Wendy the Whippet

You can view these photos of whippet dogs.

The first vertical column is of typical whippets.

The middle vertical column is of whippets with one normal copy, and one myostatin mutation copy - you see, as is often the case, one trait is NOT recessive to the other, both genes are expressed, and these whippets run faster than other whippets - read from the link.

The right-side vertical column are the whippets with two copies of the mutated gene. They have huge muscles.

http://commons.wikipedia.org/
(enter: myostatin)