animal news - a dog's size is determined by their genes:

In a fascinating study, it has been determined that the size of a dog is actually a result of their genes. Why is this important? Dogs have 200 to 300 diseases in common with humans ranging from high blood pressure to cancer. The study is saying that if you can understand how genes effect a dog both positively and negatively, you can possibly carry that over to human diseases. Please click the following link to read more about this "ap" news story on how a dog's genes determines their size.