As I understand it this was hard because most mechanisms we have for sequencing genes work by first splitting large sequences of genes into random chunks and se

As I understand it this was hard because most mechanisms we have for sequencing genes work by first splitting large sequences of genes into random chunks and sequencing each chunk individually. These chunks then need arranged properly to form the entire genome. This is possible at all because we can get overlap between the chunks, but when a sequence has repeating sections overlap still isn’t enough to stitch everything together correctly. There’s also a newer technique involving nano pores. The dna is literally pulled through a little hole and the electrical properties change depending on which base pair is inside the pore, sadly it’s liable to errors in a deterministic way depending on the sequence. I don’t have access to the full paper so I’m not quite sure what was done here, but I have heard people talk about combining the two approaches above