The proposed relationship of William Scott as the father of Mary Polly Scott and Francis Marion Scott is supported by DNA evidence indicating shared ancestry within the family lines.

Specifically, DNA evidence confirms a distant cousin relationship between JS (a descendant of the Francis Marion Scott ancestral line) and DL (a descendant of the Mary Polly Scott ancestral line) with a shared segment of 19.16 cM across 1 HIR segments.

This match is consistent with their placement within these shared ancestral branches.