Understanding CRISPR-Cas9

This video is a deep-dive into CRISPR-Cas9, but it takes the time to explain terms and concepts carefully, so that students who are new to the topic will understand it, and those who already understand what CRISPR is, but have unanswered questions will find the depth of answers they are looking for. Now that VCAA have intimated that they expect students to have more than a superficial knowledge and understanding of CRISPR (for example they have to know about PAM sequences), many of the videos and websites I'd once have recommended are no longer sufficient because they leave out details in an effort to make the concepts easy to grasp. Others which do include details are unassailable to students because of the prerequisite knowledge and terminology they assume. That's why I made this video. It goes deep (really deep, actually), but I hope that stepping through it slowly, and explaining terminology as we go will make it a valuable resource for students really wanting to understand. It covers both the way that bacteria use CRISPR-Cas9 as an adaptive immune system, and the way it can be used for gene editing by molecular biologists. It also answers lots of the questions that people have when learning about CRISPR-Cas9, such as: is there a difference between gRNA and sgRNA? (and what is the difference between crRNA and gRNA?, or between cr:tracrRNA and gRNA?) how does Cas9 differentiate between 'self' and 'non-self' why doesn't Cas9 cut the spacer in the bacterial CRISPR array? why don't Cas1-Cas2 make spacers out of the bacterial DNA? how is Cas9 used to 'knock out' a gene. how is Cas9 used to insert a gene at a specific location using the cells DNA-repair machinery. etc.