Heuertz M, Carnevale S, Fineschi S, Sebastiani F, Hausman J F, Paule L, Vendramin G G
Centre de Recherche Public-Gabriel Lippmann, CREBS Research Unit, 41 rue du Brill, L-4422 Belvaux, Luxembourg.
Mol Ecol. 2006 Jul;15(8):2131-40. doi: 10.1111/j.1365-294X.2006.02897.x.
We investigated range-wide phylogeographic variation in three European ash species (Fraxinus sp., Oleaceae). Chloroplast DNA (cpDNA) microsatellites were typed in the thermophilous Fraxinus angustifolia and Fraxinus ornus and the observed haplotypes and the geographic distribution of diversity were compared to cpDNA data previously obtained in the more cold-tolerant Fraxinus excelsior. We found wide-ranging haplotype sharing between the phylogenetically close F. angustifolia and F. excelsior, suggesting hybridization (i) in common glacial refuges in the Iberian Peninsula, northern Italy, the eastern and/or Dinaric Alps and the Balkan Peninsula, and/or (ii) during postglacial recolonization. The data allowed us to propose additional glacial refuges for F. angustifolia in southern Italy and in Turkey, and populations from the latter region were particularly polymorphic. There was evidence for refuge areas in Italy, the Balkan Peninsula and Turkey for F. ornus, which did not share any single chloroplast haplotype with the other species. In both F. angustifolia and F. ornus, cpDNA diversity (h(S) = 0.027 and h(S) = 0.009, respectively) was lower and fixation levels (G(ST) = 0.964 and G(ST) = 0.983, respectively) higher than in sympatric F. excelsior (h(S) = 0.096, G(ST) = 0.870). These diversity patterns could be due to temperature tolerance or the demographic history.
我们研究了三种欧洲白蜡树属物种（木犀科白蜡树属）在整个分布范围内的系统地理学变异。对喜温的窄叶白蜡树和牛筋条白蜡树的叶绿体DNA（cpDNA）微卫星进行了分型，并将观察到的单倍型和多样性的地理分布与之前在更耐寒的欧洲白蜡树中获得的cpDNA数据进行了比较。我们发现，系统发育关系较近的窄叶白蜡树和欧洲白蜡树之间存在广泛的单倍型共享，这表明（i）在伊比利亚半岛、意大利北部、东部和/或迪纳拉阿尔卑斯山以及巴尔干半岛的共同冰川避难所中发生了杂交，和/或（ii）在冰期后重新定殖期间发生了杂交。这些数据使我们能够提出意大利南部和土耳其为窄叶白蜡树的额外冰川避难所，并且来自后一地区的种群特别多态。有证据表明，牛筋条白蜡树在意大利、巴尔干半岛和土耳其存在避难区，它与其他物种没有共享任何单一的叶绿体单倍型。在窄叶白蜡树和牛筋条白蜡树中，cpDNA多样性（分别为h(S)=0.027和h(S)=0.009）低于同域分布的欧洲白蜡树（h(S)=0.096），固定水平（分别为G(ST)=0.964和G(ST)=0.983）高于欧洲白蜡树（G(ST)=0.870）。这些多样性模式可能是由于温度耐受性或种群统计学历史造成的。
