CRISPR-Cas9 is a new(ish) technology that is used for knocking out human genes in cell lines for the purpose of seeing what these genes do. CRISPR-Cas9 has a “protein scissor”, the cas-9 protein, and a location that shows the cas9 where to bind to. The “location” is actually a strand of RNA that is complementary to a specific strand of DNA. This RNA strand is like glue in that it binds to the DNA and allows the Cas9 to cut the DNA. This process or the CRISPR-Cas9 technology is like an endless cycle of cutting and repairing DNA until the repair enzyme can no longer repair the DNA or makes a mistake. This technology can make the process of cutting and disabling genes five times faster. It allows scientists to edit parts of a genome by altering, removing, or adding certain sections of DNA. While this technology can be very useful in trying to understand what genes do it does have a downside, “these approaches are costly and time-consuming to engineer, limiting their widespread use, particularly for large scale, high-throughput studies.” The picture below shows what this process looks like on a very basic scale. Hopefully this technology will eventually allow us to fully understand what every gene does.