Question

which individuals in the pedigree are identified and labeled carriers for red - green color blindness?
lisa and monica
sam, tim, bella, and joshua
ben, jenny, mike, carol, katie, and chris
ben and lisa

Explanation:

Red - green color blindness is an X - linked recessive disorder. Carriers are typically heterozygous females (having one normal X and one mutated X, represented as \(X^{B}X^{b}\) where \(B\) is normal and \(b\) is mutated for color blindness). Looking at the pedigree:

• Lisa has genotype \(X^{B}X^{b}\) (partially filled circle, indicating carrier).
• Monica has genotype \(X^{B}X^{b}\) (partially filled circle, indicating carrier).
• Sam, Tim, Bella, Joshua have genotypes indicating they are affected (not carriers, as males with \(X^{b}Y\) are affected, and Bella with \(X^{b}X^{b}\) is affected).
• Ben, Jenny, Mike, Carol, Katie, Chris have genotypes that are normal or not carrier - like.
• Ben is \(X^{B}Y\) (normal male), Lisa is a carrier, so the first option (Lisa and Monica) fits as they are heterozygous females (carriers).

Answer:

A. Lisa and Monica