The 1949 Chinese Revolution nearly erased the Shih Tzu from China, and today every pedigree dog traces back to just 13 exported ancestors

The Shih Tzu breed was on the brink of extinction in China after the 1949 Communist Revolution. A select group of thirteen ...
The New York Times

But how much does breed shape a dog’s health and behavior?

Humans have a long history of reshaping their canine companions, which evolved from ancient wolves. At least 10,000 years ago, Arctic peoples were using selective breeding to create sled dogs, ...