Question

Discuss how each of the following recent develop- ments—resulting from improvements in medicine,

technology, pubic health, and from evolution— may affect the frequency of alleles that cause cystic fibrosis (CF).
a. Many women with CF now survive long enough to have children. (CF causes problems with re- productive ducts, but many CF women can bear children nonetheless. CF men are usually sterile.)
b. Typhoid fever in developed nations has declined to very low levels since 1900.
c. In some populations, couples planning to have children are now routinely screened for the most common CF alleles.
d. Drug-resistant typhoid fever has recently ap- peared in several developing nations.

Answer 1

Developments in medical treatment, public health, and screening, as well as the appearance of drug-resistant typhoid fever, may increase or decrease the frequency of cystic fibrosis alleles, depending on factors like longer lifespans of CF patients, reproductive choices, and potential heterozygote advantages connected to disease resistance.

Step-by-step explanation:

Improvements in medicine and public health as well as evolutionary factors can impact the frequency of alleles that cause cystic fibrosis (CF). Longer lifespans of women with CF who can now bear children may lead to a higher transmission rate of CF alleles. The decreased incidence of typhoid fever—one of the public health achievements—may reduce the hypothesized heterozygote advantage for CF carriers, potentially affecting allele frequencies.

Increased understanding and screening could lead to a higher detection rate of carriers and thus influence reproductive decisions. The relationship between typhoid resistance and the CF allele frequency may be complex, reflecting a balance between medical intervention, public health improvements, and the natural course of the disease.