Problem:
Has the result of alpha-complementation ever happened via mutation through evolutionary time, and been preserved in modern day organisms?
In other words, has a functional gene product ever been split or terminated by mutation, exhibit alpha-complementation, and has since been preserved as a quaternary protein? This could be found out by comparison of proteins in closely-related species, but don't know of any specific examples. Has such a thing ever happened? Please explain (no word limit count).