The theory of Mendel's Law and the Blue Gene

In memory of Lance Hicks, without whom I would not understand the genetics of poultry to the extent I do
NOW, I am NOT saying I know a lot, as I don't, I only know enough to get me by with my chosen colours

Black X Black - 100% Black
Blue X Blue = 50% Blue, 25% Splash, 25% Black
Black X Blue = 50% Blue, 50% Black
Splash X Splash = 100% Splash
Black X Splash = 100% Blue
Splash X Blue = 50% Splash, 50% Blue

So the theory of Mendel's Law goes
But this also depends on how many chickens you hatch for the mixed hatches (where Blue is used to breed from), as theoretical % will require average hatchings of 1,000 birds for these %

In Australia, the gene responsible for Blue, either in lacing or in ground colour is the Blue diluter (written as Bl ).

It is the same gene in all breeds.

This gene acts to dilute Black (shown as bl) to Blue in one dose (it is more correctly grey, being between Black and White, but called blue in poultry terminology).

One Black gene and one Blue gene = Blue (or Bl/bl = Blue).

 

Breeding Blue

You can tell if a chicken has blue or not straight away, just by looking at it. There is no need to do test matings to find out if it is present. Blue is dominant, and effects Black only. One Blue gene will change a Black bird to Blue one. 2 Blue genes will change Black to a whitish bird with random darker Blue/Black feathers, a Splash.

If the Blue gene isn't present the chicken is black. If one Blue gene is present, it will be Blue. If the bird has 2 doses of the gene it is a Splash.

Blue is not sex-linked. If one parent has the Blue gene then about 50% of the offspring should have it. Both a Blue male and female will pass the trait on to both sexes in the offspring.
This is unlike the barred factor, where the male will pass the trait on to his sons and daughters. However the female will only pass the trait on to her sons.

Mating Results:

Repeating the different mating combinations for the Blue gene

Blue X Blue = 25% Black (without the gene) 50% Blue (with 1 gene) and 25% Splash (with 2 genes).

Black X Blue = 50% Black and 50% Blue.

Black X Splash = 100% Blue.

Blue X Splash = 50% Blue and 50% Splash.

Splash X Splash = 100% Slash. Being in many breeders opinion the true ‘Blue’ as it requires 2 Blue genes to produce it


The ‘Mendel's Law table’ does not take into consideration the Cuckoo factors in the Blue Cuckoo as this colour was not in existence at the time the table was written



What is Splash

A double dose of Blue (Bl/Bl) will give Slash. Splash can exhibit as nearly white, with random flecks of Blue and/or Black. It can also exhibit as a mid range Blue with dark Blue and/or Black random flecking. As stated above, Splash will actually breed true. Splash cross Splash = 100% Splash

 Many breeders don't like the Blue gene. Possibly because they don't understand it. Also, some prefer their breeding pens all one colour; as a result they will keep several different pens. Often discovering after a few generations that the Blue colour has faded substantially in the Blue X Blue pen.

Because of the genetics, the 3 different 'colours' can be kept in one breeding pen. There is no need to separate the colours. A Blue male with 1 or 2 Black hen/s and 1 or 2 Splash hen/s will produce all 3 colours. A Blue male with 1 or 2 Blue hen/s will also produce all 3 colours.
This gene is responsible for 3 different colours from one breeding pen.

So how does the Blue gene turn Black to Blue?

Visualise a feather as being a whole lot of long thin tubes (straws) that are filled with pigment. The first pigment laid down is Black and the tubes are filled quickly.

One dose of Blue (Bl/bl)+ changes the filling process by interfering with the rate of Black fill, causing a grey (Blue) colour. This interference does not act evenly on every feather tube, giving black specks. If there are enough specks it produces feathers with black portions.


It has to be considered that the colour of the Blue also relates to the quality of the black being diluted.

IE:- a black bird, with all the Black enhancing genes present (there are many) will give a very dark Blue when Bl is present. But in a Black with only one Black gene, the Blue will be lighter.

Also note, it is believed that Blue is an incomplete dominant gene but with variable penetration



# subject to copyright laws of Australia, copied by others with permission