Olfaction written in bone: cribriform plate size parallels olfactory receptor gene repertoires in Mammalia
Olfaction written in bone: cribriform plate size parallels olfactory receptor gene repertoires in Mammalia
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DOI：
10.1098/rspb.2018.0100
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发表时间：
2018-03-14
影响因子：
4.7
通讯作者：
Van Valkenburgh, Blaire
中科院分区：
文献类型：
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作者：
Bird, Deborah J.;Murphy, William J.;Van Valkenburgh, Blaire
哺乳动物嗅觉的进化表现在不同物种间基因谱系、神经解剖学和头骨形态上的显著差异。嗅觉受体基因(Orgs)启动气味分子到气味感知的转换，并帮助动物分辨嗅觉世界，其数量在不同物种中从几个到数千个不等。在鼻腔内，这些器官中的每一个都由一个离散的嗅觉神经元(OSN)群体唯一地表达，这表明新进化的器官可能与鼻上皮中新的OSN群体相耦合。由于OSN轴突束在穿过筛板(CP)到达大脑时在骨骼中留下高保真的穿孔(孔洞)，我们预测具有较大ORG谱系的分类群将在CP孔处按比例扩大足迹。以前的工作发现ORG数和绝对CP大小之间的相关性在考虑了身体大小后消失了。使用来自高分辨率CT扫描的更新的数字测量数据，并重新检查CP与身体大小的关系，我们报告了来自所有哺乳动物超目的跨物种的相对CP面积与功能器官数量之间的显著线性相关性。这种相关性表明，在嗅觉通路中，基因、神经元和头骨形态之间存在着强烈的发育联系。此外，由于ORG数与嗅觉辨别功能有关，这种相关性支持将相对CP大小作为推断现代和灭绝物种嗅觉能力的可行指标。通过量化锯齿猫化石的CP区域，我们预测了这种灭绝猫科动物可能的ORG曲目。
The evolution of mammalian olfaction is manifested in a remarkable diversity of gene repertoires, neuroanatomy and skull morphology across living species. Olfactory receptor genes (ORGs), which initiate the conversion of odorant molecules into odour perceptions and help an animal resolve the olfactory world, range in number from a mere handful to several thousand genes across species. Within the snout, each of these ORGs is exclusively expressed by a discrete population of olfactory sensory neurons (OSNs), suggesting that newly evolved ORGs may be coupled with new OSN populations in the nasal epithelium. Because OSN axon bundles leave high-fidelity perforations (foramina) in the bone as they traverse the cribriform plate (CP) to reach the brain, we predicted that taxa with larger ORG repertoires would have proportionately expanded footprints in the CP foramina. Previous work found a correlation between ORG number and absolute CP size that disappeared after accounting for body size. Using updated, digital measurement data from high-resolution CT scans and re-examining the relationship between CP and body size, we report a striking linear correlation between relative CP area and number of functional ORGs across species from all mammalian superorders. This correlation suggests strong developmental links in the olfactory pathway between genes, neurons and skull morphology. Furthermore, because ORG number is linked to olfactory discriminatory function, this correlation supports relative CP size as a viable metric for inferring olfactory capacity across modern and extinct species. By quantifying CP area from a fossil sabertooth cat (Smilodon fatalis), we predicted a likely ORG repertoire for this extinct felid.