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The species

Eperua falcata Aubl. (Fabaceae) Is the most frequent tree species of the Guiana shield. Although it is endemic of that region, due to its abundance it is one of the twenty most common tree species in Amazonian forests (1)⁠.

Samples

Population samples were obtained from two sites: Laussat, in Western French Guiana, has 2500 mm/yr rainfall, white sand soil (with occasional ferralitic patches) and gentle slopes. Régina, eastern French Guiana, has 3500 mm/yr rainfall, mostly ferrallitic soil with occasional quartzite sand patches and a granite rock bed at the bottom of streams (2)⁠.

In both sites, twenty samples were drawn from “hilltop” and “down-slope” elevations, within continuous populations, for a total of eighty samples (see Figure, taken from Brousseau et al (2)⁠).

Sequencing data

Data were obtained by HiSeq high-throughput sequencing of four equimolar pools of DNA samples (Régina hilltop, Régina bottomland, Laussat hilltop, Laussat bottomland), with target depth of 100X for each pool. Assembly was obtained with the Ray software package (3)⁠. Variants were filtered based on quality (Brousseau et al., in preparation). After filtering, only variants with depth≥40 within each pool were retained for subsequent analyses.

Bayesian analyses

Bayesian analyses were performed according to the method developed in Brousseau et al. in prep. and will not further detailed here. See the “Hierarchical Bayesian Modelling and Outlier detection (SNP level)” page for additional information.