Here’s a new way of looking at dog breeds:
This comes from a newly released study that appears in PLoS Genetics.
More than 170,000 SNP’s were genotyped in 46 breeds and wolves. SNP’s are short for single-nucleotide polymorphisms, which is a DNA sequence variation that occurs when there is a difference in a single nucleotide between individuals in the same species. One can make comparisons about relationships through examining these variations.
The recent studies that found the red wolf to be mostly coyote and found that dogs were mostly derived from Middle Eastern wolves also examined SNP’s, but they examined only around 50,000 of them.
This one examined 170,000 SNP’s, so the resolution, so to speak, is much clearer.
Let’s look at the neighbor-joining tree. Here are some highlights that I think can be confirmed in the historical record.
- Modern flat-coated retrievers fit within the golden retriever breed. As I’ve noted, golden retrievers reflect much of the diversity in phenotype that existed within the old wavy and flat-coated retriever breed. Goldens and flat-coats share many foundational sires and dams, and one would expect that flat-coats would be closely related to goldens. The flat-coated retriever nearly became extinct in the Interwar Period, while the golden became extremely popular following the Second World War. This change in fortunes happened after the two breeds were officially placed in their own separate registries. Because the flat-coated retriever became rare, the modern representatives of that breed reflect only those flat-coats that survived that population crash. Goldens continued to reflect much more of the diversity in type and in genes that once made up the entire population– even though they are of a recessive color.
- Newfoundlands and retrievers are close relatives. I’ve always said that a Newfoundland is just a big retriever, but really, the Newfoundland is an offshoot of the St. John’s water dog that was imported to the United Kingdom from Newfoundland. It was selected to be a much larger dog than one normally found in Newfoundland, and it became a popular family pet for much of the nineteenth century. The golden, Labrador, and flat-coated retrievers derive St. John’s water dogs that were imported from Newfoundland and were selected to be gun dogs. Richard Wolters made the assessement that the large Newfoundland was derived from the St. John’s water dog, and this breed should be regarded as the common ancestor of the retriever-Newfoundland family.
- Nova Scotia duck-tolling retrievers are more closely related to border collies and Australian shepherds than retrievers. I have said that there is no evidence that they are related to golden retrievers, even though they superficially resemble dogs of that breed. I also suggested that we should think of the toller as a small retrieving collie. It also suggests that the recent cross-breeding of a toller to an Australian shepherd actually has greater merit than breeding it to another retriever.
- Dalmatians are related to Weimaraners, which are related to other pointing breeds. The postulate that the Dalmatian is derived from pointer crosses appears to have some merit.
- Border terriers are just one of the fancy varieties derived from the fell or Patterdale terrier. Patterdales are widely acknowledged to have Staffordshire bull terrier and bull terrier in them. But this map suggests that this infusion of bulldog or bull and terrier blood happened before the border terrier became fancy.
- Gordon setters are widely said to have border collie in them. It now appears that some Gordon setters do derive from border collies or from the ancestral collie that gave us the border collie, but others are more closely related to English.
- The theory that Large Münsterländers are derived from English or Gordon setters that were crossed with German long-hairs appears to have some merit. They are more closely related to one lineage of Gordon setter than to the Weimaraner.
- The pug may be more closely related to the spitz breeds because much of its development occurred in the West, particularly in the Netherlands. Spitz breeds were very common as pets in the seventeenth century Dutch Republic, and they were probably used to develop the pug in its present form. There were not likely vast numbers of pugs coming from China at this time, and the Dutch just used a local dog to make the breed more genetically diverse.
- The boxer is related to the bulldog, and we know that the bulldog was often bred into boxer lines. The boxer lines are longer because the boxer has had its full genome sequenced.
- This study does not necessarily show that German shepherds are derived from wolves. Rather the authors write:
The most obvious clustering of breeds is exhibited by two wolf hybrids: Sarloos and Czechoslovakian wolf dog, which exhibit a closer relationship to the wolf than other breeds as predicted by their known origin. The German shepherd also clusters with this group, although this is likely to be a result of its close relationship with the Czechoslovakian wolf dog, rather than with wolf. The tree is consistent with previous studies and supports the accuracy and reliability of the array.
Each time more SNP’s are analyzed, greater resolution is provided, and the result will be different. So let’s not assume that these results are going to remain unchanged.
However, I am amazed at how much this tree appears to confirm certain aspects that appear in various breed histories.