Hybridization and Gene Flow in Plant Systems

Hybridization and gene flow play pivotal roles in plant evolution, driving genetic diversity, adaptation and speciation across a range of ecosystems. When distinct populations or species interbreed, the resulting hybrids can exhibit novel trait combinations and altered ecological tolerances. Gene flow via pollen or seed dispersal can blur species boundaries, generate hybrid swarms and facilitate the transfer of adaptive alleles between lineages. The outcomes range from transient hybrid zones to the establishment of stable hybrid taxa, with the dynamics shaped by factors such as reproductive barriers, environmental heterogeneity and demographic history. Asymmetries in hybrid formation and backcrossing often reflect differences in mating systems, phenology or ecological preferences, while epigenetic modifications may influence hybrid fitness under novel climates. Understanding these processes informs conservation strategies, forest management and the use of wild relatives in crop improvement, highlighting the global significance of hybrid-driven diversity in the face of habitat change and climate warming.

Research from Nature Portfolio

Recent studies have revealed the complex interplay between genetic, epigenetic and ecological factors in natural plant hybrids. Investigations into two aromatic sage species demonstrated homoploid hybridisation at both morphological and molecular levels, with hybrids forming discrete F1 cohorts and exhibiting elevated genetic and epigenetic variability. Environmental modelling of parental niches showed imbalanced climatic suitability, shedding light on the limited gene flow despite ongoing contact. Elsewhere, work on two long-lived rhododendron species quantified multiple reproductive barriers at pre-zygotic and post-zygotic stages, revealing strong overall isolation even where occasional hybridisation occurs. Geographic separation and pollinator specificity emerged as key pre-zygotic filters, while asymmetric post-zygotic fitness effects highlighted the potential for biased introgression in one lineage.

Hybridization and Gene Flow in Plant Systems publication trend

The graph below shows the total number of articles in hybridization and gene flow in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Hybridization: The interbreeding of individuals from genetically distinct populations or species.

Gene flow: The transfer of genetic material between populations via pollen, seed dispersal or vegetative propagation.

Introgression: The incorporation of genetic variants from one species into the genome of another through repeated backcrossing.

Homoploid hybrid speciation: The formation of a new hybrid species without a change in chromosome number, often through stabilised reproductive barriers.

Reproductive isolation: Biological mechanisms, including pre-zygotic and post-zygotic factors, that restrict gene exchange between populations or species.

References

1. Asymmetric Introgression and Cryptic Natural Hybridization between Two Species of Teucrium Section Polium (Lamiaceae) on the Balkan Peninsula. Plants (2024).
2. Homoploid hybridization of plants in the Hengduan mountains region. Ecology and Evolution (2019).
3. Strong reproductive isolation despite occasional hybridization between a widely distributed and a narrow endemic Rhododendron species. Scientific Reports (2016).
4. Morphological, genetic and epigenetic aspects of homoploid hybridization between Salvia officinalis L. and Salvia fruticosa Mill.. Scientific Reports (2019).
5. Chloroplast DNA variation in a hyperdiverse tropical tree community. Ecology and Evolution (2019).