the trick with doing any kind of research is figuring out how to ask the question such that the answer you get is meaningful. that how can be as broad-ranging as which type of technique to use or what statistical analysis, but is also as narrowly defined as the particulars of any one given technique: use this brand buffered solution in your western blot and it’ll work fine, but use an off-brand or unbuffered one and nothing runs right. some of these how-to tips are nothing more than black-box voodoo¹, but plenty are entrenched Fact.
in animal research, a lot of those Facts revolve around reducing outside variables. we acquire very clean, specially bred for the purpose creatures; we feed them very clean, specially analyzed feed; we house them in cages that can’t harbor outside diseases. after all, if you have animals with random diseases, how can you be sure your drug is treating what you thought it was, vs simply having an impact on that random and unexpected viral infection? the most extreme version of our need to standardize stuff is in the mouse world, where inbred (effectively, genetically identical) animals are commonly used.
in theory, we’ve cut out all the background noise of inadequate nutrition and extraneous diseases. this recent article about some mouse work being done at perdue calls that into question though. it turns out that some carefully selected variability actually makes the results more stable, more faithfully reproducible elsewhere. perhaps what the extreme standardization actually does is amplifies any tiny background blip (vibrations from the local highway, a flickering light bulb in the room, the secretary’s perfumes) into an actual issue. making a (controllably) heterogenous population then, instead, smooths over these random and meaningless blips to let the real impact of things stand out all the more clearly.
i’m sure figuring out how much heterogeneity is a good thing vs a wrench in the works could be the next lifetime’s worth of residency projects…
scientific researchers are weirdly enough some of the most superstitious people ever. as the man said, “if we already knew all the answers, we wouldn’t call it research,” but because those answers can be so elusive, we tend to get very touchy about those moments they do work. lucky socks and all. or, to illustrate the point, a good friend who happens to be an atheist used to set up a virgen de guadalupe votive candle near some of the equipment when the cells weren’t behaving properly.