Why natural selection eliminate cystic fibrosis allele?

Cystic fibrosis is a genetic disorder caused by a mutation in the CFTR gene. This mutation results in the production of a defective protein that leads to the buildup of mucus in the lungs, digestive tract, and other organs. This can cause a variety of symptoms, including respiratory problems, digestive problems, and infertility.

Cystic fibrosis is a recessive disorder, which means that both parents must carry the defective CFTR gene in order for their child to inherit the disease. If only one parent carries the defective gene, the child will be a carrier, but they will not have the disease.

Natural selection is the process by which organisms that are better adapted to their environment are more likely to survive and reproduce. In the case of cystic fibrosis, the defective CFTR gene is a disadvantage because it makes individuals more susceptible to infection and other health problems. As a result, individuals with cystic fibrosis are less likely to survive and reproduce than those who do not have the disease. This leads to a decrease in the frequency of the defective CFTR gene in the population over time.

However, cystic fibrosis is not completely eliminated by natural selection because it is a recessive disorder. This means that carriers of the defective CFTR gene can still reproduce, even if they do not have the disease. As a result, the cystic fibrosis allele can still be passed on to future generations.

In addition, there are some factors that can help individuals with cystic fibrosis to survive and reproduce. For example, advances in medical care have improved the life expectancy of individuals with cystic fibrosis. This means that they are more likely to live long enough to reproduce. Additionally, some individuals with cystic fibrosis are able to have children through the use of assisted reproductive technologies.

As a result of these factors, the cystic fibrosis allele is not completely eliminated by natural selection. However, its frequency in the population does decrease over time.