Kat - And the final story I thought was just quite amusing. It’s research published in the journal Science from a team of US researchers including some at the Jackson Lab which is a huge mouse facility. They've basically been putting mice on drugs.
Nell - Yes, indeed. Actually, what they found is very interesting. They were looking at the way that mice respond to things like cocaine and methamphetamine using a strain of mice that's been bred for a long, long time. But actually, what's happened over almost 100 years of this particular mouse strain being used is that different subpopulations have emerged. So, although one lab mouse may look very much like another, they are in fact different in some quite crucial ways. By looking at the way they responded to these different types of drugs, they've discovered that there are quite subtle but important changes within the same types of mice.
Kat - I think it’s a bit sad they used black mice rather than “Walter White” mice – a bit of a Breaking Bad reference... But this research really does highlight the importance of knowing what kind of mice you're dealing with. A lab mouse is not a lab mouse the world over. The mice that they were looking at came from the founder of the Jackson Laboratory, Clarence Cook Little and this was back in 1921, and these mice are used all over the world. I remember seeing some research done in the ‘60s that said, “Researchers, you need to be aware that there's a lot of differences in how mice strains that seem to be very similar respond to things like drugs”. So, it is a message for researchers using animals that they need to be very careful about what strains they use.
Nell - Yeah, absolutely. The scientists highlight that, especially when you're looking at things like behavioural data because it’s so hard to unpick exactly what's going on there. So, knowing about these very, very small genetic differences between the different mice that might be being used is really crucial. Actually, what they do at the Jackson Laboratory is they try to make sure that they're kind of going back and refreshing the population of mice every so often so that they know exactly which strain they're using, they know exactly what types of changes might be there.
Kat - Yeah, it’s interesting. They use frozen IVF embryos to do that. So, they're always going back to this stock of frozen embryos and they know exactly what they're like. But certainly fascinating research, and probably one to watch in the future.