Data from: Geographical parthenogenesis and population genetic structure in the alpine species Ranunculus kuepferi (Ranunculaceae)

Geographical parthenogenesis describes the enigmatic phenomenon that
asexual organisms have larger distribution areas than their sexual
relatives, especially in previously glaciated areas. Classical models
suggest temporary advantages to asexuality in colonization scenarios
because of uniparental reproduction and clonality. We analyzed population
genetic structure and self-fertility of the plant species Ranunculus
kuepferi on 59 populations from the whole distribution area (European
Alps, Apennines and Corsica). Amplified fragment length polymorphisms
(AFLPs) and five microsatellite loci revealed individual genotypes for all
populations and mostly insignificant differences between diploid sexuals
and tetraploid apomicts in all measures of genetic diversity. Low
frequencies of private AFLP fragments/simple sequence repeat alleles, and
character incompatibility analyses suggest that facultative recombination
explains best the unexpectedly high genotypic diversity of apomicts.
STRUCTURE analyses using AFLPs revealed a higher number of partitions and
a stronger geographical subdivision for diploids than for tetraploids,
which contradicts expectations of standard gene flow models, but indicates
a reduction of genetic structure in asexuals. Apomictic populations
exhibited high admixture near the sexual area, but appeared rather uniform
in remote areas. Bagging experiments and analyses of pollen tube growth
confirmed self-fertility for pollen-dependent apomicts, but self-sterility
for diploid sexuals. Facultative apomixis combines advantages of both
modes of reproduction: uniparental reproduction allows for rapid
colonization of remote areas, whereas facultative sexuality and polyploidy
maintains genetic diversity within apomictic populations. The density
dependence of outcrossing limits range expansions of sexual populations.