Large scale patterns of genetic variation and differentiation in sugar maple from tropical Central America to temperate North America

Abstract

BackgroundGeological events in the latter Cenozoic have influenced the distribution, abundance and genetic structure of tree populations in temperate and tropical North America. The biogeographical history of temperate vegetation that spans large ranges of latitude is complex, involving multiple latitudinal shifts that might have occurred via different migration routes. We determined the regional structuring of genetic variation of sugar maple (Acer saccharum subsp. saccharum) and its only subspecies in tropical America (Acer saccharum subsp. skutchii) using nuclear and chloroplast data. The studied populations span a geographic range from Maine, USA (46°N), to El Progreso, Guatemala (15°N). We examined genetic subdivisions, explored the locations of ancestral haplotypes, analyzed genetic data to explore the presence of a single or multiple glacial refugia, and tested whether genetic lineages are temporally consistent with a Pleistocene or older divergence.ResultsNuclear and chloroplast data indicated that populations in midwestern USA and western Mexico were highly differentiated from populations in the rest of the sites. The time of the most recent common ancestor of the western Mexico haplotype lineage was dated to the Pliocene (5.9 Ma, 95 % HPD: 4.3–7.3 Ma). Splits during the Pleistocene separated the rest of the phylogroups. The most frequent and widespread haplotype occurred in half of the sites (Guatemala, eastern Mexico, southeastern USA, and Ohio). Our data also suggested that multiple Pleistocene refugia (tropics-southeastern USA, midwestern, and northeastern USA), but not western Mexico (Jalisco), contributed to post-glacial northward expansion of ranges. Current southern Mexican and Guatemalan populations have reduced population sizes, genetic bottlenecks and tend toward homozygosity, as indicated using nuclear and chloroplast markers.ConclusionsThe divergence of western Mexican populations from the rest of the sugar maples likely resulted from orographic and volcanic barriers to gene flow. Past connectivity among populations in the southeastern USA and eastern Mexico and Guatemala possible occurred through gene flow during the Pleistocene. The time to the most common ancestor values revealed that populations from the Midwest and Northeast USA represented different haplotype lineages, indicating major divergence of haplotypes lineages before the Last Glacial Maximum and suggesting the existence of multiple glacial refugia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0518-7) contains supplementary material, which is available to authorized users.

Influence of northern limit range on genetic diversity and structure in a widespread North American tree, sugar maple (Acer saccharumMarshall)

“…yr BP; Figure ). Interestingly, a genetic signature of these same refugia was identified for red maple ( Acer rubrum L.; McLachlan et al., ) and multiple refugia for sugar maple (Vargas‐Rodriguez, Platt, Urbatsch, & Foltz, ).…”

Phylogeography of a widespread eastern North American shrub, Viburnum lantanoides

“…In considering these patterns, it is important to note that most phylogeographic studies of ENA plants have been conducted in wide‐ranging, wind‐pollinated trees, with fruits/seeds that are not dispersed by birds: for example, Fagus grandifolia (Morris et al., 2010), Liquidambar styraciflua (Morris et al., 2008), Pinus strobus (Nadeau et al., 2015; Zinck and Rajora, 2016), and species in the genera Acer (McLachlan et al., 2005; Saeki et al., 2011; Vargas‐Rodriguez et al., 2015), Betula (Thomson et al., 2014), and Carya (Bemmels and Dick, 2018). Despite their diverse ecologies, these plants are long lived, with generally large population sizes (Savolainen et al., 2007; Krutovsky et al., 2012; Alberto et al., 2013).…”

Gas Exchange, Water Use Efficiency, and Biomass Partitioning among Geographic Sources of Acer saccharum Subsp. saccharum and Subsp. nigrum Seedlings in Response to Water Stress

“…The molecular research on sugar maple genetics has been mostly taxonomic, showing differences among related species and ecotypes [ 15 , 24 ]. While our study measured the morphological and physiological responses to imposed moisture stress preconditioning and moisture stress, there our molecular explanations behind the results [ 69 ]. Sugar maple has shown large-scale patterns with genetic variation and nuclear chloroplast data from western populations as detected in refugia populations as resulting from geologic events [ 69 ].…”

“…While our study measured the morphological and physiological responses to imposed moisture stress preconditioning and moisture stress, there our molecular explanations behind the results [ 69 ]. Sugar maple has shown large-scale patterns with genetic variation and nuclear chloroplast data from western populations as detected in refugia populations as resulting from geologic events [ 69 ]. Yet, there appears to be little genetic difference, rather inducible responses to environmental conditions as imposed in this study between black and sugar maple [ 32 ].…”