"Y-DNA and mt-DNA would only give the same information if matings between invader males and native females were equally likely as matings between invader females and native males-which cannot possibly be true." So, unless both the Y-DNA and the mt-DNA are considered in any sample population, then you're not getting a true picture of that population? That would make The Seven Sisters/Daughters Of Eve stories BS, huh?
There's now 27 sisters of Eve. 7 are European and the rest are Asian and African.