The problem with short reads

1:03:35called catastrophic DNA degradation. Here's how sequencing works. Okay? You've got a giant thing of DNA. When I treat it with detergent, it's going to break up into short parts. Okay. And I'm going to get a bunch of different short parts. And now I have a combinatoric puzzle to stitch together all of these short parts into a big part. Right. >> Yes. >> The problem is these short reads are about 150 base pairs long max. It's not a lot. Okay. Because a lot of times nothing happens. Okay. And so if I've got repetitive sequences of DNA, I could just fool myself into thinking, oh, this is all part of the same sequence rather than this is the first repeat, this is

1:04:15the second repeat. It's kind of like, have you seen that like crazy puzzle of the Beatle White album, >> right? Where it's just it's a the Beatles white album and it just says the Beatles with a white and like it's incredibly difficult because everything is white. So imagine here like if I've got repeated sections of DNA, I don't know whether this thing came from this part or this part or this part, right? >> 100%. And some puzzle pieces go together when they're not supposed to be next to each other. >> Yeah. Yeah. Yeah. Because the because just, you know, >> just kind of the >> Yeah. It's like it's like this side of the puzzle piece goes together, but when you put it together with the rest, the other three parts don't make any sense. Yeah. Like it's it's a really incredibly hard puzzle. Right. So that's one reason why you don't want that. The next is loss of alic phasing. Right. If I want

1:04:58to study non-Mandelian inheritance, what I really like to know is which parent