Partitive genitive in English
-Aside from microbes, most of which reproduce asexually, Wheelwright said mountaintops, small islands and other isolated habitats are places where today's incestuous reproducers are most commonly found. "If your relatives are the only game in town you don't have much of a choice," he said.-
Is ''much of a choice'' partitive genitive?
Why ''much choice'' wasn't used?
I think you could go either way in this sentence: "much of a choice" or "much choice". Maybe the author liked the sound/flow/ rhythm/etc. of the added two short syllables?"
"Is 'much of a choice' partitive genitive?"
It is partitive but it's not genitive.
"Why 'much choice' wasn't used?"
Quatarrh pretty much answered this.
In "much choice", "choice" is being used in a uncountable sense, while in "much of a choice" it's being used in a countable sense. "Not much choice" means that there aren't many options. "Not much of a choice" means that you have an option, but it isn't really freely chosen. In this context, "not much choice" would mean that you don't have very many potential mates, which is not the case. "Not much of a choice" means that you are being forced by circumstaces to mate with a relative.
It seems to me, in this context "much choice" is better or even the only correct version.
I think "much of a choice" means "a good choice".
-Why is she dating Jonathan? He's not much of a choice.
"Much of a choice" technically would be positive, but you'll notice that it's virtually always used with a negative -- you *don't* have much of a choice, it *isn't* much of a choice, etc.
I would disagree that "much choice" was better or more more correct; the original sentence sounds just fine the way it is, and neither is "better" grammatically. It also represents a natural way of speaking, and I wouldn't personally think of "much of a choice" as colloquial.
"Much choice" isn't wrong /grammatically/, but it is wrong in the sense of not conferring the correct meaning. There are two choices here: a general choice of whether or not to mate with a relative, and which mate in particular to choose. "Much choice" can refer to both, while "much of a choice" can only refer to the first. Therefore, as the one avoiding ambiguity, it is the correct choice.
As for "Why is she dating Jonathan? He's not much of a choice", that's yet another meaning. In the original, "choice" is describing the status of the chooser (as in, something it does or doesn't have). Here, "choice" is describing Jonathan. There also are such phrases as "choice beef".