The jatobás, as they are popularly known, are trees belonging to the genus Hymenaea L, inserted in tribe Detarieae of the family Leguminosae. This genus occurs in the Neotropics, and, in Brazil, it can be found across different vegetation formations. Nowadays, Hymenaea has 14 species and two varieties, but some authors suggested changes in the taxonomic interpretation of some infraspecific taxa and considered them as separated species. Cytogenetic studies have shown the importance of karyotypic characters, specially chromosome numbers, for the understanding of the evolution of some taxonomic groups in Leguminosae. However, only chromosome counts are available for some Hymenaea species, without any information on chromosome length and size. Moreover, more elaborated techniques, such as banding or in situ hybridization, have never been applied on this genus. Our aim is to investigate the holding of the different propositions concerning the taxonomic status of the species and infaspecific taxa of the genus Hymenaea occurring in Brazil. To attain this task, we intend to characterize karyotypes of several taxa of the genus Hymenaea and, if possible, other genera of the tribe Detarieae. We intend to apply conventional staining, CMA/DAPI banding and FISH techniques. These techniques can allow us to determine chromosome numbers and to collect morphometric data, as well as to evidence specific regions along the chromosomes, such as some heterochromatic regions (rich in GC or AT) and DNAr sequences. Stands out the preparation of genus-specific probes for FISH by PCR. The data that we can record will be furnished to Rafael Barbosa Pinto, who is developping his Ph.D. thesis in the Plant Biology Graduate Course/Institute of Biology/UNICAMP. We hope that our data, when applied together with a thorough taxonomic analysis of Hymenaea (developed by Rafael), can help understanding the evolution and delimitation of Hymenaea species.
News published in Agência FAPESP Newsletter about the scholarship: