In order to understand Red Charlie, a new red coat variant, breeders must first understand the inheritance and DNA testing for the main coat color gene. The following is a brief summary.
Coat Color inheritance: The main gene that controls the base coat color in cattle is called the extension gene. Historically, it was believed there were three alleles (variations) for this gene in cattle: black (ED), wild type (E+), or red (e). Black coat color is a dominant trait and will mask the presence of other coat color alleles. The wild type allele is dominant to red. Each animal will have two copies of the extension gene (one from each parent) and it can be any combination of the three alleles.
Since Black is dominant, a black animal could have three different pairing of the coat color alleles. A black animal can be homozygous black (ED/ED) or heterozygous black (ED/E+ or ED/e). An animal that is truly homozygous black should always pass a black gene to the progeny. Therefore, an animal that tests homozygous black should always have black progeny. Heterozygous black animals can pass on the wild type or red allele to the next generation and have wild type or red calves. Conversely, as red is a recessive trait, red animals are typically homozygous for the e allele (e/e) and would always pass the red allele to their calves. Sometimes red animals can carry the wild type allele so the example is a little over simplified.
DNA testing for coat color: The DNA marker for the red allele is a mutation in the extension gene that makes the gene unable to make a protein product. Without this protein, an animal will have a red coat. The DNA marker associated with the black allele makes the protein always active and the animal then has a black coat color. Wild type animals have the ability to either have black or red hair and are therefore can be affected by other genes for different coat color patterning (tiger striping or darker hair on the extremities).
There are an infinite number of possibilities that could result in the loss of function of the coat color gene, resulting in a new red coat variant. Red Charlie is a prime example.
Q : What is Red Charlie?
A : Red Charlie is a newly discovered red coat color variant (allele). It works exactly like the existing red coat color allele except it wasn’t being detected by the DNA test for Coat Color. Like the red allele, Red Charlie causes a loss of function of the extension gene. Until recently, we did not know about this mutation so existing coat color test was unable to detect the Red Charlie mutation. Therefore, some animals were testing homozygous black but having red progeny.
Q : What does it mean if my animal is a Red Charlie carrier?
A : Being a Red Charlie carrier is equivalent to being a red carrier. Red Charlie carrier should be viewed just like an animal that tests heterozygous black (carries the red allele).
Q : How can I tell if an animal is a potential Red Charlie carrier?
A : Log-in to Herdbook Services, go to Data Search, Animal Search, enter in the ASA registration number, hit search. Click on TraitTrac. Look under Genetic Traits, Red Charlie is abbreviated as RC. Verify your animal’s status by using the legend key on the left and look to see if there are Red Charlie test results or carriers in the lineage.
Q : How can I order Red Charlie testing?
A : As of 5/12, Red Charlie is not available as a commercial test. However, GeneSeek is working on the final stages of making Red Charlie a publicly available test. Once available, tests can be ordered through the usual DNA test procedure – either call the office at 406-587-4531 or email the DNA department at DNA@simmgene.com.
Q : Will ASA be able to use the sample that was submitted for coat color testing to run Red Charlie?
A : Yes, the ASA can use any viable DNA sample to test for Red Charlie. Please contact ASA by emailing email@example.com or calling our office and providing us with the ASA registration number of the animal you would like to test. We will have the lab pull the sample and see if there is enough sample left to run the RC test.
Q : Does this mean all coat color testing done up to now is wrong?
A : No, animals without Red Charlie carriers in the lineage are likely okay (although this is not a guarantee).
Q : Should I be worried about the validity of my animals homozygous black coat color results?
A : Using TraitTrac will help identify animals that have the possibility of carrying Red Charlie. If an animal has coat color test results already and has a carrier in the lineage for Red Charlie, then there is a possibility that this animal carries Red Charlie as well. If there is no indication of Red Charlie in the TraitTrac system then the odds are low that the animal would carry this allele. However, there may be carriers that the ASA doesn’t know about so no known risk in the pedigree is not a guarantee of being free of Red Charlie.
Q : Is Red Charlie the same as Wild Type?
A : No, Red Charlie has nothing to do with the wild type coat color allele.
Q : Are red or wild type coat color test results affected by Red Charlie?
A : No, Red Charlie is linked only to the Black coat color allele so will only change black coat color test results.
Q : How do we know the Red Charlie coat color variant isn’t present in other pedigrees?
A : It isn’t likely to show up in other pedigrees but this is not a certainty.
Q : Will this affect animals that are tested heterozygous?
A : Animals that tested heterozygous black should be unaffected by Red Charlie. Red Charlie is only linked to the black allele and makes that black allele function like a red allele. So, if an animal tested heterozygous black and appears black, then this animals black allele must be functional and therefore does not carry the Red Charlie variant.
Q : What are the implications of breeding with a Red Charlie Carrier?
A : A Red Charlie carrier has a 50% chance of passing the Red Charlie allele to its progeny and a 50% chance of passing the black allele. See the punnett square below for a more detailed explanation. A Red Charlie carrier has a 50% chance of passing the Red Charlie allele to its progeny and a 50% chance of passing the black allele. See the punnett square below for a more detailed explanation.
Punnett Square showing the progeny outcomes when mating two heterozygous black animals
e can represent either the traditional red coat color variant or the Red Charlie variant
- ¼ of the calves will be homozygous black: These will appear black and always have black calves.
- ½ of the calves will be heterozygous black: These will appear black and half of their calves will inherit the black allele.
- ¼ of the calves will be homozygous red: These will appear red and always pass on the red allele.
To read more about Red Charlie and to view a list of tested Red Charlie carriers as of 5/12/16, click here.
If you have additional questions not answered above, please email firstname.lastname@example.org or call our office at 406.587.4531 and push number 3 for assistance.