Genetic structuring in three closely related circumpolar plant species: AFLP versus microsatellite markers and high-arctic versus arctic–alpine distributions

Abstract

Genetic structuring in response to the glacial cycles has been investigated for many plant species, but exclusively high-arctic ones have not been studied. Such extremely coldadapted species have probably experienced range reductions under the present climate. Here we compare three predominantly selfing species of Draba with different distributions and hardiness (D. subcapitata, high-arctic; D. nivalis, arctic to arctic-alpine; D. fladnizensis, arcticalpine) for genetic structuring on the basis of two different types of molecular markers (10 microsatellite loci and 160 amplified fragment length polymorphisms (AFLPs)). The degree of genetic structuring within these species is of particular interest because it has been shown that they contain many cryptic biological species. The high-arctic D. subcapitata had less phylogeographic structure, less diversity and fewer private alleles than the other two species, suggesting that long-distance dispersal may occur more frequently in the high arctic, that hardy plants may have higher probability for establishment after dispersal under high-arctic conditions and that high-arctic species may have experienced a bottleneck during the present interglacial. In contrast, D. fladnizensis and D. nivalis showed distinct phylogeographic structure and more diversity, suggesting separate long-term refugia in Eurasia and North America/Beringia. The AFLP markers revealed more phylogeographic structuring than the microsatellites, possibly because of the higher number of loci surveyed and/or because structure at very large geographic scales is blurred by high mutation rate leading to homoplasy at microsatellite loci. The number of genetic groups detected was in any case insignificant compared with the numerous cryptic biological species known within these species, supporting rapid development of sterility barriers.

Pheno-morphological variation, genetic diversity and population structure of Tunisian Echinus Medic (Medicago ciliaris L.)

“…Herein, the two primer combinations used revealed a high number of AFLP fragments per primer combination and per population; which is superior to the results previously cited and to those reported by Elazreg et al (2011). This permitted us to assess the level of genetic polymorphism and to analyze the genetic structure of these M. ciliaris populations, consistent with previous studies of genetic diversity in closely related species carried out over different geographic ranges using AFLP molecular markers (Skrede et al, 2009;Keivani et al, 2011).…”

Molecular Variation and Phylogeography of the Moss Campion Silene Acaulis (L.) Jacq. (Caryophyllaceae) in the North of Europe and the Svalbard Archipelago

“…Уровень внутрипопуляционного генетического раз-нообразия у Silene acaulis (0,06-0,19) сходен и даже превышает таковой у ряда арктических растений, таких как Draba fladnizensis 0,02-0,11, D. nivalis 0,01-0,11 (Skrede et al, 2009), Arabis alpina 0-0,108 и Cassiope tetragona 0,068-0,126 (Eidessen et al, 2007-b). Оценки генетического разнообразия Silene acaulis в Европе, полученные по аллозимным маркерам, выявили полиморфизм по 90 % локусов по сравнению с 50 % типичными для растений в среднем (Abbot et al, 1995).…”

“…2, 3). Такой паттерн наблюдается и у ряда других аркто-альпийских видов: Dryas octopetala (Skrede et al, 2006), Vaccinium uliginosum (Eidesen et al, 2007, Draba fladnizensis (Skrede et al, 2009). Монтанная группа оказывается неоднородна, и, в свою очередь, ее можно разделить.…”

Genetic diversity and sexual reproduction in relict populations of Betula nana

“…In turn, AFLPs were most variable in IZER and least variable in LIN. Diversity patterns obtained by microsatellite and AFLP systems were also poorly correlated at the population level in Pinus pinaster Aiton (Mariette et al 2001), Eryngium alpinum L. (Gaudeul et al 2004) and three Draba species (Skrede et al 2009). Mariette et al (2002) and Gaudeul et al (2004) stated that lack of congruence between different molecular markers could result from uneven coverage of a genome by different marker systems, the differences in mutation rate of microsatellites and AFLPs, low heterogeneity of populations for their diversity and recently created populations.…”