It is now 25 years since Sidney Lerner published his study in Hoofbeats of the relationship between the top two year olds of 1984-85 and their maternal families. He found that over 80 % of the best two year olds in North America traced back to one of the top 40 families from the 1,334 taproot mares then recognized.
A look at the current two year old crop shows that little has changed. Lerners top 40 families are responsible for 34 (83%) of the top 40 pacers and 32 (80%) of the top 40 trotters in 2010.
The leading families include
Medio with 10; Mambrino Beauty and Sally Sovereign 6 each; Minnehaha, Jessie Pepper, Lizzie Witherspoon, Mamie and Miss Duval with 4 each,; Midnight with 3; Miss Copeland, Jane Hunt each with 2; and Esther and Jane Hunt with 1 apiece. This group , which constituted Lerner's 13 member Group 1, totals 48 (60%) of the top 80 two year olds in my own survey. The top two families in Group 2, Ab and Dolly B contributed 4 more to that total.
Needless to say this information is not widely known since shortly after Lerner's publication the maternal family information was dropped from major sales catalogues. These days what is not on the catalogue page may be more important than what is.