Genetic analysis based on plastidial and ribosomal sequences of the endemic bi-edaphic taxon Jurinea pinnata (Lag.) DC. (Compositae) in the Guadix-Baza Basin

Jurinea pinnata (Lag.) DC. is one of the three species of the genus that grows in the Iberian Peninsula. This species grows on gypsum and dolomite, substrates rich in endemic taxa. Actually, the genus Jurinea Cass. is particularly rich in endemic taxa associated with special substrates. The island-like distribution of J. pinnata makes it an interesting case for the study of genetic differentiation processes. The geographical proximity of J. pinnata and J. humilis makes this evolutionary puzzle even more difficult to solve. These facts could affect the genetic attributes of the species as far as diversity and differentiation are concerned. Our field research involved the sampling of individuals from eight populations of J. pinnata. Of them, six were located in the Guadix-Baza Basin. We used sequences of ribosomal and plastid DNA to perform the genetic analyses. Results revealed no differences between individuals occurring on the two kinds of substrates and evidences of hybridization between J. pinnata and J. humilis. Furthermore, the phylogenetic analysis revealed a possible polyphyletic origin for the adaptation to special substrates within the Jurinea genus, while monophyly was observed in species from the Iberian Peninsula. This could indicate a more general adaptation to arid or saline environments.