Citogenética evolutiva en leguminosas Americanas.

LIDIA POGGIO, SHIRLEY M. ESPERT & RENEE H. FORTUNATO

RODRIGUESIA

Rodriguesia

Año: 2008 vol. 58 p. 423 - 433

0370-6583

(Evolutionary cytogenetics in Americans Legumes) Chromosomic features described so far for Americanslegumes are reviewed and analyzed, simultaneously with morphological and molecular characters. This is aninvaluable opportunity to propose hypotheses about chromosome changes during the family divergenceand speciation processes. The chromosome studies showed wide inter-generic, inter and intra-specificvariability, as well as marked differences in genome sizes between genera, species and populations. Bypostulating an ancestral basic number of seven (x=7) it is possible to deduce that polyploid hybrid speciationwas very important in the diversification of the family as a whole. Due to increasing and decreasing diploidyprocesses, secondary basic numbers and modified polyploids series could have arised both at diploid andpolyploid levels. On the other hand, recurrent origin of polyploids, occurrence of inter-genomic rearrangements,hybridization and secondary polyploidy are all processes that make it difficult to group the taxa within theLeguminosae family in a natural sequence.Key words: Leguminosae, cytogenetics, poliploidía, chromosome evolution, hybridization, America.