Chicken Genetics

1. Chooks & Genetics

2. Which sex,
which type of comb,
how many toes,
the colour of the bird’s
shank,
the pattern / colour in the
feathers,
are all determined by the
information that is stored in
the bird’s ‘genes’

3. The genes are located on
pairs of ‘chromosomes’
(In chickens there are 39
pairs of chromosomes)

4. One of these pairs is called Male bird
the ‘sex chromosomes’
In a male bird the ‘sex
chromosomes’ are similar.
Female
In a female bird one of the bird
‘sex chromosomes’ is
almost empty

5. Most genes have two parts
eg.
The gene for whether or not a bird has a
rose comb
‘R’ is the symbol for the rose comb form
this bird’s genotype is R/R
The gene for whether or not a bird has
mottled plumage
‘mo’ is the symbol for the mottled form
this bird’s genotype is Mo+ / mo

6. The only genes that have one
part are those that are on the
females sex chromosomes
The gene for whether the bird is based on
silver or gold S/-
The gene for whether the bird is barred or
not B/-
The gene for whether the bird has an
inhibitor of melanin or not Id / -

8. All genes that affect the appearance of the bird
usually have two or more different forms;
one form from the original (red) jungle fowls
(RJF), marked with a ‘+’ after the symbol, called
‘wildtype’
Male RJF
e+/e+ s+/s+
Female RJF
e+/e+ s+/-

9. ALL the other forms have arisen from mutations
eg. for type of comb there are different forms
for single comb, which is the wildtype
r+/r+ p+/p+
for rose comb, ‘R’ is the form
R/R p+/p+
for pea comb, ‘P’is the form
r+/r+ P/P

10. Some forms of a gene are ‘dominant’ to other
‘recessive’ forms
the dominant form’s symbol will be capitalised
eg. rose comb R is dominant to wildtype r+
a bird will have a rose comb with R/R or R/r+
R/R is also written ‘ hom R ‘
R/r+ is also written ‘ het R ‘
r+/r+ is also written ‘ hom R ‘ single (wildtype) comb

12. The most important gene for the plumage is the
‘ e – gene ’
There are five forms, in usual order of dominance
E ‘extended black’
E^R ‘birchen’
e+ ‘wildtype’
e^b ‘brown’
e^Wh ‘wheaten’

13. E Ancona, black mottled Langshan, Australian
Australorp Leghorn, White Plymouth Rock, Barred
E^R Campine, gold & silver Hamburg, silver spangled
Modern Game, brown-red Sebrights, gold & silver
e+ Dorking, silver-grey all Jungle Fowls
Leghorn, pullet-breeding (light) brown
Modern Game, ginger Old English Game, ginger
e^b Barnevelder, double-laced Hamburg, gold spangled
Leghorn, cockerel-breeding (dark) brown Silkie, white
most Wyandottes
e^Wh Faverolle, salmon New Hampshire RIR
Sussex, light

14. The next most important gene for the plumage is
the ‘ Silver – gold gene ’
Silver S
(dominant)
gold s+
(recessive)

15. Modern Game, Birchen................... ER/ER S/S (S/-) )
Ancona, Black Mottled (white/dark).................E/E (or ER/ER) (S/S
S/-) Modern Game, Brown Red....................ER/ER s+/s+ (s+/-)
Modern Game, Ginger........................e+/e+ s+/s+ (s+/-)
Australian Langshan, Black (red) .......................... E/E s+/s+ (s+/-)
New Hampshire................................... eWh/eWh s+/s+ (s+/-)
Australorp, Black (red) ............................ E/E s+/s+ (s+/-) Old English Game, Ginger................... e+/e+ s+/s+ (s+/-)
Old English Game, Black Breasted Red, Dark Leg......... e+/e+ s+/s+
(s+/-)
Barnevelder, Double-laced (red).............. eb/eb s+/s+ (s+/-)
Plymouth Rock, Dark Barred .......... E/E S/S (S/-) B/B (B/-) K/K (K/-
Campine, Gold (white).............................. ER/ER s+/s+ (s+/-) )
Campine, Silver (white)............................... ER/ER S/S (S/-)
Rhode Island Red, Single Comb...(exhibition)... eWh/eWh s+/s+
Dorking, Silver Grey (red) ...................... e+/e+ S/S (S/-) (s+/-)
Faverolle, Salmon (red) ......................... eWh/eWh S/S (S/-) Sebright Bantam, Gold..................... ER/ER s+/s+ (s+/-)
Sebright Bantam, Silver.................... ER/ER S/S (S/-)
Hamburg, Gold Spangled (white) ............... eb/eb s+/s+ (s+/-)
Hamburg, Silver Spangled (white)............. ER/ER or eb/eb S/S (S/- Silkie,White...................................... eb/eb s+/s+ (s+/-) or S/S (S/-)
)
Sussex, Buff...................................... eWh/eWh s+/s+ (s+/-)
ISA Brown (red)..................................... eWh/eWh s+/s+ (s+/-) Sussex, Light.................................... eWh/eWh S/S (S/-)
Japanese Bantam, Black................ ER/ER Id/Id (Id/-) Welsummer, Partridge........................ e+/e+ s+/s+ (s+/-)
Jungle Fowl, Red........................... e+/e+ all wildtype Wyandotte, Black (CB)........................ ER/eb
Wyandotte, Black (PB)........................ eb/eb
Leghorn, Brown (CB) (dark)........... eb/eb s+/s+ (s+/-) Wyandotte, Blue Laced Gold.............. eb/eb s+/s+ (s+/-)
Leghorn, Brown (PB) (light)........... e+/e+ s+/s+ (s+/-) Wyandotte, Blue Laced Red............... eb/eb s+/s+ (s+/-)
Leghorn, White.............................. E / E S/S (S/-) I / I Wyandotte, Gold laced...................... eb/eb s+/s+ (s+/-)
Wyandotte, Silver Laced (CB)......... eb/eb S/S (S/-)

16. Autosomal Genes
Extended E Birchen E^R Wheaten e^Wh Wildtype e+ Brown eb
Co co+ Columbian eg. Light Sussex, New Hampshire
Ml ml+ Melanotic eg. Black Australorps, Black Langshans
Pg pg+ Pattern
Mh mh+ Mahogany eg. Rhode Island Reds
ig Ig+ Inhibitor of Gold (when homozygous) eg. Cream Legbar, true-breeding Golden Duckwing Leghorn
I i+ Dominant White eg. White Leghorn
Bl bl+ Blue (when heterozygous) eg. Blue anything
mo Mo+ Mottled (when homozygous) eg. Ancona
c C+ Recessive White (when homozygous) eg. Light Sussex, White Langshans
R r+ Rose Comb eg. Wyandottes, Hamburgs
P p+ Pea Comb
Sex Chromosome Genes
S s+ Silver / Gold (when homozygous) eg. Silver-Grey Dorkings, Partridge Wyandottes
B b+ Barring eg. Dark & Light Barred Plymouth Rocks