The normal embryogenesis of marine animals is typically confined to a species-specific range of temperatures. Within that temperature range development results in a consistent, or canalized, phenotype, whereas above and below the range abnormal phenotypes are produced. This study reveals a high temperature threshold, occurring over a 1-2 °C range, for normal embryonic development in C. intestinalis. Above that threshold the prevalence of morphological abnormalities increases significantly, beginning with cleavage and gastrula stages, and becoming more pronounced as embryogenesis proceeds. However, even in highly morphologically abnormal temperature disrupted (TD) embryos, muscle, endoderm, notochord, epidermis, and sensory pigment cells are recognizable, as evidenced by histochemical markers or morphology. On the other hand, morphogenesis of the notochord and other structures is dependent on precise cell movement and shape changes after the gastrula stage, which are disrupted above the high temperature threshold. These findings suggest that morphogenetic processes may be more sensitive to high temperature than cell type specification events. They also point to avenues for investigation of the limiting factors to developmental canalization in marine invertebrates.

中文翻译：

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高温对小肠海鞘发育管化的限制

海洋动物的正常胚胎发生通常限于特定物种的温度范围。在该温度范围内，发育导致一致的或渠道化的表型，而高于和低于该范围会产生异常表型。这项研究揭示了一个高温阈值，发生在 1-2 °C 的范围内，对于肠衣原体的正常胚胎发育。高于该阈值，形态异常的发生率显着增加，从卵裂和原肠胚阶段开始，随着胚胎发生的进行而变得更加明显。然而，即使在高度形态异常的温度破坏 (TD) 胚胎中，肌肉、内胚层、脊索、表皮和感觉色素细胞也是可识别的，如组织化学标记或形态所证明的那样。另一方面，脊索和其他结构的形态发生取决于原肠胚阶段后精确的细胞运动和形状变化，这些在高温阈值以上被破坏。这些发现表明，与细胞类型规范事件相比，形态发生过程可能对高温更敏感。他们还指出了研究海洋无脊椎动物发育运河的限制因素的途径。