Basic Genetics

Basic Genetics

Judges Seminar

Albufeira

May 2010

Who am I?

Ole Amstrup Cattery name: DK Feles Grata Breeding: Oriental shorthair preferably

blotched tabby, with silver, in all colours and

patterns. How long: Since 1983

Who am I?

Why color genetics?

– Because I once breed budgerigars!– Because I love mathematics!

To see a cat

Some see a cat!

To see a cat

I see:a female catgenetic blackcolor not dilutedwith whiteit’s a tortiemackerel tabbyshorthair

To see a cat

I see:A - non agoutiBB blackD - not dilutedLL shorthairMc - mackerelSs bi-colour

xox tortie

To see a cat

A cat is ”built” of many different elements – a puzzle which can be joint together in many ways.

– color– sex– pattern– hair lenght– etc.

What is the color of the cat about?

Back to the basic!

Felis Sysvestris Lybica

Original genetics

The original model:

AA BB CC DD ii LL McMc ss xy ww

Original genetics

The original model:

agoutiblackno dilutionnon silvershort hairspottedno whiteno pointsno red

AA BB CC DD ii LL McMc ss xy ww

Original genetics

Before I start!

Look at the pattern of the wild !

An agouti background and a pattern in a little darker tone.

Original genetics

Original genetics

Most hairs is of this type (ticked or banded hairs):

The pattern is

areas of darker

ticking on a

lighter ticked

ground

The agouti ground The pattern

Original genetics

Nature goes for the average

We go for the extreme


Production of color pigmentation and the distribution of the pigment granules

Some modifying factors


Production of melanine– Different types (black, choc and cin.)– Amount of melanines

Normal Overproduction (non agouti /pattern) None (red) Distribution (dilution) Modification (amber)


Production of pheaomelanine

– Distribution (dilution) – None (silver)– Modification (rufism)


Pattern / modification of pattern

– original pattern (spottet/blotched)– ticked (ticked tabby)– wide band (shaded/tipped)


No production of pigment

– all white (the white colour)– piebald spotting (the white spotting)– gloves (SBI)– white spots (??)


Reduction of pigmentetion

– normal– burmese– siamese– ressecive white– albino


The quality of the colour and pattern

Polygenetic modifications

Genes

Colour genes (color and pattern)

– Each gene controls one feature– Can be dominant, recessive or partly dominant

Genes

Polygenes– A lot of ”small” genes work together– They work in different ways– “Qualitymakers”– Modifyers– Treshold characters

Chromosomes

Genes are placed on the chromosomes There are several thousands genes on every

chromosome The color genes we know control one exact

feature.

Chromosomes

There are three different types of genes controlling one feature:

– dominant– recessive– partly dominant

Chromosomes

18 pairs with two identical 1 pair is not always identical

X Y X X

X carries genes. Y carries no genes. You can only deduct that this individual will be a male

Colour genetics

I will look at one feature at a time.

They can be combined later on.

B alleles – Black/brown colour

B > b > bl

Decides the shape of the euamelanin granules

B = normal shape black

b = oval shape chocolate

bl = rod shape cinnamon


B > b > bl

BB / Bb / Bbl Black

bb / bbl Chocolate

blbl Cinnamon .


B > b > bl

BB the natural colour – only black

MCO – NFO – SIB – TUV – RUS – KOR - SOK B and the b mutation – Black and chocolateBRI – PER/EXO – SBI – BUR

B and the bl mutation – Black and cinnamon(sorrel)ABY – SOM

B, b and the bl mutation – Black, chocolate and cinnamon

Category IV – RAG – SNO – ACL – ACS – DRX – DRX – GRX

B genes – colour distribution

Distribution of B genes / B black – b chocolate

black X black black (choc.) X black (choc.)

100% black 75% black ( 25/50), 25% choc.

B B

B BB BB

B BB BB

B b

B BB Bb

b Bb bb

B genes – colour distribution

Distribution of B genes / B black – b chocolate

black (choc.( X choc. choc. X choc. 50% black / 50% choc. 100% choc.

B b

b Bb bb

b Bb bb

b b

b bb bb

b bb bb

The red colour

The red color.The red color is sex linked.The gene is placed on the X chromosome.

No eumelanin is prodcued, no matter the type.

Black, chocolate and cinnamon colours can not be produced!.

The red colour

Only phaeomelanin (the yellow/red color)

is produced

The red colour

I have chosen to mark this gene for orange/red as a variation of the normal X gene, as the placement of the red allele is at the X chromosome.

X the normal coloured catXo redY carry no genes

This way I think it is more clear that the color is sex linked and the explanation about the outcome as a result of mating red/tortie cat is more clear.

This is my way of seeing it – and not all share my opinion on this matter.

The red colour

Xo blocks the production of eumelanine. Only phaomelanine will be produced.

In order to work fully there must be two Xo in a female .

