Fig. 4: Geography and climate explain spatial genomic variation of lesser kestrels.
a Pairwise genetic distance (ΦST/1 – ΦST) correlates positively with geographic and climatic distance. Mantel tests and their associated p-values (one-sided) are reported. Background colours reflect the density of points (blue indicating low density and red indicating high density) and show a discontinuity consistent with a scenario of two distant and differentiated genetic clusters. Distances between localities in the same or different evolutionarily significant units (ESUs) are shown as triangles and circles, respectively. b Principal component analysis (PCA) of 61 climate-associated single-nucleotide polymorphisms (SNPs) showing that the two putative adaptive units (AUs) coincide with the identified evolutionarily significant units (ESUs). c Allelic turnover functions relative to the two highest ranking bioclimatic variables from a gradient forest (GF) analysis of 61 climate-associated SNPs, i.e., precipitation of the coldest quarter (BIO19) and temperature annual range (BIO7). Y-axis values report the cumulative importance of SNPs in the GF models, which reflects the total amount of allele frequency turnover across the environmental gradient. Thin lines show allelic turnover functions for each of the 61 candidate SNPs. Thick blue and red lines show allelic turnover functions across all candidate SNPs and thick black lines across all putatively non-adaptive reference SNPs. Higher turnover values for candidate SNPs compared to neutral SNPs evidence the stronger association of candidate SNPs with climate. Circles at the top represent sampling localities coloured based on the ESU they belong to (orange: Western; blue: Eastern) ordered along the BIO19 and BIO7 gradients. d (Left) Hierarchical clustering of associations between bioclimatic variables (columns) and allele frequencies for the 61 climate-associated SNPs (rows) (Spearman correlation, absolute values). Bioclimatic variables associated with temperature and precipitation are coloured in red and blue, respectively. (Right) Tiles are coloured in grey when the candidate SNP is found within a gene identified, through a literature search (Methods), as being related to local adaptation (first column), phenotypic traits important for local adaptation (second column), adaptation to urban environments or domestication (third column), and/or stress response (fourth column) in vertebrates. Data underlying all components of Fig. 4 are provided at https://doi.org/10.5281/zenodo.14988067.
