PATTERNS OF GENETIC-VARIATION DETECTED BY RAPD SUGGEST A SINGLE ORIGIN WITH SUBSEQUENT MUTATIONS AND LONG-DISTANCE DISPERSAL IN THE APOMICTIC FERN DRYOPTERIS-REMOTA (DRYOPTERIDACEAE)
J. Schneller et al., PATTERNS OF GENETIC-VARIATION DETECTED BY RAPD SUGGEST A SINGLE ORIGIN WITH SUBSEQUENT MUTATIONS AND LONG-DISTANCE DISPERSAL IN THE APOMICTIC FERN DRYOPTERIS-REMOTA (DRYOPTERIDACEAE), American journal of botany, 85(7), 1998, pp. 1038-1042
Debates on speciation processes in pteridophytes have revived. In orde
r to study the evolutionary origin of an apomictic fern species, we in
vestigated the genetic variation in the strictly agamosporous Dryopter
is remota. We determined the genotypes of 22 individuals from many dif
ferent locations within the species' European distribution and of 20 i
ndividuals from a Swiss population. A previous study on isozyme variat
ion showed no intraspecific genetic variation in a similar sample set
(Schneller and Holderegger, 1994, America Fern Journal 84: 94-98). In
contrast to this, four out of 12 random amplified polymorphic DNA (RAP
D) primers tested revealed low genetic diversity among individuals of
D. remota from different locations. Intrapopulational genetic variatio
n was also very low, but in the single population studied, a unique mu
ltiband genotype could be detected. The geographic distribution of gen
etic Variation found in D. remota was best explained by the assumption
of a single origin, the accumulation of somatic mutations during spre
ad, and occasional, but effective, events of dispersal over large dist
ances. The present study thus stresses the importance of long-distance
dispersal in evolutionary processes and biogeography of ferns.