Horse Genetics and Genealogy Horse Winter Series 28

Horse Genetics and Genealogy Horse Winter Series 28 February 2016 4 H, URI

Summary of Today’s Topics �How to read horse pedigrees �Basics of Genetics �Horse Coat Color Genetics overly simplified! �Genetic crosses for color

Horse Pedigrees Like genealogy for horses

Trace Pedigrees for Breeding �Make sure the horses are from different lines �Choose traits to increase the likelihood of getting the kind of foal you want �Do genetic testing to make sure that a foal will be healthy

American Pharoah http: //www. pedigreequery. com/american+pharoah

http: //hawaii. edu/math/Courses/Mat h 100/Chapter 1/Notes/Exercises/Prac 121. h tm

Secretariat

To read a pedigree �Top line represents all the males �Bottom line represents all the females �Pink is for girls, blue is for boys �Information about when born, where born

Appaloosa pedigree

Basics of Genetics Works the same for people and horses

DNA https: //sites. psu. edu

Organized into Chromosomes Horse chromosomes

Comparing people to horses �People have 23 pairs �Horses have 32 pairs of chromosomes �Individuals give ½ their chromosomes to their kids �Kids get 23 from mom and 23 from dad of chromosomes �Horses give ½ their chromosomes to their kids �Horses get 32 from Sire and 32 from Dam

Genes are on chromosomes http: //www. genomenewsnetwork. org/

Get 2 copies of a Gene �Each copy is called an Allele �You get one allele from mom, one allele from dad http: //biology. about. com/od/geneticsglossa ry/g/alleles. htm

Alleles vary in strength �Some are dominant, usually represented with capital letters �AA, EE, Aa, Ee all look the same �Some are recessive, represented with lower case letters. �aa, ee look different

Coat color and pattern are controlled by A LOT of genes!

Horse pattern BTW, this was photoshopped! http: //www. snopes. com/photos/animals/hor sehorse. asp

Appaloosa www. dfappaloosas. com

Coat Color Ridiculously simplified, because it’s ridiculously complex

Coat color results from pigments �More than 10 genes give color �Base color of all horses Black or Chestnut �Two main pigments controlled by gene E (which is a covering gene, called the Extension gene) � 3 alleles, E+ , e, ea �Eumelanin – Black E+ �Phaeomelanin – Red for chestnut e, ea �Black horse E+E+, E+e or E+ea �Chestnut ee or eea or eaea

Black – have eumelanin Have the genotype E+E+, E+e or E+ea http: //www. theequinest. com/colors/base/bl ack/

Chestnut – have phaeomelanin Have the genotype ee or eea or eaea http: //www. theequinest. com/colors/base/bl ack/

Color Modifiers �Distribution of black pigment is the agouti gene – A � 4 alleles, A+, AA, At , Aa �Makes body color different from the main, tail and points �Bay coloring http: //www. theequinest. com/colors/modifier s/bay/

Grey Horse Color Modifier http: //www. theequinest. com/colors/modifier s/greying/

G gene � 2 alleles, G+ or GG � 3 possible combinations �G+ G+ �G+ GG �GG GG

Dilution Genes �Dun - have dorsal stripe �Crème – palomino, cremello and buckskin �Silver – affects black pigment �Champagne – turns red pigment golden (grullo) �Pearl �Mushroom (not all breeds)

Dun

Creme

Silver

Champagne Image from Kumana @ Wild Equines

Pattern has another suite of genes �Roan �Pinto �Appaloosa �Rabicano http: //www. theequinest. com/colors/whitepatterns/pinto/

Appaloosa

Predict the foal color Try some Genetic Crosses with horse color

All horses are B+ B+ �We ignore this gene and concentrate on the other 2 genes, E and A, extension and agouti

Base Coat Gene E �Base color of all horses Black or Chestnut � 3 alleles, E+ , e, ea �Eumelanin – Black E+ �Phaeomelanin – Red for chestnut e, ea �Black horse E+E+, E+e or E+ea �Chestnut ee or eea or eaea

Black mare with a Black stallion Black Mare E+ E+ Black E+ E+ Black

What if they weren’t E+E+? Black stallion Black Mare E+ E+ Black e E+ e Black e e Chestnut

To breed bay horses Black Mare E+e Black stallion E+ea AA AA AA A A Bay AA A a Aa AA A a Bay Aa A a Aa Bay All Black

What is your favorite color horse? �Think about what it’s genotype might be �What other genotype would you cross with it to get the same color foal?

Website to do it for you! http: //www. animalgenetics. us/Equine/

Check out these websites �http: //www. horse-genetics. com/horse-colors. html �http: //www. theequinest. com/ �http: //www. mustangs 4 us. com/Horse%20 Colors/g enes 1. htm �http: //www. animalgenetics. us/Equine/