Who created 'yo mama' jokes?

They may have been created by slaves who came from Africa. Imagine being chained to people who cannot even speak your language and being on a ship with captors who cannot speak your language either. But you realize everyone with you has a mother, and that "mama" is one of the few words that most of you all share. So here it is, you are hungry, tired, in pain, smelling some pretty rotten odors, depressed, scared, angry, and bored. So you might then find it funny to shout mama and maybe a few swear words. Then maybe point at the others, use your word for "your" and say mama after it.

Then let's suppose later, you are forced to work in a field and you start to learn some basic English. So now you have a little bit of a language in common and can come up with longer insults. This becomes a part of your culture, and you pass it onto your descendants. So even after slavery is gone, this tradition which very well could have come from slavery remains.