Sufferers of this disease produce a thick, sticky mucus which coats their airways and lungs. If it is not cleared by daily massage and physiotherapy, and treated with antibiotics, the person can get serious chest infections.
The cause of the disease was discovered in 1989 as being a recessive allele. This allele is carried by about 1 in 20 of people.
Let's call the recessive allele c and the dominant, normal allele C.
If a person is heterozygous (Cc) then they are a carrier but have a…