RIBOSOMAL DNA DISTRIBUTION AND A GENUS-WIDE PHYLOGENY REVEAL PATTERNS OF CHROMOSOMAL EVOLUTION IN ALSTROEMERIA (ALSTROEMERIACEAE)
RIBOSOMAL DNA DISTRIBUTION AND A GENUS-WIDE PHYLOGENY REVEAL PATTERNS OF CHROMOSOMAL EVOLUTION IN ALSTROEMERIA (ALSTROEMERIACEAE)
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DOI：
10.3732/ajb.1200104
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发表时间：
2012-09-01
影响因子：
3
通讯作者：
Renner, Susanne S.
中科院分区：
文献类型：
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作者：
Chacon, Juliana;Sousa, Aretuza;Renner, Susanne S.
这项研究的前提是：了解单子叶植物基因组的灵活性需要一个系统发育框架，到目前为止，只有少数几个单子叶植物基因组具有系统发育框架。2800个属。在这里，我们使用一个分子树为南美洲属Alstroemeria放置核型信息，包括荧光原位杂交（FISH）信号，在一个明确的进化背景。从基于大多数Alstroemeria物种的质体，核和线粒体序列的同源性，我们选择了早期分支（智利）和衍生（巴西）种，我们获得了18 S-25 S和5S rDNA FISH信号;我们还分析了染色体数目、1C值和端粒FISH信号（在两个物种中）。rupestris和A. pulchella证实2n = 16是该属的典型特征，该属78种中有29种的染色体计数。rDNA位点在种间和种内均表现出多态性，Alstroemeria cf.结论：尽管染色体数目恒定，但近缘种的rDNA差异很大，表明这些基因的快速增加、减少或易位。先前提出的巴西和智利核型组不是自然的，并且Alstroemeria中的n = 8染色体与其姐妹属Bomarea中的n = 9染色体相比可能来自罗伯逊融合。
Premise of the study: Understanding the flexibility of monocot genomes requires a phylogenetic framework, which so far is available for few of the ca. 2800 genera. Here we use a molecular tree for the South American genus Alstroemeria to place karyological information, including fluorescent in situ hybridization (FISH) signals, in an explicit evolutionary context.Methods: From a phylogeny based on plastid, nuclear, and mitochondrial sequences for most species of Alstroemeria, we selected early-branching (Chilean) and derived (Brazilian) species for which we obtained 18S-25S and 5S rDNA FISH signals; we also analyzed chromosome numbers, 1C-values, and telomere FISH signals (in two species).Key results: Chromosome counts for Alstroemeria cf. rupestris and A. pulchella confirm 2n = 16 as typical of the genus, which now has chromosomes counted for 29 of its 78 species. The rDNA sites are polymorphic both among and within species, and interstitial telomeric sites in Alstroemeria cf. rupestris suggest chromosome fusion.Conclusions: In spite of a constant chromosome number, closely related species of Alstroemeria differ drastically in their rDNA, indicating rapid increase, decrease, or translocations of these genes. Previously proposed Brazilian and Chilean karyotype groups are not natural, and the n = 8 chromosomes in Alstroemeria compared to n = 9 in its sister genus Bomarea may result from a Robertsonian fusion.