Summary
Recent investigations in neurogenomics have opened up
new lines of research into a crucial genetic problem—the
pathway from genes to behavior. This paper concentrates
on the involvement of protein elements in the brain
neurotransmitter serotonin (5-HT) system in the genetic
control of aggressive behavior. Specifically, it describes:
(1) the effect of the knockout of MAO A, the principal
enzyme in 5-HT degradation, (2) the association of
intermale aggression with the polymorphism in the
Tph2 gene encoding the key enzyme in 5-HT synthesis
in the brain, tryptophan hydroxylase (TPH), and (3) the
effect of selective breeding for nonaggressive behavior
on 5-HT metabolism, TPH activity and 5-HT1A receptors in
the brain. The review provides converging lines of
evidence that: (1) brain 5-HT contributes to a critical
mechanism underlying genetically defined individual
differences in aggressiveness, and (2) genes encoding
pivotal enzymes in 5-HT metabolism (TPH and MAO A),
5-HT-transporter, 5-HT1A and 5-HT1B receptors belong
to a group of genes that modulate aggressive behavior.
BioEssays 28:495–503, 2006.