Susan

This is the fun part! Well...at least for me it is. If you get this, you won't ever have to use a progeny predictor again. You may get writer's cramp, however.

The Punnett square is a handy dandy tool used to figure out all the different gene combinations that can result from a specific pairing. The more genes you work with, the larger your square will be (and the greater potential offspring...genotypically anyway).

Starting simply: Normal X Anery (BB X bb)

Each parent can only give 1 gene to the offspring. One parent's gene(s) are written along the top of the square (columns). The other parent's gen(s) are written along the side (rows). The above pairing would look like this:

.....B / B
b / Bb Bb

b / Bb Bb

All the offspring are normal het anery (Bb).
Also, most people, in the above case, would only show one of the same gene (one column of B and one row of b).

Adding another gene into the mix: Normal (AABB) X Snow (aabb - amel & anery)

........AB
ab / AaBb

All the offspring are normal het amel and anery (AaBb - also called het snow).

Now lets do that hypolavender motley X diffuse opal...

................A h D l m
a H d l M / Aa Hh Dd ll Mm

As you can see, the dominant gene (capital letter) is always written first, no matter which parent it came from (as indicated by color). All the offspring are lavender het amel, hypo, diffuse and motley.

Of course, when each gene in each parent is homozygous, it's easy to do the square. The REAL fun begins when you have heterozygous gene pairs! That will be the next lesson...need more coffee!