In the male, who only has one X chromosome, one Xo gives a red male

Red mating – colour distribution

Male: red Females: normal - tortie - red

females: tortie red or tortie red males: normal normal or red red

½

xo y

x xox xy

x xox xy

xo y

xo xo xo xo y

x xox xy

xo y

xo xo xo xo y

xo xo xo xo y

Red mating – colour distribution

Male: Normal Female: normal - tortie - red

females: normal normal and tortie tortie

male: normal normal and red red

½

x y

x xx xy

x xx xy

x y

xo xo x xo y

x xx xy

x y

xo xo x xo y

xo xo x xo y

Colour pigmentation

The basic colurs

Black BB / Bb / Bbl Black eumelanine Chocolate bb / bbl Chocolate

eumelanine Cinnamon blbl Cinnamon

eumelanine Red No eumelanine

Colour pigmentation

The basic colurs

black chocolate cinnamon red

Colour pigmentation

The basic colurs

Explanation to why there is no difference between a genetically black, chocolate or cinnamon based red!

No eumelanine is produced to give the difference!!!

D allele - dilution

DD / Dd

controles the distribution of pigment granules in the hair.

DD and Dd give an even distribution dd gives uneven deposit the hair appears lighter

D allele - dilution

DD / Dd

cross section of a normal coloured hair (dense). colour pigment evenly distributed in the hair colour is black, choc., cinnamon

D - allele - dilution

dd

Diluted hairColour pigment is placed in groupsLight can pass through the hairThe hair appears palerUneven placement of pigment

black blue choc. lilac cinnamon fawn red creme

D - allele - dilution

dd

Even though the pigment granules are distributed in an other way this will have no effect on the eyecolour.

”Mating” black [Bb Dd ] X lilac [bb dd]

Distribution of B genes and D genes

50% black / 50% choc. 50% dense/ 50 diluted

B b

b Bb bb

b Bb bb

D d

d Dd dd

d Dd dd

”Mating” black [Bb Dd ] X lilac [bb dd]

Distribution

Dd Bb Dd n black

Bb

dd Bb dd a blue

Dd bb Db b choc.

bb

dd bb dd c lilac

Tabby patterns

We have seen the tabby pattern of the wild!

Two different shades of agouti

In the tabby pattern is ahigher production ofeumelanine.

Varying from almost the same

level to an almost black hair.

Tabby patterns

We have seen the tabby pattern of the wild!Two different shads of agouti

In the tabby pattern is ahigher production ofeumelanine.

Varying from almost the same

level to an almost black hair.

Tabby patterns

All cats have a tabby pattern!!

But you cannot always see it!!

The structure of the hairs.

Is still there.

When it can be seen, it is a

coloured pattern / a darker agouti area on an (lighter)

agouti background

Tabby patterns

Mc/mc gene controls if it is mackerel or blotched

Ta/ta gene which causes the ticked tabby pattern – this is partly dominant.

A / a gene which turn the tabby pattern on and off

I do believe that the breaking up in spots is polygenetic and has to be managed via selection.

A allele – agouti / non agouti

AA (Aa) is the original pattern for cats

and the tabby pattern can be seen.

A causes bands of different colours in the single hairs (eumelanine and phaomelaine bands)

The hairs will be ticked – provide an agouti base

The coloured pattern sits on this agouti base.

A genes – agouti / non agouti

aa is the mutation.

Causes an overproduction of eumelanine.Fills up the entire hair with the type of eumelanine.

Looks like there are only single coloured hairs

- but the agouti structure is still there!!


Ticked hair. Bands of eumelanine on the ground colour. of phaeomelanine. Phaomelanine gives ground colour. The warm yellowish coloured bands. Which is the same in all colours.


Non-agouti hairOne colorThe phaomelanine is“overruled”/covered by the overproduction of eumelanine.

aa genes – red

A red self??

aa causes an overproduction of eumelanine to “fill” the hairs with the melanine (black, chocolate and cinnamon)xo blocks the production of melanine

Result: The red color “overrules” the non agouti in the red cat.A red is ALWAYS non agouti!!!

Non agouti

The tabby pattern isstill there (hair structureis the same) – but youcan not se it.

aa turns it off!

Agouti

A tabby pattern

Different grades of agoutihairs.

In the pattern moreeumelanine is produced.

Mc genes

Mc / mc control the basic tabby pattern

The difference in appearance is polygenetic

Mc genes

mc mc

Ta genes

The Ta gene cover the ”normal” tabby patern.

Is only partly dominant.

Ta genes

Ta Ta Ta ta ta ta

Ta genes

Homozygot ticked tabby

A - McMc TaTa

Ta genes

Heterozygot ticked tabby

A - McMc Tata

Tabby patterns

Tabby patterns

Patterns mainly found in wild / domestic hybrids

I allele – Silver (inhibitor)

[II] & [Ii] cause suppression of the phaomelanine pigment in the individual hairs.

That leaves only the eumelanine in the hair.

(no warm colors left).

