Cystic fibrosis (CF) is an autosomal recessive monogenetic condition which affects the lungs, sweat glands and digestive system. Allele frequencies as high as 1:20 are seen in Caucasian populations. It was once thought that this high allele frequency in Caucasian populations was due to CF heterozygote advantage to cholera. However, it is now believed that the most influential factor in causing this high CF prevalence among those with European ancestry is due to heterozygote advantage to tuberculosis.

Question

Explain how there could be a CF heterozygote advantage to cholera

Answer 1

There is no evidence to suggest that CF heterozygotes have any advantage against cholera. In fact, CF is not known to provide any advantage against any infectious diseases. The idea that CF heterozygosity provides an advantage against cholera was a hypothesis proposed in the past but has since been disproven. The actual reason for the high allele frequency of CF in certain populations is due to a different factor, as mentioned in the original statement.