Genetic structure and phylogeography in Juniperus oxycedrus subsp. macrocarpa around the Mediterranean and Atlantic coasts of the Iberian Peninsula, based on AFLP and plastid markers

Abstract

The Spanish populations of Juniperus oxycedrus subsp. macrocarpa are restricted to coastal dune habitats of the Mediterranean and Atlantic coasts. Here, we investigate the genetic structure in this taxon and the possible existence of detailed phylogeographic structure associated with the Strait of Gibraltar using data from amplified fragment length polymorphism (AFLP) and plastid markers for 14 populations in three regions: Andalusia, the Valencian Community and the Balearic Islands. Principal coordinate analysis (PCOA) data revealed a lack of clear genetic structure in J. oxycedrus subsp. macrocarpa based on AFLP. The highest AFLP genetic diversity was found in Andalusia. Plastid markers revealed 14 haplotypes, only two of them were shared among the regions. Andalusian populations had the highest number of exclusive haplotypes. Our results support Andalusia as a reservoir of genetic diversity for J. oxycedrus subsp. macrocarpa, and, as for other gymnosperms, this area could be considered as a genetic refugium. The frequent presence of common and exclusive haplotypes in Andalusia might indicate the colonisation of the Spanish Mediterranean coast from the Atlantic populations. Colonisation of these new areas could be promoted by biological factors, such as the existence of long-lived individuals or potential for seed dispersal. Finally, the Strait of Gibraltar did not constitute a natural barrier to the expansion of this species along the coast, as identical haplotypes are found on the Atlantic and Mediterranean coasts.

Balearic insular isolation and large continental spread framed the phylogeography of the western Mediterranean Cheirolophus intybaceus s.l. (Asteraceae)

“…This scenario is consistent with northwards dispersion routes across the Iberian Peninsula proposed for other plants and animals (De Jong 1998; Sanmartín 2003; Pérez‐Collazos et al. 2009; Juan et al. 2011).…”

The biogeography and genetic relationships ofJuniperus oxycedrusand related taxa from the Mediterranean and Macaronesian regions

“…Nevertheless, the levels of genetic diversity and differentiation detected in our study were similar to those described recently when SSR markers were used in J. excelsa (Douaihy et al ., ), isoenzymes were used in J. phoenicea L. (Boratyński et al ., ) and inter simple sequence repeat (ISSR) and random amplification of polymorphic DNA (RAPD) were used in J. brevifolia (Silva et al ., ). However, the genetic diversity and differentiation were higher than those for amplified fragment length polymorphism (AFLP) for J. thurifera L. (Terrab et al ., ) and J. macrocarpa (Juan et al ., ) and RAPD for J. phoenicea (Dzialuk et al ., ). A planted population of J. cedrus showed relatively high genetic variability ( H E = 0.459), but the considerable excess of homozygotes, despite the lack of null alleles, indicates that the seeds used for establishment purposes were collected from a limited number of mother trees.…”

“…Junipers are keystone species of Mediterranean arid and semi‐arid ecosystems, and are essential components of the high biodiversity and endemism noted in this part of the world (Greuter, Burdet & Lang, ; Farjon, ; Adams, ). However, the current rate of human‐induced environmental alterations and concomitant climate changes may threaten the long‐term persistence of some juniper species in the near future (Castro et al ., ; Douaihy et al ., ; Juan et al ., ). This situation exemplifies the general concerns about the future of the entire Mediterranean biome, which is assumed to be highly vulnerable to global environmental changes (Petit, Hampe & Cheddadi, ).…”

North‐south population subdivision of Juniperus seravschanica in Kyrgyzstan revealed through novel plastid DNA markers

“…This geographic pattern of genetic variation supports the scenario of postglacial spread from the south to the north (Petit et al, 2003). On the regional level, Juniperus species with similar ecology often exhibit low levels of population differentiation following postglacial range expansion (e.g., Guo et al, 2010; Juan et al, 2012). With the applied highly polymorphic minisatellite markers, we were able to identify landscape effects at the regional level.…”

“…In the present study, we focus on plastid DNA, which is putatively paternally inherited in junipers (Provan et al, 2008). Plastid DNA has already been used to characterize genetic diversity and population structure in other Juniperus species in Asia (Zhang et al, 2005; Guo et al, 2010; Opgenoorth et al, 2010) and Europe (Provan et al, 2008; Juan et al, 2012). Here, we investigate the population history of J. seravschanica as a model for the juniper forest community in the region in order to assess hypotheses regarding the spread of the species after the LGM, and to characterize patterns of genetic diversity, population differentiation, and gene flow in the species.…”