question about differing yeast strains
i have a question about the different yeasts that we use for our cultures, namely, are they really so different?
i have read that over time, the dominant yeast in a culture can change from one strain to another. i always create my culture simply by using KA flour (I never buy a culture) and that is the same flour i use to feed my culture. in other words, even if i created a camoldoli culture, for example, i am feeding it with flour that has a presumably different dominant yeast strain. with this in mind, i have two questions:
1. exactly how different ARE these cultures over time. can anyone say that without a doubt, over time, they have managed to keep two different strains and that those strains make noticeably and significant differences in the dough?
2. how different are the various strains in the various brand name flours that we use. are they all different, or do they all basically have the same strain of yeast.
Thanks in advance.