Genetic Diversity and Population Structure in Forest Trees

Genetic diversity, the variation in DNA sequences among individuals, underpins the capacity of forest tree species to adapt to changing climates, pests and pathogens. It is shaped by mutation, recombination, gene flow and historical demographic events such as glaciations. Population structure arises when genetic variation is non-randomly distributed across geographic or ecological gradients, often as a result of isolation by distance, environmental selection or barriers to dispersal. Modern genomic tools—ranging from single nucleotide polymorphism (SNP) arrays and restriction-site-associated sequencing to whole-genome approaches—have enabled fine-scale resolution of diversity patterns. Analyses of population structure, using metrics such as FST, clustering algorithms and admixture models, reveal how historical gene flow, local adaptation and genetic drift interact. Insights into the spatial organisation of genetic variation inform conservation strategies, guiding seed sourcing, assisted migration and the management of genetic resources to sustain forest resilience under global change.

Research from Nature Portfolio

Recent population genetic analyses have revealed that ancient introgression from a high-elevation cypress species contributed adaptive alleles to a related low-elevation taxon, facilitating its expansion into cooler and drier mountain habitats. Whole-transcriptome sequencing identified candidate loci that enhance stress tolerance and environmental adaptation, demonstrating that hybridisation can be a continuous source of beneficial variation. This work highlights how deep-time gene flow events shape contemporary genetic diversity and structure in forest trees confronted by climatic shifts.

Genetic Diversity and Population Structure in Forest Trees publication trend

The graph below shows the total number of articles in genetic diversity and population structure in forest trees across all publications each year (not limited to Nature Index journals).

Technical terms

Genetic diversity: Variation in DNA sequences among individuals of a species.

Population structure: Non-random distribution of genetic variation among populations.

Single nucleotide polymorphism (SNP): A single base-pair change in the genome used as a genetic marker.

Introgression: Transfer of genetic material between species or populations through hybridisation and backcrossing.

Local adaptation: Evolution of traits that enhance fitness in specific environmental conditions.

Genetic drift: Random fluctuations in allele frequencies across generations.

Refugia: Areas where populations persist during adverse climatic periods, serving as sources for post-crisis recolonisation.

Isolation by distance (IBD): Pattern in which genetic similarity decreases with geographic distance.

Isolation by environment (IBE): Pattern in which genetic differentiation correlates with environmental differences.

References

1. Ancient introgression drives adaptation to cooler and drier mountain habitats in a cypress species complex. Communications Biology (2019).
2. Genomic clines across the species boundary between a hybrid pine and its progenitor in the eastern Tibetan Plateau. Plant Communications (2023).
3. Genetic Adaptation of Siberian Larch (Larix sibirica Ledeb.) to High Altitudes. International Journal of Molecular Sciences (2023).
4. Adaptive divergence, historical population dynamics, and simulation of suitable distributions for Picea Meyeri and P. Mongolica at the whole-genome level. BMC Plant Biology (2024).