system
Given the following post, respond as if you're commenting on Reddit:
human
How were early humans able to get around inbreeding in their small tribes?

I recently read somewhere that scientists came up with the number of 160 people necessary to populate a space colony to minimize the amount of mutations from inbreeding.  How were early humans able to get around this?  Early tribes could not have all had 160 genetic lines to mix.
gpt
The simple answer is that earth is not an isolated space colony, and never was. Tribes would often meet up with each other. Mechanisms for genetic spread include tribes merging, tribes diverging, tribes conquering others, members of one tribe stealing a few females from another during a late-night raid, impromptu inter-tribal rape, one-night stands by two strangers who met in the woods, two lovers from rival tribes running off together to find a new one to join because they're scared of being persecuted by their parents, one tribe offering a gift of females to another tribe's leader as a sign of good will (ie don't kill us, we're your friends), one man giving his daughter as a wife to a respected man of moderately high position in another tribe in an effort to boost his own power and influence and attach himself to a more powerful family, etc etc etc. 

Honestly, even just a few instances of crossover every few generations is enough to keep the genetic material flowing at a decent rate, and is actually an important factor in how our race evolved.