Individuals heterozygous for the RB⁺ and RB^- alleles can develop tumours as a result of A) a mitotic crossover that leads to homozygosity for both RB⁺ and RB^-. B) a somatic mutation in the RB⁺ allele that leads to homozygosity for RB^-. C) a somatic mutation in the RB^- allele that leads to homozygosity for RB⁺. D) the fact that RB^- is dominant to RB⁺. E) either a mitotic crossover that leads to homozygosity for both RB^- or a somatic mutation in the RB⁺ allele that leads to homozygosity for RB^-.

Question

Quizplus · Accepted Answer

Individuals heterozygous for the RB⁺ and RB^- alleles can develop tumours if they become homozygous for the RB^- allele, which can occur through either a mitotic crossover or a somatic mutation. This is because the RB^- allele is associated with a higher risk of tumorigenesis compared to the RB⁺ allele. Therefore, option E is the best choice as it includes both possibilities.

Individuals Heterozygous for the RB+ and RB- Alleles Can Develop

Individuals Heterozygous for the RB⁺ and RB^- Alleles Can Develop