Consider a healthy adult animal in which 10¹⁵ cell divisions have taken place since birth. Spontaneous mutations can occur at a rate of approximately one nucleotide out of about ten billion nucleotides every time DNA is replicated. The animal has a diploid genome size of about 2 billion nucleotide pairs. Assuming that only about 5% of mutations occur within genes or gene regulatory sequences, and further assuming that about 0.1% of those may cause cancer, how many potential cancer-causing mutations has the animal been able to successfully suppress (i.e. has been able to survive) during its lifetime?

Question

Quizplus · Accepted Answer

The number of cancer-related mutations is calculated from these assumptions as:
(10¹⁵ cell divisions) × (10-¹⁰ mutations/nucleotide/division) × (2 × 10⁹ nucleotides/genome)
× (5 × 10-² genic mutation/mutation) × (10-³ cancerous mutations/genic mutations)
= 10¹⁰ cancerous mutations/genome.

Consider a Healthy Adult Animal in Which 10¹⁵ Cell Divisions