Adaptation to infectious disease. Australia antigen and hepatitis

Infectious diseases have probably acted as selective forces to generate polymorphisms in human populations. An example is given of a study related to this concept. There is evidence that “Australia antigen” is a hepatitis virus or closely associated with it. In some tropical populations there appears to be an inherited susceptibility to chronic infection with “Au(1) virus” controlled by a simple genetic mechanism. There are strikingly different frequencies of Australia antigen in different populations and these may have been determined by differences in the selective pressures in different environments.