A step to the gigantic genome of the desert locust: chromosome sizes and repeated DNAs
A step to the gigantic genome of the desert locust: chromosome sizes and repeated DNAs
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DOI：
10.1007/s00412-014-0499-0
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发表时间：
2015-06-01
期刊：
影响因子：
1.6
通讯作者：
Bakkali, M.
中科院分区：
文献类型：
--
作者：
Camacho, J. P. M.;Ruiz-Ruano, F. J.;Bakkali, M.
沙漠蝗（Schistocerca gregaria）已被用作许多细胞遗传学研究的材料。其基因组大小估计为8.55 Gb，包含11个常染色体和X染色体。因此，其X 0/XX性染色体决定论导致女性有24条染色体，而男性有23条。令人惊讶的是，人们对这种蝗虫巨大染色体的DNA含量知之甚少。在这里，我们使用Feulgen图像分析密度和C-分带技术，分别估计每一条染色体的DNA量和异染色质含量。我们还确定了三个卫星DNA使用限制性内切酶和下一代测序。然后，我们使用荧光原位杂交，以确定这些卫星DNA的染色体位置，以及6个串联重复DNA基因家族。这项工作中获得的结果的组合允许区分不同的染色体，不仅通过大小，而且通过它们包含的重复DNA的种类。最近发表的飞蝗（Locusta migratoria）基因组草图是迄今为止测序的最大的动物基因组，邀请测序更大的基因组。S.麦地那龙线虫是一种造成严重经济损失的害虫。因此，它是基因组测序的主要候选者之一。但该物种的基因组比L.虽然下一代测序目前允许对大基因组进行测序，但测序将意味着更大的挑战。这里提供的染色体大小和标记不仅有助于计划测序项目和指导组装，而且还有助于将组装的连锁群分配给实际染色体。
The desert locust (Schistocerca gregaria) has been used as material for numerous cytogenetic studies. Its genome size is estimated to be 8.55 Gb of DNA comprised in 11 autosomes and the X chromosome. Its X0/XX sex chromosome determinism therefore results in females having 24 chromosomes whereas males have 23. Surprisingly, little is known about the DNA content of this locust's huge chromosomes. Here, we use the Feulgen Image Analysis Densitometry and C-banding techniques to respectively estimate the DNA quantity and heterochromatin content of each chromosome. We also identify three satellite DNAs using both restriction endonucleases and next-generation sequencing. We then use fluorescent in situ hybridization to determine the chromosomal location of these satellite DNAs as well as that of six tandem repeat DNA gene families. The combination of the results obtained in this work allows distinguishing between the different chromosomes not only by size, but also by the kind of repetitive DNAs that they contain. The recent publication of the draft genome of the migratory locust (Locusta migratoria), the largest animal genome hitherto sequenced, invites for sequencing even larger genomes. S. gregaria is a pest that causes high economic losses. It is thus among the primary candidates for genome sequencing. But this species genome is about 50 % larger than that of L. migratoria, and although next-generation sequencing currently allows sequencing large genomes, sequencing it would mean a greater challenge. The chromosome sizes and markers provided here should not only help planning the sequencing project and guide the assembly but would also facilitate assigning assembled linkage groups to actual chromosomes.