Genetic Diversity in Tropical Forest Tree Species

Genetic diversity underpins the adaptive potential and long-term viability of tropical forest tree species. It arises through mutation, recombination and the reshuffling of alleles by gene flow, and is shaped by demographic processes such as genetic drift and natural selection. High levels of variation within and among populations confer resilience to environmental change, pests and disease, while low diversity can increase extinction risk. Tropical trees often exhibit complex population structure, reflecting historical refugia, patterns of dispersal and landscape heterogeneity. Molecular tools—from microsatellites to genome-wide single-nucleotide polymorphisms—have revealed latitudinal and regional gradients in diversity, with Amazonian and Southeast Asian forests harbouring some of the greatest genetic variation on Earth. Habitat loss, fragmentation and climate change are accelerating the erosion of this diversity, compromising ecosystem services such as carbon storage and pollination. Conservation strategies now integrate genetic data to identify management units, design seed-collection zones and guide restoration efforts. By mapping connectivity corridors and prioritising genetically rich stands, practitioners can bolster adaptation and maintain the evolutionary processes essential for sustaining tropical forest biodiversity.

Research from Nature Portfolio

Recent studies have employed high-throughput markers to resolve hybrid zones and assess introgression between sympatric tree species. In one example, genome-wide genotyping identified single-nucleotide markers that unambiguously distinguished two medicinal camphor species and their hybrids. Results revealed bidirectional gene flow in human-modified landscapes and demonstrated how seed-orchard buffer zones can preserve genetic purity. The molecular toolkit arising from this work offers both a means to trace wood provenance and a foundation for selective breeding and evolutionary research.

Genetic Diversity in Tropical Forest Tree Species publication trend

The graph below shows the total number of articles in genetic diversity in tropical forest tree species across all publications each year (not limited to Nature Index journals).

Technical terms

Single-nucleotide polymorphism (SNP): A variation at a single base pair in DNA, used as a genetic marker.

Heterozygosity: The proportion of individuals in a population that carry two different alleles at a given genetic locus.

Gene flow: The movement of alleles between populations through dispersal of pollen or seeds, which counteracts genetic divergence.

Genetic drift: Random fluctuations in allele frequencies, most pronounced in small or isolated populations.

Introgression: The incorporation of genetic material from one species into the gene pool of another via repeated hybridisation and backcrossing.

References

1. Conservation genomic study of Hopea hainanensis (Dipterocarpaceae), an endangered tree with extremely small populations on Hainan Island, China. Frontiers in Plant Science (2024).
2. Genetic structure of an endangered species Ormosia henryi in southern China, and implications for conservation. BMC Plant Biology (2023).
3. Identification of hybridization and introgression between Cinnamomum kanehirae Hayata and C. camphora (L.) Presl using genotyping-by-sequencing. Scientific Reports (2020).
4. Introgression across evolutionary scales suggests reticulation contributes to Amazonian tree diversity. Molecular Ecology (2020).