Among the 67 microsatellite markers tested, 26 produced successful amplification and five were genome-specific. serotina, and evidence that conserved markers were genome-specific was found by demonstrating their typical Mendelian diploid inheritance in embryos resulting from controlled crosses. species were tested for cross-amplification in P. Sixty-seven microsatellite primers described in cultivated Prunus L. by finding genome-specific primers (i.e., primers that are specific to one of the two genomes that initially formed the species). The objective of this study was to solve these problems in the allotetraploid Prunus serotina Ehrh. I show that small changes in the value of the clonal threshold can lead to very different conclusions regarding the level of clonal reproduction in natural populations.The utility of microsatellite markers to characterize the genetic diversity of a polyploid species with disomic inheritance is often hampered by the impossibility of determining allele frequencies and the complexity of inheritance patterns. To determine the sensitivity of estimates of clonal reproduction, I calculated several clonal diversity indexes for the natural populations of each of the five species guided by the range in clonal threshold values observed across the five Piper species. Clonal threshold values for the different species ranged from 0% to 5% AFLP genetic dissimilarity distance.
#GENODIVE PROBLEMS SERIES#
I then sampled all individuals of each shade-tolerant species in a 1-ha plot, and of each light-demanding species in 25 × 35-m plot, to estimate the frequency of asexual recruitment in natural populations using a series of different thresholds including the threshold set with the preliminary sampling. I sampled multiple ramets per individual from widely distributed plants for each of the five Piper species to set a threshold at the point where the error rate of clonal assignments was lowest. Here, I determine the consistency of the clonal threshold across five species in the tropical plant genus Piper, and evaluate the sensitivity of genetic diversity indices and estimates of frequency of clonal reproduction to the threshold value selected. Most studies to date have reported threshold values between 2% and 4%. Pairwise AFLP distances that distinguish known clones from nonclones have been used to identify a threshold genetic dissimilarity distance below which samples are considered to represent a single clone. We hypothesize that maintenance of genetic diversity and superior colonizing abilities of apomicts in temporally and spatially heterogeneous environments are important for their distributional success.Īmplified fragment length polymorphism (AFLP) has been widely used for clone identification, but numerous studies have shown that clonemates do not always present identical AFLP fingerprints. Habitat differentiation and a tendency to inhabit artificial meadows is more pronounced in apomictic than in sexual populations. Genetic diversity is partitioned mainly among apomictic populations and is not geographically structured, which may be due to facultative sexuality and/or multiple colonizations of sites by different clones. Two microsatellite loci discriminated genotypes separated by the accumulation of few mutations (‘clone mates’) within each AFLP clone. This local facultative sexuality may have a great impact on regional genotypic diversity. genotype/genodive and character incompatibility analyses suggest that genotypic variation within apomictic populations is caused by mutations, but in one population probably also by recombination. Polyploid populations consist either of a single AFLP genotype or of one dominant and a few deviating genotypes.
Whereas two diploid populations showed high levels of genetic diversity, as expected for sexual reproduction, eight populations are hexaploid and harbour lower degrees of genotypic variation, but maintain high levels of heterozygosity at many loci, as is typical for apomicts. Population studies (amplified fragment length polymorphisms, microsatellites) and karyological methods (Feulgen DNA image densitometry and flow cytometry) were employed for characterization of genetic diversity and ploidy levels of 10 populations of Ranunculus carpaticola in central Slovakia. Sources and implications of genetic diversity in agamic complexes are still under debate.
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