Early adaptation to training

The HTR1A gene

The results


This horse does not have the HTR1A mutation associated with excessive equine anxiety.

While some yearlings do not have the mental capabilities to thrive in a racing environment at two, alert and curious youngsters like this horse are better suited to withstand the pressures.

Thoroughbreds with a genotype like this horse tend to adapt to new environments and conditions faster than other horses.


This result is found in elite horses that have achieved at least one start as a two-year-old.

All thoroughbreds mature mentally and physically at different rates. Some have a genetic predisposition conducive to early racing, while others may not have the mental capabilities to thrive in such an environment.

Genetic markers can predict anxiety, fearfulness and dominance behavior that can influence a young horse’s mental and psychological responses to new situations, training methods and high stress environments.

These markers can predict whether a yearling can withstand the rigors of early racing or needs more time to develop and mature.

The HTR1A mutation is associated with easy-handling and behavior in early training.

The importance of adaptability

An adaptable thoroughbred exhibits a form of accepting, compliant behavior which ensures easy handling and high trainability.

TThoroughbreds with this genotype can provide owners with a quicker and higher financial return on their initial investment because they will react more positively to different stimuli.

These horses are less likely to be adversely affected by stress, boredom, fear or isolation, and can recover faster than other horses from emotional challenges.

Adaptable horses are quick learners that will accept new experiences such as bathing, loading into a trailer and clipping. They are less rebellious, aggressive, and fearful, and are therefore easier to back, easier to train, and quicker to race.

TTrainable, early maturing horses like this horse are more likely than others to perform well at two, without negatively affecting their ability to race as a three-year-old.

Early starters have been recorded as having significantly longer racing careers than horses that take longer to mature.

The genetic details

The HTR1A gene has been found to influence anxiety, depression, and stress in numerous species. Within the gene there is a mutation that influences anxiety-related traits and adaptability.

How the gene influences the trait is not fully understood: it is likely the mutation affects serotonin receptors in the brain. Within the gene, there is a switch in one of the four base pairs that make up a DNA molecule: Guanine (G) is replaced by adenine (A). When this switch occurs, there is an increased anxiety and stress response, which influences the behavior of the young horse.