London (ddp). The genetic predisposition for the attention deficit disorder ADHD may have had in the evolutionary history of man are also benefits for those affected. To indicate a genetic testing American researchers to originally living nomads in Kenya. People with a Gene Variant that is associated with the occurrence of ADHD in combination, were better nourished on average, as the scientists observed. ADHD could benefit the life of an itinerant nomads, is constantly in search for food and water, and would have received during the evolution of man and even spread, scientists have suggested. The researchers to Dan Eisenberg of Northwestern University in Evanston, Illinois report in the journal «BMC Evolutionary Biology» their results (online toilette). The concerned gene carries the information for the construction of receptors in the brain that respond to the neurotransmitter dopamine. It therefore affects both properties such as impulsivity, curiosity or anxiety, as well as the ability to control the desire for food. The gene can occur in several variants, of which one is known for encouraging such impulsive behavior and thus also called ADHD syndrome. Now, researchers took gene samples from two groups of living in the North of Kenya’s Ariaal, a people who still partly nomadic lives, has however been firmly settled in part. With a total of about 150 representatives of both ways of life, researchers observed no differences in the frequency of the Gene Variant, which favours the occurrence of ADHD. When the body mass index (BMI) as a measure of the nutritional status, a clear difference however revealed: the nomadic subjects with the Gene Variant were better nourished than their tribesman without this assessment for ADHD. It was exactly reversed in the sedentary subjects, and investment turned out to be detrimental to the physical state. The behaviors typical for carriers of the Gene Variant impacted positively only when nomads, where the erratic almost belong to the over life concept, explain the scientists. But already in the Ariaal have become settled this gene variant put disadvantages already, since the institution of the variant could focus less on agriculture or trade. The attention deficit disorder add or ADHD also occurs in developed countries three to nine percent of all children, while boys are more often affected than girls. It is expressed in concentration, emotional unpredictability and memory problems. How exactly it comes, is so far unclear. Scientists are based on a strong genetic component however, whose Auswirkungen can be strengthened or also suppressed by the living conditions.