Animals: Pall of the Wild
( Excerpt from Chapter 6 )
Discussion: Dogs and Darwinism
Dogs are a species we have been breeding, and inbreeding, for 12,000
years. They are a study in genetic heritability. We find in dogs that you
can selectively breed for:
• Physical traits (coat color and size).
• Personality (intelligent terriers, docile retrievers).
• Specific behaviors (herding dogs and guard dogs).
Dogs branched off from the wolves in the not-so-distant past. As we evolved
from gatherers to farmers, we began to collect in settlements, and wolves
collected on the borders. Animals that were particularly useful-for example
those that brought killed game to the camp, or fetched slippers-were
rewarded with scraps of food. Those that were dangerous were killed or
driven away. People kept their favorite dogs alive through lean times. Thus
an artificial selection was applied to the animals surrounding our
We have taken the dog genome and selected for particular traits, and in
doing so created dog breeds-inbred lines with less genetic diversity. Each
dog breed represents a subset of the entire genome. Saint Bernards are
large, muscular, and furry. Golden retrievers are golden brown, docile, and
prone to spinal degeneration. Sheepdogs try to corral sheep, children, and
grocery carts. One variety of guard dog barks when a stranger is a mile
away, another when the stranger is twenty feet away. Guess which is quieter
in your backyard!
A genetic defect common in large breeds of dogs provides an example of the
dangers of limiting genetic diversity. Large purebred dogs such as German
shepherds are prone to hip dysplasia, a degenerative nerve disorder that
gradually paralyzes the spinal nerves beginning at the tail. Mongrel dogs
occasionally come down with the disease as well, but far less frequently
than susceptible breeds.
It is a small, inbred gene pool that sets the stage for a greater incidence
of this dangerous genetic illness. Mongrels have more genetic diversity and
fewer instances of the disease-causing allele than purebreds. Breeders are
currently trying to reduce the incidence of hip dysplasia by not breeding
those dogs suffering from this defect.
We also bred out traits such as aggression and violence. Today, dogcatchers
and city restrictions on vicious dogs continue to eliminate dangerous
behaviors. Put down a vicious animal, and you eliminate its vicious
contribution to the dog genome. It is a community effort to limit the
spread of dangerous dog genes-though, admittedly, dangerous dogs are often
trained now rather than born as there is an unfortunate trend among a
limited number of dog breeders to favor ferocious behavior in fighting
dogs. But, overall, breeders select well-behaved dogs.
In short, our many dog breeds represent thousands of generations of genetic
manipulation. Reshaping the dog genome-playing God with Dog-is a
commonplace hubris that few question.
We learn from dogs that many canine personality traits are inherited, so
surely human personality is also linked to the genome. We are born with the
capacity for speech; other complex systems may well have a genetic
basis. Might we also have innate confidence, ruthlessness, optimism, and a
tendency to ignore authority? We haven't defined the full extent of genetic
influence on personality, in humans or in animals.
Though we haven't defined the exact proportion of nature versus nurture
when it comes to personality traits, most have a clear genetic
component. How quickly we have selected for specific traits in dogs! If we
wanted to, we could do the same for humans. Can you imagine breeding out
violent aggression in man, as we do in dogs? Humankind condemns the notion,
known as Social Darwinism, that humans can be selectively bred to become a
better species. Our society forbids taking such ideas into the realm of
reality, as happened during Hitler's abhorrent ethnic cleansing campaign.
We find similarly repugnant other practices which affect the gene pool. The
unsavory idea that Homo sapiens murdered intelligent cousins in our rise to
ascendancy reeks of selective breeding. And we have nearly universal
prohibitions against incest and cannibalism. Our cultural taboos parallel
our need for genetic diversity, thus the very ethical notions that we hold
in such great regard may themselves be genetically determined!
The evil aspect of selective breeding lies in the imposition of the idea on
unwilling victims. But most of us feel no particular grief when a person
inflicts genetic improvement on himself by eliminating his genes through
his own foolish actions. So enjoy the following Darwinian examples of
self-selection-with animal assistance!
C h a p t e r 6 S t o r i e s
Darwin Awards - Honorable Mentions - Urban Legends - Personal Accounts
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