Coat Color Genetics Elizabeth Share, Lorain County 4-H Educator Masa Williams, State Extension Associate Ohio%4'H%Horse%Program% www.horse.osu.edu* What We Will Cover Today •*What*is*Gene1cs? * •*Major*Color*Loci* •*E,*A,*C,*D* •*Major*Modifying*Loci* •*G,* Rn,*T* •*Changes*to*Coat*Color*Gene1cs*in*Upcoming*Resources* •*Horse*Smarts* vs*The*Horse* •*Color*Gene1cs*Games* Excellence%in%Junior%Fair%Ac9vi9es%•*Catch*a*Horse* •*Matching*and*Memory* Ohio%4'H%Horse%Program% www.horse.osu.edu* What is Genetics? •*The*study*of*heredity*and*the*varia1on*of*inherited*characteris1cs.* •%Inside%every%living%cell%are%sets%of%instruc9ons%called% GENES% •GENES%provide%instruc9on%on%what%the%animal%looks%like,%how%it%is% to%survive,%etc.% •Each%cell%contains%25,000'35,000%GENES% What is Genetics? •GENES%are%strung%together%in%long%strands%of%DNA%called% CHROMOSOMES% •Horses%have%pairs%of%chromosomes%(one%from%each%parent)% located%in%the%nucleus%of%their%cells% Excellence%in%Junior%Fair%Ac9vi9es% https://history.nih.gov/exhibits/genetics/kids.htm Genetics •One%chromosome%can%contain%hundreds%to%thousands%of%pairs% of%GENES% •Genes%are%located%at%a%physical%posi9on%on%the%chromosome% called%a%LOCUS%% Locus E E Alleles Excellence%in%Junior%Fair%Ac9vi9es%https://history.nih.gov/exhibits/genetics/kids.htm •Like%chromosomes,%genes%also%come%in%pairs% •These%genes%pairs%are%known%as%ALLELES% Genetics •Alleles%found%on%a%locus%can%be%either%% •%The%same,%known%as%HOMOZYGOUS% •%Different,%known%as%HETEROZYGOUS% E E E e Homozygous Heterozygous https://history.nih.gov/exhibits/genetics/kids.htm Genetics •Addi9onally,%genes%found%on%a%locus%can%be%either%% •%DOMINANT,%usually%denoted%by%“capital%leZers”% •%RECESSIVE,%usually%denoted%by%“lower'case”%leZers% Dominant E E E e Recessive •In%most%cases%of%heterozygous%alleles,%dominant%genes%mask% the%expression%of%recessive%ones!% https://history.nih.gov/exhibits/genetics/kids.htm Genetics •* The%GENOTYPE%represents%the%actual%gene9c%makeup%of%an% animal,%for%example:% Loci %%%%%%%% ee%%%%%%AAddCC%%%=% •* The%PHENOTYPE%represents%what%the%animal%looks%like%based% on%the%gene9c%interac9on%of%the%alleles%present% Major Color Loci •E'%Extension%Gene% •A'%Agou9%Gene% •C'%Cream%Gene% Excellence%in%Junior%Fair%Ac9vi9es% •D'%Dun%Gene% Extension Locus •*‘E’*or*‘ e’* •Determines*BLACK*‘E’**or*RED*‘ e’* •BLACK*is*dominant* •* Genotypically*expressed*as*EE*or%Ee% •RED*(chestnut,*sorrel)*is*recessive* •* Genotypically*expressed*as*ee% •*Considered*BASE*COAT*colors* •ALL*other*colors*are*modifica1ons/restric1ons*of*these*two*base*coats* Excellence%in%Junior%Fair%Ac9vi9es% EE or Ee ee Agouti Locus •*‘A’*or*‘a’* •*‘A’*S*restricts*black*pigment*to*points** •*Points=*(mane,*tail,*lower*legs,*ear*rim,*muzzle)* •*‘a’*S*does*not*restrict*black*pigment*to*points* •Produces %Bays%and*Browns%on*a*Black*coat*(EE*or*Ee)* •Does*NOT*affect*red*( ee)* •Agou1*is*dominant* •* Genotypically*expressed*as*AA*or%Aa% Excellence%in%Junior%Fair%Ac9vi9es%•*Recessive* genotypically*expressed*as*aa% Agouti Locus EE or Ee/ AA or Aa ee/ AA or Aa or aa EE or Ee/ aa Cream Locus •*‘C’*or*‘ ccr’** •In*this*case,*‘ ccr*’*is*the*dominant*allele* •Known*as*the* DILUTION*gene* •*‘ ccr’Smodifies*the*base*coat*color*by*reducing*level*of* pigmenta1on* •Can*have* PARTIAL%DOMINANCE%gene*ac1on* •Heterozygote*is*intermediate*between*two* homozygotes* •*Expressed*when* Cccr* •Known*as* SINGLE%DILUTION% Excellence%in%Junior%Fair%Ac9vi9es%•Red*( ee)*will*be*Palomino*(ee*Cccr)* •*Bay*(EEAA,* EEAa,*EeAA,*EeAa)*will*be*Buckskin*(E_A_Cccr)* •Black*( Eeaa,EEaa)*will*be*Smoky*Black*BUT*will* phenotypically*appear*Black* Cream Locus- Single Dilution E_A_ ee AA or Aa or aa E_A_Cccr ee AA or Aa or aaCccr E_aaCccr E_aa Cream Locus •Homozygote*is:* •*Expressed*when* ccrccr* •Known*as* DOUBLE%DILUTION% •*‘ ccrccr’Smodifies*the*base*coat*color*by*reducing*level*of* pigmenta1on*even*more* •Red*( ee)*will*be*Cremello*(ee*ccrccr)* •*Bay*(EEAA,* EEAa,*EeAA,*EeAa)*will*be*Perlino*(E_A_ccrccr)* •Black*( Eeaa,EEaa)*will*be*Smoky*Cream*(E_aaccrccr)* •Phenotypically ,*all*double*dilu1ons*can*appear*the*same* Excellence%in%Junior%Fair%Ac9vi9es%•Creamy*in*color* •Blue*or*green*eyes* •Predominantly*pink*skin* •White*markings*may/may*not*be*visible* Cream Locus- Double Dilution E_A_ ee AA or Aa or aa E_A_ccrccr ee AA or Aa or aaccrccr E_aa E_aaccrccr Dun Locus •*‘D’*or*‘d’* •‘D *’*dilutes*base*coat*color* •*‘d’*–*does*not*dilute*coat*color* •Produces %Grullo%on*a*Black*coat*(E_aa)* •Produces %Dun%on*a*Bay*coat*(E_A_)* •Produces %Red%Dun%on*a*Red*coat*(ee)* •Dun*is*dominant* •* Genotypically*expressed*as*DD*or%Dd% •*Recessive* genotypically*expressed*as*dd* Dun Locus E_A_ ee AA or Aa or aa E_A_D_ ee AA or Aa or aa D_ E_aaD_ E_aa Major Modifying Loci •G'%Gray%Gene% •Rn '%Roan%Gene% •T'% Tobiano%Gene% •Lp '%Appaloosa%Gene% Gray Locus •*‘G’*or*‘g’* •*‘G’*–progressively*grays*out*base*coat* •*Masks*gene*expression*of*all*other*color*genes* •*‘ g’*–*allows*regular*color*expression* •Produces %Gray%on*all*coat*colors!* •Black,*Bay,*Red,*Roan,*Appaloosa,*Paint* •Gray*is*dominant* •* Genotypically*expressed*as*GG*or%Gg% Excellence%in%Junior%Fair%Ac9vi9es%•*Recessive* genotypically*expressed*as*gg% Gray Locus E_A_ ee AA or Aa or aa E_A_G_ ee AA or Aa or aaG_ E_aa E_aaG_ Roan Locus •*‘ Rn’*or*‘rn’* •*‘ Rn’*–results*in*white*hairs*mingled*with*basic*coat*color*hairs* •White*hairs*do*not*increase*in*frequency*with*age*aaer*adult* coat* •*‘ rn’*–*does*not*affect*base*coat*color* •Produces %Blue%Roan%on*a*Black*coat*(E_aa)* •Produces %Bay%Roan%on*a*Bay*coat*(E_A_)* •Produces %Red%Roan%on*a*Red*coat*(ee)* •Phenotypically *can*affect*ALL%coat%colors% Excellence%in%Junior%Fair%Ac9vi9es%•ie .*palomino*roan,*dun*roan,*buckskin*roan,*grullo*roan** •Roan*is*dominant* •* Genotypically*expressed*as*RnRn*or%Rnrn% •*Recessive* genotypically*expressed*as*rnrn* Roan Locus E_A_ ee AA or Aa or aa E_A_Rn_ ee AA or Aa or aaRn_ E_aa E_aaRn_ Tobiano Locus •*‘T’*or*‘t’* •*‘T’*– paben*for*white*spocng* •White*over*back*and*high*leg*white* •*‘ t’*–*does*not*cause*spocng* •Can*affect*all*coat*colors* •Tobiano *is*dominant* •* Genotypically*expressed*as*TT*or%Ta% •*Recessive* genotypically*expressed*as*Z% Tobiano Locus eett E_A_T_ E_aaT_ Genetics •* Remember'%a%horse’s%GENOTYPE%(gene9c%code)%determines%his% PHENOTYPE%(what%he%looks%like)% %%%%%%%% cr %%%%%Ee Aa dd%%%%%%%%%%%%% Cc%%%%=% Extension Dun Agouti Cream •Most%horses%do%not%possess%ALL%color%genes%discussed%today!