Heterozygosity is of major interest to students of genetic variation in natural populations. It is often one of the first "parameters" that one presents in a data set. It can tell us a great deal about the structure and even history of a population. ... High heterozygosity means lots of genetic variability.

Why do heterozygotes have an advantage?

Heterozygotes are therefore more resistant to the debilitating effects of malaria than the normal homozygotes. This heterozygote advantage in many sickle-cell carriers outweighs the severe reproductive disadvantage of the rarer sickle-cell homozygotes.

Is heterozygosity good or bad?

In sexually reproducing organisms, heterozygosity is generally regarded as 'better' in terms of adaptability and evolutionary advantage. Why then do we seldom, if ever, regard allelic heterozygosity as an advantage when it comes to genes linked with health and disease?