the human brain – the primary role of which is in the processing and recall of emotional reactions.

Dr MacKenzie said the breakthrough was in focusing on the switches that drive the genes rather than the genes themselves.

He likened it to "moving from looking at a car to examining its engine" and said the distances between the switch and the part of the brain they affected were "as surprising as having a light bulb in London with the switch for controlling it in Liverpool".

Researchers will now team up with Liverpool University and King's College London to launch a £1 million research programme in the hope of finding a cure for the debilitating condition.

They will work with people who have depression to examine their DNA and look for common changes in their genetic switches. This could lead to drug treatments which will target the cause of depression and not just its symptoms.

Professor Darren Monckton, a genetic expert at Glasgow University said identifying the switches could be one of the biggest challenges for scientists.

He said: "Normally, when you looking for a disease-causing mutation, it's inside the DNA, but in a linear form it can be distant from the gene it is affecting."