High levels of genetic diversity and population structure in an endemic and rare species: Implications for conservation

High genetic diversity was found in rare Petunia secreta (pink flowers) compared with the other Petunia species. The two genetic lineages of P. secreta (light and dark pink) corresponded to the two separate sites of species occurrence in different landscapes.

The analysis of genetic structure and variability of isolated species is of critical importance in evaluating whether stochastic or human-caused factors are affecting rare species. Low genetic diversity compromises the ability of populations to evolve and reduces their chances of survival under environmental change. In a recent study published in AoB PLANTS, Turchetto et al. investigated the genetic diversity of two populations of Petunia secreta, a rare and endemic species, growing in two different landscapes approximately 21 Km apart from each other. They found that P. secreta presented high genetic diversity that was equivalent to or even higher than that of widespread Petunia species. Two evolutionary lineages were found and were correlated to the different landscapes in which P. secreta was growing: open areas in conglomerate sandstone towers at an elevation of approximately 300–400 m or along the road growing in an open vegetation flat area. Therefore the major risk to P. secreta maintenance is its rarity, suggesting the need for a preservation programme.