Intraspecific molecular variation inHieracium sect.Alpina (Asteraceae), an apomictic group

Intraspecific variation of four agamospecies of Hieracium sect. Alpina was studied using RAPD and isozyme techniques. No variation in either multiprimer RAPD or multi-enzyme phenotypes was observed within H. holosericeum, suggesting that this widespread species consists of only a single genotype. A low level of within-population isozyme variation was seen in H. tenuifrons and H. calenduliflorum, the origin of which appears to be consistent with somatic mutation. Most isozyme and all RAPD variation in these two species was partitioned between populations. A strong correlation with geography suggests that its cause may be due to polytopic (=polyphyletic?) origin or perhaps to mutation and dispersal. The most variable species was H. alpinum, in which isozyme variation occurred mostly within populations rather than between them, suggesting occasional sexual events or that the parents of H. alpinum were heterozygous. RAPD variation in this species, in contrast, was partitioned between Scottish and Swiss populations, suggesting the existence of geographical races.