The embryonic development of the centipede Strigamia maritima
The embryonic development of the centipede Strigamia maritima
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DOI：
10.1016/j.ydbio.2011.11.006
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发表时间：
2012-03-01
影响因子：
2.7
通讯作者：
Akam, Michael
中科院分区：
文献类型：
--
作者：
Brena, Carlo;Akam, Michael
地形蜈蚣Strigamia maritima是研究多足动物发育和进化的一种新模式。最近完成了基因组序列草图，使其成为比较基因组学和更广泛的多足动物生理学研究的重要参考。在这里，我们提出了第一个详细的描述多足动物的发展，使用现代技术。我们描述了胚胎发育的时间轴，并根据活卵和固定胚胎的照片建立了详细的分期系统。我们发现，早期，卵裂和核迁移，发展阶段显着延长，占近一半的总发展时期（约22 48天，在13摄氏度）。在这一时期结束时，卵裂细胞迁移到卵的外周，形成一个均匀的胚盘。不对称性很快变得明显，因为卵子前半部分的细胞在腹侧凝聚形成假定的头部。五个前段，下颌骨到第一支腿支撑段（第一LBS）几乎同时通过绒毛膜清晰可见。然后，在短暂的停顿之后，接下来的35个腿轴承节段以每3.2小时1个节段的均匀速率出现（在13摄氏度下）。然后，在胚带弯曲的戏剧性运动之前不久，当胚胎的左半部分和右半部分分离并且胚胎深深地折叠到蛋黄中时，节段添加减慢到40-45 LBS停止。弯曲后，节形态发生和器官发生进行了进一步的10天，在卵孵化。在此期间添加最后几个支腿承载段，速度要慢得多，以1-2段/天的速度添加。最后一个生腿节只有在胚胎角质层脱膜后才完全确定，因此在孵化时胚胎显示出最终成年生腿节的数量（在我们的种群中通常为47-49）。(C)2011 Elsevier Inc. All rights reserved.
The geophilomorph centipede Strigamia maritima is an emerging model for studies of development and evolution among the myriapods. A draft genome sequence has recently been completed, making it also an important reference for comparative genomics, and for studies of myriapod physiology more generally. Here we present the first detailed description of myriapod development using modern techniques. We describe a timeline for embryonic development, with a detailed staging system based on photographs of live eggs and fixed embryos. We show that the early, cleavage and nuclear migration, stages of development are remarkably prolonged, accounting for nearly half of the total developmental period (approx 22 of 48 days at 13 degrees C). Towards the end of this period, cleavage cells migrate to the egg periphery to generate a uniform blastoderm. Asymmetry quickly becomes apparent as cells in the anterior half of the egg condense ventrally to form the presumptive head. Five anterior segments, the mandibular to the first leg-bearing segment (1st LBS) become clearly visible through the chorion almost simultaneously. Then, after a short pause, the next 35 leg-bearing segments appear at a uniform rate of 1 segment every 3.2 h (at 13 degrees C). Segment addition then slows to a halt with 40-45 LBS, shortly before the dramatic movements of germ band flexure, when the left and right halves of the embryo separate and the embryo folds deeply into the yolk. After flexure, segment morphogenesis and organogenesis proceed for a further 10 days, before the egg hatches. The last few leg-bearing segments are added during this period, much more slowly, at a rate of 1-2 segments/day. The last leg-bearing segment is fully defined only after apolysis of the embryonic cuticle, so that at hatching the embryo displays the final adult number of leg-bearing segments (typically 47-49 in our population). (C) 2011 Elsevier Inc. All rights reserved.