The fish species Astyanax mexicanus with its sighted and blind eco-morphotypes has become an original model to challenge vertebrate developmental evolution. Recently, we demonstrated that phenotypic evolution can be impacted by early developmental events starting from the production of oocytes in the fish ovaries. A. mexicanus offers an amenable model to test the influence of maternal effect on cell fate decisions during early development, yet the mechanisms by which the information contained in the eggs is translated into specific developmental programs remain obscure due to the lack of specific tools in this emergent model. Here we describe methods for the generation of gastruloids from yolkless-blastoderm explants to test the influence of embryonic and extraembryonic properties on cell fate decisions, as well as the production of chimeric embryos obtained by intermorph cell transplantations to probe cell autonomous or non-autonomous processes. We show that Astyanax gastruloids have the potential to recapitulate the main ontogenetic events observed in intact embryos, including the internalization of mesodermal progenitors and eye development, as followed with Zic:GFP reporter lines. In addition, intermorph cell grafts resulted in proper integration of exogenous cells into the embryonic tissues, with lineages becoming more restricted from mid-blastula to gastrula. The implementation of these approaches in A. mexicanus will bring new light on the cascades of events, from the maternal pre-patterning of the early embryo to the evolution of brain regionalization.

中文翻译：

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拟南芥和嵌合体在墨西哥Astyanax鱼类中探索早期evo-devo

具有视觉和盲目生态形态类型的墨西哥鱼类Astyanax已经成为挑战脊椎动物发育进化的原始模型。最近，我们证明了从鱼卵巢中卵母细胞的产生开始，早期发育事件会影响表型的进化。墨西哥曲霉我们提供了一个合适的模型来测试母体效应在早期发育过程中对细胞命运决定的影响，但是由于这种新兴模型缺乏特定的工具，卵中所含信息转化为特定发育程序的机制仍然不清楚。在这里，我们描述了从无蛋黄胚芽外植体生成胚状体的方法，以测试胚胎和胚外特性对细胞命运决定的影响，以及通过间质细胞移植来探查细胞自主或非自主过程而获得的嵌合胚的产生。我们证明了Astyanax胃类固醇有可能概括完整胚胎中观察到的主要个体发育事件，包括中胚层祖细胞的内在化和眼睛发育，随后是Zic：GFP报告基因系。此外，间质细胞移植物导致外源细胞正确整合到胚胎组织中，从中胚层到胃胚的谱系变得更加受限。这些方法在墨西哥曲霉中的实施将为事件的级联提供新的思路，从母体对早期胚胎的预模式到大脑区域化的演变。