Multiple choice

Consider a family where both father and son have retinoblastoma. DNA analysis from the child's tumor shows only a single allele from the Rb locus on chromosome 13. Both parents are heterozygous in blood, as is the child. Which allele would you expect is preserved in the tumor?

  1. Mother's

  2. Father's

  3. There is a 50:50 chance that it is the mother's or father's allele.

  4. Both alleles would be abnormal due to genetic rearrangement.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The father's allele would be preserved in the tumor. This is a mutant allele, based on the fact that the father has retinoblastoma.