[ii] is the normal coloured cat. (non-silver)


The I gene works different in agouti and non agouti hairs.In non agouti hairs it leaves lower part of the hair without pigments (looks white)Non agouti and silver = smoke.

non-agouti hair smoke hair.


When reducing the

pigments the hair

structure can be

seen and the tabby

pattern shows.


In agouti cats, the I gene supresses the phaomelanin (the yellow/red colour) and the ticked hairs wil be the colour af the eumelanine and white without coloured bands.

agouti hair silver agouti hair


In agouti cats the I gene inhibits the phaomelanin (the yellow/red color) and the ticked hair will be black and white without coloured bands.

non silver OSH n 22 silver OSH ns 22


Silver and red!

The I (silver) allele supresses the creation of phaomelanine!

The xo (red) allele supresses the creation of eumelanine!


Silver and red!

No pigment granules are (supposed to be) created!!

But some phaomelanine is left in the red/creme silvers!?


Rufism/tanning?

– Unwanted colouring on legs, neck and sides….

– Selection will reduce

the problem– Is it connected to the

warmth in color??

Shaded / tipped

We do not know much about genetics.

We know:

It is an agouti / tabby cat

Only shaded/tipped if one of the parents is shaded/tipped

Has been closely connected to silver

Shaded / tipped

Works only together with AA or Aa.

Restrict the creation of eumelanine and creates the lover part of the hair totally without eumelanine

In combination with silver (no phaomelanine produced) creates the chinchilla / silver shaded

Without silver (with phaomelanine produced) golden tipped and golden shaded.

Shaded / tipped - silver

tipped shaded normal

Shaded / tipped - golden

tipped shaded normal

Shaded / tipped

This is what I think!

A unpatterned tabby gene different from the tick tabby gene (no stripes on the legs)

Combined with a wide band gene which widens the lover part of the hairs to without color

- and probably several polygenes

Shaded / tipped

So may be the genetic is like this:

[A - ] to be non agouti

[Mc - ]/[mcmc] to have a tabby pattern

[Ta - ] /[ta ta] to have or not to have the tick tabby pattern

[ U - ] to have the ”unpatterned” tabby pattern

[Wb - ] to have the lover part of the hair without pigment.

+ some polygentic factors.

Black modifier - Amber

A recessive gene– Dm for normal colour– dm for amber

Do not work with red (epistatic)

Cancels the blocks the work of [ a a ]


Modifies/reduces the production of eumelanine or give an overproduction of phaomelanine

Do not work with red because there is no euamelanine to modify or reduce. (epistatic to red)

The overproduction of eumelanine is blocked or reduced and the phaomeline tabby pattern is visible (blocks the work of [ a a ])


BB Dd Mc- bmbm

Still a small amount

of eumelanine left

but mainly the

phaomelanine shows.

C alleles – albino serie

Pigmentation is linked to the temperature.

The coldest areas will have color.Colour on legs, tail, ears and face.The warmer areas will be lighter.Eyes will be deep blue.

A pointed cat is genetically a cat in whatever color, which is lighter in the warmest parts of the cat.

At birth all kittens are white (no pigmentation)


C genes have 5 levels. C normal colour cb burmese point

cs siamese point (siamese, colour point,

sc. birma, ragdoll) ca recessive white (blue-eyed albino) c red-eyed albino


Strength between the 5 different genes are:

C > cb > cs > ca > c

– C dominates all others– cb onyl partly dominates cs (tonkanese)

I will only deal with C or cs.

W – genes – dominant white

Dominant white.

Surpresses all production of pigment from in the coat.

Cover up ALL other colours/paterns!

Eyecolour can be blue, orange/green or one of each (odd eyed).

W – genes – dominant white

Can cause deafness in white cats.

The deafness will ”follow” the W gene and is more linked to the blue eyecolour than to the orange/green.

W – genes

Gen-code:

-- -- -- -- -- -- -- --

-- -- -- W-

S - genes Piebald spotted

S genes are only partly dominant towards s

That means that there is a difference between [SS] or [Ss]

S gene causes a small or large distribution of white in the normal color.


The variation is very big and it is impossible to predict any outcome of the white pattern!!!


The amount of white is controlled on the basis of the cell / polygenetic, and it is possible to find cats with the genetic [SS] or [Ss] which have the same amount of white.


Grades of white

ss

Ss

SS

Dilute modifier

Not recognized in FIFe!

Does it actually exist??

Modifies diluted colours (can only be seen when the cat is homozygot [ d d ])

The EMS code is for registration purposes only in imported cats from other organisations.

Dilute modifier

2 x ”caramel” or 1 x lilac?

Dilute modifier

2 x ”caramel” or 1 x lilac?

lilac silver ticked

Dilute modifier

B - dd Dm - blue-based caramel

b - dd Dm - lilac-based caramel

blbl dd Dm - fawn-based caramel

- - dd Dm - xoy/xoxo apricot (+ all torties)

Basic Genetics

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