Patterns ofmtDNA variation reveal complex evolutionary history of relict and endangered peat bog pine (Pinus uliginosa)

Abstract

Estimates of genetic differentiation at intra- and interspecific level are often hindered by the lack of suitable molecular markers. Low phylogeographic resolution limits development of appropriate conservation strategies especially in case of endangered forest tree species with small and disjunct distribution. In this study, we assessed fine-scale genetic structure of relict and endangered peat bog pine ( Pinus uliginosa ) and two other closely related European pine species ( Pinus mugo and Pinus uncinata ) using a set of 15 newly developed maternally inherited and seed-mediated mitochondrial DNA ( mt DNA) markers and two previously known polymorphic mt DNA regions ( nad1 , nad7 ). Three main groups, corresponding in general to three investigated species were revealed in the haplotype network analysis. However, only P. uncinata was clearly distinct at all levels of analysis, whereas great genetic similarity and haplotype sharing was observed between P. uliginosa and P. mugo . Strong phylogeographic structure was found in P. uliginosa that showed high differentiation at relatively short geographical distance among populations and the existence of mitochondrial lineages of different evolutionary history. Hybridization with other pine species has likely contributed to genetic differentiation of P. uliginosa as indicated by contemporary distribution of mt DNA haplotypes. The research emphasizes the importance of accurate assessments of genetic structure of endangered species with complex evolutionary history for development of efficient conservation strategies.

Development of a single nucleotide polymorphism array for population genomic studies in four European pine species

“…Although the number of samples from individual populations was limited, the analysis showed the array's potential for discriminating populations at broad spatial scales. Within species, populations showed clear structure, while those from P. uliginosa appeared to be most clearly diverged, supporting results from a recent study using mt DNA markers (maternally inherited in pines; Łabiszak, Zaborowska, & Wachowiak, 2019). There was evidence for distinct population clusters in other species for highly diverged populations at the species' margins (including P. sylvestris in Scotland, P. mugo from the Abruzzi Mountains in Italy and P. uncinata from Castiello de Jaca in Spain).…”

Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

“…Those results may reflect their rapid divergence after the split, facilitated by the geographic isolation and contemporary disjoint distribution of sympatric populations found only in the Alps, with P. uncinata primarily located in the western and P. mugo in the eastern parts of the mountains. Patterns of mitochondrial DNA variation support this ongoing divergence, as both species, could be clearly delineated by mitochondrial markers, and P. uncinata harbors unique and fixed mitotypes [33]. Nevertheless, there is evidence for interspecific gene exchange between those pines in their contact zone in the Alps [82].…”

“…The wide distribution of P. sylvestris and its known long-distance migration associated with postglacial recolonization of Europe could facilitate overlap with other pine species and locally restricted gene flow. Previous studies reported similarities between Scots pine populations from Poland and Finland [85,86], reflecting their common phylogeographic history, and mitotype sharing between P. uliginosa, P. mugo, and P. sylvestris in their contact zones was also reported [33,80].…”

“…Pines from the P. mugo complex are closely related to Scots pine (Pinus sylvestris L.), which has the largest distribution of all pines, mostly lowland, and forms forests of great ecological importance and economic value in Europe and Asia. Due to their relatively recent divergence, weak reproductive barriers, and similar genetic variation at neutral loci but at the same time phenotypical and ecological differentiation, the P. mugo complex pines are especially suitable for speciation, hybridization, and local adaptation studies [33][34][35][36][37].…”

Molecular and paleo‐climatic data uncover the impact of an ancient bottleneck on the demographic history and contemporary genetic structure of endangered Pinus uliginosa

“…Previous studies on P. uliginosa were mostly focused on its complex evolutionary history and on the taxonomic relationships with its close relatives: Pinus sylvestris and pines from a broader group called Pinus mugo complex, including dwarf mountain pine ( P. mugo Turra) and Pyrenean pine ( Pinus uncinata Ramond) (Hamernik & Musil, 2007; Boratyńska & Lewandowska, 2009; Wachowiak & Prus‐Glowacki, 2009; Łabiszak et al, 2019). These species diverged from their common ancestors about 5 million years ago (Wachowiak et al, 2011).…”