Spatial Patterns of Intraspecific Genetic Diversity Follow no General Rule Across Climatic and Geographic Gradients.

Area of Science:

• Evolutionary Biology
• Ecology
• Conservation Genetics

Background:

• Intraspecific genetic diversity (ISD) is crucial for eco-evolutionary processes.
• Understanding spatial ISD distribution across species' ranges is limited at broad scales.
• The central-marginal paradigm predicts higher ISD near niche optima.

Purpose of the Study:

• To test if populations near climatic niche optima exhibit higher ISD.
• To investigate ISD variation relative to climatic and geographic centroids.
• To explore drivers of ISD patterns across diverse taxa.

Main Methods:

• Meta-analysis of publicly available mitochondrial DNA sequence data.
• Species distribution models and comparative analyses.
• Interpolation of gene-specific data to create spatially explicit ISD surfaces.
• Random Forest framework to predict ISD-centroid correlations.

Main Results:

• ISD-centroid correlations were highly variable and species-specific.
• No uniform macroecological or evolutionary processes consistently govern ISD patterns.
• Predictive models for ISD patterns showed poor performance.

Conclusions:

• ISD patterns reflect lineage-specific histories, ecological contexts, and demographic factors.
• Broad-scale predictions of genetic diversity are challenging.
• Species-tailored approaches are essential for effective conservation planning.