Departamento de Agricultura (Botánica), Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, Ctra. Cuarte km 1, 22071 Huesca, Spain.
Mol Ecol. 2012 Apr;21(7):1702-26. doi: 10.1111/j.1365-294X.2012.05495.x. Epub 2012 Feb 21.
Studying the biogeography and the phylogeography of the endemic Macaronesian red Festuca species (Loliinae, Poaceae) is of prime interest in understanding the speciation and colonization patterns of recently evolved groups in oceanic archipelagos. Coalescence-based analyses of plastid trnLF sequences were employed to estimate evolutionary parameters and to test different species-history scenarios that model the pattern of species divergence. Bayesian IM estimates of species divergence times suggested that ancestral lineages of diploid Macaronesian and Iberian red fescues could have diverged between 1.2 and 1.57 Ma. When empirical data were compared to coalescence-based simulated distributions of discordance and p-distance statistics, two species-history models were chosen in which the first branching lineage derived in Canarian Festuca agustinii. Its sister lineage could have involved a recent polytomy leading to the Madeiran Festuca jubata, the Azorean Festuca francoi + Festuca petraea and the continental Festuca rivularis lineages (Canarian model) or the sequential branching of lineages leading to F. jubata and finally to the sister clades of F. rivularis and F. francoi + F. petraea (Sequential model). Nested clade phylogeographic analysis (NCPA) and a first adapted host-parasite co-evolutionary ParaFit method were used to detect the phylogeographic signal. NCPA inferred long-distance colonizations for the entire diploid red Festuca complex, but allopatric-fragmentation and isolation-by-distance (IBD) patterns were inferred within archipelagos. In addition, the ParaFit method suggested a generalized pattern of a stepping-stone model at all hierarchical levels. Maximum-likelihood-based dispersal-extinction-cladogenesis (DEC) models were superimposed on the Sequential model species tree. The three-independent-colonization (3IC) model was the best supported biogeographic scenario, concurring with previous analysis based on multilocus AFLP data.
研究特有马卡罗内西亚红羊茅物种（Lolinae，禾本科）的生物地理学和系统地理学，对于理解海洋群岛中新进化群体的物种形成和殖民模式至关重要。基于合并的叶绿体 trnLF 序列分析来估计进化参数，并测试不同的物种历史情景模型，以模拟物种分化模式。贝叶斯 IM 估计的物种分歧时间表明，二倍体马卡罗内西亚和伊比利亚红羊茅的祖先谱系可能在 1.2 到 1.57 Ma 之间分化。当将经验数据与基于合并的不和谐和 p 距离统计的模拟分布进行比较时，选择了两个物种历史模型，其中第一个分支谱系起源于加那利群岛的羊茅。其姐妹谱系可能涉及最近的多分支，导致马德拉岛的羊茅、亚速尔群岛的羊茅弗朗西奥+羊茅皮特亚和大陆的羊茅里维拉利谱系（加那利群岛模型）或谱系的顺序分支导致 F. jubata 和最终 F. rivularis 和 F. francoi+F. petraea 的姐妹分支（顺序模型）。嵌套分支系统地理学分析（NCPA）和第一个适应的宿主-寄生虫共同进化 ParaFit 方法用于检测系统地理学信号。NCPA 推断整个二倍体红羊茅复合体的远距离殖民，但在群岛内推断出了异域-片段化和隔离距离（IBD）模式。此外，ParaFit 方法在所有层次水平上都表明了一个阶段性模型的一般模式。基于最大似然的扩散-灭绝-分支发生（DEC）模型被叠加在顺序模型物种树上。3IC 模型是最支持的生物地理情景，与之前基于多位点 AFLP 数据的分析一致。
