基于基因组大小变异揭示的布氏石竹细胞型的分布与多样性
Distribution and diversity of cytotypes in Dianthus broteri as evidenced by genome size variations.
作者信息
Balao Francisco, Casimiro-Soriguer Ramón, Talavera María, Herrera Javier, Talavera Salvador
机构信息
Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, E-41080 Sevilla, Spain.
出版信息
Ann Bot. 2009 Oct;104(5):965-73. doi: 10.1093/aob/mcp182. Epub 2009 Jul 25.
BACKGROUND AND AIMS
Studying the spatial distribution of cytotypes and genome size in plants can provide valuable information about the evolution of polyploid complexes. Here, the spatial distribution of cytological races and the amount of DNA in Dianthus broteri, an Iberian carnation with several ploidy levels, is investigated.
METHODS
Sample chromosome counts and flow cytometry (using propidium iodide) were used to determine overall genome size (2C value) and ploidy level in 244 individuals of 25 populations. Both fresh and dried samples were investigated. Differences in 2C and 1Cx values among ploidy levels within biogeographical provinces were tested using ANOVA. Geographical correlations of genome size were also explored.
KEY RESULTS
Extensive variation in chromosomes numbers (2n = 2x = 30, 2n = 4x = 60, 2n = 6x = 90 and 2n = 12x =180) was detected, and the dodecaploid cytotype is reported for the first time in this genus. As regards cytotype distribution, six populations were diploid, 11 were tetraploid, three were hexaploid and five were dodecaploid. Except for one diploid population containing some triploid plants (2n = 45), the remaining populations showed a single cytotype. Diploids appeared in two disjunct areas (south-east and south-west), and so did tetraploids (although with a considerably wider geographic range). Dehydrated leaf samples provided reliable measurements of DNA content. Genome size varied significantly among some cytotypes, and also extensively within diploid (up to 1.17-fold) and tetraploid (1.22-fold) populations. Nevertheless, variations were not straightforwardly congruent with ecology and geographical distribution.
CONCLUSIONS
Dianthus broteri shows the highest diversity of cytotypes known to date in the genus Dianthus. Moreover, some cytotypes present remarkable internal genome size variation. The evolution of the complex is discussed in terms of autopolyploidy, with primary and secondary contact zones.
背景与目的
研究植物细胞型和基因组大小的空间分布可为多倍体复合体的进化提供有价值的信息。在此，对具有多个倍性水平的伊比利亚石竹——布氏石竹的细胞学类群的空间分布和DNA含量进行了研究。
方法
采用样本染色体计数和流式细胞术（使用碘化丙啶）来测定25个种群的244个个体的整体基因组大小（2C值）和倍性水平。对新鲜和干燥样本均进行了研究。使用方差分析检验生物地理省内倍性水平之间2C和1Cx值的差异。还探讨了基因组大小的地理相关性。
主要结果
检测到染色体数目存在广泛变异（2n = 2x = 30、2n = 4x = 60、2n = 6x = 90和2n = 12x = 180），并且该属中首次报道了十二倍体细胞型。关于细胞型分布，六个种群为二倍体，11个为四倍体，三个为六倍体，五个为十二倍体。除了一个包含一些三倍体植株（2n = 45）的二倍体种群外，其余种群均表现为单一细胞型。二倍体出现在两个不连续的区域（东南部和西南部），四倍体也是如此（尽管地理范围要宽得多）。脱水叶片样本提供了可靠的DNA含量测量值。基因组大小在一些细胞型之间存在显著差异，在二倍体种群（高达1.17倍）和四倍体种群（1.22倍）内也有广泛差异。然而，这些变异与生态和地理分布并非直接一致。
结论
布氏石竹表现出石竹属迄今为止已知的最高细胞型多样性。此外，一些细胞型呈现出显著的内部基因组大小变异。从同源多倍体以及初级和次级接触区的角度讨论了该复合体的进化。
Zotero 插件