The GSB says that Hobby Mare (dam of the famous racemare Brocklesby Betty) was out of Piping Peg. However, evidence in early breeder Cuthbert Routh's stud book, various 18th century stallion adverts and Racing Calendars clearly evidence that Hobby Mare was out of Piping Peg's dam, not Piping Peg.
mtDNA analysis of family 23 found 3 different haplotypes showing the family consists of three separate founder mares. One haplotype is found in the trunk and both branches and is most plausibly that of Piping Peg's Dam. Another haplotype is found only in branch 23-a, and the third only in branch 23-b, indicating pedigree errors at some point in both branches.
Piping Peg's Dam is dam of top class racehorse Brocklesby Betty (4 King's Plates 1716 to 1718): of the King's Plate winners Brocklesby and Long Megg; and of the good stallion Hip, which sires a number of mares which breed on, including an unnamed mare which is dam of Sampson - winner of six King's Plates and sire of high class race horse Engineer, the sire of top class racehorse Mambrino