This might be a bit esoteric, and certainly off the wall, but here it is anyway.
As long as you keep your starter going with regular feedings, the higher the likelihood of sister, or 'clone' reproduction keeping the starter of EXACTLY the same animal - down to shared genes. They just feed, grow, and divide. During one stage of the ferment cycle, it sounds like they are capable of also reproducing sexually, which means that if you have a healthy and well fed starter, you are going to have cloning most of the time, and a little sexual reproduction once a cycle, just to keep the party going...
Makes for a pretty consistent, if incestuous, party.
Once there is a threat to the beasties' lives, they begin to release spores - which would only be haploid, containing one half of the full gene - and these spores later combine to make 'children' of the previous generation. Really close, and resembling the parents, but hardly identical. Add to that the sheer number of beasties we are talking about and there is a lot of room for variance.
It is amazing that in the end it is the strongest, fittest yeasts that 'weed out' the rest of the possible yeasts and bacteria. The best illustration that I have heard is that it is like a really green grass lawn - if it is well tended it will choke out the other species.
But then, arguably, some of the best sourdoughs are symbiotic relationships with yeast and lactose friendly bacteria. I will not make any allegory for this group, and I'll just be pleased with the fine flavor and smile!