Variation in DRD4, a gene associated with temperament, in Carolina and Black-capped chickadees

BAINS, ASHVEEN; FERRETTI, VALENTINA; CURRY, ROBERT

Williamsburg

Congreso; 125th Annual Meeting of the Wilson Ornithological Society; 2013

Personality in animals plays a role in evolution because differences in behavioral phenotypes will affect how animals interact with the environment, ultimately affecting survival and reproduction. Studies in mammals and a few bird species have shown that polymorphisms in the Dopamine Receptor D4 (DRD4) gene are associated with variation in personality. As a prelude to considering whether personality differences influence hybridization, we studied polymorphisms in DRD4 in Carolina Chickadees (Poecile carolinensis) and Black-capped Chickadees (P. atricapillus) in southeastern Pennsylvania at sites just outside this species pair’s regional contact zone. We sequenced DRD4 genes from DNA extracted from blood samples collected from breeding adults (48 female and 49 male Carolina and 23 female and 22 male Black-capped chickadees). Preliminary analysis revealed four single nucleotide polymorphisms (SNPs), at position 8 of fragment SNP830C/T, and positions 5, 24, and 59 of fragment ID15. Individuals of both species exhibited C and T nucleotides at this site, but frequencies of homozygous T/T or heterozygous (C/T) genotypes differed between species. Allele frequencies for all ID15 SNPs differed between the species. The hybrid zone of Carolina and black-capped chickadees is moving, possibly as a result of behavioral asymmetries between the two species. This is the first study that explores DRD4 in North American parids and the first to explore species differences in DRD4 for animal species that hybridize