Yes but draw an arbitrary line around any group. Call them HNdrathals if you want. Define them at one instaneous snapshot in time as 100% conserved gene corpus. Then watch generation after generation, as some of the HNers (against all odds) interbreed with the surrounding populace. After one hundred generations, should we expect many people to be more than 2% HNdrathal? Yet did the HNdrathals ‘die out’?