Agouti locus controls distribution of black pigment throughout the coat. This DNA test determine if a horse is A/A, A/a or a/a for the Agouti. To determine base colour Extension and Agouti testing are needed. Buy the Base colour test and get DNA tests for Agouti (A) and Extension (E) loci. Sample requirements and submission form 30 to 40 hair roots or 5 mL of blood in a K3 EDTA tube Get the sample submission form here Turnaround time Standard processing - Results in 3-5 working days after sample arrival at the laboratory. Clients organize and support the costs of sending the samples to the laboratory. PREMIUM processing - Results in 1 days after sample arrival. Includes free express delivery** . The laboratory organizes Express shipping with pick-up of the package at the client's address and delivery at the laboratory. ** PREMIUM SERVICES INCLUDE AN EXPRESS SHIPPING DELIVERY FOR EUROPEAN COUNTRIES FROM NON-REMOTE REGIONS. Check here to know if you are in a remote European region. For remote/outreach regions EXTRA fees are applied. Why test? Agouti is not shown physically on red (e/e) horses. Therefore, a breeder might want to test a chestnut base horse to see if it is an Agouti carrier. Testing bay horses might be desired to see whether the horse carries one (A/a) or two (A/A) copies of the Agouti allele. A homozygous Agouti (A/A) horse will always pass Agouti to its offspring whereas a heterozygous (A/a) horse will have a 50% chance of passing on the gene. Another reason to test for Agouti might be if there is some doubt whether a black horse is truly black or a very dark bay. The effects of other genes might also make it hard to tell if Agouti is present or not. Results description A/A - Bay or Brown - Dominant Homozygous for Agouti. Black pigment restricted to the points. The horse cannot have black foals regardless of the coat color of the mate. The basic coat color will be bay or brown in the absence of other color modifying genes. A/a - Bay or Brown - Heterozygous for Agouti. Black pigment distributed in point pattern. The horse can transmit either (A) or (a) allele to its offspring. The basic coat color will be bay or brown unless modified by other coat color modifying genes. a/a - Black - Recessive homozygous for Agouti. Black pigment distributed uniformly. The basic coat color will be black in the absence of other coat color modifying genes. Additional information The Agouti gene controls the distribution of black pigment. This pigment can be either uniformly distributed or distributed to “points” of the body (ear rims, lower legs, mane, tail). Agouti has been linked to a deletion of 11 nucleotides in the Agouti locus. The 11 nucleotide deletion of this gene is the recessive form of the gene. Only when the agouti gene is homozygous for the deletion (aa) is the black pigment evenly distributed. Heterozygous (A/a) or homozygous for the absence of the 11 nucleotide deletion (A/A) results in point distribution of black pigment. Agouti has no effect on homozygous positive red factor (ee) horses as there has to be black pigment present for agouti to have an effect.
