Read on Twitter
So on Friday my Molecular Bio students did a lab about fish fraud. Their Super Important Homework Assignment (TM) was to go out for sushi and take a small sample home in a ziploc bag (EAT THE REST. Wasting food is uncool). Label the supposed fish, put it in the freezer.
Bring it into the lab next time on campus, put it in our "class freezer" on the bottom shelf.
On Friday, we took those samples, minced them so small it would make world-class chefs shed tears of envy, and extracted the DNA from the fish. Amplified the CO1 gene using PCR.
On Friday, we took those samples, minced them so small it would make world-class chefs shed tears of envy, and extracted the DNA from the fish. Amplified the CO1 gene using PCR.
Notoriously, students are pretty bad at PCR. Then again, EVERYONE is pretty bad at PCR. It's the kind of thing that you have to practice a lot, it's hard to get a whole class to practice a lot (resources and time and all that), so we use "instructor samples" downstream.
But this time? HOLY BANANAS THEY ALL GOT RESULTS. I ran the gels today for them & posted results on our course website. Kids, I'm so excited for what these sequences will reveal. The results were *so good*. Better than I've seen in a very long time even considering my own results
Thursday I'll send them for sequencing and we'll collectively cross our fingers to see what we get. Here's the gel images in case you're curious. Keep in mind this is the...3rd PCR most of these students have set up, and some wells are negative controls.
1 of the results, which I think is the one in the L gel, top row, 2nd well from the R, is one that I found *exceptionally unlikely* that it would work. The origin of that sample was from a dogfish shark another one of my classes had dissected. Prior to processing, it ate a meal!
Since it was half-a-fish (no head) and had no other distinguishing characteristics other than "silver", I thought it would be neat to see if we COULD get a DNA sample out of it. Turns out...we can't. At least, not with the protocol we used.
So now my class of 16 will have a set of samples to look at real-life prevalence of food fraud in the seafood industry. What are we going to find? No idea! But I'm willing to put $5 on that NOT being "red tuna". The tilapia is also almost certainly red snapper. We'll see! 
