Extensive duplication of the Wolbachia DNA in chromosome four of Drosophila ananassae
Extensive duplication of the Wolbachia DNA in chromosome four of Drosophila ananassae
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DOI：
10.1186/1471-2164-15-1097
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发表时间：
2014-12-12
期刊：
影响因子：
4.4
通讯作者：
Hotopp, Julie C. Dunning
中科院分区：
文献类型：
--
作者：
Klasson, Lisa;Kumar, Nikhil;Hotopp, Julie C. Dunning
背景：在节肢动物和线虫基因组测序项目中，类似于20%的节肢动物和线虫基因组测序项目检测到来自细菌沃尔巴克氏菌内共生体的侧向基因转移(LGT)。结果：在这里，我们重新测序了来自亚洲和太平洋的三个包含沃尔巴克氏菌大片段LGT的亚洲和太平洋地区的水华丝虫基因组。我们发现，在这三个品系中，沃尔巴克氏菌基因组的多个副本都转移到了果蝇的核基因组中。在来自印度尼西亚的达氏丝虫品系中，核基因组中沃尔巴克氏菌DNA的副本在大小和序列上几乎相同，从而在沃尔巴克氏菌基因组上产生了均匀的图谱阅读。相比之下，来自夏威夷和印度的Danansae品系显示沃尔巴克氏菌基因组上的图谱阅读覆盖不均匀，这表明这些LGT的不同部分以不同的拷贝数存在。在夏威夷品系中，我们发现这种LGT在三龄幼虫中的表达不足，表明它是异色的。有丝分裂染色体的荧光原位杂交证实，夏威夷株系中的LGT是异染色质的，与4号染色体(点染色体，Muller元件F)上20%的序列相似。结论：该亲缘系包含由多个Wolbachia基因组组成的大规模横向基因转移，这些基因组构成了鹅掌金线虫基因组的2%(类似于5Mbp)，并部分解释了鹅绒草4号染色体异常大的原因。
Background: Lateral gene transfer (LGT) from bacterial Wolbachia endosymbionts has been detected in similar to 20% of arthropod and nematode genome sequencing projects. Many of these transfers are large and contain a substantial part of the Wolbachia genome.Results: Here, we re-sequenced three D. ananassae genomes from Asia and the Pacific that contain large LGTs from Wolbachia. We find that multiple copies of the Wolbachia genome are transferred to the Drosophila nuclear genome in all three lines. In the D. ananassae line from Indonesia, the copies of Wolbachia DNA in the nuclear genome are nearly identical in size and sequence yielding an even coverage of mapped reads over the Wolbachia genome. In contrast, the D. ananassae lines from Hawaii and India show an uneven coverage of mapped reads over the Wolbachia genome suggesting that different parts of these LGTs are present in different copy numbers. In the Hawaii line, we find that this LGT is underrepresented in third instar larvae indicative of being heterochromatic. Fluorescence in situ hybridization of mitotic chromosomes confirms that the LGT in the Hawaii line is heterochromatic and represents similar to 20% of the sequence on chromosome 4 (dot chromosome, Muller element F).Conclusions: This collection of related lines contain large lateral gene transfers composed of multiple Wolbachia genomes that constitute >2% of the D. ananassae genome (similar to 5 Mbp) and partially explain the abnormally large size of chromosome 4 in D. ananassae.