The Cys83Gly amino acid substitution in feather keratin is associated with pigeon performance in long-distance races

The aim of this study was to investigate the association of the g.710T>G polymorphism in the keratin gene, which results in a cysteine to glycine amino acid change at position 83 (Cys83Gly) in feather keratin, with homing pigeon racing performance. A total of 123 homing pigeons were investigated. The data set used in this study consisted of scores from 17 short races (less than 400 km) and 11 long races (greater than 500 km) that took place in the 2011 and 2012 racing seasons (2589 race records in total). The genotyping of the g.710T>G polymorphism was performed using the artificially created restriction site-PCR assay. The T allele and the TT genotype were prevalent with frequencies of 0.658 and 0.447, respectively. The TT pigeons had the highest mean of ace points in the long races and in all races overall, while the GT birds scored the best in the short races. Nevertheless, the effect of the polymorphism was significant only in the long races (P = 0.0451), in which the pigeons carrying the TT genotype showed better racing performance in comparison with those carrying the GG genotype (P ≤ 0.05). In order to explain this phenomenon, several bioinformatics tools were employed to check for the possible consequences of the Cys83Gly substitution for feather keratin. The cysteine at position 83 was indicated to form a disulphide bond, while the Cys83Gly substitution was predicted to disturb the stability of the protein. However, the predictions preformed using the different tools were not entirely consistent. Nevertheless, the loss of the cysteine at position 83 of pigeon feather keratin may affect the structure of feathers, thus changing their biomechanical characteristics, and consequently, may influence the flying ability of pigeons.