Additional Research on MAO Knockout Mice

Kevin Chen , Ph.D.

Associate Research Professor in Pharmacology and Pharmaceutical Sciences, University of Southern California.

Compulsive behavior identified in knockout A mice


Recently Dr.Chen generated a series of MAO A Lox P mice, which exhibit various phenotypes including paralysis, abnormal hair growth, tremors and aggression.

The mouse with a chimeric coat color has a long history as a pet (fancy mouse). The distinct color pattern might be caused by genes involved in the serotonin pathway.  The color of the mouse’s coat can be a useful marker for genetic analysis.

The loss of hair on the face presents an interesting compulsive behavior call barbaring, one example of compulsive behavior. The presence of one mouse in a cage can cause all the cage mates to lose facial hair including the whiskers.  If a male mouse loses his whiskers, he may lose social ranking.

A litter of MAO A Lox P mice in Dr. Shih’s lab

Dr. Kevin Chen holds a litter of MAO A Lox P mice. Sometimes, depending on the mother’s genotype, the pups are removed from their mother’s cage because she will try to attack and kill them.