Why do certain mutations cause cystic fibrosis? cystic fibrosis is the most common lethal genetic disease in the united states. it strikes one out of every 2,500 people of european descent, though it is less common in other groups. cystic fibrosis is the result of mutations in the cystic fibrosis transmembrane conductance regulator (cftr) gene. over 1,800 different mutations have been identified that can cause cystic fibrosis. people who inherit two recessive cftr alleles have the disease. below is a partial mrna and amino acid sequence for the wild-type cftr protein?

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: