Reduction of chromosome number in Eleocharis subarticulata (Cyperaceae) by multiple translocations
Reduction of chromosome number in Eleocharis subarticulata (Cyperaceae) by multiple translocations
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DOI：
10.1111/j.1095-8339.2005.00449.x
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发表时间：
2005-12-01
影响因子：
2.4
通讯作者：
Vanzela, ALL
中科院分区：
文献类型：
--
作者：
Da Silva, CRM;González-Elizondo, MS;Vanzela, ALL
马蹄（Eleocharis subarticulata）是莎草科染色体数目减少的第三个种（n = 3），仅次于细喙藓（Rhynchospora tenuis）（n = 2）和伞形飘拂草（Fimbristylis umbellaris）（n = 3）。对于Eleocharis，迄今为止记录的数量从2n = 10到2n = c不等。196，x = 5作为可能的基数。E.采用常规染色（有丝分裂和减数分裂）、C-CMA（3）/DAPI显带、45 SrDNA和端粒探针FISH等方法对subarticulata的染色体进行了研究。染色体没有初级缢痕，正如莎草科全着丝粒染色体所预期的那样。减数分裂行为是异常的，在中期I的6条染色体的一个单一的多价环，导致多易位。在后期I六个染色单体迁移到每一极，证明了反向减数分裂，这些群体在中期II也可见。C-CMA（3）/DAPI显带技术仅显示4个末端GC富集区。FISH与45 S rDNA探针揭示了四个终端信号，可能与GC丰富的块。端粒探针定位在所有染色体的末端信号，除了在中间的大对杂交位点。异位端粒位点的发生以前没有被描述为全动染色体核型和染色体数目减少的植物。这些数据加强了多重易位染色体数目减少的假设。(c)2005年，林奈学会伦敦，林奈学会植物学杂志。
Eleocharis subarticulata is recorded as the third species of Cyperaceae with a reduced chromosome number (n = 3), following reports on Rhynchospora tenuis (n = 2) and Fimbristylis umbellaris (n = 3). For Eleocharis, the numbers recorded to date vary from 2n = 10 to 2n = c. 196, with x = 5 as the possible basic number. The karyotype of E. subarticulata was studied using conventional staining (mitosis and meiosis), C-CMA(3)/DAPI banding, and FISH with 45S rDNA and telomere probes. The chromosomes showed no primary constrictions, as expected in the holocentric chromosomes of Cyperaceae. The meiotic behaviour was abnormal, with a single multivalent ring of six chromosomes at metaphase I, resulting from multiple translocations. At anaphase I six chromatids migrated to each pole, evidencing the inverted meiosis, and these groups were also visible at metaphase II. The C-CMA(3)/DAPI banding technique showed only four terminal GC-rich blocks. FISH with 45S rDNA probes revealed four terminal signals, probably associated with GC-rich blocks. The telomeric probe located terminal signals in all the chromosomes, besides a hybridization site in the middle of the large pair. The occurrence of ectopic telomeric sites has not been described previously for plants with holokinetic karyotypes and with reduced chromosome numbers. These data reinforce the hypothesis of the reduction in chromosome number by multiple translocations. (c) 2005 The Linnean Society of London, Botanical Journal of the Linnean Society.