What it does not establish, with the granularity that the evidence available provides, is that every aspect of the later Northwest Coast cultural tradition is the direct, unbroken product of the same single founding community that Shuká Káa belonged to.

Human population history is never perfectly simple.

Even when the broad pattern is one of continuity — of a founding population remaining in place and gradually developing the traditions of its descendants — there is almost always some degree of demographic complexity overlaid on that basic pattern.

People move.

Communities interact.

Genes flow between populations through marriage and migration.

Specific events — volcanic eruptions, tsunamis, epidemics, conflicts — can displace populations from specific areas and be followed by reoccupation from elsewhere.

The finding of deep genetic continuity on the Northwest Coast does not require that there were no demographic perturbations over 10,000 years — only that the overall pattern is one in which the founding genetic ancestry of the early coastal people is well-represented in the later populations.