Scientists Make Mice Glum
Lab mice are probably not the happiest of creatures. Food is not much of a problem (unless they are in one of those starvation-diet experiments) but roaming is discouraged, the environment is not that cozy and I imagine they don’t get given the wifi password. Even so, most of them don’t have to put up with researchers deliberately making them depressed.
All in a good cause, naturally, from the human point of view. Researchers, mostly at UCSF, identified a variant form of the PER3 gene in humans, which is involved with the circadian clock. The variant also seems to be linked to a tendency to sleep and wake very early (Familial Advanced Sleep Phase, or FASP) — and also with seasonal affective disorder (SAD). SAD is a relatively common kind of depression related somehow to changes in the length of the day, especially in the fall.
There is a long, long way to go before anyone can even think about using this linkage in therapeutic approaches, but it could be an important clue as to how sleep and mood disorders may be linked.
Bring on the mice. The scientists made transgenic mice with the human gene variant. And controlled the lighting to match the changing seasons. Bingo:
The model mice slept and behaved normally when their days and nights were of equal length, but developed depression-like symptoms as nights became longer than days.
You can’t do talk therapy with mice, but basically when they are feeling under the weather they don’t wriggle as much and they give up quick when something disturbing happens, like someone with a white coat picking them up.
The variant gene produces a less stable protein, and affects the performance of related circadian-linked genes. The authors note that this provides "a mechanistic explanation for the circadian trait.” This clearly could be a significant finding, eventually, but in the meantime, the poor old mice get bummed out.
They’re not the only ones. The researchers made mutant fruit flies too:
Although we were not able to test mood in fruit flies, we did uncover a sleep trait similar to that seen in humans in flies carrying the human variants.
Fruit flies are, or course, classic research subjects, and this is real science, but the observational work seems ... challenging. Imagine someone trying to test an alleged “criminality gene” in insects? Would they bite harder, perhaps? Or more often? Or both?
Previously on Biopolitical Times:
- A Monkey Circles in a Cage
- Gene of the Week: The Nice Gene
- Promoting a Genetic Basis for Crime
- A Literal Reductionist?
Image via Wikimedia