The punnett square

The punnett square is an easy way to know the outcome of your chicks.

But it's only possible when you work with only 1 mutation.

It can be used by all mutation forms, Autosomal recessive, Autosomal Dominant, Sex-linked recessive and Sex-linked Dominant.

But when dealing with a Sex-linked mutation you have to write the Sex chromosomes aswell. And the colour is only on the Z chromosome, the W chromosome of the female don't contain any colour. Examples you can see at the Sex-linked mutations.

It is very easy just draw a square (the so called punnett square)

Then write above the male, in this case a blue bird. (so both genes got the blue factor)

And on the side the female which is split for blue, (so she got a normal gene and a blue gene).

You can work with symbols or the first letter of the mutation, what you prefer, but I keep it simple and write it complete.

blue x normal split blue

Now all you have to do is fill in the blanks. Every colour need to write 2 times , so every combination is possible.

Now you see in the square,

  • 2 x normal and blue
  • 2 x blue blue

So 50% are normal split for blue and 50% is blue

You see this is not so difficult.

But as told before, when dealing with a Sex-linked mutation, you need to write also the Sex chromosome aswell, but as you can see in the example below, it is also not so difficult.

In the example below I have a male normal split for lutino x lutino female.

The colour is only on the sex chromosome Z , the W chromosome from the female don't contain colour information, so you don't write anything behind the W.

As you can see you get:

Z lutino Z normal =  male(ZZ) normal split for lutino

Z lutino Z lutino = male (ZZ) lutino

Z normal W = female (ZW) normal

Z lutino W = female (ZW) lutino


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