These early studies “highlighted both the potential that we could learn from dogs, but also that we would need much larger sample sizes to do that really well,” said Elinor Karlsson, a geneticist at UMass Chan Medical School and the Broad Institute. And so researchers began creating large citizen science projects, searching for DNA samples and data from dogs across the United States.
Pet owners have risen to the challenge. The Golden Retriever Lifetime Study, which began recruiting in 2012, has followed more than 3,000 dogs in an attempt to identify genetic and environmental risk factors for cancer, which is particularly common in the breed. Since 2019, the Dog Aging Project, a long-term study of health and longevity, has enrolled nearly 50,000 dogs.
The personal project of Dr. Karlsson, Darwin's Dogs, has 44,000 canines and continues to grow. (About 4,000 have had their genomes sequenced.) Researchers are mining data for clues about bone cancer, compulsive behavior and other traits. Among the early findings: Although many behavioral traits, such as sociability and trainability, are hereditary, they are widely distributed across the canine kingdom, and breed is a poor predictor of an individual dog's personality.
This spring, Dr. Karlsson unveiled a long-awaited expansion: Darwin's Cats. “I'm a total cat lover, never owned a dog,” she said. Later, in an email, she added, “I'd like to know if the 'cat sleeping on your head' thing is influenced by genetics.”
Data Driver
These projects were made possible by faster and cheaper genomic sequencing. But the “tremendous enthusiasm” of pet owners was key, said Dr. Ostrander, who now leads the Dog10K project, an effort to build a comprehensive global catalog of canine genetic diversity.