Let's say I want to test the effect of gene A that I've modified somehow -- to mimic a human disease, say -- on a mouse (assuming, of course, that the results are then generalizable to people). I put the modified gene into the zygotes of a laboratory mouse strain, let's say C57/Bl, and watch what happens as the animals develop. Of course I need controls, unmodified mice, so that I can compare my transgenic modifications to the unmodified C57/Bl. When I write my experiment up, I will refer to the 'mutant' (transgenic) mouse and the 'wild-type'.
|Wild-type axolotl (Wikimedia)|
As judges, we just heard a student research presentation in a high-school science project competition that we wrote about on Tuesday, in which the student compared the effect of a modified protein to that of the wild-type. This student was plunked into a fancy lab and clearly got this term from her mentors in the lab, without knowing where it came from (other than that the protein "was cloned into E. coli") or thinking about what that meant. We would assert with nearly 100% confidence that the mentor never thought about it either.
But, who cares?
Scientists like other scholars or, perhaps, those in any profession, coin jargon to use in their work. Sometimes a term is clear and stands for a specific thing, but says it more simply. We can say, for example, that the frequency of a genetic variant in a population 'drifted' over time. What we clearly mean is that "the allele frequency changed randomly over many generations because it did not cause an effect on the organism that carried it that affected that organism's survival or reproduction". Just saying 'drifted' saves lots of words. Properly used, such technical terminology is completely reasonable and useful.
Sometimes we are using terms to show off, to seem intelligent, insightful or perceptive, or to give an aura of technical expertise. The humanities--we're sorry to have to assert--typically wallow deeply in terms so contorted and arcane that even they don't seem to agree on their meanings. That is, the jargon is obscurative rather than efficient or clarifying.
|Mutant axolotl (reduced pigmentation); Wikimedia|
But sometimes even in natural science, terminology becomes an obstacle rather than a shortcut. Many analysts of science and the philosophy and history of science have noted how deeply we can be embedded in rhetoric which is not just shorthand, and not just showing off, but which carries connotations that actively affect how we think and what we do. Technical terms can allow airy underpinnings to be taken as having substance. Then it becomes quite dangerous to science (even if, perhaps, it helps get grants and your name in the paper)!
In our areas of genetics and evolutionary biology, as a rule, terms at least have somewhat of a precise meaning, even if referring to, say, the 'wild type' sounds like insider talk. This particular term might seem to be absolutely no problem, since it's so simple. But what is the 'wild type', even of a single gene? Is it 'the' sequence of the gene found in the wild? Almost never! Why? Because the 'same' gene will have varying sequences among individuals in a population, or in a species, or, even more so among species.
So to say you're comparing the risk of a variant to 'the' wild type is to make an assumption that there is such a type. Do you mean the 'normal' variant? If so, how do you define normal, and by what reason do you assume, much less actually think, that there is only one such type out there in the 'wild'?
|Type specimen 'pitcher plant' (Wikimedia)|
However, we know that was a very poor understanding of evolution, of the nature of DNA sequence variation, and it was a hyper-Darwinian stereotypical treatment of nature. It was, we think, entirely analogous to the idea of the 'type specimen'. That's the bedraggled stuffed lion in the Natural History museum, taken to represent all lions. Of course, if we're careful in our thinking, we know that no other lion is quite like the Snagglepuss in the museum. But science is not always careful--in part because the rat-race for status in the field encourages simpler, if not simplistic thinking, in which we scientists routinely indulge.
If you're studying the mice in your laboratory, comparing the animals of the strain you tinkered with by introducing an altered gene to those in the strain that you did nothing to, then you're likely to call the latter the 'wild type'. But that is preposterous! There is nothing 'wild' or 'typical' about a laboratory mouse! They are the result of, at the very least, many generations of inbreeding and cage maintenance and as the old quip goes, wouldn't survive for more than 5 minutes out in the, yes, wild!
Walk away from the wild-type side of thinking!
If we really want to understand Nature, we should wean ourselves from habits that can be very, if subtly, misleading. We've often mentioned the related and comparably misleading ideas of genes or selection 'for' a given trait, or the sloppy and slippery assumption that every trait was produced by natural selection, or naming genes 'for' some trait (like 'bithorax' or 'presenillen' for genes that, when mutated in particular ways in particular individuals can cause, respectively, a double thorax in insects, or early onset Alzheimer's disease in humans). Or our routine reference to 'the' human genome--a sequence that we've posted about before, that doesn't exist in a particular individual, never has, and never will.
We often have no need whatever for special terms, and we should stay away from them like the plague. If we want a term, then instead of the stereotypical notion of a 'wild type', that can end up not being properly checked or used in interpreting results, we should use terms like 'reference', or 'baseline', or 'control', or even, if we're careful, 'average'. Those terms clearly state what you mean, without latent connotations that can affect your audience's thinking....or even your own. You can choose an inapt referent, or the average may or may not be a good baseline, but at least the meaning should be clear and your conclusions then fairly discussed.
So to keep from being wildly misled, don't walk on the wild-type side!