scholarly journals Coevolution of the olfactory organ and its receptor repertoire in ray-finned fishes

2021 ◽  
Author(s):  
Maxime Policarpo ◽  
Katherine E Bemis ◽  
Patrick Laurenti ◽  
Laurent Legendre ◽  
Jean-Christophe Sandoz ◽  
...  
Keyword(s):  
Olfactory Receptor ◽  
Evolutionary Dynamics ◽  
Olfactory Receptors ◽  
Gene Families ◽  
Olfactory Organ ◽  
Functional Link ◽  
Receptor Repertoire ◽  
Mola Mola ◽  
Main Gene ◽  
Olfactory Receptor Genes

Ray-finned fishes (Actinopterygii) perceive their environment through a range of sensory modalities, including olfaction 1,2. Anatomical diversity of the olfactory organ suggests that olfaction is differentially important among species 1,3,4. To explore this topic, we studied the evolutionary dynamics of the four main gene families (OR, TAAR, ORA/VR1 and OlfC/VR2) 5 coding for olfactory receptors in 185 species of ray-finned fishes. The large variation in the number of functional genes, between 28 in the Ocean Sunfish Mola mola and 1317 in the Reedfish Erpetoichthys calabaricus, is the result of parallel expansions and contractions of the four main gene families. Several ancient and independent simplifications of the olfactory organ are associated with massive gene losses. In contrast, polypteriforms, which have a unique and complex olfactory organ, have almost twice as many olfactory receptor genes as any other ray-finned fish. These observations suggest a functional link between morphology of the olfactory organ and richness of the olfactory receptor repertoire. Further, our results demonstrate that the genomic underpinning of olfaction in ray-finned fishes is heterogeneous and presents a dynamic pattern of evolutionary expansions, simplifications and reacquisitions.

scholarly journals Massive Loss of Olfactory Receptors But Not Trace Amine-Associated Receptors in the World’s Deepest-Living Fish (Pseudoliparis swirei)

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 910
Author(s):  
Haifeng Jiang ◽  
Kang Du ◽  
Xiaoni Gan ◽  
Liandong Yang ◽  
Shunping He
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptors ◽  
Gene Families ◽  
Evolutionary Divergence ◽  
Ecological Adaptations ◽  
Receptor Repertoire ◽  
Trace Amine ◽  
Feeding Habitat ◽  
Or Genes ◽  
Pressure Analysis

Olfactory receptor repertoires show highly dynamic evolution associated with ecological adaptations in different species. The Mariana snailfish (Pseudoliparis swirei) living below a depth of 6000 m in the Mariana Trench evolved degraded vision and occupies a specific feeding habitat in a dark, low-food environment. However, whether such adaptations involve adaptive changes in the chemosensory receptor repertoire is not known. Here, we conducted a comparative analysis of the olfactory receptor (OR) and trace amine-associated receptor (TAAR) gene repertoires in nine teleosts with a focus on the evolutionary divergence between the Mariana snailfish and its shallow-sea relative, Tanaka’s snailfish (Liparis tanakae). We found many fewer functional OR genes and a significantly higher fraction of pseudogenes in the Mariana snailfish, but the numbers of functional TAAR genes in the two species were comparable. Phylogenetic analysis showed that the expansion patterns of the gene families were shared by the two species, but that Mariana snailfish underwent massive gene losses in its OR repertoire. Despite an overall decreased size in OR subfamilies and a reduced number of TAAR subfamilies in the Mariana snailfish, expansion of certain subfamilies was observed. Selective pressure analysis indicated greatly relaxed selective strength in ORs but a slightly enhanced selective strength in TAARs of Mariana snailfish. Overall, our study reveals simplified but specific OR and TAAR repertoires in the Mariana snailfish shaped by natural selection with respect to ecological adaptations in the hadal environment. This is the first study on the chemosensation evolution in vertebrates living in the hadal zone, which could provide new insights into evolutionary adaptation to the hadal environment.

scholarly journals InsectOR—Webserver for sensitive identification of insect olfactory receptor genes from non-model genomes

