Ancient split of major genetic lineages of European Black Pine: evidence from chloroplast DNA

Abstract

International audienceThe European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260, 000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (Nst > Gst) typ- ically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The labora- tory analysis was performed by fragment analysis—i.e. elec- trophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individ- uals as a control. Intense sampling of chloroplast DNA poly- morphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (Gst(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration his- tories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest com- munity associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia

Geographically Related Variation in Epicuticular Wax Traits of Pinus nigra Populations from Southern Carpathians and Central Balkans – Taxonomic Considerations

“…dalmatica and transitional population between them). All these results support the fact the Balkan Peninsula was one of the main hotspots of diversity of coniferous taxa in Europe, primarily because of its role as refugium during Pleistocene ice ages .…”

“…However, if we accept the recent concept (based on chloroplast DNA markers), proposed by Naydenov et al . , who identified three differentiated genetic formations consisted with European Black Pine's natural geographic distribution (Westerns Mediterranean, the Balkan Peninsula and Asia Minor), all the populations analyzed in this study belong to the Balkan Peninsula group. Even in this case, it is obvious from the data shown here that considerable variability and differentiation of the populations exists, and these populations could be delineated as different infraspecific taxa.…”

The genetic structure of the European black pine (Pinus nigraArnold) is shaped by its recent Holocene demographic history

“…Focusing on Western Europe, they were able to identify five barriers to gene flow including, similarly to ours, between the Alps and the Calabria -Corsica 3 7 5 group, between Corsica and Southern France and between Southern Spain and the Pyrenees. However, our results strongly depart from those of Naydenov et al (2016Naydenov et al ( , 2017 who identified three genetic groups from three different geographical areas: Western Mediterranean, Balkan Peninsula and Eastern Mediterranean. They estimated their most recent common ancestor to be older than 10 million years and dated the most recent splits between groups in the late Pliocene.…”

“…We sampled natural populations across the entire range of the species. We discuss why our results differ from, or concur with, the few previous molecular studies carried out at a similar scale on this species (Nikolić & Tucić 1983;Naydenov et al, 2016;Rafii & Dodd 2007). We also considered how habitat suitability might have affected demography by correlating climate variables at different Pleistocene ages with genetic diversity estimates under the assumption that harsher climate conditions 1 1 5 and thus declining habitat suitability, would produce demographic contractions with observable signatures in the genetic data (Conord et al, 2012).…”

“…The population genetic pattern of the Pinus nigra biogeographical islands of today (particularly at the southern and western edges of the species) should thus be the result of relatively recent fragmentation. 9 5 Figure 1: Native geographic distribution area of Pinus nigra (in blue, from Isajev et al, 2004) (Naydenov et al, 2016;.…”