Clear
Genotype: N / N [ Homozygous normal ]
The horse is noncarrier of the mutant gene.
It is very unlikely that the horse will develop Distichiasis*. The horse will never pass the mutation to its offspring, and therefore it can be bred to any other horse.
Carrier
Genotype: N / [ Heterozygous ]
The horse carries one copy of the mutant gene and one
copy of the normal gene.
It is very unlikely that the horse will develop Distichiasis* but since it carries the mutant gene, it can pass it on to its offspring with the probability of 50%. Carriers should only be bred to clear horses.
Avoid breeding carrier to carrier because 25% of their offspring is expected to be affected (see table above)
Affected
Genotype: / [ Homozygous mutant ]
The horse carries two copies of the mutant gene and
therefore it will pass the mutant gene to its entire offspring.
The horse is likely to develop Distichiasis* and will pass the mutant gene to its entire offspring
