In the Section "Investigating Life: Does Natural Selection Maintain Cystic

question 56

Multiple Choice

In the section "Investigating Life: Does Natural Selection Maintain Cystic Fibrosis?," if two carriers of the defective CFTR gene have a child,what is the probability that the child will have cystic fibrosis?

• A)75%
• B)50%
• C)100%
• D)0%
• E)25%

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Definitions:

Dominant Gene

A gene that expresses its trait in the phenotype even when heterozygous, overshadowing the effect of a recessive gene if present.

Recessive Gene

A gene that can lead to a phenotype only when two copies are present, as opposed to a dominant gene where one copy is sufficient for expression.

Genetic Map

A representation of the positions of genes or markers on chromosomes, showing their relative distances.

Cleft Palate

A congenital split in the roof of the mouth that occurs when the tissue doesn't fuse together during pregnancy.