Chapter 10.1, Problem 1CSC

The Rainbow Connection

The genetic variability or the Giddings children started out as mutations that occurred thousands of years ago. Take hair color: Our distant ancestors probably all had dark hair, its color controlled by multiple genes located on several different chromosomes. The alleles that produced Tess's blond hair originated as mutations in genes that control the amount and type of hair pigment. Tess probably inherited only “pale hair” alleles of all of these genes, so for any given hair color gene, she has the same pale hair allele on both homologous chromosomes. Chris, on the other hand, inherited both dark and pale hair alleles for at least some of the genes, so his homologues have different alleles. As we will see in Chapter 11, in many cases one allele (in this case, the dark hair allele) overrides the effects of the other allele (the pale hair allele), so Chris has black hair. What combinations of alleles might have been packaged in Tess's eggs and Chris's sperm, which would combine to produce their diverse children?