Biology Reference
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nervous dogs no longer needed to be kept with a normal dog.
McBryde and
Murphee (1974)
concluded that breeding an animal continuously for a
certain genetic trait often resulted in the occurrence of other less desirable
traits. In the 1990s the Arkansas pointer lines were terminated. However,
they contributed to our understanding of how genes and environment influ-
ence behavioral difference between dogs,
including the development of
potential therapies for shy or nervous dogs.
Inherited Neurological Defects
Arman (2007)
states that the prevalence of inherited defects in dogs is too
high. Breed associations should encourage selecting dogs for their function-
ality and allow the introduction of new genetics into the registered breeds.
The list of neurological problems in dogs is huge (
Ackerman, 2011
). Many
examples of neurological defects in other animals can be found in the genet-
ics literature. For example, roller-tumbler pigeons are bred to roll in flight.
Pigeon fanciers select for birds with an intermediate expression of this trait.
Birds with an excessive expression of this trait continue rolling in flight until
they crash into the ground (
Entrikin and Erway, 1972
). Pigeons that roll in
flight have acceptable welfare, but when they hit the ground, welfare is
severely compromised. In comparison to pointer dogs, a slightly abnormal
orienting response makes a good bird dog, but an excessive amount of the
trait results in a dog that is a nervous wreck.
NERVOUS DEFECTS IN RODENTS AND SMALL MAMMALS
For hundreds of years, the Japanese have bred “fancy” mice as a hobby. In
Europe, there is also a long tradition of mouse fanciers (
Morse, 1978
). Some
fancy mice were selected for abnormalities of movement. Most of the fancy
mouse mutations can be found in today's laboratory mice. One is called the
“Japanese Waltzer.”
Cools (1972a,b)
reported that these animals have an
abnormality of the inner ear, are also hyperactive and behave like mice
injected with amphetamines (
Cools, 1972a,b
).
Researchers have bred rodents with many abnormalities such a seizure-
prone rats (
Seyfried, 1982; Serikawa and Yamada, 1986; Wimmer and
Wimmer, 1985
). Some rats have epileptic seizures triggered either by lower-
ing their body temperature or by sound. Mutant, seizure-prone rats are so
sensitive that a minor disturbance, such as changing drinking bottles, can
cause convulsions (
Serikawa and Yamada, 1986
). Others are generally prone
to seizures, and many different types of stimuli can trigger a seizure. There
are also strains of rodents with juvenile onset or adult onset susceptibility to
seizure. Rabbits have also been selectively bred for susceptibility to sound-
induced seizures (
Hohenboken and Nellhaus, 1970
). A preference for alcohol
has also been genetically selected (
Wimmer and Wimmer, 1985
).
McClearn
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