Departamentos de Genética y de Botánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
Ann Bot. 2013 Dec;112(9):1793-802. doi: 10.1093/aob/mct233. Epub 2013 Oct 29.
Subtribe Centaureinae appears to be an excellent model group in which to analyse satellite DNA and assess the influence that the biology and/or the evolution of different lineages have had on the evolution of this class of repetitive DNA. Phylogenetic analyses of Centaureinae support two main phases of radiation, leading to two major groups of genera of different ages. Furthermore, different modes of evolution are observed in different lineages, reflected by morphology and DNA sequences.
The sequences of 502 repeat units of the HinfI satellite DNA family from 38 species belonging to ten genera of Centaureinae were isolated and compared. A phylogenetic reconstruction was carried out by maximum likelihood and Bayesian inference.
Up to eight different HinfI subfamilies were found, based on the presence of a set of diagnostic positions given by a specific mutation shared by all the sequences of one group. Subfamilies V-VIII were mostly found in older genera (first phase of radiation in the subtribe, late Oligocene-Miocene), although some copies of these types of repeats were also found in some species of the derived genera. Subfamilies I-IV spread mostly in species of the derived clade (second phase of radiation, Pliocene to Pleistocene), although repeats of these subfamilies exist in older species. Phylogenetic trees did not group the repeats by taxonomic affinity, but sequences were grouped by subfamily provenance. Concerted evolution was observed in HinfI subfamilies spread in older genera, whereas no genetic differentiation was found between species, and several subfamilies even coexist within the same species, in recently radiated groups or in groups with a history of recurrent hybridization of lineages.
The results suggest that the eight HinfI subfamilies were present in the common ancestor of Centaureinae and that each spread differentially in different genera during the two main phases of radiation following the library model of satellite DNA evolution. Additionally, differential speciation pathways gave rise to differential patterns of sequence evolution in different lineages. Thus, the evolutionary history of each group of Centaureinae is reflected in HinfI satellite DNA evolution. The data reinforce the value of satellite DNA sequences as markers of evolutionary processes.
在分析卫星 DNA 并评估不同谱系的生物学和/或进化对这一类重复 DNA 的进化的影响方面，Centaureinae 亚族似乎是一个极好的模型群体。对 Centaureinae 的系统发育分析支持两个主要辐射阶段，导致两个不同年龄的主要属群。此外，不同的进化模式在不同的谱系中观察到，反映在形态和 DNA 序列上。
从 Centaureinae 的十个属的 38 种属中分离并比较了 HinfI 卫星 DNA 家族的 502 个重复单位的序列。通过最大似然法和贝叶斯推断进行了系统发育重建。
根据一组特定突变在一组序列中共有的一组诊断位置，发现了多达 8 种不同的 HinfI 亚家族。亚家族 V-VIII 主要存在于较老的属中（亚族的第一个辐射阶段，晚始新世-中新世），尽管在一些衍生属的一些物种中也发现了这些类型的重复。亚家族 I-IV 主要分布在衍生支系的物种中（第二辐射阶段，上新世至更新世），尽管在较老的物种中也存在这些亚家族的重复。系统发育树没有根据分类亲缘关系对重复序列进行分组，而是根据亚家族来源对序列进行分组。在较老的属中观察到 HinfI 亚家族的协同进化，而在物种之间没有发现遗传分化，并且在最近辐射的群体或具有谱系反复杂交历史的群体中，甚至存在几个亚家族共存。
结果表明，HinfI 亚家族在 Centaureinae 的共同祖先中存在，并且在两个主要辐射阶段之后，在不同的属中以不同的方式扩散，遵循卫星 DNA 进化的文库模型。此外，不同的物种形成途径导致不同谱系的序列进化模式不同。因此，每个 Centaureinae 亚族的进化历史都反映在 HinfI 卫星 DNA 的进化中。这些数据强化了卫星 DNA 序列作为进化过程标记的价值。
