Associations between temperament and gene polymorphisms in the brain dopaminergic system and the adrenal gland of sheep.
Sheep of calm or nervous temperament differ in their physiological (cortisol secretion) and behavioural (motor activity) responses to stressors, perhaps due to variation in genes that regulate glucocorticoid synthesis or brain dopamine activity. Using ewes that had been selected over 20 generations for nervous (n=58) or calm (n=59) temperament, we confirmed the presence of a polymorphism in a gene specifically involved in cortisol production (CYP17), and identified polymorphisms in three genes specifically associated with personality and behavioural traits: dopamine receptors 2 and 4 (DRD2, DRD4), and monoamine oxidase A (MAOA). The calm and nervous lines differed in their frequencies of CYP17 SNP628 (single nucleotide A-G mutation at position 628) and DRD2 SNP939 (single nucleotide T-C mutation at position 939), but not for other SNPs detected in DRD2 or MAOA. In a second experiment, we then genotyped a large, non-selected flock of ewes for DRD2 SNP939 and CYP17 SNP628. Responses to the 'arena' and 'isolation box' challenges were associated with the DRD2 SNP939 genotype and the response to ACTH challenge was associated with the CYP17 SNP628 genotype. We conclude that, for sheep, a combination of the DRD2 SNP939 C allele and the CYP17 SNP628 A/A genotype could be used as a genetic marker for nervous temperament, and that a combination of DRD2 SNP939 T/T and CYP17 SNP628 G/G could be used as a genetic marker for calm temperament.
UWA Institute of Agriculture and School of Animal Biology, The University of Western Australia, Crawley 6009, Australia.
Xiaoyan
X
Qiu
UWA Institute of Agriculture and School of Animal Biology, The University of Western Australia, Crawley 6009, Australia.
Jason
J
Ledger
UWA Institute of Agriculture and School of Animal Biology, The University of Western Australia, Crawley 6009, Australia; College of Animal Science and Technology, Gansu Agricultural University, 730070, PR China.
Chen
C
Zheng
UWA Institute of Agriculture and School of Animal Biology, The University of Western Australia, Crawley 6009, Australia.
Graeme B
GB
Martin
UWA Institute of Agriculture and School of Animal Biology, The University of Western Australia, Crawley 6009, Australia. Electronic address: dominique.blache@uwa.edu.au.
Dominique
D
Blache
D000311:Adrenal Glands / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D017849:Animals, Inbred Strains; D001921:Brain / Q000502:physiology*; D059290:Dopaminergic Neurons / Q000502:physiology*; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D005838:Genotype; D006854:Hydrocortisone / Q000097:blood; D008995:Monoamine Oxidase / Q000235:genetics; D009043:Motor Activity / Q000235:genetics; D010912:Pituitary-Adrenal Function Tests; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D012756:Sheep; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics; D013694:Temperament / Q000502:physiology*
D005819:Genetic Markers; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4; D000324:Adrenocorticotropic Hormone; D013254:Steroid 17-alpha-Hydroxylase; D008995:Monoamine Oxidase; D006854:Hydrocortisone
CYP17; Dopamine receptor; Glucocorticoid; Monoamine oxidase; Stress