Ecological factors drive natural selection pressure of avian aryl hydrocarbon receptor 1 genotypes.
The aryl hydrocarbon receptor (AHR) mediates dioxin toxicities. Several studies have suggested that two amino acid residues corresponding to the 324(th) and 380(th) positions in the ligand binding domain (LBD) of the chicken AHR1 (Ile_Ser as high sensitivity, Ile_Ala as moderate sensitivity, and Val_Ala as low sensitivity), could be an important factor determining dioxin sensitivity in avian species. Here, we analyzed the association between ecological factors and AHR1 LBD genotypes of 113 avian species. Cluster analyses showed that 2 major clusters and sub-clusters of the cluster 3 were associated with specific AHR1 genotypes depending on the food, habitat, and migration of the animal. The majority of the species with Ile_Ala type were the Passeriformes, which are omnivorous or herbivorous feeders in the terrestrial environment. The species with Val_Ala type was primarily composed of raptors and waterbirds, which have been exposed to naturally occurring dioxins. An in vitro reporter gene assay revealed that the sensitivity to a natural dioxin, 1,3,7-tribromodibenzo-p-dioxin was in the order of Ile_Ser > Ile_Ala > Val_Ala. These results suggest that ecological factors related to the exposure of natural dioxins contribute to natural selection of the avian AHR1 genotype, which consequently leads to different sensitivity to man-made dioxins.
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Korea.
Ji-Hee
JH
Hwang
Nature Conservation Research Division, National Institute of Environmental Research, Hwangyoungro 42, Seo-Gu, Incheon 404-708, Korea.
Jin-Young
JY
Park
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Korea.
Hae-Jeong
HJ
Park
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Korea.
Su-Min
SM
Bak
Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, 790-8577, Japan.
Masashi
M
Hirano
Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, 790-8577, Japan.
Hisato
H
Iwata
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Korea.
Young-Suk
YS
Park
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Hoegi-Dong, Dongdaemun-Gu, Seoul 130-701, Korea.
Eun-Young
EY
Kim
D000595:Amino Acid Sequence; D025041:Animal Migration; D000818:Animals; D002645:Chickens / Q000235:genetics; D004147:Dioxins / Q000633:toxicity; D017753:Ecosystem; D019143:Evolution, Molecular; D005838:Genotype; D008024:Ligands; D046109:Passeriformes / Q000235:genetics*; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics*; D012641:Selection, Genetic / Q000235:genetics*; D016415:Sequence Alignment; D013045:Species Specificity
D004147:Dioxins; D008024:Ligands; D018336:Receptors, Aryl Hydrocarbon