2. The “Warrior gene” has been used in court as a defence for brutal crimes. MAO-A or Monoamine oxidase A to be precise, is a gene that breaks down serotonin, a chemical in our brain that we need to feel good. When MAO-A is less active, explains Dr Sally McSwiggan, the result is a higher concentration of serotonin in our grey matter. Some think this results in us becoming more impulsive, more emotional and more aggressive. Up to 60% of us are walking around with the low activity “warrior” version of MAO-A and most will never commit a crime.
PAX6 is the gene that tells an embryo to build an eye. It is expressed very early on, as Professor Veronica van Heyningen explains, only a week or two after fertilisation in the human embryo. Before the brain is even really a brain – more a tube of nerve cells – the eyes begin to “bud out”. PAX6 is then expressed in all different layers of the eye from the retina to the cornea to the lens.
Huntington’s disease is an inherited neurological disorder which stops parts of the brain working properly over time. Initial symptoms can include difficulty concentrating and involuntary movements of the limbs and body. There's currently no cure for Huntington's disease or any way to stop it getting worse.