The locus MAOA pops up every year or so in a study which attempts to correlate variation in these region with behavior. In particular, anti-social or pathological behavior. So another one is out, Monoamine oxidase A genotype is associated with gang membership and weapon use:
The low MAOA activity alleles conferred an increased risk of joining a gang and using a weapon in a fight for males but not for females. Moreover, among male gang members, those who used weapons in a fight were more likely to have a low MAOA activity allele when compared with male gang members who do not use weapons in a fight.
Here's a regression table which shows the main results:
This figure in particular is striking:
The MAOA variant is on the X chromosome, so obviously the genetic architecture is different for males and females (males have only one X). They didn't find much ...
