Patients are susceptible to chronic pulmonary infections. In 1985, three research groups independently reported that the gene controls this disease was located on the seventh chromosome. By 1989, it was known that this gene is 27 kb in length, encodes contains 1480 amino acids, and has 27 exons. Recombinational DNA techniques were used to put normal CFTR gene into retrovirus. This recombinant retrovirus currently is being used to introduce a normal CFTR gene into the airway-lining cells of cystic fibrosis patients.
Genetic mapping is, in short, to find the approximate locations and order of genes in genome.
There are 3 ways to map genes on chromosome. The further apart two genes located, the higher the crossover frequency. This method had been used for the longest time and the one that was used by Sturtevant to construct the first genomic map in fruit flies in 1913. In the class, we concentrated on the second method of genetic mapping. Recombination and the resulting phenotypic variability is necessary for this type of genetic mapping.