All over the place. Really a grab bag of genetic material that subsequently creates a huge range of variation. Apples in particular demonstrate this. Every Fall I spend a couple weekends harvesting feral apples at an abandoned township near where I live (for pressing into cider). Every tree is unique and highly variable. Modern eating apples are always reproduced through grafting, whereas apples that have gone feral are all over the map (and they will readily mate with pears, making it even more complex).

I'm seriously considering doing some grafting myself this year. The place I go has probably 1000+ trees spread out over a couple hundred acres. There is a huge range of variation in terms of flavor. But my favorite ones for making cider are the pips (small, when fullsize, maybe the size of an oblong plumb). They make by far the best cider.