In the past two lectures, we discussed the concept of a gene mutation, and we examined the different types of gene mutations that exist in nature. Now, let's actually summarize our results, and let's begin by looking at the following flowchart. So, this flowchart basically describes the many different types of mutations that can arise in nature. And it also tells tells us the reasons for our gene mutation. Now, a gene mutation is basically a change in the nucleotide sequence on the DNA that is not a result of genetic recombination. Now, basically, there are two reasons for a gene mutation in the first place.