Breeding methods for producing Persian show cats

Normal and Major Mutant Gene Inheritance in the Cat
(Principles of Mendelian Inheritance)

Normal:

Except for the XY, there is a pair of genes for each function located at the same loci on sister chromosomes. One pair of normal genes is represented as dots on a homologous pair of chromosomes.

Dominant:

A single mutant (changed) gene is dominant if it causes an evident abnormality. The chance of inheritance of the mutant gene (left) is the same as the chance of inheriting a particular chromosome of the pair: 50%.

Heterozygous recessive:

A single mutant gene is recessive (left) if it causes no evident abnormality, the function being well covered by the normal partner gene (its allele). Such a cat may be referred to as a heterozygous carrier.

Homozygous recessive:

When both genes are a recessive mutant, the abnormal effect is expressed. The parents are generally carriers, and their risk of having another affected offspring is the chance of receiving the mutant from one parent (50%) times the chance from the other parent (50%), or 25 % for each offspring.

X Y

X-linked recessive:

An X-linked recessive will be expressed in the male because he has no normal partner gene. His daughters, receiving the X, will all be born carriers, and his sons, receiving the Y, will all be normal.

X X

X-linked recessive:

An X-linked recessive will not show overt expression in the female because at least part of her "active" X's will contain the normal gene. The risk for affected sons and carrier daughters will each be 50%.

Comparison of Dominant and Recessive Genes in Feline Genetics

Dominant Gene

Recessive Genes

Possible Genotypes

Typical Phenotypes

A
(agouti)
Tabby coat
pattern

a
(non-agouti)
Black coat masks
tabby pattern

AA
Aa
aa

(Homozygous agouti)
(Heterozygous agouti)
(Homozygous non-agouti)

Visible tabby pattern
Visible tabby pattern
Solid coat color,
tabby pattern is masked

B
(black)

b
(chocolate)

bl
(cinnamon)

BB
Bb

Bbl

bb
bbl

blbl

(Homozygous black)
(Heterozygous black,
chocolate carrier)
(Heterozygous black,
cinnamon carrier)
(Homozygous chocolate)
(Heterozygous chocolate,
cinnamon carrier)
(Homozygous cinnamon)

Black
Black

Black

Chocolate
Chocolate

Cinnamon

C
(full color)

ca
(albino,
blue-eyed)

c
(albino,
pink-eyed)

cb
(Burmese)

cs
(Siamese)

CC
Cca
Ccb
Cc
Ccs
caca
cac
cbca
cbcb
cbc
cc
csca
cscb
cscs

(Homozygous full )
(Heterozygous full, albino carrier)
(Heterozygous full, Burmese carrier)
(Heterozygous full, albino carrier)
(Heterozygous full, Siamese carrier)
(Homozygous albino)
(Heterozygous albino)
(Heterozygous Burmese)
(Homozygous Burmese)
(Heterozygous Burmese)
(Homozygous albino)
(Heterozygous Siamese)
(Heterozygous siamese)
(Homozygous siamese)

Full coat color
Full coat color
Full coat color
Full coat color
Full coat color
Albino
Albino
Burmese
Burmese
Burmese
Pink-eyed albino
Tonkinese
Siamese
Siamese

Cu
(curled ears)

cu
(straight ears)

CuCu
Cucu
cucu

(Homozygous curled ears)
(Heterozygous curled ears)
(Homozygous straight ears)

American Curl
American Curl
Straight ears

D
(non-diluted)

d
(diluted coat)

(Homozygous non-diluted coat)

(Heterozygous non-diluted coat)

(Homozygous diluted coat)

Black, chocolate,
cinnamon, red
Black, chocolate,
cinnamon, red
Blue, liliac, fawn, cream

Fd
(folded ears)

fd
(straight ears)

FdFd
Fdfd
fdfd

(Homozygous folded ears)
(Heterozygous folded ears)
(Homozygous straight ears)

Scottish Fold
Scottish Fold
Straight ears

Hr
(normal coat)

hr
(hairless coat)

HrHr
Hrhr
hrhr

(Homozygous normal coat)
(Heterozygous normal coat)
(Homozygous hairless coat)

Normal coat
Normal coat
Sphynx

I
(inhibitor coat
pigment -
affects the
undercoat)

i
(coat pigment
non-inhibited)

(Homozygous inhibited)

(Heterozygous inhibited, carriers
non-inhibited)
(Homozygous non-inhibited)

Silver (Chinchilla, Shell,
            Shaded, Smoke)
Silver (Chinchilla, Shell,
           Shaded, Smoke)
Solid coat

L
(short hair)

l
(long hair)

LL
Ll

(Homozygous short hair)
Heterozygous short hair, long hair
carrier)
(Homozygous long hair)

Short hair
Short hair

Long hair

M
(Manx tail)

m
(normal tail)

