Analysis of a candidate gene for behavioural trait variability in horses: catechol-O-methyltransferase (COMT)

摘要

Catechol-O-methyltransferase gene is composed of six exons, the first two of which are non-coding, and two alternative promoters (Tenhumen et al. 1994). The expression of the gene produces mRNA transcripts which differ at the 5′ end and the synthesis of at least two enzymes. The enzyme with highest extension at the C-terminal is a membrane bound protein (MB-COMT) expressed mainly in the brain, the other is a soluble form (S-COMT) expressed in different tissues. The two isoforms are involved in the catabolism of catecholamines, such as the neurotransmitter dopamine, their metabolites and L-DOPA substrates (Tunbridge et al. 2006). The COMT gene, for its function and for the experimental results identified in humans and rodents (Tunbridge et al. 2006), is a candidate gene for the variability of different traits such as cognitive function, anxiety, aggression, pain sensitivity as well as behaviour related to the sexual sphere.