colorgenotypediscussion8

POSSIBLE COLOR GENOTYPES

BAY & BAY-to-GREY

Introduction

The Basics

What Makes Grey (G)

What Makes Black (E)

What Makes Bay & Chestnut (A)

Possible Color Genotypes

Possible Color Genotypes/Black & Black-to-Grey

Possible Color Genotypes/Bay & Bay-to-Grey

Possible Color Genotypes/Chestnut & Chestnut-to-Grey

Sample Matings

Glossary of Terms Conclusion

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BAY

ggAAEE -- There is no dominant silvering allele (G) needed to produce grey, and there are two of the dominant Agouti allele (A) needed to produce bay and two of the dominant extension allele (E) needed to produce black. This horse is homozygous bay because it CANNOT have a black or chestnut offspring since it will always contribute a dominant A allele AND a dominant E allele. Thus, all of its offspring will be bay unless influenced by a dominant G allele from the other parent.

ggAAEe -- There is no dominant silvering allele (G) needed to produce grey, two dominant Agouti alleles (A) needed to produce bay, and one dominant extension allele (E) needed to produce black. This horse's offspring can only be bay or chestnut but never black because it will always contribute the dominant A allele, thus producing a bay in the presence of the dominant E allele. It may also produce a grey if the other parent contributes a dominant silvering allele (G).

ggAaEE -- There is no dominant silvering allele (G) needed to produce grey, one dominant Agouti allele (A) needed to produce bay, and two dominant extension alleles (E) needed to produce black. This horse's offspring can only be bay or black but never chestnut because it will always contribute the dominant E allele producing black or producing bay in the presence of a dominant A allele. It may also produce a grey if the other parent contributes a dominant silvering allele (G).

ggAaEe--There is no dominant silvering allele (G) needed to produce grey, one dominant Agouti allele (A) needed to produce bay, and one dominant extension allele (E) needed to produce black. This horse's offspring may be bay, chestnut, or black based upon the various contributions it can make. It may also have the same colors for its offspring based upon the contributions of the other parent, also including grey.

Bay foals do not have the full bay coloring at birth--it will be a combination of bay and black. The body will be reddish in color with the mane and tail being definitely black. However, the lower legs will have the same kind of mousy/cloudy color found on a black foal. When the winter coat comes in, it is not unusual for fawn-colored (light brown and sort of mousy-looking) hair to be on the lower legs, around the muzzle, and on the flank--this may appear until they are about two to four years old.

Storrmy Surprise--6 days old

Storrmy Surprise-1 year old

BAY-to-Grey

GgAAEE, GgAAEe, GgAaEE, GgAaEe -- The base foal coat of this horse is bay, but it might be mistaken for black or chestnut, and it might not be determined until later as an adult using colors found in its mane/tail and body hairs or DNA testing. This horse's offspring will have a 50/50 chance of being grey based only upon this parent's contribution.

GGAAEE, GGAAEe, GGAaEE, GGAaEe -- The base foal coat of this horse is bay, but it might be mistaken for black or chestnut, and it might not be determined until later as an adult using colors found in its mane/tail and body hairs or DNA testing. This horse's offspring will ALWAYS be grey because it will ALWAYS contribute the dominant G allele. This horse is considered to be homozygous grey since it has two dominant G alleles.

A grey's base foal coat of bay is often mistaken as black or chestnut, especially if the silvering process proceeds quickly. If thought to have a black foal coat, the correct foal coat identification can be made when reddish hairs are later seen on the body. If thought to have a chestnut foal coat, the correct foal coat identification can be made when black hairs are later seen in the mane and tail. It is also helpful to know the genotypes of the parents to help with identifying this base coat.