Polymorphisms in the Extracellular Region of Dopamine Receptor D4 Within and Among Avian Orders

Polymorphisms in the dopamine receptor D4 gene ( DRD4 ) have been widely investigated to assess their correlation with variations in animal behavior. We precisely examined polymorphisms in the extracellular region of DRD4 in 75 avian species belonging to 16 orders and detected high degrees of polymo...

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Bibliographic Details
Published in:Journal of molecular evolution 2011-03, Vol.72 (3), p.253-264
Main Authors: Abe, Hideaki, Ito, Shin’ichi, Inoue-Murayama, Miho
Format: Article
Language:English
Subjects:
Adaptive radiation
Animal behavior
Animal Genetics and Genomics
Animals
Biomedical and Life Sciences
Birds
Cell Biology
Cellular biology
Evolutionary Biology
Galliformes
Life Sciences
Microbiology
Neurotransmitters
Passeriformes
Passeriformes - genetics
Plant Genetics and Genomics
Plant Sciences
Polymorphism
Polymorphism, Genetic - genetics
Receptors, Dopamine D4 - genetics
Sequence Analysis, DNA
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Summary:Polymorphisms in the dopamine receptor D4 gene ( DRD4 ) have been widely investigated to assess their correlation with variations in animal behavior. We precisely examined polymorphisms in the extracellular region of DRD4 in 75 avian species belonging to 16 orders and detected high degrees of polymorphism at inter- and intraordinal levels. The existence of a variable number of proline repeats (2 to 12 times) in the extracellular region was a common feature in all Neognathae, and a strong codon bias at synonymous sites was found among Passeriformes, Galliformes, and other non-passerine Neoaves. Furthermore, significantly higher values of the pairwise disparity index were detected in Passeriformes, suggesting either a substantial difference in the evolutionary processes or a higher level of mutation rate in the passerine clade. The differences in both codon bias and other genetic parameters among avian taxa would be explained by different levels of selective pressure on the extracellular region of DRD4 . Our study suggested that different conformations determined in a sequence-dependent manner at the extracellular region could be one of the key factors affecting the efficiency and accuracy of DRD4 expression. Our findings further imply a possibility that behavioral diversity, which would be important during the processes of adaptive radiation, may be enhanced by the selection acting on indels or single-nucleotide substitutions in the extracellular region of DRD4 .
ISSN:0022-2844
1432-1432
DOI:10.1007/s00239-011-9432-9