The Ancestral Lineage of a Thoroughbred
Thoroughbred race horses inherit mental and physical characteristics from their Sire (father of a race horse) and Dam (mother), each passing on to their offspring the genetic code provenant from the two ancestral lines.
Therefore in the breeding is where the destiny of a race horse is written, the impact of lineage upon both ability and Class is ever present; the pedigree will define whether a race horse ends up in the claiming ranks or moves up through the conditions and makes it to stakes level competition.
When examining pedigree for the purpose of handicapping a thoroughbred horse race (as opposed to breeding purposes), it's important to appreciate the impact breeding will have in various types of races, over different surfaces, at varying distances.
The genetic factor will be more influential in certain races and less so in others but may be decisive in turf races, maiden special weight, Grade 1 and Grade 2 races; also in races restricted to statebreds, races with two year olds and where certain horses are trying a new surface or stretching out in distance for the first time.