We can see that most genes fall in the range of 10-50 mutations in a very sharp peaked distribution leaned towards zero.
To find a probability distribution to interpret the data, several distributions where tested with the aid of the Mathematica software. With the best fit showing a mixture of the Negative Binomial distribution (74%, r=4, p=0.185) and the Geometric Distribution (25%, p=0.0053), fitted with a p of \(7.72 \times 10 ^{-16}\). This is shown in Figure 2.