New Dog Breed Evolutionary Tree

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Discussion Overview

The discussion revolves around a newly produced evolutionary tree of dog breeds based on DNA sequences from over 100 breeds. Participants explore the implications of the tree's structure, the classification of certain breeds, and the relationships between dogs and their wolf ancestors.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants note that the basenji is closest to the root of the evolutionary tree, suggesting it may represent one of the oldest breeds.
  • There is a contention regarding the appropriateness of using a tree structure to represent dog breed relationships, with some arguing that a network would better reflect the complexities of breed origins.
  • One participant questions the absence of the "Pitbull" breed in the tree, suggesting that it may not be recognized as a formal breed.
  • Another participant proposes that pit bulls may be closely related to the Staffordshire Bull Terrier, which is represented in the tree.
  • There is a discussion about how to measure the distance of breeds from wolves, with some asserting that all breeds share a common ancestor and are equally distant from wolves, while others focus on specific branching points in the tree.
  • A participant mentions that the boxer was the first dog sequenced due to its low genetic diversity, which may contribute to genetic problems in dog breeds.
  • Some participants express uncertainty about the accuracy of early branching events in the phylogeny, noting that many early branches lack strong support from the data.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the classification of breeds, the interpretation of the evolutionary tree, and the relationships between breeds and wolves. The discussion remains unresolved with no consensus reached on several points.

Contextual Notes

Participants highlight limitations in the data, such as the incomplete representation of all breeds and the potential inaccuracies in early branching events in the phylogeny.

BillTre
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A new evolutionary tree of dog breeds has been produced based on DNA sequences from over 100 breeds.
The basenji is closest to the root in this survey. These are interesting dogs that don't bark, but make lots of other noises.

The tree is circular with the root (oldest part) in the center and more derived groups branching off farther from the middle.
A tree structure for dog breeds is not (IMHO) the most accurate way to display this information since some breeds were generated by crosses between other breeds (for example Dobermans). A plot better reflecting this kind of relationship would be a network rather than a tree structure. However, the tree probably just reflects the strongest genetic signals.
 
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Where is the "Pitbull" breed that seems to have become so unpopular with cities and municipalities as being the "biting" dog, and the urge is on to ban their existence.
I do not see it in the blue section, which is where I think it should be marked.
Perhaps there is no such thing as a pitbull breed.
 
I was looking for that too since I have a dog that is some kind of hound-pit bull mix.
I think pit bulls are close to or the same as a staffordshire bull terrier which is in there at about 4 o'clock.

Even if that's not it, they did not get DNA from what they figure are all the breeds, only about half of them.
 
Greg Bernhardt said:
So the boxer is the farthest from from a wolf?

Depends how you want to measure farthest.

The Basenji is closest to the wolf (presumably the unlabeled black parts) in that it has the fewest branch points and its branch point is closest to the center of the figure). Its clade branched off first in this view. It also has no other branches, so no other clade was derived from it. It could have changed a lot from a wolf though (does not look like a wolf).

Other breeds branch further out (more recent events). The boxer is not the most recent branch in that respect.
Another way to look at it would be the number of splits (dots at branch points) leading to a breed. The boxer has something like 26. Some of the breeds have many little splits with in their colored clades. There may well be some with more than the boxer. I have not done all the counting.
In another sense, they all have evolved for the same period of time and could all be equally changed from the wolf.
Dogs that look the most like a wolf (to me) and might therefore be argued are least changed structurally, like German Shepards and Huskies, are pretty far apart on the tree so?

Interesting trivia: A particular individual Boxer was the first dog sequenced. It was chosen because preliminary studies showed it had the least heterogenetity in it DNA sequence. The two sequences (two sets of chromosomes) it carried were 70% identical (very inbred). This is probably why so many dog breeds have genetic problems. Now DNA information combined with inteligent breeding may be able to get rid of some of their genetic problems.
 
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BillTre said:
Depends how you want to measure farthest.

The Basenji is closest to the wolf (presumably the unlabeled black parts) in that it has the fewest branch points and its branch point is closest to the center of the figure). Its clade branched off first in this view. It also has no other branches, so no other clade was derived from it. It could have changed a lot from a wolf though (does not look like a wolf).

All dogs share a common ancestor which descended from a common ancestor with wolves. Therefore, all dog breeds are equally close/far from wolves (the question is akin to asking who is more closely related to your cousin, you or your sibling). According the to the diagram, Basenji seem to be one of the first breeds to branch off from other breeds (but see the note below), but this does not imply that they are more related to wolves than other breeds.

Here is a link to the paper being discussed by the news article in the OP (accessible for free): http://www.cell.com/cell-reports/fulltext/S2211-1247(17)30456-4
Here's the cladogram from Fig 1
gr1_lrg.jpg

Note that branches with a high degree of support from the data are marked with various symbols (shown in the lower right-hand corner). Many of the early branches are not marked by these symbols, indicating that the data could not very accurately resolve some of the early branching events in the phylogeny. The diagram represents a best guess, but it would not be surprising of some of the early branches were drawn incorrectly.
 
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