Presentation Details
| Evolutionary diversity and function of odorant receptors in birds Robert Driver1, Mona Marie1, Hiroaki Matsunami1, Christopher Balakrishnan2. 1Duke University School of Medicine, Durham, NC, USA.2National Science Foundation, Alexandria, VA, USA |
Abstract
An incredible variety of chemicals are perceived as smell by animals. To detect this vast range of volatiles, odorant receptors (ORs) have diversified into one of the largest gene families in vertebrates; for example, many mammals have over 1,000 OR genes. Birds, with over 10,000 extant species, inhabit nearly all land environments and exhibit diverse breeding and foraging behaviors yet were long thought to make limited use of olfactory signals. Here, we used genomic and molecular approaches to demonstrate the relevance of the avian olfactory system. We show that, like mammals, bird genomes often contain hundreds – or in some cases, thousands – of intact ORs, including the nocturnal kiwi (Apteryx manetllii), which possesses the largest number of ORs known from any animal. The majority of avian ORs belong to a bird-specific expansion known as gamma-c ORs. We found that this expansion was characterized by extensive gene conversion leading to mosaic open reading frames with diverse regions interspersed with regions nearly identical in nucleotide sequence. We show that avian ORs are expressed in olfactory sensory neurons and respond to specific odors in vitro and in vivo. Notably we identify for the first time ligands for avian ORs documenting both unique function in gamma-c ORs and shared function with a deeply divergent mammal OR. Our findings highlight commonalities between mammals and birds in olfactory system function but also reveal a unique evolutionary feature: the widespread role of gene conversion shaping the majority of bird ORs. Our results challenge prior assumptions and underscore the importance of olfaction in the life history of birds.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
Content Locked. Log into a registered attendee account to access this presentation.