Identifying genetic culprits
People with red hair are more prone to sunburn. This is because most redheads also inherit pale skin. But they have a high risk of burning because of their pale skin, rather than their red hair. Scientists looking for genes involved in common illnesses face a similar problem: they have to pick out real culprits from the innocent bystanders. They also have to work out the interaction of genes with other influences, such as diet.
