Chapter 16

  1. If the differences in cancer rates are due to genetic differences in the two populations, then people who migrated from Utah or Shanghai to other locations should have rates of prostate cancer incidence similar to those of people who stayed in Utah or Shanghai. If the cancer rates are due to environmental factors, then people who migrated from Utah or Shanghai should have rates of prostate cancer determined by their new locations and not by their place of origin.

    1. 50%.

    2. Bilateral.

    3. The father may have unilateral retinoblastoma because of incomplete penetrance of the mutation in the RB gene. That is, alleles at another locus, or at multiple other loci, may have contributed to resistance to retinoblastoma in the father, so that he suffered from retinoblastoma in only one eye. Alternatively, it may have just been good fortune (random chance) that one of his eyes was spared the second mutation event that would have led to retinoblastoma in his other eye.

  3. Because oncogenes promote cell proliferation, they act in a dominant manner. In contrast, mutations in tumor-suppressor genes cause loss of function and act in a recessive manner. When introduced into cells, the mutated palladin gene increases cell migration. Such a dominant effect suggests that palladin is an oncogene.