We started off today with me handing back the DNA codes from the overnight lab. Some codes came back complete, some didn’t. I gave two complete codes to all of the groups who did an excellent job with yesterday’s lab. For the group who did an okay job, I handed back one complete code and one that said “bad sample.”
After that, we discussed what the DNA codes meant. A healthy human is supposed to have a code with 46 pieces of DNA*. Our codes had 47 pieces. So we concluded that one of the pieces must be the virus. Upon further inspection, we also remembered that the human chromosomes came in pairs. What we really had was a DNA code with 23 pairs of code and one extra. That lone DNA strand toward the bottom of the paper? That must be the virus!
This was a great “Aha!” moment for students. After all, viruses are DNA invaders. The fact that both patients had the same additional piece of code (a) suggests that we are dealing with a virus and (b) would probably tell us what type of virus it was. After our discussion, students got to work typing up their lab reports.
*Of course, in real life, each chromosome would be millions of letters long. But hey, I was trying to save paper!