Genetic variation in the endemic and endangered Rosmarinus tomentosus Huber-Morath & Maire (Labiatae) using RAPD markers

Rosmarinus tomentosus Huber-Morath & Maire. an endemic species of southern Spain, is critically endangered as a consequence of habitat destruction by anthropogenic activities. Random amplified polymorphic DNA (RAPD) markers w ere used for initial evaluation of genetic variation in this species; among zones, among populations (within zones and independently of zones), and am ong individuals (within populations and zones). The eight primers used to s tudy five populations provided 126 reliable bands, of which 109 (86%) were polymorphic. Analyses of the RAPD markers conducted using different approac hes (cluster analysis, Shannon's diversity measure and analysis of molecula r variance-AMOVA) showed similar results concerning genetic structure of po pulations of R. tomentosus. The three zones studied, and their corrrespondi ng populations, were clearly defined through UPGMA analysis. AMOVA analyses indicated that 18.0% of the total genetic variation was attributable to di fferences among zones. When total variance was partitioned without consider ing the zonal distribution of the populations, 34.1% was attributable to di fferences among populations, and 65.9% to differences among individuals wit hin populations. Similar results were obtained using Shannon's information measure. Significant genetic distances (Phi(st) values) were obtained betwe en ally two populations. This strong genetic differentiation among zones po pulations and subpopulations may be explained by geographical distances and limited gene flow. This study will be of considerable help during subseque nt formulations of conservation strategies for the endangered species A. to mentosus.