‘Transcontinental and genetic evolutionary convergence of critically endangered genera (Borderea, Epipetrum) of the yam family (Dioscoreaceae)’

Andrea Premoli, José Gabriel Segarra Moraguez, Luis Villa Pérez.

Borderea and Epipetrum are critically endangered, endemic relict genera of the yam family (Dioscoreacea), present in small numbers in the Pyrenees (Spain and France) and Chile. Both genera exhibit a marked evolutionary convergence as evidenced by their similar dwarf stature and creeping habit, and their ecological adaptation to extreme environments (mountains and deserts), despite belonging to distantly related lineages.

The goal of our study is to evaluate evolutionary parallelisms in these groups through a comparative phylogeographic and population genetic study of their species using microsatellite, isoenzymatic and molecular markers, and focusing on the three listed as critically endangered (B. chouardii, E. bilobum and E. polyanthes) with a view to adopting suitable strategies for their conservation. The more widely studied genus Borderea can serve as a model for the study of the largely unknown Epipetrum. In this project we will analyse the differentiation, genetic structure and phylopatric diversification of Epipetrum species, elucidating the biological, ecological and evolutionary factors giving rise to the genetic variability of today’s populations.

Another of the project’s aims is to increase our knowledge of the historical processes that may be affecting the only known population of the flowering yam Borderea chouardii. By analysing progenitors and natural and artificial progenies, and the correlations between genetic distances and microspatial distributions, we hope to detect possible depression processes due to endogamy/exogamy, as well as varying degrees of adaptation by population sub-nuclei (demes) to different microenvironments.