Cystic fibrosis gene polymorphism

The restriction fragments of different sizes (restriction-fragment length polymorphisms, or RFLPs) that come about as a result of different base sequences on paired chromosomes were used as genetic markers to determine the exact position of the cystic fibrosis gene on chromosome 7. 

Map of restriction fragment length polymorphisms (RFLPs) closely linked to the cystic fibrosis (CF) gene. The inverted triangle near the right-hand end indicates the location of the AF508 mutation characteristic of most persons with cystic fibrosis disease. (Source ... 

Southern blotting can be used to follow the inheritance of selected genes. Mutations within restriction sites change the sizes of restriction Ifagments and hence the positions of bands in Southern-blot analyses. The existence of genetic diversity in a population is termed polymorphism. The detected mutation may itself cause disease or it may be closely linked to one that does. Genetic diseases such as sickle-cell anemia, cystic fibrosis, and Huntington chorea can be detected by RFLP analyses. 

Kahl BC, MeUmann A, Deiwick S, Peters G, Harmsen D (2005) Variation of the polymorphic region X of the protein A gene during persistent airway infection of cystic fibrosis patients reflects two independent mechanisms of genetic change in Staphylococcus aureus. J Chn Microbiol 43 502-505... 

Genetic variations sometimes cause a disease phenotype. Due to the disease, some evolutionary selection against these single-gene polymorphisms is present. Cystic fibrosis, sickle-cell anemia. 

---