Dogs, a genetic map of various breeds and how they are related

 

Genomic analysis of dog breeds.

Most hunting breeds are tightly clustered. Retrievers all share a similar pool of ancestors. Ditto for spaniels and scent hounds.

There are a few breeds that are genetic islands and are not closely affiliated with any major clusters of breeds: Basenji, Samoyed, Finish Spitz, Tibetan Terrier, Pumi and Puli are examples of those islands.

The Poodles, Chihuahuas and Shih Tzu are distant from most European breeds which may be why Poodle, Chihuahua and Shih Tzu crosses are cornerstones of boutique breeds. They are distant enough to minimize the chances of reinforcing recessive, genetic defects.

A pretty picture

The analysis uncovered some potential breeder hanky-panky. Cane Corso, a rare, large breed of dog was "polluted" with Rottweiler DNA in the US but not in Italy, its country of origin. One can only guess that an unscrupulous breed was pawning off Rotty-crosses as full blooded Cane Corso.

This is a very readable academic paper. Sample:

Dogs have been in the Americas for more than 10,000 years, likely traveling from East Asia with the first humans (Wang et al., 2016). However, studies of mitochondrial DNA suggest that the original New World dogs were almost entirely replaced through European contact (Castroviejo-Fisher et al., 2011, Wayne and Ostrander, 1999, Witt et al., 2014) and additional Asian migrations (Brown et al., 2015). As colonists came to the Americas from the 16^th to the 19^th centuries, they brought Old World livestock, and therefore the dogs required to manage and tend the livestock, to the New World (Crosby, 1972). Many of the newly introduced animals outcompeted the native animals, which may explain the surprising and very strong herding dog signature in the native hairless breeds of South and Central America that were not developed to herd. In this analysis, we observe that the ancient hairless breeds show extensive hybridization with herding dogs from Europe and, to a lesser extent, with each other. We also identify two additional clades of New World breeds, the American terriers and the American toys (Figures 2I and 2J), two monophyletic clades of small-sized breeds from North/Central America, which include a set of related terriers, and the Chihuahua and Chinese crested. Written records state that the terriers trace their ancestry to the feists, a North American landrace dog bred for hunting...