I said most cultures in Africa don't have a flood myth, not that no cultures in Africa have a flood myth. The Wikipedia entry you quoted starts "Although the continent has relatively few flood legends".

There are many more than five cultures in Africa. Any suggestion of a universal common source must explain why those other cultures don't have a flood myth. Including Japan.

(Here's a more complete list of flood myths: http://www.talkorigins.org/faqs/flood-myths.html Compare the number in Africa to the number from Central America.)

> But the Sisters show up on all continents

What are the examples for the Americas, Australia, or Polynesia?

And the claim was "universal interpretation of the Pleiades as seven sisters" not "widespread."