Hi Andrew,
How would you punctuate this:
Clearly, the one gene-one protein relationship does not apply to schizophrenia.
One gene-one protein relationship? One-gene one-protein relationship? One-gene/one-protein relationship? One gene, one protein relationship? Some other way?
I'm leaning toward separating the one gene and one protein with a comma because the comma would then serve as a substitution for an implied and: Clearly, the one gene [and] one protein relationship does not apply to schizophrenia.
Or if you're alienated by the scientific context, there might be the same issue with a sentence like this: They were a one child, one parent family. I agree with you about the comma. However, . . . .
Personally, I don't like this kind of sentence in situations where I want to be precise. I'd prefer to write something like They were a family that consisted of one child and one parent. The precise meaning of 'a one-child, one parent family' seems unclear to me. Is it a family that has several children but only wants one? Or a family with two parents, and two children, and each parent takes care of only one of the children? I know these are rather silly examples, but my point is that, when you just pile noun phrases in front of another noun, the precise relationship and meaning start to get lost.
Best wishes, Clive