Mary Alden, was born at Duxbury, Plymouth Colony before 1650. She was the daughter of Alden-63 and Priscilla Mullins Alden. She died after June 13, 1688.  No record has been found proving that Mary Alden ever married. Rebecca Alden not Mary Alden married Thomas Delano.
Woodworth-Barnes, Esther Littleford and Williams, Alicia Crane, Mayflower Families through Five Generations, Vol 16 Part 1 of 3, John Alden, Boston, Mass.: General Society of Mayflower Descendants, 2002.
It may be possible to confirm family relationships with Mary by comparing test results with other carriers of her ancestors' mitochondrial DNA.
Mitochondrial DNA test-takers in the direct maternal line: