The Cystic Fibrosis Gene
...main effects on the digestive system and the
lungs. This disease is the most common genetic disorder
amongst Caucasians. Cystic fibrosis affects about one in
2,500 people, with one in twenty five being a heterozygote.
With the use of antibiotics, the life span of a person
afflicted with CF can be extended up to thirty years
however, most die before the age of thirteen.1 Since so
many people are affected by this disease, it's no wonder
that CF was the first human genetic disease to be cloned by
geneticists. In this paper, I will be focusing on how the
cystic fibrosis gene was discovered while at the same time,
discussing the protein defect in the CF gene, the
bio-chemical defect associated with CF, and possible
treatments of the disease.
Finding the Cystic Fibrosis Gene:
The classical genetic approach to finding the gene that is
responsible for causing a genetic disease has been to first
characterize the bio-chemical defect within the gene, then
to identify the mutated protein in the gene of interest, and
finally to locate the actual gene. However, this classical
approach proved to be impractical when searching for the CF
gene. To find the gene responsible for CF, the principle of
"reverse genetics" was applied. Scientists accomplished
this by linking the disease to a specific chromosome. After
this linkage, they isolated the gene of interest on the
chromosome and then tested its product.2
Before the disease could be linked to a specific
chromosome, a marker needed to be found that would always
travel with the disease. This marker is known as a
Restriction Fragment Length Polymorphism or RFLP for short.
RFLP's are varying base sequences of DNA in different
individuals which are known to travel with genetic
disorders.3 The RFLP for cystic fibrosis was discovered
through the...
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