Animals (canine or otherwise) inherit many characteristics from their parents. These inherited characteristics are controlled by genes.

Offspring inherit genetic material (genes) from both their sire (father) and dam (mother) in equal measure, for each genetically controlled characteristic a dog will carry two genes, one passed down from his sire and one passed down from his dam. Similarly the sire and dam will each carry two genes for each genetic characteristic inherited from their own parents. Although dogs carry two genes for each inherited characteristic ONLY ONE GENE for each characteristic is passed on from the sire and only one is passed on from the dam. This is how we get variety.

Each gene has a dominant form and a recessive form, so for example a dog may inherit the gene for solid black coat colour from his sire and the gene for solid red coat colour from his dam, because the gene for solid black is dominant and the gene for solid red is recessive the solid black gene will mask the solid red gene and the dog will be solid black in colour. When the dog produces offspring he will pass one gene only onto each of his puppies - some may inherit the gene for solid black coat colour and some the hidden recessive gene for solid red coat colour.

Genes control such characteristics as coat colour, ear carriage, length of coat, eye colour etc. Yet a litter of four pups may vary from one another in these characteristics, one may have pricked ears, one low ears, one a long coat and another a smooth coat. One of the most fascinating aspects of inheritance in the border collie is coat colour. One litter may contain for example; a black and white, a red merle, a red, and a blue and tan (blue tri) puppy.

The overall apprearance of a Border Collie's coat is not determined by just one gene but by several genes each with a dominant and a recessive form.

The table below shows the four main genes involved in determining coat colour in the border collie and defines the dominant and recessive form of each gene.

So the gene which determines solid coat colour has a dominant black form and a recessive red form whilst the gene determining whether or not a dog will display the merle (marbling) characteristic has a dominant form of merle and recessive form of no merle.