A preliminary study of genetic diversity in Cystoseira amentacea (C. Agardh) Bory var. stricta Montagne (Fucales, Phaeophyceae) using random amplified polymorphic DNA

Cystoseira amentacea var. stricta is an endemic key species in the coastal ecosystem of the northern Mediterranean basin. Because it has suffered significant population declines, it has been designated a protected species. Nothing is known about the Population genetics of Cystoseira spp. Because zygote dispersal is low among the Fucales, low genetic diversity within populations and strong differentiation among Populations were predicted. To evaluate genetic variation within and among C amentacea var. strictu populations, 54 individuals from four Populations were compared using random amplified polymorphic DNA (RAPD) markers. Data were analyzed using analysis of molecular variance (AMOVA) and Bayesian clustering of individuals into populations based on their genotypes (STRUCTURE 2.1 software). Results indicated that genetic variation is high, with most of it distributed within populations (70.93%), and with some genetic mixing among adjacent populations, a result of longer range dispersal. The Lavezzi population (Corsica) is distinct from the other three populations, suggesting isolation by distance. Although more intensive sampling is required, these preliminary results have important implications for conservation policy.