Genome size and endonuclear DNA replication in spiders
Genome size and endonuclear DNA replication in spiders
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DOI：
10.1002/jmor.10352
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发表时间：
2005-08-01
影响因子：
1.5
通讯作者：
Connelly, BA
中科院分区：
文献类型：
--
作者：
Rasch, EM;Connelly, BA
尽管现在可获得115种蛛形纲动物的基因组大小（C值）（Gregory和Short-house [2003] J赫雷德94：285-290），但在这一多样且丰富的无脊椎动物类别中伴随组织分化的基因组扩增（endoscopic DNA复制或多倍化）的程度仍然未知。为了探索这方面的蜘蛛的发展，血淋巴和其他组织的样品从野生捕获的标本作为风干涂片，染色与DNA的Feulgen反应，并使用扫描和图像分析密度测定法进行分析。来自金蛛和狼蛛（=豹蛛）中肠憩室和马氏管的细胞经常显示巨大的核，每个核含有50-100 pg的DNA，与来自同一标本的血细胞或精子的DNA含量相比，反映了至少四个循环的内分泌DNA复制。细胞核的DNA水平显着升高也出现了，但频率低得多，从其他几个蛛形纲动物物种（Antrodiaetus，Hypochilus，Latrodectus，Liphistus和Loxosceles）的组织样本，但没有发现与体细胞（2C）基因组大小的差异相关。我们的数据表明，几个DNA类的多体细胞核定期出现在某些物种的蜘蛛组织分化过程中，并可能提供一个有趣的模型系统，为进一步研究的模式，在发育过程中的DNA核内复制的组织特异性变化。
Although genome sizes (C-values) are now available for 115 arachnid species (Gregory and Short-house [2003] J Hered 94:285-290), the extent of genome amplification (endonuclear DNA replication or polyploidization) accompanying tissue differentiation in this diverse and abundant class of invertebrates remains unknown. To explore this aspect of arachnid development, samples of hemolymph and other tissues were taken from wild-caught specimens as air-dried smears, stained with the Feulgen reaction for DNA, and assayed using both scanning and image analysis densitometry. Cells from midgut diverticula and Malpighian tubules of Argiope and Lycosa (=Pardosa) often showed giant nuclei with 50-100 pg of DNA per nucleus, reflecting at least four cycles of endonuclear DNA replication when compared to the DNA content of hemocytes or sperm from the same specimen. Nuclei with markedly elevated DNA levels also appeared, but far less frequently, in tissue samples from several other arachnid species (Antrodiaetus, Hypochilus, Latrodectus, Liphistus and Loxosceles), but revealed no correlation with differences in somatic cell (2C) genome sizes. Our data show that several DNA classes of polysomatic nuclei regularly arise during tissue differentiation in some species of spiders and may provide an interesting model system for further study of patterns of tissue-specific variation in DNA endoreduplication during development.