Autosomal, dominant mutation

Autosomal, dominant inheritance means that an animal may be clear (normal homozygote), affected (abnormal homozygote) or carrier (heterozygote). Carriers and affected will both have the symptoms of the mutation.

Explanation for veterinarians:
• An animal is CLEAR/NORMAL and has two healthy alleles (normal homozygote). The animal will not acquire any symptoms.
• An animal is a CARRIER and has one healthy allele and one defective allele (heterozygote). The animal will acquire symptoms of the disease.
• An animal is AFFECTED and therefore has two defective alleles (abnormal homozygote). The animal will acquire symptoms of the disease.

Explanation for breeders:
• An animal is CLEAR/NORMAL, and in that case will have two healthy alleles (normal homozygote). This animal will not acquire any abnormalities when breeding and cannot pass on the abnormality to the next generation.
• An animal is a CARRIER, where it will have a healthy allele and a defective allele (heterozygote). The animal will pass on the mutant allele to half of its offspring. Carriers can themselves also become sick.
• An animal is a AFFECTED, which means it has two defective alleles (abnormal homozygote). Affected animals pass on the defective allele to all their offspring in the next generation, and will also develop symptoms associated with the disease.