1. Domestication and Speciation in the Canidae Family

2. Who is Who’s Best Friend?
The dog is said to be a man’s (human’s) best friend, but it could also be said that we are a dog’s best friend.
Objectives:
How to interpret phylogenetic diagrams.
Understand how natural selection can work on a population to cause speciation.
Distinguish between natural and artificial selection.

3. Dog Breeds
The winner of Best of Show at the 2009 Westminster Dog Show was a Sussex Spaniel.
“Stump” the spaniel competed against 170 other breeds of domestic dog (an intraspecies competition).
Where do so many breeds come from? How did the species we recognize as the domestic dog arise?
Image credit--
Description: Stump is named Best in Show at the Westminster Kennel Club Dog Show.
Source: also available at
Modifications: Cropped.
Author: Kjunstorm (Lori)
Licensing: This image is licensed under the Creative Commons Attribution ShareAlike 3.0 License.

4. The start of our story…
A young boy is sitting near the edge of a cave 20,000 years ago. He has just taken out the garbage from the group’s previous day’s activities. The garbage consists of mostly bones and scraps of food from a recent successful hunt. As dusk approaches, the wolves start to arrive. The boy is not frightened. He has seen the wolves many times before. In fact, their arrival is almost ritualistic. They move in from the forest and wait until all the humans have gone into the cave for the night. The boy notices that the same wolf is the first one to get to the good scraps. It doesn’t immediately run off when it sees the boy. Domestic dogs wouldn’t appear on the scene for another 5,000 years….

5. a boy looked out of a cave …
20,000 years ago,
a boy looked out of a cave …
Image credits—
Description: Cave, National Park Ojców, Poland.
Source:
Author: Jan Jerszyński (2005)
Licensing: This image is licensed under the Creative Commons Attribution ShareAlike 2.5 License.
Description: Wolf pack (Canis lupus) in animal park of Gramat in France.
Source:
Author: Julien 31
Licensing: This image is licensed under the Creative Commons Attribution ShareAlike 3.0 License.

6. The Family Canidae Image credit—
Source: Anatomical engraving from Handbuch der Anatomie der Tiere für Künstler, Wilhelm Ellenberger and Hermann Baum, and medical illustrator, Hermann Dittrich and 1911 through Scan from See also University of Wisconsin Digital Collections at
Licensing: This is a faithful photographic reproduction of an original two-dimensional work of art. The work of art itself is in the public domain its copyright has expired. This applies to the United States, Australia, the European Union and those countries with a copyright term of life of the author plus 70 years.

7. Members of the Family Canidae
Jackal
(Black-backed jackal)
Fox
(Kit fox, Red fox)
Wolf
(Gray wolf)
African wild dog
Members of the Family
Canidae
Image credits—
Slide 7 —Top, and Slide 16 —Bottom right
Description: Black-backed Jackal in the Masaai Mara, Kenya, April 2008
Source:
Author: Simyre
Licensing: This image has been released into the public domain by its author
Slide 7 —Row 2, left
Description: San Joaquin Kit Fox
Source: U.S. Fish and Wildlife Service, National Digital Library,
Author: B. Peterson
Licensing: Public domain.
Slide 7 —Row 2 right, and Slide 16 —Top right
Description: Red Fox
Source: U.S. Fish and Wildlife Service, National Digital Library,
Author: Ronald Laubenstein
Slide 7 —Row 3, and Slide 16 —Bottom left
Description: Gray Wolf, taken in the Garden for Zoologic Research, Tel Aviv University, Israel
Source:
Author: Yonidebest, Hebrew Wikipedia
Licensing: The copyright holder of this file, Yonidebest, allows anyone to use it for any purpose, provided that the copyright holder is properly attributed.
Slide 7 —Bottom
Description: African Wild Dog (Lycaon pictus)
Source:
Author: Philip Gabrielsen
Licensing: This image is licensed under the Creative Commons Attribution 2.5 License.

