IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Integrating the cytogenetic and molecular phylogenetic data to assay the major trends in karyotypic evolution of the genus Arachis
Autor/es:
ORTÍZ A.; LAVIA, G.; SILVESTRI, M C; SEIJO JG; ROBLEDO G.; SAMOLUK SS
Lugar:
Córodoba
Reunión:
Conferencia; 9th International Conference of the Peanut Research Community- AAGB 2017; 2017
Resumen:
Arachis genusincludes 81 autogamous and geocarpic species, all native from South America.Most of them are diploids with x=10, few (4) with x=9, and 5 are tetraploids withx=10. These species were arranged in 9 taxonomic sections and differentgenomes. Comparative studies by classical and molecular cytogenetics revealedlarge karyotype variability among species, however, there is still uncertaintyconcerning the major trends in the karyotype evolution of the genus. To shedlight on this topic, we constructed a dataset with  the available information on chromosomemarkers (45S and 5S rDNA and heterochromatin) and DNA content, which was furtheranalyzed in a phylogenetic context based on ITS sequences. The results revealedthat the ancestral species would have had low DNA content and karyotypescharacterized by short chromosomes and absence or low content ofheterochromatin C-DAPI+. The only general trend identified across the phylogenywas the increase of the genome size (Cx).Other important features that arose from our results are 1) the A chromosomes?have arisen only once 2) the reduction of the basic chromosome number occurred intwo independent linages, and 3) the polyploidization happened at least in threedifferent events. Despite most of chromosome characteristic analyzed did notshow a unidirectional tendency during evolutionary history, changes in thenumber of rDNA sites and in the patterns of DAPI heterochromatic distributionwere related with the differentiation of genomic groups and some species.