Instant Yeast in Levain
I've been having trouble working out a schedule that allows me to bake sourdough with my Levain, so I've been feeding it a few days at a time and then resigning it to the fridge for months at a time for around 9 months now. I remember once using leftover poolish started with instant yeast and treating it like a Levain with feedings and discardings of just flour and water (no more instant yeast ever added) I can't remember if that's still this tub or I tossed that and restarted.
My question is, if you start a Levain with instant yeast and continually take it far enough that it smells deeply of vinegar/alcohol, then let it stagnate in the fridge, and repeat this process, is the yeast culture that survives a monoculture descendent of the instant yeast, or will wild yeasts have taken over? Can instant yeast survive those conditions like the proper sourdough strains can?
I'm happy to clarify the question and conditions I've been working with if it helps. Thanks.