Question

Red-green color blindness is an X-linked recessive disorder that is passed through generations and can be traced by using a pedigree.

A pedigree is shown. Sam, Bella, Joshua, and Tim have filled-in shapes. Lisa and Monica have half-filled shapes.

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

Answer 1

In a pedigree for an X-linked recessive disorder like red-green color blindness, males (who have one X and one Y chromosome) are affected when they inherit the allele on their single X chromosome. Females (who have two X chromosomes) are carriers when they have one affected allele and one normal allele.

- The individuals with filled shapes (Sam, Bella, Joshua, and Tim) are affected; they have color blindness.
- The individuals with half-filled shapes (Lisa and Monica) are carriers; they have one affected X chromosome but are not affected themselves.

Given this information, the correct answer for the individuals identified and labeled as carriers for red-green color blindness in the pedigree would be:

**Lisa and Monica.**