Chapter 12, Problem 16P

On the following figures, genes A and B are on the X chromosome (blue) and both are subject to X inactivation, while genes C and D are on chromosome 17 (an autosome; red). F and S refer to alleles encoding fast- and slow-migrating forms of the corresponding proteins that can be discriminated by electrophoresis.

For women 2 and 3 in the figures that follow, indicate all the possible forms of the four proteins that could be expressed in clones made from different individual somatic cells that already had one or more Barr bodies. As an example, some clones from normal woman 1 could express the A , B , C , C , D , and D proteins, while other clones could express the A , B , C , C , D , and D proteins. None of the clones from woman 1 should make both the slow and fast forms of proteins A or B. Woman 2 is a heterozygote for a deletion of the XIC. Woman 3 is a heterozygote for a reciprocal translocation in which parts of the X chromosome and chromosome 17 have exchanged places.