Page "Race and genetics" Paragraph 66

Neil Risch states that numerous studies over past decades have documented biological differences among the races with regard to susceptibility and natural history of chronic diseases.

Genes may be under strong selection in response to local diseases.

For example, people who are duffy negative tend to have higher resistance to malaria.

Most Africans are duffy negative and most non-Africans are duffy positive.

A number of genetic diseases more prevalent in malaria-afflicted areas may provide some genetic resistance to malaria including sickle cell disease, thalassaemias, glucose-6-phosphate dehydrogenase, and possibly others.

Cystic fibrosis is the most common life-limiting autosomal recessive disease among people of European heritage.

Numerous hypotheses have suggested that it provides a heterozygote advantage by giving resistance to diseases earlier common in Europe.