I cannot find a solid rule on this...Can anyone help me?
I'm a tech editor of test products, and i feel like an idiot, here.
Ok, in this sentence, is the comma necessary? and WHY??? I feel like it is, but i am having trouble finding a solid rule to back me up.
This sort of "familial" cancer is most likely caused by mutation in sex cells, only.
In the piece that i'm editing, it is a multiple choice question, and the "by mutation in sex cells, only" is one of the possible answers. You may recall, this type of answer is common in multiple choice tests. Most of our "test writers" DO put this comma in there, and it looks OK to me, but i just want something or someone to back me up!
THANKS grammar monsters :)
The comma is not justified grammatically. In fact, it distances 'only' from the verb it qualifies (caused in this example). It should read:
This sort of "familial" cancer is most likely caused only by mutation in sex cells.
However, placing it at the end with the comma does have the effect of emphasising 'only', which is important to this testing regime.
It's a bit messy grammatically, but I think it's clearer. My advice would be to keep it as it is.
