Robert Driver, 2026 MGM Distinguished Fellows Travel Award Recipient

Robert Driver
Matsunami Lab
The International Ornithological Congress 2026
November 20 – December 5, 2026

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.