Animal Science 224 Companion Animal Science

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Animal Science 224Companion Animal Science

• N. Matthew Ellinwood, D.V.M., Ph.D.
• Spring 2009

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How And Why Are Pets AbleTo Fill Their Roles?
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Which species is more intelligent, a chimpanzee
or a domestic dog?
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The answer depends on what aspect of
intelligence one is asking about. In some cases
the dog is more intelligent.
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There is Something about Dogs
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Additional Books As Resources
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Objectives Origins of Domesication

• The who, what, where, and how of domestication
• Taxonomy of the dog and cat
• Discuss the origin and development of domestic
  dogs and cats
• Physical evidence
• Archeological evidence
• Recent DNA based evidence
• Mitochondrial DNA
• Nuclear DNA
• Y chromosome DNA
• Combined approaches
• Ancient DNA studies

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Terminology

• Wild
• Tame
• Opportunist
• Mutualistic
• Domestic
• Feral

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Taxonomical Classification

• Method of classifying the relationships of living
  organisms
• Based on many different methods
• Systematized organization of Life
• In a state of flux
• Criteria used to determine groupings
• physical/skeletal similarities
• ability to intermate - produce fertile offspring
• similarity of chromosomes
• gene homology
• Web resource
• http//www.ncbi.nlm.nih.gov/Taxonomy/taxonomyhome.
  html/

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Classification of Dogs and Cats

• Kingdom - Metazoa
• Phylum Chordata
• Class Mammalia
• Order Carnivora
• Family Canidae
• Genus Canis
• Species Canis familiaris
• Family Felidae
• Genus Felis
• Species Felis catus

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Origin of Carnivores

• Miacids (Miacidae family)
• 65 million years before present (ybp)
• Small, tree-dwelling
• Plantigrade
• Carnassial teeth
• Miacids
• viverines (cats)
• miacines (dogs)

www.sdnhm.org/fieldguide/ fossils/miacids.html htt
p//en.wikipedia.org/wiki/Miacids
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Domestication of the Dog

• First living thing domesticated by early man
• A model of mechanisms of domestication and
  evolution

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Early Archeology

• Domestic dog was evident as early as 15,000 ybp
• Humans were still hunter gathers

http//news.bbc.co.uk/1/hi/sci/tech/2174437.stm
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Origin of domestic dogs - fox, wolf, coyote?

• Chromosome count of members of canidae family
• Arctic fox 48
• Coyote 78
• Dingo 78
• Domestic dog 78
• Grey fox 66
• Red wolf 78
• Wolf 78

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Origin of the Domestic Dog

• Recent thinking was - dog, jackal, dingo all
  developed from the wolf
• structurally similar
• all of these will intermate - producing fertile
  offspring
• same chromosome number
• karyotyping (?) shows complete similarity of
  chromosomes

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Wolf gt Dog

• Dog is unusual in that its wild ancestor is a
  very successful species
• Natural genetic variability
• Natural selection - disposition
• Artificial selection and breeding
• Disposition
• Appearance
• Function

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Conclusions

• Canis familiaris was domesticated from the wolf
  at least 15,000 ya
• Combined with archeological and other evidence
• 40,000-15,000 ybp
• Domestication may have occurred in east Asia,
  with continued admixture of wolf genetics until
  8,000 ybp

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Conclusions

• Dingos derived from domestic dogs
• Came to Australia 5000 ya
• Possibly a one time occurrence
• Have been a distinct population since
• Are dingos domestic or feral?

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Domestication of DogsFuture trends

• Gene mutation rates
• Changes of gene expression versus gene structure
• Gene expression in the hypothalamus versus
  cerebral cortex
• Divergent morphology of dogs
• Gene stutters
• Domestication models
• Foxes selected for tameness
• Developed dog qualities
• Floppy ears
• Spotted hair coat

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Family Felidae

• Felis small cats, lynx, puma 12 genera
• Pantera large cats (leopards, tigers and
  lions) 4 genera
• Acinonyx cheetah 1 genus

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?
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Family FelidaeChromosome Number

• Some examples of karyotypes
• Domestic cat 38
• Tiger 38
• Cheetah 38
• Ocelot Geoffreys 36

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Family FelidaePhysical Characteristics

• Fewer physical changes than many domesticated
  animals
• Striped, spotted, and solid hair coat
• Greater variety in eye color than dogs
• yellow, green, gold, blue

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Domestic CatsArcheological Evidence

• 9500 ya Cyprus
• 4500 BC Egypt
• utilitarian mouser
• spiritual diety

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http//myhome.sunyocc.edu/gaddisc/HIS103/HuntCh1/
HuntCh1.1web.htm
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Domestic Cats in Ancient Egypt

• Cat goddess worshipped in ancient Egypt - Bastet
  - approx. 4,500 yr. ago
• Cat mummies found - especially in area of
  Bubastis in Nile Delta
• Domestic cats likely moved to Italy and other
  parts of Europe as a result of trade

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Domestic Ancestor of the Cat

• African Wildcat Felis silvestris lybica
• Africa, slight build and stripes
• European Wildcat Felis silvestris silvestris
• Scotland to SE Russia, stocky, distinct stripes
• Were cats domesticated in Egypt or also possibly
  in the Orient as well?
• Very recent molecular genetic data
• Domestic cat Felis catus - worldwide

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Potential Ancestors of the Domestic Cat

• African Wildcat
• European Wildcat

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Conclusions - Cat

• Domestication began 10,000 ybp
• Y chromosome evidence implicates the European
  wild cat