Question

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?

A. Ten thousand
B. One hundred thousand
C. Ten million
D. One billion
E. Ten billion

Answer 1

By calculating the given mutation rate, genome size, and the likelihood of cancer-causing mutations, we can determine that the animal has suppressed ten potential cancer-causing mutations.

Step-by-step explanation:

Calculating Potential Cancer-Causing Mutations

To answer the question, we need to calculate the number of potential cancer-causing mutations that the animal has been able to suppress based on the given data. We will follow these steps:

1. Calculate total mutations: 1015 cell divisions × 2 billion nucleotide pairs × 5% (within genes) × 0.1% (cancer-causing) × 1/10 billion (mutation rate).
2. Simplify the above expression: (10¹¹µ × 2 × 10¹) × 0.05 × 0.001 × 10⁻¹°
3. Calculate the result: This simplifies to 10 mutations.

Thus, the animal has been able to suppress ten potential cancer-causing mutations.

It is important to note that the actual suppression of mutations is far more complex and involves various DNA repair mechanisms and cellular checkpoints.