Question

Mutations in the glucose 6-phosphate dehydrogenase (G6PD) gene can cause a rare anemia when inherited. However, homozygotes with this mutation are less prone to malaria infection, a disease that historically was the most widespread deadly disease among humans. Predict how this mutation would affect the fitness of individuals living in countries where malaria is endemic.

Answer 1

G6PD deficiency can increase the fitness of individuals in malaria-endemic countries by offering resistance to the disease. This selective advantage leads to the persistence of this mutation in populations where malaria is common, despite its potential detrimental effects in homozygous individuals.

Step-by-step explanation:

Mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene can indeed affect the fitness of individuals in areas where malaria is prevalent. This condition is an X-linked recessive disorder characterized by reduced levels of G6PD, an enzyme important for the survival of red blood cells. Given the historical prevalence of malaria, the mutation offers a resistance advantage to heterozygous carriers, despite causing symptoms of anemia when two copies of the mutation are present.

In countries where malaria is endemic, individuals carrying one mutation of G6PD may have increased fitness due to reduced susceptibility to malaria, similar to carriers of the sickle cell trait. This form of natural selection keeps the mutation present in the population despite its potential harmful effects in homozygotes. The beneficial effect of the G6PD mutation in malaria-infested regions means that the mutation has a selective advantage there, contributing to higher rates of survival and reproduction among carriers.