The search for genes associated with personality made
a stride forward in 1996 with a report of the discovery of a gene related
to the tendency to seek novelty, and genes associated with buoyant and
anxious personality traits have also been discovered. The gene initially
discovered to be associated with novelty-seeking, or the "fad gene,"
is the dopamine receptor gene D4 (DRD4).
It has been reported that within DRD4 there is a repetitive sequence polymorphism,
in which a greater number of repetitions of the allele coincides with
stronger curiosity. Yoko Niimiís research group is working on the isolation
of such personality-related genes in dogs. They are attempting to verify
the potential association between specific genes in dogs and personality
and behavior, and have already published a number of research papers.
In 1999, Ms. Niimi and her associates conducted a study of this section
of canine DNA, and reported that they had confirmed the existence of the
repeated sequence in the DRD4 gene, and identified four types of allele.
In this research project, they have identified 5 more types of allele,
confirming the existence of a total of 9. In addition, they conducted
a genetic analysis focusing on these allelic genes of 14 breeds of dog,
each of which have differing behavioral characteristics.
"Upon conducting a principal component analysis based on the frequency
of these alleles, we were able to establish correlations between base
scores for each of the 14 breeds and behavioral scoring for each breed
based on a survey of canine veterinarians. Among 6 behavioral characteristics
such as playfulness and obedience, it became evident that specific alleles
were linked to obedience and aggression toward other dogs. In addition,
a comparison of varieties of dog indigenous to Europe and Asia showed
distinctions in the distribution of the frequencies of these alleles."
Currently, the training of a guide dog requires two years and involves
an enormous cost, and ultimately only one in three of them are able to
work as guide dogs. If genes associated with behavioral characteristics
can be found, it may become possible to breed dogs appropriately as well
as to selectively raise dogs more effectively.