Jennifer Doudna was researching CRISPR, which is like an immune system for bacteria. Bacteria can grab viruses, sample them, learn how to detect them, and then learn how to destroy them.
Since CRISPR cuts up the virus (using Cas9) and we can synthesize RNA, Doudna was able to use these components to edit genes.
We have been able to edit genes for a while, but it was really hard and inefficient. CRISPR provides a template for how to edit genes much more easily, which means that editing genes may soon be clinically and industrially viable. Doudna makes the analogy to computers: if you had to physically rewire a computer to make it run a different program, there would be much less software development than if you could just write a program and run it on any computer.
The talk was very interesting. If you want to learn more about gene editing, I highly recommend it.