Behavioural Genetics in Violence and XYY Syndrome

Abstract

Nowadays, violence was one of the most important problems in Thailand. It was the early causes of death people after road traffic injury of many years. With modern technology, we had known that environment influencing different kinds of behaviors, but the most significant factors was Gene. Many researches found that violent behaviors, either suicide or alcoholic consumption tied to genes. Genes worked together with environment and controled our behavior. The most influential violent gene was Monoamine Oxidase (MAOA). The research revealed that if enzyme which constructed from this gene had low activity, the person would have trend to be violence than normal. According to MAOA gene that located on chromosome X (Xp11.23-11.4), had more opportunity to deficient this gene and caused men establish violent behavior more than women. Anyway, the XYY syndrome was one type of sex chromosome abnormality (aneuploidy type) which liked crime behavior. Man who had this karyotype was always taller than normal man. During childhood, they had late development in communication and reading. However, when they grew in adulthoods, they usually looked like normal persons. The most interesting point was most criminals, which had been diagnosed their karyotype, were belonging to XYY genotype. Thus karyotyping diagnosis of new born baby and criminals were useful in kind of violent protection in the future.