SMGF did a collaboration with international geneticists, their findings are that 95% of current American Indians were from 15 women, and they traced specific maternal lines to them. They even mapped out these early 'moms'.
These 'moms' were from Siberia (just east of what is being shown on Ancestrys F/V-U mapping) and these same snippets are found in Alaska, as well as Belangia today.
Ancestry assumed SMGFs very indepth American Indian DNA samples (all of their database) - so while this is not saying that those whom show up F/V-U ARE Amer Indian, just keep in mind, that for some, these originals lived in that same area, and it isn't outside the realm.
Also, someone stated that no one has AI DNA: yes, Ancestry does. SMGF had the preeminent DNA collection, and it was used as part of this study that was done over many years, culminating in 2011. They are still continuing their initial findings, as they expect to find even more ancient 'moms' within the mtDNA