Chloroplast DNA phylogeography of the arctic-montane species Saxifraga hirculus (Saxifragaceae)

Abstract

The genetic structure of populations of an arctic-montane herb, Saxifraga hirculus (Saxifragaceae), was analysed by means of chloroplast restriction fragment-length polymorphism. Sampled populations were distributed across Europe and North America (Alaska and Colorado). There was no evidence for geographically structured genetically divergent lineages, and although no haplotypes were shared between North America and Europe, the haplotypes from different continents were intermixed on a minimum spanning tree. European populations were much more highly differentiated and had much lower levels of haplotype diversity than their Alaskan counterparts. Centres of haplotype diversity were concentrated in those Alaskan populations located outside the limits of the last (Wisconsin) glaciation, suggesting that they may have acted as refugia during the Pleistocene. It was not possible to identify putative migration routes or corresponding refugia in the European genepool. One British population, from the Pentland Hills, was genetically very distant from all the others, for reasons that are as yet unknown.

The evolutionary history of the Arabidopsis lyrata complex: a hybrid in the amphi-Beringian area closes a large distribution gap and builds up a genetic barrier

“…[32], Saxifraga hirculus L. [36], Saxifraga oppositifolia [33,31], and Vaccinium uliginosum L. [35,101]. Periglacial survival in Beringia can also be assumed for the A. lyrata complex, in particular, for the Eurasian lineage in arctic western and eastern Beringia north of Brooks Range.…”

“…ex DC.) K. Shimizu & Kudoh, an amphi-Beringian member of the A. lyrata complex; (3) Explaining Pleistocene and postglacial migration routes by analysing genetic diversity statistics: The arctic-alpine A. lyrata complex is one of the rare examples among higher plants with a distribution in both Central Europe and North America and, additionally, a circumpolar distribution - other examples are Cassiope tetragona [30], and Saxifraga oppositifolia [31]; and (4) Studying the role of Beringia as a refugia for populations of arctic A. lyrata , since Beringia is assumed to be one of the major refugia for arctic plants during Pleistocene glaciations [30-36]. …”

On the Evolutionary and Biogeographic History of Saxifraga sect. Trachyphyllum (Gaud.) Koch (Saxifragaceae Juss.)

“…Because Saxifraga has a primarily arctic-alpine distribution and those regions are dramatically impacted by climatic variability [1], saxifrages are excellent organisms for investigating biotic responses to climate change. Studies on a suite of saxifrages have helped to develop the roles that geographic isolation and dispersal have played in the process of speciation [2], [3], [4], [5]. Indeed, in depth studies concerning the evolutionary history of S. oppositifolia L. [6], [7], [8] serve as a foundation for how arctic-alpine plants have responded to the climatic shifts of the Quaternary.…”

Variabilidade no cpDNA em Manilkara huberi, espécie sob manejo sustentável na Amazônia brasileira

“…Grande parte dos estudos tem se baseado no método de PCR-RFLP, com base em iniciadores universais que permitem a análise de toda a molécula de cpDNA (Caron et al, 2000;Fineschi et al, 2000;Prentice et al, 2003;Oliver et al, 2006). Entretanto, novos estudos vêm surgindo, os quais têm se baseado em análises de polimorfismos de cpSSR universais ou seqüenciamento de regiões intergênicas (Collevatti et al, 2003;Lian et al, 2003;Lira et al, 2003;Martins et al, 2006;McGrath et al, 2007).…”