人们认为，基因复制在为物种的进化多样化生成新的遗传物质方面起着重要作用。基因复制可能是由多种机制引起的，在极端情况下，基因组中所有基因的两个副本可以由整个基因组重复（WGD）产生。
In arecent studypublished inBMC Biology, my colleagues and I analyzed the genome of the common house spiderparasteatoda tepidariorum和we have found evidence for a WGD in the lineage leading to spiders.
This event was likely shared with scorpions and probably other蛛网like whip-scorpions and whip spiders, but not with more distantly related arachnids such as ticks and mites. This suggests that the approximately 45,000 extant species of arachnopulmonates evolved from a polyploid ancestor over 400 million years ago.
Our study also suggests that this WGD in arachnids was likely independent of WGD in another group of chelicerates, the马蹄蟹. Our findings thus offer an exciting opportunity to discover more about the outcomes of WGD in terms of gene content and regulation, and how such events may contribute to animal diversification.
在脊椎动物的祖先中two rounds of WGD这些事件可能导致这些动物通过保留和利用重复基因的多样化。例如，尽管大多数动物都包含一个HOX基因簇，但像我们一样，脊椎动物有四个HOX簇，并且这些其他基因在发育中起着许多重要的作用。但是，由于WGD事件发生多种原因，可以保留或丢失基因，包括随机突变，重组和剂量效应。
Identifying whole genome duplication events
更好地理解WGD后基因保留和损失的模式以及对共同点的识别，以及可能是进化创新的基因，需要研究独立事件。然而，这种比较遭受了以下事实：迄今为止，仅在动物中描述了一些WGD的例子。
Our identification of a WGD in arachnids, consequently, provides a much-needed new data point for understanding the general and lineage specific impact of WGD events.
Our identification of a WGD in arachnids, consequently, provides a much-needed new data point for understanding the general and lineage specific impact of WGD events. The duplicated genes that have been retained in both spiders and scorpions represent many that encode proteins with important roles in development, including two copies of most Hox genes arranged in two (nearly) complete clusters.
此外，每个蜘蛛HOX基因在胚胎发生过程中的时间和空间表达的旁系同源物都不同，这表明一些新副本相对于单拷贝祖先基因执行了新功能。因此，我们的研究揭示了蜘蛛和脊椎动物中WGD的结果之间的有趣相似之处。
有趣的是，我们的研究和previous workalso reveals a high rate of retention of duplicated microRNAs. These genes are thought to modulate the expression levels of their target genes and they have perhaps been retained in high numbers after WGD to buffer the dosage effects of targeted duplicated protein coding genes, rather than contributing to the emergence of novel traits. Indeed, a possible outcome of gene duplication isdevelopmental systems drift, whereby different genes and interactions can be used to achieve the same phenotypic outcome, but this remains to be investigated systematically.
More fully understanding the consequences WGD event in arachnids requires the analysis of additional arachnid genomes to determine exactly when this event occurred and which lineages were affected. For example, it would be interesting to explore whether there is any evidence for WGD in other arachnid orders likecamel spiders, harvestmen and pseudoscorpions.
此外，将鞭子蜘蛛和鞭子蝎子的基因组与蜘蛛和蝎子进行比较可以帮助揭示大多数在WGD之后保留的基因，而WGD与谱系特定的保留和损失相比。These data will not only provide insights into arachnid genomes ‘before’ and ‘after’ the WGD event, but a better understanding of how duplicated genes produced by this event have contributed to the evolution of innovations in these animals, for example, silk production in spiders and the booklungs (novel breathing organs) of arachnopulmonates.
最后，对蛛网中WGD后基因保留和损失的模式的更详细理解将与脊椎动物中的此类事件进行很好的比较，以更好地了解WGD对动物基因组及其生物学的进化的更广泛的含义和后果。
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