8. Domestic dogs look like they are more closely related to wolves than other canids.
Gray wolf
Siberian husky
(domestic dog)
Image credits—
Slide 8 —Left, and Slide 9 —Left
Description: Gray wolf, Canis lupus
Source: U.S. Fish and Wildlife Service, National Digital Library,
Author: Gary Kramer
Licensing: Public domain.
Slide 8 —Right, Slide 16 —Top left,
Description: Siberian Husky
Source:
Author: Hinrich
Licensing: This image is licensed under Creative Commons Attribution ShareAlike 2.0 Germany License.
Slide 8 —Lower center
Description: Coyote
Source:
Author: Macmanes
Licensing: This image is licensed under the Creative Commons Attribution ShareAlike 3.0 License.
Coyote

9. Of course, looks can be deceiving!
Gray wolf
Domestic dog
(Lhasa apso)
Image credits--
Slide 9 —Right
Description: Lhasa Apso femea com 6 meses
Source:
Author: Lcfrederico
Licensing: Permission is granted to copy, distribute and/or modify this image under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
Phylogenetic analyses are more convincing.

10. Phylogenetic Analysis
Phylogenies can be based on morphology
Similarity of many morphological characteristics are used (color, size, structure, etc.)
Most recent phylogenies are based on molecular similarities
DNA
More similarities (i.e., fewer dissimilarities) = a closer relationship

11. The study of evolutionary relationships
Phylogeny
The study of evolutionary relationships
Think of it as a family tree A B C D
Recent
time
Past
Species A, B, C & D all exist in modern times

12. The study of evolutionary relationships
Phylogeny
The study of evolutionary relationships
Think of it as a family tree
Sp A
Sp B
Sp C
Sp D
Unique
ancestor
of D only
Common ancestor
of both C & D, but not A & B
Common ancestor
of A, B, C & D

13. Cladograms are another way to look at phylogenies
Image credit—
Slide 14 and Slide 29 —Left
Description: Domestic dog phylogeny
Source: Figure 1 from: Jordana J., Manteca X., Ribo O. Comparative analysis of morphological and behavioral characters in the domestic dog and their importance in the reconstruction of phylogenetic relationships in canids. Genet. Mol. Biol. [serial on the Internet] Mar [cited 2009 July 24] ; 22(1): 49–57. Available from: doi: /S
Permission: According to articles may be reproduced without specific permission from Genet. Mol. Biol. for use on a non-profit basis in teaching.

14. Species A Species B Species C Species D Species E Species F
Interpreting a cladogram
Species A & B are more similar to each other than they are to any other species
Species A-D are more similar to each other than they are to either species E or F
Species C & D shared a common ancestor in more recent times than the shared common ancestor of A-D

15. In Groups: Discuss relationships and create a cladogram for:
Fox
Domestic dog
Image credit--
Wolf
Jackal

16. CQ#2: Which of the following most closely resembles your cladogram?
Wolf
Jackal
Fox
Dog
Wolf
Jackal
Fox A. C. D.
Dog
Wolf
Jackal
Fox
Dog
Wolf
Jackal
Fox
E. Wow, mine looks like none of these

17. Canid Phylogeny Slide 18 —Center, Slide 19 —Right
Description: Canid phylogeny
Source:
Permission: According to “Images may be downloaded and reproduced for non-profit personal or educational purposes without further permission.”

18. Comparing wolves with dogs
Morphological comparisons (examples)
Dogs tend to have curled tails, wolves have straight tails.
Dogs tend to have smooth short coats.
Skull shape differs.
Molecular comparisons
Gray wolves and dogs differ by no more than 0.2% in their mtDNA sequence.
In contrast, gray wolves and coyotes differ by at least 4%.

19. How did dogs evolve from wolves?
Competing hypotheses
Ancestral wolf pups were domesticated intentionally by early humans – Artificial selection.
Ancestral wolf populations experienced natural selection forces that favored dog-like characteristics.

20. Hypotheses 1 – Artificial Selection
Arguments for
It makes intuitive sense that ancestral wolves could be domesticated easily since they are so dog-like. Early humans would have intentionally bred ancestral wolves.
Arguments against
Why would any human want to deal with an animal that avoids humans?
Modern wolves can not be “domesticated” by training alone. It takes intensive and sophisticated selective breeding.

21. Hypothesis 2 – Natural Selection
Canids are very resourceful & would have found human waste piles good foraging – wolves were living close to humans.
Wolves are shy, skittish animals – only “adventurous” wolves would have stayed close to the waste piles while humans were around.
The “adventurous” wolves were the best fed and hence had high fitness.
This hypothesis is based on Coppinger, Raymond and Lorna Coppinger Dogs: A New Understanding of Canine Origin, Behavior and Evolution. ISBN: (ISBN-10: ) Fall 2002

22. A Plausible Series of Events
Those ancestral wolves that tended to tolerate humans would have had the best access to high-quality food (scraps).
Canids likely would have protected their scrap piles from other invading animals and possibly even strange humans.