Association between fighting behavior and catecholamine biosynthetic enzyme activity in two inbred mouse sublines

Area of Science:

• Neuroscience
• Behavioral Genetics
• Animal Behavior

Background:

• The Balb/c inbred mouse strain exhibits variations between sublines.
• Adrenal catecholamine synthesizing enzymes play a role in physiological responses.
• Isolation can induce aggression in mice.

Purpose of the Study:

• To investigate the relationship between adrenal catecholamine synthesizing enzyme levels and isolation-induced fighting behavior in Balb/c mouse sublines.
• To determine the genetic basis of fighting behavior differences.

Main Methods:

• Quantification of three adrenal catecholamine synthesizing enzymes in Balb/cJ and Balb/cN mice.
• Observation and recording of fighting behavior following a 2-week isolation period.
• Genetic analysis of F(2) progeny to assess inheritance patterns.

Main Results:

• Balb/cJ mice had twice the enzyme levels compared to Balb/cN mice, with heterozygotes showing intermediate levels.
• Balb/cJ mice exhibited immediate fighting behavior, while Balb/cN mice did not fight.
• F(2) analysis indicated that a single gene determines fighting behavior, with fighting being a recessive trait.

Conclusions:

• A significant correlation exists between adrenal catecholamine enzyme levels and fighting behavior in Balb/c mouse sublines.
• The genetic basis for fighting behavior is likely controlled by a single recessive gene.
• These findings contribute to understanding the neurogenetic underpinnings of aggression.