Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, 91198, Gif-sur-Yvette, France.
NOAA National Systematics Laboratory, National Museum of Natural History, Smithsonian Institution, Washington, D.C, 20560, USA.
BMC Biol. 2022 Sep 1;20(1):195. doi: 10.1186/s12915-022-01397-x.
Ray-finned fishes (Actinopterygii) perceive their environment through a range of sensory modalities, including olfaction. Anatomical diversity of the olfactory organ suggests that olfaction is differentially important among species. To explore this topic, we studied the evolutionary dynamics of the four main gene families (OR, TAAR, ORA/VR1 and OlfC/VR2) 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, Polypteriformes, which have a unique and complex olfactory organ, have almost twice as many olfactory receptor genes as any other ray-finned fish.
We document 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.
硬骨鱼类（条鳍鱼）通过多种感觉模式感知环境，包括嗅觉。嗅觉器官的解剖结构多样性表明，嗅觉在不同物种中的重要性不同。为了探讨这个话题，我们研究了编码嗅觉受体的四个主要基因家族（OR、TAAR、ORAVR1 和 OlfCVR2）在 185 种条鳍鱼中的进化动态。
功能基因数量的巨大差异，从海洋翻车鱼 Mola mola 的 28 个到芦苇鱼 Erpetoichthys calabaricus 的 1317 个，是这四个主要基因家族平行扩张和收缩的结果。几个古老的、独立的嗅觉器官简化与大量基因丢失有关。相比之下，具有独特而复杂的嗅觉器官的多鳍鱼目鱼类，其嗅觉受体基因数量几乎是其他任何条鳍鱼的两倍。
我们记录了嗅觉器官形态与嗅觉受体库丰富度之间的功能联系。此外，我们的研究结果表明，硬骨鱼类嗅觉的基因组基础是异构的，并呈现出进化扩张、简化和再获取的动态模式。
