1) No idea 2) You found the article I was about to link actually. Basically, for a PCR test, what you're doing is making a lot of a particular sequence of DNA

1) No idea 2) You found the article I was about to link actually. Basically, for a PCR test, what you're doing is making a lot of a particular sequence of DNA if it's present. You set up the reaction conditions so that if a particular sequence of DNA is present in your test tube (actually a plate but same difference), that sequence of DNA will make a lot more of itself. If there isn't that sequence of DNA, nothing will happen. You don't get to pick the entire sequence youa re looking for. You basically hae to pick a start region and and end region for the piece of DNA you want to amplify. So if the nucleotide sequence for a coronavirus gene was atcgctatagc, and you are using 3 letter long end regions (in reality you use longer length sequences and regions), you might pick your targets as atc and agc from each end. Therefore, any sequence of dna in your sample with atg and agc will get amplified and you will get a signal telling you that a dna sequence that starts with that first target sequence and ends with that second target sequence is there. If you don't get a signal, that means no coronavirus. When picking that sequence (known as a primer sequences since it primes the replication reaction), you have to be careful. Lets say that in your body you have a gene that goes gtcatcagctga or something. Inside of that sequence, your primer sequences are present. If you run a test for your desired sequence, you're going to get signal from non-coronavirus DNA. In order to make sure there are no overlaps in your primers, you, well, this is the part that's hard to believe. You type in your sequences in to a website and hit a button. Hence the following excerpt from the article you found: “I just put the primers as input into this program and within seconds it tells you there’s problems with it,” Altman said. “It’s freely available. It’s not hard to use at all. It’s one of those things you’d do as a basic quality control check. It seems like they hand-designed these primers and it seems like they didn’t use computer tools to check it.” So, yeah. Everyone's still having a hard time wrapping their head around it. All it boils down to is that you want to find sequences of dna that are present in coronavirus but not in humans (and also maybe the reverse for some types of controls). It's, I mean. I don't have words for it. Designing primers is like the first thing an undergrad who joins a lab for a research project or internship is taught. And I had it rough when I was designing primers like 3 years ago. In those ancient times, I had to design the primer by opening a whole new tab and going to a whole new website! (The site is https://www.ncbi.nlm.nih.gov/tools/primer-blast/ https://www.ncbi.nlm.nih.gov/tools/primer-blast/). So much work. Thankfully the lab I was working in implemented an electronic lab notebook (I think it was benchling?) that had the feature built in. Now i don't have to open another tab. I'm being flippant but also, common, this is the CDC. The WHO had no problem doing it. Private labs had no problem doing it. It's not something weird about this virus. It's just, i don't know. There must have been deeper issues.