Developmental Biology of Hagfishes, with a Report on Newly Obtained Embryos of the Japanese Inshore Hagfish, Eptatretus burgeri
Developmental Biology of Hagfishes, with a Report on Newly Obtained Embryos of the Japanese Inshore Hagfish, Eptatretus burgeri
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DOI：
10.2108/zsj.25.999
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发表时间：
2008-10-01
影响因子：
0.9
通讯作者：
Kuratani, Shigeru
中科院分区：
文献类型：
--
作者：
Ota, Kinya G.;Kuratani, Shigeru
盲鳗类的原始特征是脊椎动物进化研究中的一个关键问题，尽管盲鳗类与七鳃鳗类的单系关系已被大量的分子生物学数据（包括基因组和EST序列）所证实。要解决这个问题，需要盲鳗的发育生物学知识。我们尝试从日本近海盲鳗（Eptatretus burgeri）获得胚胎，并成功地制备了几个很好的固定胚胎。基于详细的组织学观察和基因表达模式与传统的脊椎动物的比较，我们研究了一些重要的形态特征，包括神经嵴，基板，咽弓，和其他的发育过程。我们的数据显示，一些明显原始的形态特征可以被视为主要来自固定条件的文物。此外，我们对活胚胎的长期观察显示，这种动物的发育速度很慢。在这篇综述中，我们总结了最近从这些盲鳗胚胎发育的数据，并讨论了一个合理的进化方案的脊椎动物的发展，与一些旧的描述进行比较。
The apparently primitive features of hagfishes are recognized as a crucial problem in the study of vertebrate evolution, although the monophyletic relationship between these animals and lampreys has been confirmed by large amounts of molecular data, including genome and EST sequences. To solve this problem requires knowledge of the developmental biology of hagfishes. We attempted to obtain embryos from the Japanese inshore hagfish (Eptatretus burgeri) and succeeded in preparing several nicely fixed embryos. Based on detailed histological observations and comparison of gene expression patterns with those of conventional vertebrates, we examined the developmental processes involved in some important morphological traits, including the neural crest, placode, pharyngeal arches, and others. Our data revealed that some apparently primitive morphological traits can be regarded as artifacts deriving mainly from fixation conditions. In addition, our long-term observations of live embryos revealed a slow developmental rate in this animal. In this review, we summarize recent developmental data from these hagfish embryos and discuss a plausible evolutionary scenario for vertebrate development, making comparisons with some old descriptions.