What is a gene?

I remember one of the first biology-based debates I found myself in was in some random message board devoted to music. I can’t for the life of me remember what the board was, and I doubt it still exists today anyway, but I recall music being central to what brought me there. Of course, there were plenty of other subjects up for discussion at this place and in its various forums, and that led me into some useless debate with a racist metal head. (I’m sure his racism and affinity for metal were quite independent of each other.) He was making some claim about black people and intelligence, and he kept referencing some gene he seemed convinced proved his point. This was probably well over 15 years ago, so I don’t recall many of the specifics, but I do recall not really knowing what a gene was, so it was difficult to counter him effectively. I tried looking it up, but there really weren’t any easy-to-digest answers for someone who didn’t know what to look for in the first place. And, of course, this was a bit before the days of YouTube (and Wikipedia was in its infancy). Fortunately, for better or worse, the Internet is a far different place today. As such, I wanted to post a YouTube video I found in the hope that any person who finds himself in a similar situation to mine from years past would be able to gain a quick understanding of what a gene is. There’s a certain type of person who loves to use science to justify a belief he would hold no matter what, and relatively-educated racists are among them. Here’s the short video: