ABSTRACT
Campomanesia xanthocarpa is a native tree, of common occurrence in almost all Brazilian Forest formations, which has its fruits and timber with high commercial value. Using an enriched genomic library we isolated and characterized microsatellite loci for C. xanthocarpa (Myrtaceae), in order to estimate genetic diversity parameters for this and related species. Twenty-eight microsatellite loci were identified and ten of them successfully amplified and showed polymorphism in a sample of 96 individuals, from four natural populations. The number of alleles per locus ranged from two to eight, and the observed and expected heterozygosities varied from 0.042 to 1.000 and from 0.294 to 0.855, respectively. These markers were tested and validated in two related species (C. eugenioides and C. guazumifolia). The microsatellite markers will be used in further studies of population genetics of C. xanthocarpa, in order to understand the genetic variability and to define the strategies needed for the conservation of the species.
Subject(s)
Myrtaceae/genetics , Microsatellite RepeatsABSTRACT
The Brazilian Cerrado (Savannah) is a biome with great biodiversity. Many of the species found in this biome have unlimited economic potential and are used by the local population for various purposes. With the opening of the agricultural frontiers in this region, much of the native flora has been replaced by extensive areas of monocultures. Thirteen populations of the Eugenia dysenterica DC species were sampled in the northeast of the state of Goiás, Brazil, to analyze their genetic structure. Morphological traits were measured for all the progeny obtained and some of them were analyzed by using RAPD markers. The natural populations of the species showed high levels of variability for the morphological traits. The phenotypic, genotypic and genetic variabilities as structured in these populations were highly significant among populations, although most of the variability was detected within populations. The phenotypic and genetic variabilities were structured spatially as shown by the positive and highly significant correlation coefficients between the phenotypic and genetic distance matrixes and the geographic distance matrix. The ideal conservation strategy for the species in the region requires sampling of a high number of individuals of each population and also a significant number of populations to ensure suitable effective population sizes.
Subject(s)
Genetics, Population , Myrtaceae/genetics , Antidiarrheals , Biodiversity , Brazil , Eugenia/genetics , Plants, MedicinalABSTRACT
Mantel tests of matrix correspondence have been widely used in population genetics to examine microevolutionary processes, such as isolation-by-distance (IBD). We used partial and multiple Mantel tests to simultaneously test long-term historical effects and current divergence and equilibrium processes, such as IBD. We used these procedures to calculate genetic divergence among Eugenia dysenterica (Myrtaceae) populations in Central Brazil. The Nei's genetic distances between pairs of local populations were strongly correlated with geographic distances, suggesting an IBD process, but field observations and the geographic distribution of the samples suggest that populations may have been subjected to more complex evolutionary processes of genetic divergence. Partial Mantel regression was used to partition the effects of geographic structure and long-term divergence associated with a possible historical barrier. The R(2) of the model with both effects was 73.3%, and after the partition 21.9% of the variation in the genetic distances could be attributed to long-term historical divergence alone, whereas only 1.5% of the variation in genetic distances could be attributed to IBD. As expected, there was a large overlap between these processes when explaining genetic divergence, so it was not possible to entirely partition divergence between historical and contemporary processes.