MM
Mm

(Homozygous manx tail)
(Heterozygous normal tail, carrier of
manx tail gene)
(Homozygous normal tail)

Manx
Manx

Normal tail

O (X))
(orange gene,
linked with the
female X
chromosome)
"Phaeno-"
melanin

o (X or Y)
(non-orange)

"Eu-"
melanin

OO (XX)
Oo (XX)

O- (XY)

oo (XX)
o- (XY)

(Homozygous orange)
(Heterozygous orange, carrier of
non-orange)
(Heterozygous orange, carrier of
non-orange)
(Homozygous non-orange)
(Homozygous non-orange)

Red female
Tortoiseshell female

Red male

Black female
Black male

R
(straight hairs;
guard, awn, and
down)

r
(curly hairs and
lack of guard
hairs)

RR
Rr

(Homozygous straight hairs)
(Heterozygous straight hairs, carrier
of curly hairs)
(Homozygous curly hairs)

Straight hairs
Straight hairs

Cornish Rex

Re
(straight hairs of
all 3 types)

re
(curly hairs of
all 3 types)

ReRe
Rere

rere

(Homozygous straight hairs)
(Heterozygous straight hairs, carrier
of curly hairs)
(Homozygous curly hairs)

Straight hairs
Straight hairs

Devon Rex

Ro
(straight hairs of
all 3 types)

ro
(curly hairs of
all 3 types)

RoRo
Roro

roro

(Homozygous straight hairs)
(Heterozygous straight hairs, carrier
of curly hairs)
(Homozoygous curly hairs)

Straight hairs
Straight hairs

Oregon Rex

S
(white
piebald
spotting)

s
(no white
spotting)

SS
Ss

(Homozygous piebald spotting)
(Heterozygous piebald spotting,
carrier of no-white spotting)
(Homozygous no white spotting)

Bicolor
Bicolor

Solid

Se
(curly hairs of
all 3 types)

se
(straight hairs of
all 3 types)

SeSe
Sese

sese

(Homozygous curly hairs)
(Heterozygous curly hairs, carrier of
straight hairs)
(Homozygous straight hairs)

Selkirk Rex
Selkirk Rex

Straight hairs

Ta
(ticked tabby)
(incomplete
dominance)

T
(mackerel tabby)
tb
(blotched tabby)

Note: Mackerel
tabby is
dominant over
blotched tabby.

TaTa
TaT

Tatb

Ttb

TT
tbtb

(Homozygous ticked tabby)
(Heterozygous ticked tabby, carrier
of mackeral tabby)
(Heterozygous ticked tabby, carrier
of blotched tabby)
(Heterozygous mackerel tabby,
carrier of blotched tabby)
(Homozygous mackerel tabby)
(Homozygous blotched tabby)

Ticked tabby
Ticked tabby

Ticked tabby

Mackerel tabby

Mackerel tabby
Blotched tabby

W
(white - color
masking gene)

w
(non-white, true
color is not
masked)

WW
Ww

(Homozygous white)
(Heterozygous white, carrier
of non-white color )
(Homozygous non-white)

White
White

Color other than white

Wh
(wire hair)

wh
(straight hair)

WhWh
Whwh

whwh

(Homozygous wire hair)
(Heterozygous wire hair, carrier of
straight hair)
(Homozygous straight hair)

American Wirehair
American Wirehair

Straight hair

Comparison of Four Major Breeding Methods

Close Inbreeding

Linebreeding (Moderate inbreeding)

Linecrossing (Outcrossing within a breed)

Crossbreeding (Outcrossing with another breed.)

Examples:
Mother to son
Father to daughter
Brother to sister
Grandchildren to grandparents

Examples:
The mating of more distant
relatives within the same
bloodline. If much homozygosity is already established in the bloodline,
it is still considered close
inbreeding. Common ancestors of the parents must be found only in the very beginning of the breed's formation for it to be considered true line breeding.

Examples:
The mating of good breed examples from one bloodline to good breed examples from another bloodline. The cats from one bloodline should compliment the cats from the other bloodline. If a cat from bloodline A has great boning but a poor ear set, it should be mated with a cat from bloodline B that has a great ear set, but average boning.

Examples:
The mating of good breed examples from one breed to good breed examples of another breed.

Uses:
Fixes desired traits
Increases homozygosity

Uses:
Fixes desired traits
Increases homozygosity
Allows for some phenotypic and genotypic differences between individuals. This allows for greater subsequent genetic manipulations than inbreeding.

Uses:
Produces exceptional show quality cats while maintaining vigor.

Uses:
Produces new breeds such as the Ocicat (Abyssinian breed with Siamese). Also introduces new genes into a breed which was the base of the color point (Himalayan) Persian. Definitely increases hybrid vigor. (The offspring are genetically and physically healthier than their parents.)