Duplications and Positive Selection Drive the Evolution of Parasitism-Associated Gene Families in the Nematode Strongyloides papillosus.
Duplications and Positive Selection Drive the Evolution of Parasitism-Associated Gene Families in the Nematode Strongyloides papillosus.
复制标题
重复和正选择驱动乳头圆线虫寄生相关基因家族的进化。
DOI：
10.1093/gbe/evx040
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发表时间：
2017-03-01
影响因子：
3.3
通讯作者：
Rödelsperger C
中科院分区：
文献类型：
--
作者：
Baskaran P;Jaleta TG;Streit A;Rödelsperger C
基因复制是表型复杂性进化和新性状产生的主要机制。通过比较寄生性和非寄生性线虫，最近的一项研究发现，圆线虫科寄生性的进化与Astacin和CAP基因家族的大规模扩张有关。为了获得新的见解的发展过程中的绵羊寄生虫圆线虫乳头状，我们测序转录组的不同发育阶段和性别。总体而言，我们发现大多数基因是发育调控的，并且在分歧的S中具有一对一的直系同源物。ratti基因组。同时发现S. papilosus和S. Ratti，这些结果表明，在序列和表达水平上对变化起作用的强进化约束。然而，寄生和自由生活的女性之间的比较表明一个相当不同的模式，这主要是由于前面提到的Astacin和CAP基因家族的扩展。两个基因家族的更详细的系统发育分析表明，大多数成员可以追溯到单一的扩张事件早期的类圆线虫谱系，并经历了subfunctionalization导致的集群，无论是在感染性幼虫或寄生的女性高度表达。最后，我们发现，相对于全基因组预期，这两个基因家族的正选择证据增加。总之，我们的研究揭示了第一个见解的发育转录组的S。乳头状并提供了寄生虫相关基因家族的序列和表达进化的详细分析。
Gene duplication is a major mechanism playing a role in the evolution of phenotypic complexity and in the generation of novel traits. By comparing parasitic and nonparasitic nematodes, a recent study found that the evolution of parasitism in Strongyloididae is associated with a large expansion in the Astacin and CAP gene families. To gain novel insights into the developmental processes in the sheep parasite Strongyloides papillosus, we sequenced transcriptomes of different developmental stages and sexes. Overall, we found that the majority of genes are developmentally regulated and have one-to-one orthologs in the diverged S. ratti genome. Together with the finding of similar expression profiles between S. papillosus and S. ratti, these results indicate a strong evolutionary constraint acting against change at sequence and expression levels. However, the comparison between parasitic and free-living females demonstrates a quite divergent pattern that is mostly due to the previously mentioned expansion in the Astacin and CAP gene families. More detailed phylogenetic analysis of both gene families shows that most members date back to single expansion events early in the Strongyloides lineage and have undergone subfunctionalization resulting in clusters that are highly expressed either in infective larvae or in parasitic females. Finally, we found increased evidence for positive selection in both gene families relative to the genome-wide expectation. In summary, our study reveals first insights into the developmental transcriptomes of S. papillosus and provides a detailed analysis of sequence and expression evolution in parasitism-associated gene families.