Design and Manage Matings

Why the genetic type cannot be determined from evaluation of the pedigree

All individuals inherit two copies of each gene – one from the sire and one from the dam. Therefore the mare and stallion each pass on just one of their gene variants (i.e. ‘C’ or ‘T’) to the foal. A C:C type horse will always pass on a ‘C’ type gene variant to its offspring; similarly a T:T will always transmit a ‘T’ type gene variant. A C:T horse is equally likely to transmit either a ‘C’ or a ‘T’.

The table below shows the potential outcomes from a mating between two C:T horses.

In this instance, 25% of the time this mating will produce a C:C horse, 50% of the time it will produce a C:T horse and 25% of the time it will produce a T:T horse. This explains why two full-siblings may be two completely different types of horse, and therefore why this trait cannot be evaluated through pedigree analysis alone. Using the Equinome Speed Gene Test the genetic type can be determined with certainty.

Manage Matings

The potential outcomes from each breeding combination may be estimated if the genetic type of the dam and sire are known. With this knowledge mares and stallions may be matched to more consistently meet breeding objectives. Note: the stallion and mare make an equal contribution to the genetic type of the progeny for this trait.