Chloroplast DNA diversity within and among populations of the allotetraploid Prunus spinosa L.

High chloroplast DNA (cpDNA) diversity was found within and among populatio ns of Prunus spinosa sampled from seven European deciduous forests. A study of 12% of the total chloroplast genome detected 44 mutations, which were d istributed over 24 haplotypes; four were common to two or more populations and the rest were unique haplotypes. The most-abundant and widely distribut ed haplotype was H2 (frequency = 41% approximately). Six of the seven popul ations were polymorphic. All of the six polymorphic populations had "privat e" haplotypes (frequency <5%) in addition to common haplotypes. The UPGMA d endrogram demonstrated a correlation between populations and their geograph ical locations. The total diversity was high (h(T) = 0.824) and a major por tion of it was within populations (h(s) = 0.663). The level of population s ubdivision for unordered alleles was low (G(ST) = 19.5%) and for ordered al leles was lower (N-ST = 13.6%). No phylogeographic structure could be demon strated in the present geographical scale. High polymorphism in the cpDNA o f P. spinosa has to be considered carefully when planning phylogenetic stud ies involving this species.