Evolutionary biology -: Lamprey Hox genes and the origin of jaws
Evolutionary biology -: Lamprey Hox genes and the origin of jaws
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DOI：
10.1038/416386a
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发表时间：
2002-03-28
期刊：
影响因子：
64.8
通讯作者：
Cohn, MJ
中科院分区：
文献类型：
--
作者：
Cohn, MJ
颌骨的发育是脊椎动物进化中的一个关键事件，因为它开启了向捕食性生活方式的转变，但这种创新是如何产生的一直是一个谜。在有颌骨的脊椎动物的胚胎中，下颌软骨从下颌弓发育而来，那里没有Hoxgene的表达；然而，如果这些基因异位表达，颌骨的发育就会受到抑制。在这里，我展示了在七鳃鳗中，一种原始的无颌(无颌目)鱼，是下颌口目动物的姊妹类，Hoxgene在发育中的胚胎的下颌弓中表达。这一发现，再加上外部群体的比较，表明颌口动物下颌弓上HoxmRNA表达的缺失可能促进了颌骨的进化。
The development of jaws was a critical event in vertebrate evolution because it ushered in a transition to a predatory lifestyle, but how this innovation came about has been a mystery. In the embryos of jawed vertebrates (gnathostomes), the jaw cartilage develops from the mandibular arch, where none of theHoxgenes is expressed; if these are expressed ectopically, however, jaw development is inhibited,,. Here I show that in the lamprey, a primitively jawless (agnathan) fish that is a sister group to the gnathostomes, aHoxgene is expressed in the mandibular arch of developing embryos. This finding, together with outgroup comparisons, suggests that loss ofHoxexpression from the mandibular arch of gnathostomes may have facilitated the evolution of jaws.