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245324
Author(s):  
Snehal Dilip Karpe ◽  
Vikas Tiwari ◽  
Sowdhamini Ramanathan
Keyword(s):  
Genome Annotation ◽  
Olfactory Receptor ◽  
Gene Prediction ◽  
Olfactory Receptors ◽  
Gene Families ◽  
Link Type ◽  
Preliminary Identification ◽  
Olfactory Receptor Genes ◽  
Or Gene ◽  
Or Genes

Insect Olfactory Receptors (ORs) are diverse family of membrane protein receptors responsible for most of the insect olfactory perception and communication, and hence they are of utmost importance for developing repellents or pesticides. Accurate gene prediction of insect ORs from newly sequenced genomes is an important but challenging task. We have developed a dedicated webserver, ‘insectOR’, to predict and validate insect OR genes using multiple gene prediction algorithms, accompanied by relevant validations. It is possible to employ this server nearly automatically and perform rapid prediction of the OR gene loci from thousands of OR-protein-to-genome alignments, resolve gene boundaries for tandem OR genes and refine them further to provide more complete OR gene models. InsectOR outperformed the popular genome annotation pipelines (MAKER and NCBI eukaryotic genome annotation) in terms of overall sensitivity at base, exon and locus level, when tested on two distantly related insect genomes. It displayed more than 95% nucleotide level precision in both tests. Finally, given the same input data and parameters, InsectOR missed less than 2% gene loci, in contrast to 55% loci missed by MAKER for Drosophila melanogaster. The webserver is freely available on the web at http://caps.ncbs.res.in/insectOR/ and the basic package can be downloaded from https://github.com/sdk15/insectOR for local use. This tool will allow biologists to perform quick preliminary identification of insect olfactory receptor genes from newly sequenced genomes and also assist in their further detailed annotation. Its usage can also be extended to other divergent gene families.

scholarly journals Organization and distribution of glomeruli in the bowhead whale olfactory bulb

2014 ◽  
Author(s):  
Takushi Kishida ◽  
J. G. M. Thewissen ◽  
Sharon Usip ◽  
John C George ◽  
Robert S Suydam
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Receptor ◽  
Olfactory Receptors ◽  
Molecular Data ◽  
Dorsal Side ◽  
Bowhead Whale ◽  
Model Organisms ◽  
Marker Genes ◽  
Baleen Whales ◽  
Olfactory Receptor Genes

Although modern baleen whales still possess a functional olfactory systems that includes olfactory bulbs, cranial nerve I and olfactory receptor genes, their olfactory capabilities have been reduced profoundly. This is probably in response to their fully aquatic lifestyle. The glomeruli that occur in the olfactory bulb can be divided into two non-overlapping domains, a dorsal domain and a ventral domain. Recent molecular studies revealed that all modern whales have lost olfactory receptor genes and marker genes that are specific to the dorsal domain, and that a modern baleen whale possess only 60 olfactory receptor genes. Here we show that olfactory bulb of bowhead whales (Balaena mysticetus, Mysticeti) lacks glomeruli on the dorsal side, consistent with the molecular data. In addition, we estimate that there are more than 4,000 glomeruli in the bowhead whale olfactory bulb. Olfactory sensory neurons that express the same olfactory receptor in mice generally project to two specific glomeruli in an olfactory bulb, meaning that ratio of the number of olfactory receptors : the number of glomeruli is approximately 1:2. However, we show here that this ratio is not applicable to whales, indicating the limitation of mice as model organisms for understanding the initial coding of odor information among mammals.

scholarly journals Primacy model and the evolution of the olfactory receptor repertoire

2018 ◽  
Author(s):  
Hamza Giaffar ◽  
Dmitry Rinberg ◽  
Alexei A. Koulakov
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptors ◽  
Dimensional Structure ◽  
Sufficient Information ◽  
High Affinity ◽  
Receptor Repertoire ◽  
Wide Range ◽  
Evoked Activity ◽  
Low Dimensional ◽  
The Impact

