Horse color Genetics

[kalika]

Well I love Biology and My favorite part is Genetics
Combine that with the horse and you get Horse Genetics
Whoot Whoot
So here is something I made. Most of you will probably recognize this.

Regular Genes
Black- EE or Ee
Chestnut/sorrel- ee
*Notice~ Black and sorrel are the base for any color

Bay- EEAA, EEAa, EeAA, EeAa
Buckskin- same as Bay except CRCR or CRcr added to the ends

Palomino- ee CRcr
Cremello- ee CRCR

Blue roan- EERR, EERr, EeRR, EeRr
Red Roan- eeRR, eeRr
All other roans- have RR or Rr added to the rest of the genes

Smokey Black- EECRcr, EeCRcr
Smokey Cream-EECRCR, EeCRCR

Paints
All the same genes apply only difference is that they will have either TOTO, TOto or Oo

Tovero paints means it has both gene mixtures
Exception- if either gene is all capitals it means that one will be dominant.
ex. TOTO Oo - 100% Tobiano
TOto Oo - Tovero
toto Oo - 100% Overo

Notice- double Overo genes is automatic stillborn, and if it does live, it will die in less then 72hrs

Grey and Whites
As a foal they will show what genetics they have in there blood
After a while they will become either white or grey.
NOTICE. White and grey is NOT the same thing

they each have there own gene.

white- Ww
grey- Gg or GG

*Notice. two white genes is a Lethal White. Automatic Stillborn or if alive, will die in less then 48hrs.

Both whites and grey are like "cover-ups" seeing as the coloring genes are still there but are now not vissible.
So a white horse's genes could still be something like this
EeAaCRcrWw
This horse would be a buckskin if it had not had the white gene. At birth it would have looked like a buckskin

How to predict foal color
There is a really easy method that allows for this. I call it the square system.

Let's take something easy first. A black and a chestnut.
Black- EE or Ee(lets pretend in this case the horse is Ee)
Chestnut- ee

Lets pretend the black horse is the stallion and the mare is the chestnut.

make a box with 9 squares
now when you place them letters place them so...
from left to right- first row
1st box, empty
2nd box, the stallion's first letter, which is capital E
3rd box, the stalion's second letter, which is lower e

From left to right- second row
1st box, the mare's first letter, which is lower e
2nd box, empty
3rd box, empty

From left to right- third row
1st box, mare's second letter, which is lower e
2nd box, empty
3rd box, empty

So now you have something similar to this


E e

e

e


Now when you put the letters together like so...

E e

e Ee ee

e Ee ee

The stallion's letters go down and the mare's letters go across

Now that we have these four pairs you put them in a list

Ee- black
Ee- black
ee- brown
ee- brown

THis means that the foal of these two will be
50% black
50% chestnut


Lets try something harder. This time we'll use 2 different letters.
I realize that the colors have more then one way to be possible but I'm just picking something

Stalion~bay(EEAa)
Mare~Black(Ee)

since the mare does not have the Agouti gene(AA) we know that it is (aa)

Mare~Black(Eeaa)

We can't possibly mix the two letters, not possible
We can however make two tables

E E A a
E EE EE a Aa aa

e Ee Ee a Aa aa

Now to figure out what you get with the foals

here's the problem... how do we ensure that each gene is counted equally.

Simple, put numbers beside the results, watch...

S=stallion Genes
M=mare Genes

Square A
S S
M 1 2

M 3 4

Square b
S S
M 1 2

M 3 4

Squence

1a+1b
1a+2b
1a+3b
1a+4b
2a+1b
2a+2b
2a+3b
2a+4b
3a+1b
3a+2b
3a+3b
3a+4b
4a+1b
4a+2b
4a+3b
4a+4b

So if we go back to the previous

E E
E EE EE

e Ee Ee


A a
a Aa aa

a Aa aa


you now get

EEAa
EEaa
EEAa > all the first left top EE with all 4 A's
EEaa

EEAa
EEaa
EEAa > all the second right top EE with all 4 A's
EEaa

EeAa
Eeaa
EeAa > all the third, left bottom Ee with all 4 A's
Eeaa

EeAa
Eeaa
EeAa > all the third, left bottom Ee with all 4 A's
Eeaa


Now add all the same ones together
4 x EEAa
4 x EEaa
4 x EeAa
4 x Eeaa

having said that you get.
50% Black
50% Bay


The extreme
No more explaining, if you don't quite get it, please reread the previous

Stallion- Palomino Tovero(ee CRcr TOto Oo)
Mare- buckskin roan(Ee AA CRcr Rr)

E e
e Ee ee

e Ee ee

A A
a Aa Aa

a Aa Aa

CR cr
CR CRCR CRcr

cr CRcr crcr

R r
r Rr rr

r Rr rr

to to
TO TOto TOto

to toto toto

o o
O Oo Oo

o oo oo


This will be EXTREMELY long

A quick way to figure out how many results you'll have
Take the number of genes
which in this case is 6
The number of results per table is 4
so the answer is 4 to the power of 6
In other words 4^6
or the final answer 4096
and I did an improper on of only 256 by hand. Ofcourse with the help of copy and paste, but still
A LOT
and I'm not going to put the whole thing in one thread, that's ridiculous

After I did my own little practice I went onto google and found my own calculator. here is the exact thing.The engine automatically calculates all 4096 possibilities

