“IMPLICATION: The story of Genesis BORROWED from Gilgamesh.”
Or “IMPLICATION: The story of Genesis shares a common source as Gilgamesh, which is consistent with the geographical record of a flood effectively destroying Mesopotamia, which more-or-less encompassed “the entire human world” back then, and consistent with the Torah.
Now 'Baccy, you know this is not the traditional understanding. The Torah has no "source." It was written in its entirety by G-d before the universe(s) was/were created ("974 generations" according to the midrash) and was in its entirety dictated to Moses letter-for-letter. Even the ultimate rationalist, RaMBa"M, required the latter belief as absolutely fundamental to Judaism. As for the "limited flood" argument, that's just another nineteenth century liberal Xian theory that, so far as I know, has absolutely no precedent in Jewish tradition.
You should really read Rabbi Shlomo Rotenberg's Toledot `Am `Olam, or at least consult the Seder `Olam.
Sometimes I worry about you.