Helping dog breeders combat inherited diseases through understanding genetics.

Introduction

An individual dog might receive, for instance, the B form of the B gene from one parent, and the b form from the other. With regards to the E gene it might, for instance, receive the same form of that gene from both its parents, let's say it receives two copies of the e form. In this case, we would write a representation of the dog's genome like this: eeBb. Quite a few different combinations are possible: EEBB, EEBb, EeBb, eeBb, Eebb, and eebb.

The form that is written in an uppercase letter is called the dominant form. This means that, if a dog has both forms of a particular gene, it is the form that is written in capitals that has an effect on the dog — it is expressed. If there is no dominant gene the recessive (lower case) one will be expressed. In the case of our example dog eeBb, the e and the B forms will be expressed.

Just how the different forms of the E and B genes interact to give the final colour is shown on the following page.

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