It may be possible to confirm family relationships by comparing test results with Mary Anne or other carriers of her ancestors' mitochondrial DNA.
Mitochondrial DNA test-takers in the direct maternal line:
Mary Anne Johnston:
Family Tree DNA mtDNA Test Full Sequence, haplogroup A8a1, FTDNA kit #893405
It is likely that these autosomal DNA test-takers will share some percentage (beta) of DNA with Mary Anne: