Swimming through the oceans, voraciously consuming plankton and other small creatures—and occasionally startling a swimmer—the beautiful gelatinous masses known as comb jellies won9t be joining Mensa anytime soon. But these fragile creatures have nerve cells—and they offer insights about the evolutionary origins of all nervous systems, including our own. Inspired by their studies of a glue-secreting cell unique to these plankton predators, researchers have now proposed that in the last common ancestor to today9s animals, the earliest neurons arose from secretory cells whose primary function was to release chemicals into the environment. The researchers also unearthed additional evidence in jellyfish, hydra, and fruit flies that neurons and other secretory cell types come from the same progenitor cells in embryos. The work could help resolve a long debate about whether the nervous system evolved twice early in animal life.

中文翻译：

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神经元是由早期分泌细胞产生的吗？

在海洋中游泳，贪婪地吞食浮游生物和其他小生物——偶尔还会让游泳者吃惊——被称为栉水母的美丽凝胶状物质不会很快加入门萨。但是这些脆弱的生物有神经细胞——它们提供了关于所有神经系统进化起源的见解，包括我们自己的。受他们对这些浮游生物捕食者特有的分泌胶水的细胞的研究的启发，研究人员现在提出，在今天动物的最后一个共同祖先中，最早的神经元来自分泌细胞，其主要功能是将化学物质释放到环境中。研究人员还在水母、水螅和果蝇中发现了额外的证据，表明神经元和其他分泌细胞类型来自胚胎中的相同祖细胞。