The genetic code in the diminutive dogs has been  finally discovered by the scientists. There are numerous varieties in the size of domestic dogs – ranging from tiny Yorkshire terrier that fits inside a purse to great Danes weighing up to 90kg  (200 pounds). But their origin or genetic code, which so far had not been discovered, had baffled the scientists until now. 
The researchers have finally succeeded in discovering their genetics codes, and can now identify the genes, which make the small dogs small.  More than 20 scientists from eight institutions in the United States and the U.K. participated in the study The leading researcher Elaine Ostrander of the National Human Genome Research Institute's Cancer Genetics Branch in Bethesda, Maryland said "The best way to describe the role of the gene is, it's like the 'reduce' button on a Xerox machine”.
The findings have bearing on the discovery that could ultimately lead to improved medical care for both dogs and humans, by helping scientists track down genetic causes for complex diseases such as cancer, diabetes, and hormone disorders. The researchers added that the canines make good models for studying human health because they suffer from many of the same types of diseases and share the same environments, which the human beings share.