DNA fingerprinting validates seed dispersal curves from observational studies in the neotropical legume parkia.

BACKGROUND: Determining the distances over which seeds are dispersed is a crucial component for examining spatial patterns of seed dispersal and their consequences for plant reproductive success and population structure. However, following the fate of individual seeds after removal from the source tree till deposition at a distant place is generally extremely difficult. Here we provide a comparison of observationally and genetically determined seed dispersal distances and dispersal curves in a Neotropical animal-plant system. METHODOLOGY/PRINCIPAL FINDINGS: In a field study on the dispersal of seeds of three Parkia (Fabaceae) species by two Neotropical primate species, Saguinus fuscicollis and Saguinus mystax, in Peruvian Amazonia, we observationally determined dispersal distances. These dispersal distances were then validated through DNA fingerprinting, by matching DNA from the maternally derived seed coat to DNA from potential source trees. We found that dispersal distances are strongly right-skewed, and that distributions obtained through observational and genetic methods and fitted distributions do not differ significantly from each other. CONCLUSIONS/SIGNIFICANCE: Our study showed that seed dispersal distances can be reliably estimated through observational methods when a strict criterion for inclusion of seeds is observed. Furthermore, dispersal distances produced by the two primate species indicated that these primates fulfil one of the criteria for efficient seed dispersers. Finally, our study demonstrated that DNA extraction methods so far employed for temperate plant species can be successfully used for hard-seeded tropical plants.

Genetic structure and seed-mediated dispersal rates of an endangered shrub in a fragmented landscape: a case study for Juniperus communis in northwestern Europe.

BACKGROUND: Population extinction risk in a fragmented landscape is related to the differential ability of the species to spread its genes across the landscape. The impact of landscape fragmentation on plant population dynamics will therefore vary across different spatial scales. We quantified successful seed-mediated dispersal of the dioecious shrub Juniperus communis in a fragmented landscape across northwestern Europe by using amplified fragment length polymorphism (AFLP) markers. Furthermore we investigated the genetic diversity and structure on two spatial scales: across northwestern Europe and across Flanders (northern Belgium). We also studied whether seed viability and populations size were correlated with genetic diversity. RESULTS: Unexpectedly, estimated seed-mediated dispersal rates were quite high and ranged between 3% and 14%. No population differentiation and no spatial genetic structure were detected on the local, Flemish scale. A significant low to moderate genetic differentiation between populations was detected at the regional, northwest European scale (PhiPT = 0.10). In general, geographically nearby populations were also genetically related. High levels of within-population genetic diversity were detected but no correlation was found between any genetic diversity parameter and population size or seed viability. CONCLUSIONS: In northwestern Europe, landscape fragmentation has lead to a weak isolation-by-distance pattern but not to genetic impoverishment of common juniper. Substantial rates of successful migration by seed-mediated gene flow indicate a high dispersal ability which could enable Juniperus communis to naturally colonize suitable habitats. However, it is not clear whether the observed levels of migration will suffice to counterbalance the effects of genetic drift in small populations on the long run.

Identification and characterization of 12 microsatellite loci in Cnidium dubium (Apiaceae) using next-generation sequencing.

PREMISE OF THE STUDY: We present a set of 12 polymorphic nuclear microsatellite loci, identified for the first time within the herbaceous plant species Cnidium dubium (Schkuhr) Thell. using next-generation sequencing. METHODS AND RESULTS: To characterize these loci, 40 plants were analyzed genetically. The number of alleles ranged from 2 to 23, with an average of 8.3 alleles per locus. Mean observed and expected heterozygosities ranged from 0.25 to 0.95 and 0.30 to 0.94, respectively. CONCLUSIONS: All 12 nuclear microsatellite loci showed scorable and polymorphic fragments after polymerase chain reaction. The new marker set can be used for future studies of genetic diversity and differentiation as well as estimation of gene flow and spatial genetic structures.

Characterization of nuclear microsatellite loci in the Neotropical tree Parkia panurensis (Fabaceae).

PREMISE OF THE STUDY: We present here a set of nine polymorphic nuclear microsatellite loci, identified for the first time within the neotropical legume tree species Parkia panurensis Benth. ex H. C. Hopkins, which is widespread in western and central Amazonia. METHODS AND RESULTS: To characterize these loci, 33 Parkia panurensis adult trees were analyzed. The number of alleles ranged from eight to 32, with an average of 14.4 alleles per locus. Mean expected heterozygosity ranged from 0.74 to 0.955. CONCLUSIONS: All nine loci could also be verified in six other Parkia species and polymorphic fragments amplified. The new marker set can be used for future studies of genetic diversity and differentiation, as well as estimation of gene flow and parentage analyses in various Parkia species.