Data from: Phylogeography of a Tertiary relict plant, Meconopsis cambrica (Papaveraceae), implies the existence of northern refugia for a temperate herb

The perennial herb Meconopsis cambrica, a western European endemic, is the only European species of the otherwise Himalayan genus Meconopsis and has been interpreted as a Tertiary relict species. Using rbcL and ITS sequence variation, we date the split between M. cambrica and its sister clade Papaver s.str. to the Middle to Upper Miocene (12.8 My, 6.4-19.2 My HPD). Within M. cambrica, cpDNA sequence variation reveals the existence of two groups of populations with a comparable level of genetic variation: a northern group from Great Britain, the Massif Central, the western Pyrenees and the Iberian System, and a southern group from the central and eastern Pyrenees. Populations from the Cantabrian Mountains were found in both groups. Based on ITS sequence variation, the divergence between these two groups can be dated to 1.5 My (0.4-2.8 My HPD), and the age of the British populations is estimated as 0.37 My (0.0-0.9 My HPD). AFLP results confirm the distinctive nature of the populations from Britain, the Massif Central and the central and eastern Pyrenees. These patterns of latitudinal variation of M. cambrica differ from patterns of longitudinal differentiation found in many other temperate species and imply glacial survival of the northern populations in northerly refugia. The primary differentiation into northern and southern cpDNA groups dates to near the onset of the Quaternary and suggests that an ancient phylogeographic pattern has survived through several glacial periods. Our data provide evidence that the species has persisted for a long period with a highly fragmented and probably very localized distribution.多年生草本植物威尔士绿绒蒿（Meconopsis cambrica）为西欧特有种，是原本仅分布于喜马拉雅地区的绿绒蒿属（Meconopsis）中唯一分布于欧洲的物种，被认定为第三纪残遗物种。借助核酮糖-1,5-二磷酸羧化酶/加氧酶大亚基基因（rbcL）与内部转录间隔区（ITS）序列变异分析，我们推算威尔士绿绒蒿与其姊妹分支狭义罂粟属（Papaver s.str.）的分化时间为中新世中晚期（12.8百万年，最高后验密度区间6.4-19.2百万年）。在威尔士绿绒蒿种群内部，叶绿体DNA（cpDNA）序列变异显示存在两组遗传变异水平相当的种群：一类为分布于英国、中央高原、西比利牛斯山脉与伊比利亚山脉的北部种群，另一类为分布于中比利牛斯与东比利牛斯山脉的南部种群。坎塔布连山脉的种群同时隶属于这两个类群。基于内部转录间隔区序列变异，这两个类群的分化时间可追溯至1.5百万年（最高后验密度区间0.4-2.8百万年），而英国种群的分化时间估算为0.37百万年（最高后验密度区间0.0-0.9百万年）。扩增片段长度多态性（AFLP）分析结果证实，英国、中央高原以及中、东比利牛斯山脉的种群具有独特的遗传特征。威尔士绿绒蒿的这种纬度分化模式与诸多其他温带物种的经度分化模式存在显著差异，这暗示北部种群曾在北方避难所中顺利度过冰期。叶绿体DNA南北类群的分化时间大致对应第四纪的起始阶段，表明这一古老的系统地理格局在多次冰期事件中得以留存。我们的研究数据表明，该物种长期存续，其分布格局高度碎片化且大概率极为局限。