Developmental roles of pufferfish Hox clusters and genome evolution in ray-fin fish
Developmental roles of pufferfish Hox clusters and genome evolution in ray-fin fish
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DOI：
10.1101/gr.1717804
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发表时间：
2004-01-01
期刊：
影响因子：
7
通讯作者：
Postlethwait, JH
中科院分区：
文献类型：
--
作者：
Amores, A;Suzuki, T;Postlethwait, JH
河豚的骨骼没有肋骨和腹鳍，头骨和颌骨融合在一起。据推测，这种二次简化的河豚形态是由于河豚的Hox复合体的复杂性降低。为了验证这一假设，我们确定了Hox簇的基因组结构，在南方河豚Spheroides nephelus和询问基因组数据库的日本河豚红鳍东方鲀（河豚）。这两个物种都有至少7个Hox簇，包括两个Hoxb和Hoxd簇，一个Hoxc簇和至少两个Hoxa簇，以及河豚中第三个Hoxa簇的一部分。结果支持基因组复制之前，分歧的斑马鱼和河豚鱼的血统，其次是损失的Hoxc集群的河豚鱼血统和损失的Hoxd集群的斑马鱼血统。比较分析表明，重复基因持续丢失了数亿年，与基因重复永久保存的预测相反。通过原位杂交对河豚胚胎基因表达的分析揭示了复制-退化-互补模型所预测的基因表达的进化变化。这些实验排除了简化的河豚身体计划是由于减少Hox集群的复杂性的假设，并支持这样的观点，即基因组复制有助于辐射的硬骨鱼到一半的所有脊椎动物物种的增加发展多样化的重复基因的女儿血统。
The pufferfish skeleton lacks ribs and pelvic fins, and has fused bones in the cranium and jaw. It has been hypothesized that this secondarily simplified pufferfish morphology is due to reduced complexity of the pufferfish Hox complexes. To test this hypothesis, we determined the genomic structure of Hox clusters in the Southern pufferfish Spheroides nephelus and interrogated genomic databases for the Japanese pufferfish Takifugu rubripes (fugu). Both species have at least seven Hox clusters, including two copies of Hoxb and Hoxd clusters, a single Hoxc cluster, and at least two Hoxa clusters, with a portion of a third Hoxa cluster in fugu. Results support genome duplication before divergence of zebrafish and pufferfish lineages, followed by loss of a Hoxc cluster in the pufferfish lineage and loss of a Hoxd cluster in the zebrafish lineage. Comparative analysis shows that duplicate genes continued to be lost for hundreds of millions of years, contrary to predictions for the permanent preservation of gene duplicates. Gene expression analysis in fugu embryos by in situ hybridization revealed evolutionary change in gene expression as predicted by the duplication-degeneration-complementation model. These experiments rule out the hypothesis that the simplified pufferfish body plan is due to reduction in Hox Cluster complexity, and support the notion that genome duplication contributed to the radiation of teleosts into half of all vertebrate species by increasing developmental diversification of duplicate genes in daughter lineages.