**Given:** Mammalian Genome

• 3 × 10^{9} bps

• 1 × 10^{4} genes

• 1 × 10^{4} bp/gene

**1. Calculating for the total number of base pairs in mammalian genes:**

**$\mathbf{1}\mathbf{\times}{\mathbf{10}}^{\mathbf{4}}\mathbf{}\overline{)\mathbf{genes}}\mathbf{\times}\frac{\mathbf{1}\mathbf{\times}{\mathbf{10}}^{\mathbf{4}}\mathbf{}\mathbf{base}\mathbf{}\mathbf{pairs}}{\overline{)\mathbf{gene}}}$ = 1 × 10 ^{8} base pairs**

**Answer:** There are **1 × 10 ^{8} base pairs** in mammalian genes.

• There are approximately 3,000,000,000 base pairs in the mammalian genome (genes constitute only a small portion of this total).

• There are approximately 10,000 genes in the mammalian genome.

• A single gene averages about 10,000 base pairs in size.

Questions:

1. Based on the assumptions above, in the mammalian genome, how many total base pairs are in all the mammalian genes? Show your math.

2. What proportion (%) of the total genome does this represent? Show your math.

3. What is the probability that a random mutation will occur in any given gene? Show your math.

4. Only 1 out of 3 mutations that occur in a gene result in a change to the protein structure. What is the probability that a random mutation will change the structure of a protein? Show your math.