Name: Extension, Chestnut or Sorrel
Brand: Equigerminal
Price: 38.0 GBP

Product form

Extension, Chestnut or Sorrel

DNA test DNA test for the Extension gene that controls the production of black or red pigment throughout the coat....

£38.00

Sample Requirements

30 to 40 - hair roots - envelope or 5 mL - blood - K3 EDTA tube

Send your sample by regular mail or express delivery to:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

Turnaround Time

5 working days

About the test

The Extension (MC1R) DNA Test determines the genetic base coat colour by identifying whether a horse carries the dominant black pigment allele (E) or the recessive red pigment allele (e).

This test is essential for breeders wishing to predict offspring coat colours and identify horses carrying the recessive red factor, even when they display a black-based coat colour.

For complete coat colour prediction, the Extension test is recommended together with the Agouti test and other coat colour dilution tests.

Why test?

Testing the Extension gene allows breeders to:

Identify carriers of the recessive red (chestnut) allele.
Predict the base coat colour of future offspring.
Improve breeding decisions for colour selection.
Confirm whether black-based horses are homozygous or heterozygous for the Extension gene.
Combine results with Agouti and dilution genes for complete coat colour prediction.

How it works

🛒 Purchase the Test: Select and buy the test online.

📧 Receive Instructions: After payment confirmation, receive instructions for sample collection.

✨ Sample Collection: Collect 30–40 hair roots or ask your veterinarian to collect a blood sample.

📄 Download Submission Form: Download the printable submission form.

📮 Send Samples: Send your samples to:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

📄 Receive Results: Your DNA certificate will be sent by email.

Results

The DNA test for Extension gene verifies the base coat color and presents results as one of the following:

E/E- Dominant Homozygous for Extension - Black, Bay or Brown - Only the black factor is expressed. The horse can only transmit the (E) allele E/E to it offspring. It cannot have foals with basic coat colour Chestnut or Sorrel foals regardless of the color of the mate. The Agouti gene willdetermine if the basic coat color will be black, bay or brown, unless modified by other color modifying genes.
E/e - Heterozygous for Extension - Black, Bay or Brown - Both red and black factor are expressed. It can transmit either (E) or (e) allele to its offspring. The Agouti gene will determine if the basic coat color will be black, bay or brown, unless modified by other color modifying genes.
e/e - Recessive homozygous for Extension - Chestnut or Sorrel- Only the red pigment is expressed. The basic coat color is chestnut or sorrel unless modified by other color modifying genes.

Additional information

The Extension gene (MC1R) determines whether a horse produces black or red pigment, forming the foundation of every equine coat colour.

Black-based horses possess at least one dominant E allele, while chestnut horses always carry two recessive e alleles.

Although the Extension gene establishes the base pigment, other genes—including Agouti, Cream, Champagne, Silver, Pearl, Grey, and Dun—modify the final appearance of the coat.

Because black-based horses may carry the recessive red allele without showing it, DNA testing is the only reliable way to identify carriers and accurately predict offspring coat colours.