Punnet square

The Punnet square is a method for easily representing a mating (meiosis and fertilization).

I will explain how to use it with by demonstrating with a very simple example. Lets forget about all those chromosome pairs and just concentrate on 1 pair: the sex chromosomes. You can represent the birds as follows:

• Cock: X X
• Hen: X Y

The first thing you need to do when calculating a pairing is write down the gametes formed by the parent:

• Gametes cock: X and X
• Gametes hen: X and Y

Now we get to the Punnet square itself:

On the top row the gametes of the cock are written. In the first column the gametes of the hen are written. On the intersection between gametes you combine the gametes to have the offspring.

Notice how this process mimics the meiosis and fertilization that happens in reality.