SERT gene polymorphisms are associated with risk-taking behaviour and breeding parameters in wild great tits

Individual differences in coping with potentially dangerous situations are affected by a combination of genetic and environmental factors. How genetic polymorphisms and behavioural variations are related to fitness is unknown. One of the candidate genes affecting a variety of behavioural processes, including impulsivity, anxiety and mood fluctuations in both humans and other vertebrates, is the serotonin transporter gene (SERT/SLC6A). The aim of this study was to assess an association between SERT genotypes and novelty-seeking and risk-taking behaviours as well as breeding parameters of great tits (Parus major) in a natural environment. We associated polymorphisms in the promoter exonic regions of the SERT gene with parental risk-taking-related behaviour and fitness traits. Our results show that: (1) risk-taking behaviour in our great tit population is linked to single nucleotide polymorphisms in the SERT gene exon 3 and exon 8; (2) the genotype-behaviour associations are consistent with the presence of different stressors; and (3) polymorphisms in exon 8 could be associated with fitness-related traits, such as the start of egg-laying and hatching success. We showed for the first time that genetic variability of SERT plays an important role in shaping individual decision-making that affects fitness in a wild population. However, the results are based on one population and on the polymorphisms that are in a single gene. Therefore, replication studies are needed in order to confirm these preliminary results.