3.13% - Palomino Roan Overo
3.13% - Buckskin Tovero
3.13% - Buckskin Tobiano
3.13% - Buckskin Overo
3.13% - Buckskin Roan Tovero
3.13% - Buckskin Roan Tobiano
3.13% - Buckskin Roan Overo
3.13% - Buckskin Roan
3.13% - Buckskin
3.13% - Palomino Roan
3.13% - Palomino Roan Tobiano
3.13% - Palomino Overo
3.13% - Palomino Tobiano
3.13% - Palomino Tovero
3.13% - Palomino Roan Tovero
3.13% - Palomino
1.56% - Bay Tobiano
1.56% - Chestnut Roan Overo
1.56% - Chestnut Roan
1.56% - Chestnut
1.56% - Bay Roan
1.56% - Bay Roan Overo
1.56% - Bay Roan Tobiano
1.56% - Bay Overo
1.56% - Bay Tovero
1.56% - Chestnut Roan Tobiano
1.56% - Cremello
1.56% - Bay Roan Tovero
1.56% - Cremello Overo
1.56% - Perlino Tobiano
1.56% - Perlino Overo
1.56% - Perlino Roan Tovero
1.56% - Perlino Roan Tobiano
1.56% - Perlino Roan Overo
1.56% - Perlino Roan
1.56% - Perlino
1.56% - Chestnut Tobiano
1.56% - Cremello Tobiano
1.56% - Chestnut Roan Tovero
1.56% - Cremello Roan Tovero
1.56% - Cremello Roan Tobiano
1.56% - Cremello Roan Overo
1.56% - Cremello Roan
1.56% - Perlino Tovero
1.56% - Chestnut Tovero
1.56% - Bay
1.56% - Chestnut Overo
1.56% - Cremello Tovero


I hope this kind of helped, If you have any questions you can either pm me or ask questions in this thread.

[x--- αbel♥]

Wow. O__O I know a lot about horse genetics, but I probably couldn't explain it half as well. xDD great job!

[kalika]

oooh, thank you... *Blushes*

[† Kadaver †]

@.@ THAT'S not confuseing at all. xD Great job.

[harlequinduck]

"Notice- double Overo genes is automatic stillborn, and if it does live, it will die in less then 72hrs" ..

Actually, it's only if the parents are carrying the 'Lethal White Syndrome' and both parents must be carriers (and even then it may not die, but it is likely), if only one of the parents has it, the foal won't die but it can carry on the syndrome to any foals it might have.

LWS is caused by a recessive gene which causes affected foals to be born with an incomplete or underdeveloped gastrointestinal tract.

The foals appear normal at birth but after 24-48 hours develop colic as they are not able to pass the meconium, or any manure. The gene mutation that causes LWS not only cause a failure of nerve endings to develop in the bowel, but it is also responsible for the colour of the affected foals - who are pure white with blue eyes, or almost entirely white with very few dark markings [double dilutes such as cremellos and perlinos also have pink skin and blue eyes and are NOT lethal whites].

Any horse can have the LWS but it IS most common in overos.

[Lugubrious]

I love the genetics. I'm just not patient enough to go through and make posts like this. Great job. I'll give you 300 SM and sticky this. xD

And Harlequin, I believe you are correct. Most paint horses do carry the lethal white syndrome so it is pretty likely, but not all overo-carrying horses do. You can have 50 SM.

I'm feeling generous today.

[kalika]

Thank you so much Lugu. and everyone else that posted

Though I've never heard of a Lethal White survival. Nor a double Overo survivor.
And the Perlino and Cremello are abidded by the Cremello gene which is technically not even white.

[harlequinduck]

Haha thankyou Lugi. XD I just thought I should add in about the perlinos and cremellos as some people may not be aware of it's genes. x3

[Moonie!! <33]

Old thread I know - just thought I'd put my 2 cents' worth in.

The overo lethal white gene IS the frame overo gene, however you can get frame overo-like markings from sabino/splash which are types of overo.

This is the belief in Australia, at least, and if I was breeding overo horses I would certainly have all the horses genetically tested to ensure they are negative OLWS. I agree that all horses do have the potential to have lethal white syndrome but to get two copies of the frame overo gene is always lethal. Therefore I would never breed a frame overo to another frame overo as there would be a 50% chance of losing the foal.

Black to chestnut is nearly always chestnut or black but a chestnut can hide the agouti gene as it does not show and you might get a bay, or even a silver as chestnut also hides the silver gene.

The expression of paint/pinto markings depends on zygosity - a homozygous paint will nearly always have far more white on them than a heterozygous paint.

Another interesting thing about paint/pinto markings is that any white marking on any horse is a kind of sabino, but the classic sabino in low expression has 'spears' on the tops of the stockings, chin spots and a blaze, and often a belly splash. I have a friend whose mum breeds Arabians and one of this year's fillies is a gorgeous little chestnut sabino. It has been widely believed for a long time that Arabians cannot express dilute or broken colours but this little filly is pure Arabian - the stallion, who the markings come from, is 100% pure Crabbet Arabian I believe and is absolutely stunning, and it goes without saying that the filly is just as beautiful.

I am fascinated by coat colour genetics and am considering one day breeding kids' ponies for temperament, conformation, and colour as a bonus, because what little girl hasn't dreamed of having a palomino pony?? I know I did.