mtDNA analysis has shown that, in fact, Family 5 descends from 3 separate founder mares. A different haplotype to the main family trunk appears in branches 5-g and 5-h descending from Miss West; this error originates in the 1891 GSB which says Miss West is a descendant of The Massey Mare, whereas previous editions had Miss West's ancestry ending in an unspecified Basto mare, which therefore appears to have been correct.

A third haplotype appears in branches 5-d and 5-e which descend from Hag (1744). There has therefore been an error in the GSB pedigree of Hag or one (unidentified) of her descendants, the relevant horse not descending from Massey Mare.

The Massey Mare is dam of Brown Betty (1719 King's Plate [mares] Newmarket, King's Plate Newmarket); and of the good class racehorse Old Ebony, through which the maternal line of the family continues; 3rd dam of Plaistow (1737 King's Plate Newmarket, 1739 King's Plate The Curragh); and 3rd dam of Skin (1748 King's Plate Ipswich, 1749 King's Plates Winchester, Nottingham, Edinburgh)