The genus Polypterus (bichirs): a fish group diverged at the stem of ray-finned fishes (Actinopterygii).
The genus Polypterus (bichirs): a fish group diverged at the stem of ray-finned fishes (Actinopterygii).
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DOI：
10.1101/pdb.emo117
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发表时间：
2009-05
影响因子：
--
通讯作者：
Masaki Takeuchi;M. Okabe;S. Aizawa
中科院分区：
文献类型：
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作者：
Masaki Takeuchi;M. Okabe;S. Aizawa
轴和胚层的形成是脊椎动物胚胎学的中心问题，可以在斑马鱼、非洲爪哇、雏鸟和老鼠身上进行研究。一个耐人寻味的问题是，在脊椎动物进化过程中，祖先脊椎动物中存在的机制是如何被修改的。脊椎动物的主流(骨鱼目)进化成两个单系谱系：肉鳍目和放线鳍目。斑马鱼是一种广为人知和被广泛研究的硬骨鱼，高度起源于放线翅目的鳍鳍鱼类。硬骨鱼的早期分裂模式是分生组织的，与两栖动物的全母细胞分裂形成对比，两栖动物的全母细胞分裂在石棺世系的早期分化。硬骨鱼和两栖动物或放线蕨类和石棺类在胚胎发生的分子和细胞机制上有许多不同，包括Bauplan(身体平面)的差异。然而，导致硬骨鱼的谱系在辐射前经历了全基因组复制，这可能也导致了与硬骨鱼bauplan无关的分子用途的变化。在泥盆纪时期，在一条祖先的骨鱼分裂为放线鸟和肉鸡后不久，多翅目与所有其他的放线鸟类在泥盆纪时期(Mya)发生了分歧。因此，多翅目鱼类非常适合于评估骨鱼和放线鱼的祖先状态或包包计划，以及硬骨鱼和两栖动物胚胎发生过程的差异。
Axis and germ-layer formations are central issues in vertebrate embryology that can be examined in the zebrafish, Xenopus, chick, and mouse. An intriguing question is how the mechanisms that existed in an ancestral vertebrate have been modified during vertebrate evolution. A major stream of vertebrates (Osteichthyes) evolved in two monophyletic lineages: the Sarcopterygii and Actinopterygii. The zebrafish is a well-known and well-studied teleost fish highly derived in the actinopterygian lineage, ray-finned fishes. The early cleavage pattern of teleosts is meroblastic, in contrast to the holoblastic cleavage seen in amphibians, which diverged early in the sarcopterygian lineage. There are many differences in the molecular and cellular mechanisms of embryogenesis between teleosts and amphibians or actinopterygians and sarcopterygians, including the differences in bauplan (body plan). However, the lineage leading to the teleost fishes has undergone a whole-genome duplication before their radiation, which may have also caused changes in molecular usage independent of the teleost bauplan. Polypterus diverged from all other actinopterygians~ 400 million years ago (Mya) during the Devonian period, soon after the divarication of an ancestral bony fish into Actinopterygii and Sarcopterygii. Polypterus is thus uniquely well suited for studies assessing the ancestral state or bauplan of Osteichthyes and Actinopterygii, as well as the divergence of embryogenetic processes in teleosts and amphibians.