Occasionally Butterflies
© Copyright 2003 - 2008 - Ruskin Miniature Lops - All rights reserved
The punnet square is a very useful tool when calculating colour genetics. Here we will look at how to use the punnet and calculate the statistical outcome of any mating. It MUST be remembered that this works on statistics and percentages and does NOT leave room for that other common percentage called 'SODS LAW'. The punnet square calculates what WILL happen and what percentage of each you should expect. The only thing that may be different in your litter from what you calculated will be the percentage of what you have produced and not WHAT you produce.
We use one punnet square per series which is called a Monohybrid punnet. Once you have mastered using the monohybrid you can progress by adding another gene into the equation. For the purpose of this section we shall keep it simple and look at the bigger picture at the end.
The punnet square is drawn as below and a seperate unit is used to house of the genes along the top and down the sides. I tend to use the side column for the genes of the Buck and the row across the top for the genes of the Doe. Let’s look at a mating between a pure dominant Black and a pure dominant Blue.
We use one punnet square per series which is called a Monohybrid punnet. Once you have mastered using the monohybrid you can progress by adding another gene into the equation. For the purpose of this section we shall keep it simple and look at the bigger picture at the end.
The punnet square is drawn as below and a seperate unit is used to house of the genes along the top and down the sides. I tend to use the side column for the genes of the Buck and the row across the top for the genes of the Doe. Let’s look at a mating between a pure dominant Black and a pure dominant Blue.
d |
d |
|
D |
||
D |
Self Blue Rabbit aaBBCCddEE
Self Black Rabbit aaBBCCDDEE
Now let’s work out how to fill this punnet in. From the column on the left hand side we can see the two genes in the D series we are working with from the Black Buck and across the top we can see the same for the Blue Doe. Note both the bucks D series are dominant and the does are both recessive.
From the bucks genes, take the top one and write it in the square to its right, and directly below the does first gene. Now take the does gene (the one first on the left) and write in in the box below next to the one we have just written in the bucks. PLEASE REMEMBER that the dominant gene which MUST appear first in the line up and is represented with an upper case letter. Now repeat this process using the bucks second gene and the does first gene so you have then filled in the first column of the punnet. As you can see we have used both genes of the buck but have only used one gene so far from the doe. see punnet below.
From the bucks genes, take the top one and write it in the square to its right, and directly below the does first gene. Now take the does gene (the one first on the left) and write in in the box below next to the one we have just written in the bucks. PLEASE REMEMBER that the dominant gene which MUST appear first in the line up and is represented with an upper case letter. Now repeat this process using the bucks second gene and the does first gene so you have then filled in the first column of the punnet. As you can see we have used both genes of the buck but have only used one gene so far from the doe. see punnet below.
The buck goes down the side
The doe goes along the top
d |
d |
|
D |
Dd |
|
D |
Dd |
We now need to repeat this but this time using the does second gene. This will then complete the punnet. Once we have done this we can see from our square that using a dominant self black rabbit and mating it to a dominant self blue rabbit, we will produce a full litter (100%) of Blacks ALL carrying the dilute gene needed to produce blue. see punnet below.
d |
d |
|
D |
Dd |
Dd |
D |
Dd |
Dd |
