Final answer:
The allele for G6PD deficiency is a conditionally lethal allele, meaning it only leads to severe effects under certain conditions such as the consumption of fava beans. G6PD is vital for protecting RBCs from oxidative damage, and mutations in the G6PD gene can offer some protection against malaria, thereby affecting individual fitness in regions where the disease is prevalent.
Step-by-step explanation:
G6PD deficiency results from a deficiency of an enzyme that is especially important for protecting red blood cells from harmful oxidizing agents. The allele for G6PD deficiency, in this case, could be described as a conditionally lethal allele. It is conditionally lethal because it can lead to severe destruction of red blood cells (RBCs) when individuals with this allele consume fava beans, which contain high levels of oxidizing agents such as vicine, divicine, convicine, and isouramil.
Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme in the pentose phosphate pathway, which is crucial for maintaining levels of NADPH in cells. NADPH, in turn, ensures the maintenance of glutathione that helps protect the RBCs against oxidative damage. A disruption in this pathway can lead to a compromised immune system and may manifest as nonimmune hemolytic anemia due to environmental factors like severe infection, certain medications, and the consumption of certain foods like fava beans.
In areas where malaria is endemic, mutations leading to G6PD deficiency may confer a survival advantage. The deficiency offers some protection against malaria infection, influencing the fitness of individuals in those regions. This highlights the complexity of how genetic mutations can have both harmful and beneficial effects depending on environmental factors.