Genetic resistance to malaria

Development of genetic resistance to malaria

Microscopic parasites, like viruses, protozoans that cause malaria, and others, cannot replicate on their own and rely on a host to continue their life cycles. They replicate by invading the hosts' cells and usurping the cellular machinery to replicate themselves. Eventually, unchecked replication causes the cells to burst, killing the cells and releasing the infectious organisms into the bloodstream where they can infect other cells. As cells die and toxic products of invasive organism replication accumulate, disease symptoms appear. Because this process involves specific proteins produced by the infectious organism as well as the host cell, even a very small change in a critical protein may render infection difficult or impossible. Such changes might arise by a process of mutation in the gene that codes for the protein. If the change is in the gamete, that is, the sperm or egg that join to form a zygote that grows into a human being, the protective mutation will be inherited. Since lethal diseases kill many persons who lack protective mutations, in time, many persons in regions where lethal diseases are endemic come to inherit protective mutations.