A Bit of Genetics

symbro · February 11, 2006

I wanted to post this for people who seem to need a bit of basic understanding of how colours work.

There are three colours. Listed from Dominate to Recessive

Red Ash -> Blue -> Brown

Then you have the Patterns. Again listed from Dom to Recess

Dark Check -> Light Check-> Bar -> Barless

Cocks - carry two genes for colours

Homozygous - carrying two like genes

Heterozygous - Carrying two different genes

Hens - carry one gene for colour and the other gene (+) causes her to be a hen

Hemizygous - one colour gene and the little piece of gene that carries no colour

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lets pretend we have a pair of birds. at this point we will only be talking about the colour of the bird with no modifiers and no patterns.

Cock Redash//blue

Hen Redash//+

to see what we come up with you can do a simple chart

RB

___R____B___

R | | |

+ R| RR | RB |

|_____|______|

| | |

+| R+ | B+ |

|_____ |_____ |

From this pair we get four possible outcomes

RR Homozygous Red Ash Cock

RB Heterozygous Red Ash Cock with a recessive blue gene

R+ Hemizygous Red Ash Hen

B+ Hemizygous Blue Hen

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Now I will do another example using a pair which would tell you the sex of the young

Cock Blue//Blue

Hen Redash//+

B//B

___B____B___

R | | |

/ R| RB | RB |

/ |_____|______|

+ | | |

+| B+ | B+ |

|_____ |_____ |

From this pair we get two possible outcomes

RB Heterozygous Red Ash Cock with a recessive blue gene

B+ Hemizygous Blue Hen

all red ash babies are cocks and all blue babies are hens.

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One more example where all babies are same colour

Cock Redash//Redash

Hen Blue//+

R//R

___R____R___

B | | |

/ R| RB | RB |

/ |_____|______|

+ | | |

+| R+ | R+ |

|_____ |_____ |

From this pair we get two possible outcomes

RB Heterozygous Red Ash Cock with a recessive blue gene

R+ Hemizygous Red Ash Hen

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There are a few modifiers out there. Dilute and spread are two of the common ones in racing birds. Dilute changes the colour of the bird by cuting the amount of pigment. Spread takes the Pigment from the normal areas (checks or bars) and spreads them thought out the body (grizzles).

Just for fun I will show you a breeding pair

Cock - Red Ash//Red Ash - Dilute//Not Dilute

Hen - Red Ash//+ - Dilute//+

R//B D//N

___R-D____R-N_____B-D_____B-N___

R | | | | |

+ |_______|______|_______|________|

| | | | |

D ++| R+D+ | R+N+ | B+D+ | B+N+ |

// |_______|_______|________|_______|

N

From this pair we get Eight possible outcomes

RRDD - Cock Homozygous Redash showing dilute (called cream or yellow)

RRDN - Cock Homozygous Redash Recessive dilute showing red ash

RBDD - Cock Heterozygous Redash showing dilute (called cream or yellow)

RBDN - Cock Heterozygous Redash Recessive dilute showing red ash

R+D+ - Hen Red ash showing dilute (called cream or yellow)

R+N+ - Hen Red ash (regular)

B+D+ - Hen Blue showing dilute (true silver)

B+N+ - Hen Blue (regular)

you knotice that the cock can pass on a greater conbination of his genes where the hen either passes on her colour and modifier or her "hen gene". Dilute is sex-linked. some modifiers the hen will have two possible genes to pass on.

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Patterns work the same way colours do. There is no connection between the colour of the bird and the pattern it shows. simply random genes the birds get from their parents decide each seperately.

February 12, 2006

Symbro,

Just to clarify a few points in your post.You say that the colour modifyer Spread shows up as grizzle.These are two different colour modifyers.

In your last breeding example you have used a homozygos ash red cock yet the breeding results are from a heterozygos cock.

Finnally,colour and pattern do not work the same as colour is sex linked and pattern is not.

symbro · February 12, 2006

yes i changed it from homo to hetero for purpose of showing the different types of babies. also there are a few other mistakes that i wish i could correct. i was copying and pasting from my previous examples for my different examples.

as for the patterns i was simply trying to make the point in the end that the patterns have no connection at all to the colours. i was tempted to make one more example using colour, a modifer, and a pattern. but the chart would have been huge!

if a moderator wishes to contact me there are atleast three typos i wish to fix.