Two-thirds of dogs have wolf DNA: US study

Twenty years ago, the purebred boxer Tasha became the first domestic dog to have its genome sequenced, ushering in a new era in canine genetics.

- Emily Anthes

"Once that happened, everything broke open," said Dr Elaine Ostrander, a canine genomics expert at the National Human Genome Research Institute who was on the team that sequenced Tasha.

In the two decades since, scientists have sequenced the genomes of thousands of dogs.

Researchers are now comparing these genomes and cross-referencing them with other records.

These enormous data sets are allowing scientists to ask a wide variety of sophisticated questions about dogs, humans and our longstanding, still-evolving relationship.

A new collection of eight canine genomics papers, published by the Proceedings of the National Academy of Sciences on Nov 24, is a case in point.

DISAPPEARING DIVERSITY IN GERMAN SHEPHERDS

Many modern dog breeds are highly inbred, leaving them susceptible to an assortment of serious health problems. But questions remain about exactly when and how genetic diversity disappeared from purebred populations.

One possibility is that the drop in genetic diversity dates back primarily to the 19th century, when many modern breeds were created from a small number of founding dogs.

Although this phenomenon did appear to occur in German shepherds, the most significant drops in diversity did not come until the second half of the 20th century, according to one of the new papers.