For many animals, the neural activity in early olfactory circuits during a single sniff cycle contains sufficient information for fine odor discrimination. Whilst much is known about the transformations of neural representations in early olfactory circuits, exactly how odorant evoked activity in the main olfactory bulb shapes the perception of odors remains largely unknown. In olfaction, odorant identity is generally conserved over a wide range of conditions, including concentration. We present a theory of identity assignment in the olfactory system that accounts for this invariance with respect to stimulus intensity. We suggest that the identities of relatively few high affinity olfactory receptor types determine an odorant's perceived identity. This set of high-affinity receptors is defined as the primary set and the coding model based on their responses is called the primacy theory. In this study, we explore the impact that primacy coding may have on the evolution of the ensemble of olfactory receptors. A primacy coding mechanism predicts the arrangement of different receptor types in a low-dimensional structure that we call a primacy hull. We present several statistical analyses that can detect the presence of this structure, allowing the predictions of the primacy model to be tested experimentally.

scholarly journals Heterotrimeric kinesin-II is necessary and sufficient to promote different stepwise assembly of morphologically distinct bipartite cilia in Drosophila antenna

2011 ◽  
Vol 22 (6) ◽  
pp. 769-781 ◽  
Author(s):  
Swadhin C. Jana ◽  
Mukul Girotra ◽  
Krishanu Ray
Keyword(s):  
Olfactory Receptor ◽  
Primary Cilia ◽  
Olfactory Receptors ◽  
Type I ◽  
Sensory Cilia ◽  
Receptor Neurons ◽  
Olfactory Receptor Genes ◽  
Necessary And Sufficient ◽  
Stepwise Assembly ◽  
Mechanical Sensing

Structurally diverse sensory cilia have evolved from primary cilia, a microtubule-based cellular extension engaged in chemical and mechanical sensing and signal integration. The diversity is often associated with functional specialization. The olfactory receptor neurons in Drosophila, for example, express three distinct bipartite cilia displaying different sets of olfactory receptors on them. Molecular description underlying their assembly and diversification is still incomplete. Here, we show that the branched and the slender olfactory cilia develop in two distinct step-wise patterns through the pupal stages before the expression of olfactory receptor genes in olfactory neurons. The process initiates with a thin procilium growth from the dendrite apex, followed by volume increment in successive stages. Mutations in the kinesin-II subunit genes either eliminate or restrict the cilia growth as well as tubulin entry into the developing cilia. Together with previous results, our results here suggest that heterotrimeric kinesin-II is the primary motor engaged in all type-I sensory cilia assembly in Drosophila and that the cilia structure diversity is achieved through additional transports supported by the motor during development.

scholarly journals Revisiting olfactory receptors as putative drivers of cancer

2017 ◽  
Vol 2 ◽  
pp. 9 ◽  
Author(s):  
Marco Ranzani ◽  
Vivek Iyer ◽  
Ximena Ibarra-Soria ◽  
Martin Del Castillo Velasco-Herrera ◽  
Mathew Garnett ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Lines ◽  
Cancer Cell ◽  
Olfactory Receptor ◽  
Receptor Gene ◽  
Signal Transduction Pathway ◽  
Olfactory Receptors ◽  
Cancer Cell Lines ◽  
Specific Manner ◽  
Olfactory Receptor Genes

Background: Olfactory receptors (ORs) recognize odorant molecules and activate a signal transduction pathway that ultimately leads to the perception of smell. This process also modulates the apoptotic cycle of olfactory sensory neurons in an olfactory receptor-specific manner. Recent reports indicate that some olfactory receptors are expressed in tissues other than the olfactory epithelium suggesting that they may have pleiotropic roles. Methods: We investigated the expression of 301 olfactory receptor genes in a comprehensive panel of 968 cancer cell lines. Results: Forty-nine per cent of cell lines show expression of at least one olfactory receptor gene. Some receptors display a broad pattern of expression across tumour types, while others were expressed in cell lines from a particular tissue. Additionally, most of the cancer cell lines expressing olfactory receptors express the effectors necessary for OR-mediated signal transduction. Remarkably, among cancer cell lines, OR2C3 is exclusively expressed in melanoma lines. We also confirmed the expression of OR2C3 in human melanomas, but not in normal melanocytes. Conclusions: The pattern of OR2C3 expression is suggestive of a functional role in the development and/or progression of melanoma. Some olfactory receptors may contribute to tumorigenesis.

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