16 research outputs found
High genetic diversity with moderate differentiation in Juniperus excelsa from Lebanon and the eastern Mediterranean region
Juniperus excelsa constitutes a precious woody species of high ecological value able to grow up to Mountain treeline around the Mediterranean. Nuclear microsatellites were used to shed light on genetic diversity and differentiation of different Mediterranean populations. This information is essential in planning conservation strategies and reforestation programs
Late Neogene history of the laurel tree (Laurus L., Lauraceae) based on phylogeographical analyses of Mediterranean and Macaronesian populations
Aim The post-glacial range dynamics of many European plant species have been
widely investigated, but information rapidly diminishes as one moves further
back in time. Here we infer the historical range shifts of Laurus, a paradigmatic
tree of the Tethyan flora that has covered southern Eurasia since the
Oligo-Miocene, by means of phylogenetic and phylogeographical analyses.
Location Mediterranean Basin, Black Sea and Macaronesian archipelagos
(Azores, Madeira, Canary Islands).
Methods We analysed plastid DNA (cpDNA) sequence (trnK–matK, trnD–trnT)
variation in 57 populations of Laurus and three Lauraceae genera. Phylogenetic
methods (maximum parsimony and Bayesian inference) and statistical parsimony
networks were used to reconstruct relationships among haplotypes. These results
were contrasted with the fossil record and bioclimatic niche-based model
predictions of past distributions to infer the migration routes and location of
refugia.
Results The phylogenetic tree revealed monophyly for Laurus. Overall sequence
variability was low within Laurus, but six different haplotypes were distinguished
and a single network retrieved, portraying three lineages primarily related to
geography. A strongly divergent eastern lineage occupied Turkey and the Near
East, a second clade was located in the Aegean region and, lastly, a western clade
grouped all Macaronesian and central and western Mediterranean populations.
A close relationship was observed between the Macaronesian populations of
L. azorica and the western populations of L. nobilis.
Main conclusions The phylogeographical structure of Laurus preserves the
imprints of an ancient contraction and break-up of the range that resulted in the
evolution of separate cpDNA lineages in its western- and easternmost extremes.
Intense range dynamics in the western Mediterranean and multiple glacial refugia
contributed to the generation and long-term conservation of this phylogeographical
pattern, as shown by the fit between the haplotype ranges and
past suitable areas inferred from bioclimatic models. Finally, our results challenge
the taxonomic separation of Laurus into two distinct species