Problem
Consider the following pedigree from a human family containing a male with Klinefelter syndrome (XXY individual, indicated with a shaded box). A and B refer to codominant alleles of an X-linked gene. The phenotypes of each individual (A, B, or AB) are shown on the pedigree.
If the protein encoded by this gene is a membrane-bound protein that comes in two forms A and B, what is the expected phenotype of a heterozygous female?
She will have patches of cells that express one form and patches of cells that express the other form.
All somatic cells of her body will express the same protein form on each cell.
All somatic cells of her body will express both protein forms on each cell.
Her phenotype will depend on the parental origin of the X chromosome carrying each allele.
She will have exactly equal ratio of each protein form in her body.