Without a doubt, one of the phrases that gives our authors a lot of trouble is “wild type”—specifically, whether it should have a hyphen or not. Spawned back in the TH Morgan days when pioneering geneticists captured wild-type fruit flies from the “wild” —if the miasma of decaying bananas surrounding these labs could be called the “wild”— the term has persisted even as geneticists have come to realize that the concept of a single wild type may be outdated. What is wild type, in the face of natural phenotypic variation?
Compound words, also called “portmanteau” words, because they’re packed together, tend to evolve over time. Sun flower becomes sunflower and back bone becomes backbone. Some compound words stick together as nouns or adjectives, but separate for use as verbs—for example, carryover. So, you might have some carryover money in your consumables budget, but your granting agency might not let you carry over that money into the next fiscal year. So, buy those microfuge tubes now.
For our particular phrase, I’m just counting the days until “wild type” merges into “wildtype” and my authors no longer have to worry about whether to hyphenate or not. Until that time, a simple rule to guide you is that the noun form takes no hyphen. So, for example, you might observe high chlorophyll levels in the wild type. However, the adjective does take a hyphen, so you measure chlorophyll levels in wild-type plants.
Please hyphenate responsibly whenever you take a walk on the wild type.
*I’d like to thank Blake Meyers for the superb title.