Olfactory Receptor Subgenomes Linked with Broad Ecological Adaptations in Sauropsida

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Khan, I (Author) Other; Yang, ZK (Author) Other; Maldonado, E (Author) Other; Li, C (Author) Other; Zhang, GJ (Author) Other; Gilbert, MTP (Author) Other; Jarvis, ED (Author) Other; O'Brien, SJ (Author) Other; Johnson, WE (Author) Other; Agostinho Antunes (Author) FCUP

Journal

Title: Molecular Biology and Evolution

Vol. 32

Pages: 2832-2843

ISSN: 0737-4038

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 58 Citations

Scopus - 58 Citations

Other information

Authenticus ID: P-00G-S86

DOI: 10.1093/molbev/msv155

Abstract (EN): Olfactory receptors (ORs) govern a prime sensory function. Extant birds have distinct olfactory abilities, but the molecular mechanisms underlining diversification and specialization remain mostly unknown. We explored OR diversity in 48 phylogenetic and ecologically diverse birds and 2 reptiles (alligator and green sea turtle). OR subgenomes showed species- and lineage-specific variation related with ecological requirements. Overall 1,953 OR genes were identified in reptiles and 16,503 in birds. The two reptiles had larger OR gene repertoires (989 and 964 genes, respectively) than birds (182-688 genes). Overall, birds had more pseudogenes (7,855) than intact genes (1,944). The alligator had significantly more functional genes than sea turtle, likely because of distinct foraging habits. We found rapid species-specific expansion and positive selection in OR14 (detects hydrophobic compounds) in birds and in OR51 and OR52 (detect hydrophilic compounds) in sea turtle, suggestive of terrestrial and aquatic adaptations, respectively. Ecological partitioning among birds of prey, water birds, land birds, and vocal learners showed that diverse ecological factors determined olfactory ability and influenced corresponding olfactory-receptor subgenome. OR5/8/9 was expanded in predatory birds and alligator, suggesting adaptive specialization for carnivory. OR families 2/13, 51, and 52 were correlated with aquatic adaptations (water birds), OR families 6 and 10 weremore pronounced in vocal-learning birds, whereas most specialized land birds had an expanded OR family 14. Olfactory bulb ratio (OBR) andOR gene repertoire were correlated. Birds that forage for prey (carnivores/piscivores) had relatively complex OBR and OR gene repertoires compared with modern birds, including passerines, perhaps due to highly developed cognitive capacities facilitating foraging innovations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12