Is G-T substitution in the sequence of CAG repeats within the androgen receptor gene associated with aggressive behaviour in the red fox Vulpes vulpes?

Studies were carried out on one of the largest European red foxVulpes vulpes (Linnaeus, 1758) farms in Śniaty and Batorówka (Poland). A test created by Nowicki and Przysiecki (NP) was used to describe behaviour of the animals. The results of the NP behaviour test showed 4 types of behaviour in foxes: aggressive, curious, indifferent and apprehensive. While analyzing a fragment of exon 1 in the androgen receptor gene in 184 individuals, four alleles were found, ie 10, 10T, 12 and 13. The most frequent allele was allele 10, both in males and females (65.85 and 57.39%, respectively). The next in order of frequency were allele 10T (24.39 and 31.25%), 13 (7.32 and 9.09%) and 12 (2.44 and 2.27%, respectively). On the basis of further analysis an association was shown between behaviour of the red fox and its genotype. In aggressive females allele 10 was found significantly more frequently (76%) than in curious females (57%). While analyzing the genotypes of aggressive females it was shown that there were 15 individuals with genotype 10/10 (15.56%), 11 heterozygotes (9.87%) and only 1 individual with genotype 10T/10T (1.56%). In curious females the distribution of these genotypes was 15 (13.71%), 18 (20.57%) and 9 (7.71%), respectively. Although the result of Pearson Χ2 analysis was not significant (Χ2,p=0.0793), the Armitage’s chi-squared test for trend showed a significant difference Χ2,p=0.0305). This results may suggest that the androgen receptor gene may be suitable in studies on psychological traits.