Genetics and Animal Welfare - Genetics and the Behavior of Domestic Animals - page 453

USE BIOTECH CAREFULLY
Genetic engineering is used to make animal models for various human
diseases by inserting genes into animals. Today there are hundreds of geneti-
cally engineered mice for use as animal models for human neurological
conditions ( Crawley, 2007; McFarlane et al., 2007; Wellberg, 2011;
Walberg, 2011 ). For example, mice that have autistic-like behaviors can be
purchased from a commercial company. The “autistic” mice have increased
repetitive behavior, such as self-grooming ( McFarlane et al., 2007 ). To avoid
a possible welfare problem in this animal model, the mice should be care-
fully monitored to ensure that excessive self-grooming does not turn into
self-injurious behavior. Mice altered by removing a gene involved in the reg-
ulation of serotonin display behavior that resembles obsessive

compulsive
disorder (OCD) in humans. The mice altered by genetic engineering methods
ran around repeatedly in the same alley of a maze. Normal mice will quickly
try a new alley ( Chen et al., 1994 ). Hooper et al. (1987) created a mouse
model for Lesch-Nyhan syndrome. Children afflicted with Lesch-Nyhan
syndrome self-mutilate and bite themselves. If this model is developed to the
point at which the syndrome is fully expressed, the welfare of the mice will
be severely compromised ( Rollin, 1995 ). Transgenic cattle and pigs are also
being used to produce substances useful in human medicine ( Murray et al.,
2010 ). For readers interested further in this topic, there is an excellent illus-
trated topic to help technicians monitor health and welfare of mice, rats, and
rabbits ( Pritchett-Corning et al., 2011 ).
It is beyond the scope of this chapter to discuss all the ethical arguments
about genetic engineering, but there is a greater ethical justification to cause
some suffering in a mouse if the mouse model makes it possible to cure
Lesch-Nyhan syndrome. This syndrome is one of the most horrible genetic
conditions that can affect a child. It is the opinion of both authors that
causing pain in order to make a pig grow slightly faster is absolutely not
acceptable.

Unexpected Linked Traits
Genetically altering an animal by knocking out selected genes can affect
the behavior of the animal in unexpected ways. Researchers and commer-
cial companies using biotechnology should be careful and not forget that
changing a targeted piece of genetic code can have unexpected effects.
Researchers are cautioned to avoid repeating the mistakes we reviewed in
the first edition of this topic. For example, Silva et al. (1992a,b) used
genetic engineering methods to knock out the gene that encodes for a
substance called calcium/calmodulin-dependent kinase II. This substance is
involved in the mechanisms of learning. The “knock-out” mutant mice
displayed impaired spatial

learning when tested in a water maze that