% HORSE COAT COLOR PANEL TEST RESULTS MAYA WISDOM Case: NQ34468 8128 PLANKTOWN RD. Date Received: 26-Jan-2017 SHILOH, OH 44878 Print Date: 01-Feb-2017 Report ID: 4552-3112-9555-1044 Verify report at www.vgl.ucdavis.edu/myvgl/verify.html Horse: 16F TAXI'S DIAMOND Reg: DOB: 05/25/2016 Sex: Mare Breed: Rocky Mountain Horse Sire: ALLIANCE'S GONE N DUN IT Reg: 2010043197 Dam: TAXI'S DIAMOND Reg: 2006014721 SPLASHED RED FACTOR Both black and red factors detected. Not requested. E/e WHITE If present, black pigment is distributed AGOUTI LEOPARD Not requested. a/a uniformly over the body. CREAM N/Cr 1 copy of Cream dilution detected. PATTERN-1 Not requested. PEARL N/N No copies of Pearl dilution detected. GRAY Absent Gray gene is absent. Horse will not turn gray. 2 copies of Silver dilution detected. Horse is SILVER DUN 1 copy of Dun dilution and 1 copy of nd2. Z/Z expected to have MCOA eye abnormalities. D/nd2 DOMINANT LETHAL WHITE Not requested. WHITE (W5, W10, Not requested. OVERO W20) SABINO 1 Not requested. TOBIANO Not requested. CHAMPAGNE N/N No copies of Champagne dilution detected. For more detailed information on Horse Coat Color results, please visit: www.vgl.ucdavis.edu/services/coatcolorhorse.php Tests for Gray, Leopard/Appaloosa, Lethal White Overo and Tobiano are performed under license. Upcoming Changes •Dun:* •The*Horse :*DD*or*dd* •Horse*Smarts :*DD*or*d1,*d2* •Cream:* •The*Horse :*CC=no*dilu1on*(recessive),** ***ccrS*dilu1on*(dominant)* •Horse*Smarts :*CR=dilu1on*(dominant)* **cr=*no*dilu1on*(recessive)* Excellence%in%Junior%Fair%Ac9vi9es%•Roan:* •The*Horse :*RnRnS*listed*as*lethal* •Horse*Smarts :*RNRN* •RNRNS*no*longer*thought*to*be*lethal* •No*“strawberry*roan”** Upcoming Changes •Tobiano :* •The*Horse :*TT*or*b* •Horse*Smarts :*TO*or*to* •Overo :* •The*Horse :*OO=*no*spocng*pabern**(dominant)S*allows* * ***** ******normal*expression*of*genes*at*other*loci,** ******Oo=*no*spocng*pabern**(dominant)* ***oo=*spocng*pabern**(recessive)* *****oe=*causes*lethal*when*homozygous*(recessive* Excellence%in%Junior%Fair%Ac9vi9es%******for*overo*spocng*pabern*)* •Horse*Smarts :*OO=*lethal* ******Oo=*spocng*pabern*(dominant)* ***oo=**no*spocng*pabern*(Recessive)* Upcoming Changes •Appaloosa:* •The*Horse :*Ap*or*ap* •Horse*Smarts :*Lp*or*lp* Excellence%in%Junior%Fair%Ac9vi9es% What’s NOT Covered in This •Colors% Presentation •Overo * •Frame* •Sabino * •Splashed*White* •Appaloosa* •Champagne* •Silver* Excellence%in%Junior%Fair%Ac9vi9es%•Pearl* •Dominant*White* •Lethals % •Punnet %Square% Horse Smarts •New*in*2018** for*Ohio* • $124 • 1,196 pages •Will*be*used*at* 2017*Na1onal* Contests* Excellence%in%Junior%Fair%Ac9vi9es% hbp://www.ayhc.com/productSpage/horseSsmarts* Color Genetics Games! • Matching and Memory • Template available online! • Catch a Horse Excellence%in%Junior%Fair%Ac9vi9es%.