The amphioxus Hox cluster:: Characterization, comparative genomics, and evolution
The amphioxus Hox cluster:: Characterization, comparative genomics, and evolution
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DOI：
10.1002/jez.b.21213
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发表时间：
2008-07-15
影响因子：
2.2
通讯作者：
Stadler, Peter F.
中科院分区：
文献类型：
--
作者：
Amemiya, Chris T.;Prohaska, Sonja J.;Stadler, Peter F.
文昌鱼Hox集群通常被视为脊索动物谱系的“原型”。在这里，我们提出了一个描述性的帐户的448 kb的区域跨越Hox集群的文昌鱼Branchiostoma floridae从Hox14到Hox1。我们提供了所有14个先前描述的文昌鱼序列的完整编码序列，并给出了保守的非编码调控序列元件的详细分析。我们发现，后部的Hox集群是如此高度衍生，即使是完整的基因组序列是不足以决定是否后Hox基因产生的独立的重复，或者他们是否是真正的直系同源相应的gnathostome parabolites组。相比之下，前区保存得更好。文昌鱼Hox集群强烈排除重复的元素，除了两个重复的岛屿在后部区域。重复排除也观察到在gnathostomes，但不是原口Hox集群。因此，我们假设，更短的脊椎动物的Hox集群的结果是广泛的决议后，基因组复制的冗余调控DNA，而不是选择压力的后果，以消除非功能性序列的Hox集群。
The amphioxus Hox cluster is often viewed as "archetypal" for the chordate lineage. Here, we present a descriptive account of the 448 kb region spanning the Hox cluster of the amphioxus Branchiostoma floridae from Hox14 to Hox1. We provide complete coding sequences of all 14 previously described amphioxus sequences and give a detailed analysis of the conserved noncoding regulatory sequence elements. We find that the posterior part of the Hox cluster is so highly derived that even the complete genomic sequence is insufficient to decide whether the posterior Hox genes arose by independent duplications or whether they are true orthologs of the corresponding gnathostome paralog groups. In contrast, the anterior region is much better conserved. The amphioxus Hox cluster strongly excludes repetitive elements with the exception of two repeat islands in the posterior region. Repeat exclusion is also observed in gnathostomes, but not protostome Hox clusters. We thus hypothesize that the much shorter vertebrate Hox clusters are the result of extensive resolution of the redundancy of regulatory DNA after the genome duplications rather than the consequence of a selection pressure to remove nonfunctional sequence from the Hox cluster.