Genetic diversity and structure ofJatropha curcas L. in its centre of origin
M. Salvador-Figueroa, J. Magana-Ramos, J.A. Vazquez-Ovando, M.L. Adriano-Anaya and I. Ovando-Medina
To investigate the genetic diversity and structure of Jatropha curcas L. oilseed plant, in this
study, native populations from Chiapas, Mexico, were evaluated, using microsatellite DNA
markers. A total of 93 representative samples were selected from seven sites in two regions
in the state of Chiapas grouped by geographical proximity, where leaf samples were collected
to isolate the genomic DNA. Individual polymerase chain reactions were carried out with ten
pairs of specific oligonucleotides for the microsatellites of J. curcas, separating the products
of amplification by acrylamide electrophoresis. Twenty-seven fragments were detected (77%
polymorphic) with which heterozygous individuals were distinguished. The most informative
microsatellite was Jcps20 (nine alleles, polymorphic index content 0.354). The average poly-
morphism per population was 58%. The Hardy–Weinberg tests revealed a reproductive pattern
of non-random mating. The diversity descriptors and the analysis of molecular variance
revealed that the populations were structured and moderately differentiated (FST 0.087) and
that this differentiation was not due to isolation by distance, as the Mantel test was not signifi-
cant (P 1⁄4 0.137), but rather due to allopatry. Bayesian analysis revealed that the accessions
belonged to only four genetic groups and confirmed the differentiation between the regions.
Because some loci were in Hardy–Weinberg disequilibrium, it is proposed that differentiation
is due to the clonal reproduction of J. curcas practised by farmers in Chiapas, along with the
anthropogenic dispersion at regional levels. The results of this study reveal that J. curcas in
Chiapas has genetic diversity that is greater than that reported in other parts of the world,
which represents a potential germplasm pool for the selection of genotypes.
