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The Consequences of Domesticating the Domestic Dog (Canis lupus familiaris)

Introduction
The transition from hunter gatherer lifestyle to food production and agriculture began around 8,500
BC due to the unpredictable climate change, decrease in large game species and increase in human
occupation of available habitats (Flannery, 1969)
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It is thought South West Asia’s Fertile Cresent was the earliest
site of domestication and other regions subsequently followed, although the speed of the transition
varied significantly among different areas (Diamond, 2002)
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Of the 14 domesticated species this essay will be focusing on
the domestication of the Wolf (Canis lupus) and its transition to what is now commonly known as the
domestic dog (Canis lupus familiaris), its history, and the consequences of the domestication process
with regards to genetics, anatomy, physiology and behaviour
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More
recent genetic studies using mitochondrial DNA (mtDNA) suggest that dogs may have been
domesticated as long as 40,000 years from now (Savolainen et al, 2002)
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The ancestry of the domestic dog has also come into question
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Modern genetics studies however support that the Gray wolf is the
principle if not the exclusive ancestor of the domestic dog (Lindbland-Toh et al, 2005), sharing 98%
of their mitochondrial DNA (mtDNA) (Vila et al, 1997)
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Did it happen as a single event, or many individual events across the globe?
This is a question the archaeological record itself cannot resolve (Clutton and Brock, 1999)
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The larger variation in genetics from East Asia in comparison to other regions
suggest an East Asian Origin
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As well as this, archaeological remains of dogs have been discovered and confidently
dated across the globe (Larson et al, 2012) See figure 1
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Green circles represent the regions where dog remains have been found and dated
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Red dogs represent
basal breeds, their location on the map is based on their suspected geographical origin (Larson et al,
2012)
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With the dog being the first known species to be domesticated, it follows that it is probably the species
that has been put under artificial selection for the longest period of time (Svartberg, 2006)
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In early domestication dogs were selected for purposeful roles such as hunting,
herding, fighting and guarding, but due to cultural changes in the last century particularly in western
societies, selection and use of dogs is different
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With artificial selection by humans being the driving force behind diversity of the species, particularly
between different breeds, it has been suggested breeds differ in many behavioural aspects
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This is further supported by Bradshaw et al (1996) who categorised breed
specific behaviours for different breeds
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Traits such as reactivity and immaturity that
commonly exist among breeds today were not reported in ancestral dogs, which may be explained by
change in selection pressure in historical time (Svartberg, 2006)
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It has been suggested that basic
emotional traits such as fearfulness are strongly influenced by genes and are assumed to have a simple
genetic base in dogs (Scott and Fuller 1965)
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Although all domestic dogs descend from a
common ancestor, selection of physical traits has resulted in remarkable differences between breeds
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Artificial
selection has unfortunately produced some devastating consequences for the dog, what looks
appealing to humans may not always be healthy
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The Consequences of Domestication
Perhaps one of the biggest controls humans have on domestic dogs is reproduction, with the focus
now being on physical appearance humans are now choosing mates for dogs in order to breed
desirable characteristics
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Pedigree dogs have been bred to conform to a published aesthetic with the use of studbooks, selective
breeding and repeated use of popular sires (Summers et al, 2010)
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Breeding for appearance resulted in competitive dog
showing in the late 18th century and 1873 saw the arrival of the Kennel Club, a board which regulated
the standard of dog breeds
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The result of artificial selection and the standards the Kennel Club upholds is genetic based problems
in terms of hereditary disease and disfigurement, physical disabilities and behaviour problems
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Inbreeding has also resulted in shocking physical consequences
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Bulldog and Pug breeds suffer from brachycephalic airway syndrome (BAS) as a
result of exaggeration of brachycephaly, which essentially means a flat face (Oechtering et al, 2007)
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Rhodesian Ridgebacks commonly suffer from dermoid sinus, a small opening in the skin on
the spine through with fatal infection can travel (Gammie, 1986)
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German Shepherds commonly suffer, from an ataxic gait, an unsteadiness in the limbs, often a
symptom of degenerative myelopathy, again common in this breed of dog (Longhof et al, 1990)
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Prevention of such abnormalities and diseases can be achieved by
neutering the affected dogs so they can no longer breed, although this is down to the decision of the
owner
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Behavioural problems in dogs are one of the main reasons causes of relinquishment of dogs into
animal shelters (Patronek et al, 1996; Houpt et al, 1996)
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These problems may be caused by
upsetting events experienced by the dog itself or a genetic predisposition due to breeding (Serpell and
Jagoe, 1995)
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One of the main causes for the problem is thought to
be competitive dog showing, and the Kennel Club breed standard (BBC, 2008)
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Caboli et al (2008) found that in 10
different breeds of dogs 90% of genetic diversity has been lost
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If the Kennel
Club does not alter the standard in order to improve the welfare of dogs, pedigree owners are likely
to continue to breed their dogs on cosmetic grounds

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