Genetic link to human intelligence

Scientists have provided the first direct biological evidence for a genetic contribution to people's intelligence. Previous studies on twins and adopted people suggested that there is a substantial genetic contribution to thinking skills, but this new study - published in the journal Molecular Psychiatry - is the first to find a genetic contribution by testing people's DNA for genetic variations. The team studied two types of intelligence in more than 3,500 people from Edinburgh, Aberdeen, Newcastle and Manchester. The paper, by Neil Pendleton and colleagues, found that 40% to 50% of people's differences in these abilities could be traced to genetic differences. The study examined more than half a million genetic markers on every person in the study. The new findings were made possible using a new type of analysis invented by Professor Peter Visscher and colleagues in Brisbane. As well as the findings in people from Scotland and England, the team checked their results in a separate group of people from Norway.