help with ap biology question

Test Preparation AP Test Preparation
1

<p>Cystic fibrosis (CF) is caused by a genetic mutation resulting in defective proteins in secretory cells, mainly in the epithelial lining of the respiratory tract. The one in every 2,000 Caucasian babies who has the disease is homozygous for the recessive mutant. Although medical treatment is becoming more effective, in the past most children with CF died before their teens. About 20 Caucasians in 2,000 are carries of the trait, having one mutant and one normal allele, but they do not develop this disease. According to the rules of population genetics, the frequency of the homozygous recessive genotype should be rarer than it is. What is one possible explanation for the unusually high frequency of this allele in Caucasian populations?</p>

<p>sorry that the question is long... i would REALLY appreciate any help i can get</p>

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<p>
[quote]
medical treatment is becoming more effective

[/quote]

There's your answer right there. Not only are CF-afflicted people living longer, but some even reproduce.</p>

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<p>hmm ok thanks a lot!</p>

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<p>actually it's autosomal recessive</p>

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<p>What does that have to do with the question? Of course it's autosomal recessive.</p>

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<p>that is the reason for the high frequency... guess there wasnt to much thought involved in that question</p>

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<p>disregard that last statement.. i think it is where the mutation originated which happened to be in caucasians</p>