It's amusing to think on two such populations of this human diaspora surviving to eventually reunite one day, probably tens of thousands of years after the original colonization event faded from their collective cultural memories.
One would hope having one's solar system murdered by a rouge star might help a species grow up but right now I'm skeptical.
https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next...
Pretty sure if today's scientists had access to a dozen alien populations, DNA analysis would be one of the first things they set about. I'm not a trekky, but I would think that this should have happened chronologically much earlier in the canon.
Unfortunately, that was a two-part afterthought and the canon in that respect was never really explored. You could set an entire season or series around it, and Star Trek had a lot of dropped ideas with potential like that.