Final answer:
The sickle cell trait, which is the presence of one mutated hemoglobin S allele, does confer protection against malaria. This is particularly true in malaria-endemic regions like parts of Africa, where such genetic traits provide a survival advantage.
Step-by-step explanation:
Yes, carrying one allele for sickle cell trait provides protection against malaria. This beneficial effect is observed in heterozygotes, who have just one mutated hemoglobin S allele. In regions of Africa where malaria is prevalent, individuals with sickle cell trait have a survival advantage as their red blood cells, with their abnormal hemoglobin, make it more difficult for the malaria parasite to thrive and cause infection.
However, those who are homozygous for the mutation, having two copies of the hemoglobin S allele, develop sickle cell anemia, which is severe and does not confer the same level of protection against malaria. These individuals suffer from symptoms like pain and tissue damage due to the misshapen red blood cells blocking blood flow.
The persistence of the sickle cell allele in certain populations is an example of a genetic adaptation to an environment where malaria is a significant threat to life, thus keeping the allele in the gene pool.