The maternal relationship between Cooper and her son Billy Williams Sr is confirmed by the direct inheritance path of autosomal DNA down to their DNA tested descendant SG.

The segmental (via DNA segment triangulation) and total DNA shared between SG and other confirmed descendants of WC is consistent with the expected ranges for their respective relationships. Since SG descends from WC through Cooper and her son Billy Williams Sr, the presence of significant shared DNA between SG and other known descendants of WC validates the generational links along this maternal line.

This supports the conclusion that DNA was passed from MRCA WC through Cooper to Billy Williams Sr, and ultimately to SG, confirming this direct ancestral connection through multiple generations.