Low Chloroplast DNA Diversity in Red Dogwood (Cornus sanguinea L.)

The red dogwood Cornus sanguinea L. is a deciduous shrub of the temperate and Mediterranean zones. It is often used in landscape gardening for miscellaneous purposes. Chloroplast DNA markers, the so-called cpDNA haplotypes, are a very potential marker type to characterise the large scale variation pattern within the natural range of a species. In this study, a total of 86 populations and 673 individuals were sampled all over Europe. Eight different haplotypes were recognised by combinations of several PCR-RFLP patterns. They are divided into 3 groups of related types. There is no association between these 3 groups and their geographic occurrence within the tested material. One haplotype strongly dominates in the whole distribution area. It takes nearly 90 percent whereas the remaining seven haplotypes together reach to approximately 10 percent. Besides the low number of haplotypes, the total genetic variation HT = 0.15 is much lower in Cornus sanguinea compared to other European tree and shrub species. Despite the low level of variation, several cases of introduced populations could be detected. Other haplotypes than the common type are found only in narrow areas. This result indicates that after the colonisation of the European continent only a very restricted gene flow could have taken place.