Is a comma or any other punctuation needed between each “to-phrase” in a sentence like this one (which is meant to say that the trait has been passed on first from Generation I to Generation II, then from Generation II to Generation III, and so on):
A. This trait has been passed on from Generation I to Generation II to Generation III and to all subsequent generations.
If commas are used, the sentence will become …
B. This trait has been passed on from Generation I to Generation II, to Generation III, and to all subsequent generations.
Which sentence is correct or more preferable? And what is the grammar rule that covers this matter called?