Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Thursday, April 27, 2017

Going to the dogs

I am the proud owner of two dogs, both rescues, who are at this point basically members of the family whose contributions to the household consist of barking at the UPS guy, sleeping most of the day, getting hair all over everything, and making sure that we get our money's worth out of the carpet steamer we bought five years ago.

First, there's Lena the Wonder-Hound:

And her comical sidekick, Grendel:

Both of them are sweet and affectionate and spoiled absolutely rotten.  Lena's ancestry is pretty clear -- she's 100% hound, probably mostly Blue-tick Coonhound, Redbone, and Beagle -- but Grendel's a bit of a mystery.  Besides his square face and coloration, other significant features are: (1) a curly tail; (2) a thick undercoat; and (3) a tendency to snore.  This last has made us wonder if he has some Pug or Bulldog in his background somewhere, but that's only speculation.

This all comes up because of a recent delightful study in one of my favorite fields, cladistics.  The idea of cladistics is to create a tree of descent for groups of species based on most recent common ancestry, as discerned from overlap in DNA sequences.  And a group of researchers -- Heidi G. Parker, Dayna L. Dreger, Maud Rimbault, Brian W. Davis, Alexandra B. Mullen, Gretchen Carpintero-Ramirez, and Elaine A. Ostrander of the Comparative Genomics Branch of the National Human Genome Research Institute -- have done this for 161 breeds of dog.

The authors write:
The cladogram of 161 breeds presented here represents the most diverse dataset of domestic dog breeds analyzed to date, displaying 23 well-supported clades of breeds representing breed types that existed before the advent of breed clubs and registries.  While the addition of more rare or niche breeds will produce a denser tree, the results here address many unanswered questions regarding the origins of breeds.  We show that many traits such as herding, coursing, and intimidating size, which are associated with specific canine occupations, have likely been developed more than once in different geographical locales during the history of modern dog.  These data also show that extensive haplotype sharing across clades is a likely indicator of recent admixture that took place in the time since the advent of breed registries, thus leading to the creation of most of the modern breeds.  However, the primary breed types were developed well before this time, indicating selection and segregation of dog populations in the absence of formal breed recognition.  Breed prototypes have been forming through selective pressures since ancient times depending on the job they were most required to perform.  A second round of hybridization and selection has been applied within the last 200 years to create the many unique combinations of traits that modern breeds display.  By combining genetic distance relationships with patterns of haplotype sharing, we can now elucidate the complex makeup of modern dogs breeds and guide the search for genetic variants important to canine breed development, morphology, behavior, and disease.
Which is pretty cool.  What I found most interesting about the cladogram (which you can see for yourself if you go to the link provided above) is that breeds that are often clustered together, and known by the same common name -- such as "terrier" -- aren't necessarily closely related.  This shouldn't be a surprise, of course; all you have to do is look at the relationships between birds called "buntings" or "sparrows" or "tanagers" to realize that common names tell you diddly-squat about actual genetic distance.  But it was still surprising to find that (for example) Bull Terriers and Staffordshire Terriers are more closely related to Bulldogs and Mastiffs than they are to (for example) Scottish Terriers; that Corgis are actually related to Greyhounds; and that Schnauzers, Pugs, Pomeranians, and Schipperkes are all on the same clade.  The outgroup (most distantly related branch) of the entire clade is the peculiar Basenji, a Central African breed with a strange, yodel-like bark, a curly tail, and pointed ears, whose image has been recorded almost unchanged all the way back to the time of the ancient Egyptians.

Anyhow, it's an elegant bit of research, and sure to be of interest to any other dog owners in the studio audience.  Me, I'm wondering where Grendel fits into the cladogram.  Considering his peculiar set of traits, he might have a branch all his own, and give the Basenji a run for its money as the oddest breed out there.


  1. Very interesting. I finally got a DNA study of one of my mystery mutts.

  2. Honestly, with the amount of admixture going on there I doubt a bifurcating tree is the best representation anyway. I suspect a 3D clustering diagram or network would probably do better.

    Just sayin'