In class we investigated the reason cystic fibrosis is maintained in the human population in higher frequency than we expected given the deleterious effects of being homozygous at the CFTR gene. We calculated the actual mutation rate of the CFTR gene to be 6.7 x 10-7. The mutation rate expected under mutation-selection balance was 4 x 10-4. What is the most plausible explanation as to why cystic fibrosis is maintained in the human population at a higher frequency than we expect? a. Negative selection against the CFTR deleterious alleles is too weak to eliminate the alleles from the human population. b. Positive selection for the CFTR deleterious alleles is likely occurring in response to some other selective pressure in the human population, possibly resistance to typhoid fever. c. The CFTR gene has an exceedingly low mutation rate causing humans to have no genetic variation at that gene. d. The CFTR gene has an exceedingly high mutation rate and that is why the disease is maintained at a higher rate than we expect.
In class we investigated the reason cystic fibrosis is maintained in the human population in higher frequency than we expected given the deleterious effects of being homozygous at the CFTR gene. We calculated the actual mutation rate of the CFTR gene to be 6.7 x 10-7. The mutation rate expected under mutation-selection balance was 4 x 10-4. What is the most plausible explanation as to why cystic fibrosis is maintained in the human population at a higher frequency than we expect?
a. |
Negative selection against the CFTR deleterious alleles is too weak to eliminate the alleles from the human population. |
|
b. |
Positive selection for the CFTR deleterious alleles is likely occurring in response to some other selective pressure in the human population, possibly resistance to typhoid fever. |
|
c. |
The CFTR gene has an exceedingly low mutation rate causing humans to have no |
|
d. |
The CFTR gene has an exceedingly high mutation rate and that is why the disease is maintained at a higher rate than we expect. |
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