Coat Color Genetics - Ohio 4-H › sites › ohio4h › files › imce › animal... ·...

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Coat Color Genetics

Elizabeth Share, Lorain County 4-H Educator Masa Williams, State Extension Associate

Excellence%in%Junior%Fair%Ac9vi9es%

Ohio%4'H%Horse%Program%www.horse.osu.edu*

• *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*

• *Catch*a*Horse*• *Matching*and*Memory*

What We Will Cover Today

• *The*study*of*heredity*and*the*varia1on*of*inherited*characteris1cs.*

What is Genetics?

• %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%


• 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%

What is Genetics?

https://history.nih.gov/exhibits/genetics/kids.htm


• One%chromosome%can%contain%hundreds%to%thousands%of%pairs%of%GENES%• Genes%are%located%at%a%physical%posi9on%on%the%chromosome%called%a%LOCUS%%

Genetics


E E

• Like%chromosomes,%genes%also%come%in%pairs%• These%genes%pairs%are%known%as%ALLELES%

Locus

Alleles

• Alleles%found%on%a%locus%can%be%either%%• %The%same,%known%as%HOMOZYGOUS%• %Different,%known%as%HETEROZYGOUS%

Genetics


E E Homozygous

E e Heterozygous

• Addi9onally,%genes%found%on%a%locus%can%be%either%%• %DOMINANT,%usually%denoted%by%“capital%leZers”%• %RECESSIVE,%usually%denoted%by%“lower'case”%leZers%

Genetics


• In%most%cases%of%heterozygous%alleles,%dominant%genes%mask%the%expression%of%recessive%ones!%

E e E E Dominant Recessive

• *The%GENOTYPE%represents%the%actual%gene9c%makeup%of%an%animal,%for%example:%

% % % % % % %%% % % % % %%%=%

Genetics

• *The%PHENOTYPE%represents%what%the%animal%looks%like%based%on%the%gene9c%interac9on%of%the%alleles%present%

eeAAddCC%

Loci


• E'%Extension%Gene%

• A'%Agou9%Gene%

• C'%Cream%Gene%

• D'%Dun%Gene%

Major Color Loci


• *‘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*

Extension Locus

ee EE or Ee


• *‘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%• *Recessive*genotypically*expressed*as*aa%

Agouti Locus

Agouti Locus

ee/ AA or Aa or aa

EE or Ee/ AA or Aa

EE or Ee/ aa


• *‘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%• 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

Cream Locus- Single Dilution

E_A_

E_A_Cccr

ee AA or Aa or aa

ee AA or Aa or aaCccr

E_aa E_aaCccr


• 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*

• Creamy*in*color*

• Blue*or*green*eyes*• Predominantly*pink*skin*

• White*markings*may/may*not*be*visible*

Cream Locus

Cream Locus- Double Dilution

ee AA or Aa or aa E_A_

E_aaccrccr

E_aa

E_A_ccrccr ee AA or Aa or 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_

E_A_D_

ee AA or Aa or aa

ee AA or Aa or aa D_

E_aa E_aaD_

• G'%Gray%Gene%

• Rn'%Roan%Gene%

• T'%Tobiano%Gene%

• Lp'%Appaloosa%Gene%

Major Modifying Loci


• *‘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%• *Recessive*genotypically*expressed*as*gg%

Gray Locus

Gray Locus


E_aaG_

E_aa

E_A_G_ ee AA or Aa or aaG_


• *‘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%

• 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

Roan Locus


E_aaRn_

E_aa

E_A_Rn_ ee AA or Aa or aaRn_

• *‘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

Tobiano Locus

eett E_A_T_

E_aaT_

• *Remember'%a%horse’s%GENOTYPE%(gene9c%code)%determines%his%PHENOTYPE%(what%he%looks%like)%

% % % % % % %%% % % % %%%%%%%%%%%%%%%%%%=%

Genetics

• Most%horses%do%not%possess%ALL%color%genes%discussed%today!%

Ee Aa Cccr dd

Extension Agouti

Dun Cream

HORSE COAT COLOR PANEL TEST RESULTSMAYA WISDOM

01-Feb-2017

8128 PLANKTOWN RD.SHILOH, OH 44878

Case: NQ34468

Print Date:

Date Received: 26-Jan-2017

Horse: 16F TAXI'S DIAMOND

Sire:Dam:

2010043197Reg:

Report ID: 4552-3112-9555-1044Verify report at www.vgl.ucdavis.edu/myvgl/verify.html

TAXI'S DIAMONDALLIANCE'S GONE N DUN IT

2006014721

Reg:

Reg:

DOB: 05/25/2016 Sex: Mare Breed: Rocky Mountain Horse

RED FACTOR E/e Both black and red factors detected. SPLASHEDWHITE

Not requested.

AGOUTI a/a If present, black pigment is distributeduniformly over the body. LEOPARD Not requested.

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.

SILVER Z/Z 2 copies of Silver dilution detected. Horse isexpected to have MCOA eye abnormalities. DUN D/nd2 1 copy of Dun dilution and 1 copy of nd2.

LETHAL WHITEOVERO

Not requested.DOMINANT

WHITE (W5, W10,W20)

Not requested.

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.


• 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)*

• 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*

******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*

Upcoming Changes


• Colors%• Overo*

• Frame*

• Sabino*• Splashed*White*

• Appaloosa*• Champagne*

• Silver*• Pearl*• Dominant*White*

• Lethals%• Punnet%Square%

What’s NOT Covered in This Presentation


Horse Smarts

hbp://www.ayhc.com/productSpage/horseSsmarts*

• New*in*2018**for*Ohio*

• Will*be*used*at*

2017*Na1onal*

Contests*

• $124 • 1,196 pages


Color Genetics Games! • Matching and Memory

• Catch a Horse

• Template available online!

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