The specific population-genetic analysis involved statistical methods for comparing patterns of allele sharing — the degree to which two individuals or populations share specific genetic variants at specific positions in the genome — across many thousands of genomic positions.

The pattern of allele sharing between Shuká Káa and different reference populations (modern Native Americans from different regions, ancient individuals from different periods and locations) established his genetic position relative to those populations.

The conclusion that Shuká Káa showed the closest genetic affinity to the later peoples of the Northwest Coast — rather than to populations from the interior of North America or from the Arctic coast — was the specific finding that supported the interpretation of deep coastal continuity.

It indicated that the founding ancestry of the Northwest Coast peoples was already present in the Alexander Archipelago by 10,300 years ago, and that the population history of the coast since then has been primarily one of in-place development rather than replacement by immigrants from elsewhere.