Genetic Dynamics and Population Structure of Salamanders

The study of salamander genetics has revealed complex interactions between evolutionary processes, environmental heterogeneity and life‐history traits in shaping population structure. Across diverse genera, from stream‐breeding fire salamanders to terrestrial plethodontids, population connectivity is governed by the interplay of gene flow, genetic drift and selective pressures. Landscape features such as topography, hydrological networks and anthropogenic barriers modulate dispersal, often creating hierarchical genetic subdivisions at local and regional scales. Viviparous and larviparous reproductive modes further influence patterns of multiple paternity and effective population size, with trade‐offs between offspring quality and quantity affecting genetic diversity. Hybrid zones between divergent lineages and subspecies underscore the role of secondary contact and admixture in driving both adaptive and neutral variation. Contemporary approaches combining microsatellite and genomic data within landscape genetics frameworks have refined estimates of population connectivity, elucidating metapopulation dynamics in forest versus fragmented habitats. The global significance of this work spans conservation planning, management of endemic taxa and prediction of species’ responses to environmental change.

Research from Nature Portfolio

Recent studies have elucidated the influence of landscape and demographic processes on genetic variation in fire salamanders. One investigation applied a mainland–island metapopulation framework to forest and bocage habitats, revealing panmixia within large woodlands but strong genetic drift and founder effects in isolated hedgerow populations. This work highlights the predominance of geographic over ecological divergence in shaping microsatellite diversity and supports a model of secondary contact between differentiated lineages. Another study contrasted larviparous and pueriparous populations in a viviparous salamander, demonstrating that the evolution of terrestrial birth does not reduce multiple paternity. On the contrary, smaller broods of larger juveniles exhibit equal or higher numbers of sires, suggesting behavioural mechanisms that maintain genetic diversity under reduced fecundity and potentially buffer isolated populations against inbreeding.

Genetic Dynamics and Population Structure of Salamanders publication trend

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

Technical terms

Gene flow: Movement of genes among populations through dispersal of individuals or gametes, counteracting genetic differentiation.

Genetic drift: Random changes in allele frequencies, particularly pronounced in small or isolated populations.

Metapopulation: A set of spatially separated populations of the same species that interact through dispersal.

Microsatellite markers: Short, tandemly repeated DNA sequences used to assess genetic variation and population structure.

Effective population size (Ne): The number of breeding individuals in an idealised population that would show the same genetic drift as the actual population.

Hybrid zone: A geographic region where genetically distinct populations meet and interbreed, producing admixed offspring.

References

1. Detecting a hierarchical genetic population structure: the case study of the Fire Salamander (Salamandra salamandra) in Northern Italy. Ecology and Evolution (2015).
2. Assessment of intra and interregional genetic variation in the Eastern Red-backed Salamander, Plethodon cinereus, via analysis of novel microsatellite markers. PLOS ONE (2017).
3. ‘Mainland-island’ population structure of a terrestrial salamander in a forest-bocage landscape with little evidence for in situ ecological speciation. Scientific Reports (2020).
4. The evolution of pueriparity maintains multiple paternity in a polymorphic viviparous salamander. Scientific Reports (2020).
5. Genetic variation in Plethodon cinereus and Plethodon hubrichti from in and around a contact zone. Ecology and Evolution (2020).