Punnett's Square

Let's say you want to find the possible genotypes (the "genetic code") for a planned Pointer litter.
The stud dog's phenotype is black (the acutal coloration of the dog) and you know that his
genotype is a Black 3, black carry orange (BBEe). The bitch's phenotype is liver and you know
that her genotype is a Liver 6, liver carry lemon (bbEe).

Here's an easy way to set up the Punnett's Square to find the off springs' possible genotypes.

First take the "B" part of each of the dogs' genotype. Put the stud dog's "B's" (BB) along the top of the graph and the bitch's "B's" (bb) along the side.

This is how the square will look set up.

-	B	B
b	-	-
b	-	-

Then you take a "B" from the stud dog and match it with a "B" from the bitch to fill in the graph.

-	B	B
b	Bb	Bb
b	Bb	Bb

Now do the same with the "E's". The dog and the bitch are both Ee.

-	E	e
E	EE	Ee
e	Ee	ee

Now you need to find all possible combinations between the two. From the "B" square, we see that the only outcome is Bb. From the "E" square we have several combinations; EE, Ee and ee. So the combinations would present as follows; BbEE, BbEe and Bbee. Then find the combinations on the Genotype chart to see what could be expected.

Black 1 - BBEE carrying no recessive type
Black 2 - BbEE carrying liver
Black 3 - BBEe carrying orange
Black 4 - BbEe carrying liver, orange and lemon
Liver 5 - bbEE carrying no recessive type
Liver 6 - bbEe carrying lemon
Orange 7 - BBee carrying no recessive type
Orange 8 - Bbee carrying lemon
Lemon 9 - bbee carrying no recessive type

So we see that the possible genotypes would be Black 2, Black 4 and Orange 8.
Therefore, according to the phenotype chart the possible outcome would be 75% black and 25% orange colorations produced.

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