Data from: An ecological history of the relict genetic lineage of Arabidopsis thaliana
Toledo, Bernardo et al. (2019), Data from: An ecological history of the relict genetic lineage of Arabidopsis thaliana, Dryad, Dataset, https://doi.org/10.5061/dryad.nn7188m
The combination of extensive population sampling with whole-genome sequencing in the annual plant Arabidopsis thaliana has recently allowed the identification of a genetically differentiated relict lineage. The most important nuclei of relict A. thaliana is found in the Iberian Peninsula and North Africa, although relict accessions have also been found scattered across Atlantic oceanic islands, eastern Mediterranean Basin, South and East Africa and China. We hypothesised that relict A. thaliana long survived and adapted to a wide array of environments in the Iberian Peninsula and North Africa due to the fact that the region repeatedly acted as glacial refugia. Given the lack of evidence to support this hypothesis, we addressed this issue by studying the ecological history of Iberian and North African relict A. thaliana. To this end, we analysed the relationship between the current habitat suitability of relict A. thaliana, estimated with species distribution models, and the vegetation dynamics in the region over the last millennia using pollen fossil data from sediment cores and reconstructions of past distribution ranges of the most important tree species occurring in the region. Overall, our results indicated that a higher current habitat suitability of relict A. thaliana was correlated with more stable vegetation dynamics since the Last Glacial Maximum and during the Holocene. Given that relict A. thaliana is known to harbour genetic variation specific to its relict nature, we also evaluated the differentiation between relict and non-relict A. thaliana accessions at the functional genetic level for the known flowering genes, CRY2 and TSF. Genomic surveys detected the existence of haplogroups of these genes occurring at very high frequency only among relict accessions. Overall, our study reinforced the relict character of this lineage thought to be at the base of the species' early history. We stress the need to sample in depth other geographic areas harbouring relict A. thaliana and conduct further functional genetic analyses between relict and non-relict accessions to keep disentangling the evolutionary trajectory of this annual plant.