Variação cromossômica e evolução da heterocromatina em espécies brasileiras de Araceae.

Abstract

The Araceae family comprises about 3300 species distributed in 105 genera. It has a cosmopolitan distribution with greater representation in tropical regions. The present work analyzed the karyotype of 13 species of the Araceae family, using conventional techniques of analysis and banding with CMA/DAPI. The species showed a variable karyotype with acrocentric, submacentric and metacentric chromosomes in all taxa analyzed with chromosomal numbers ranging from 2n = 26 in the genera Dracontium and Dracontioides, to 2n = 60 in Monstera adansonii. The analysis of the CMA / DAPI band pattern was quite variable and informative in differentiating the karyotypes of the Araceae family. The Anthurium genus exhibited CMA+ /DAPIpericentromeric bands in most species, in addition to regions strongly stained with DAPI located mainly in the distal regions of almost all Anthurium scandens chromosomes. The Philodendron genus presented CMA+

/DAPIbands in all analyzed species, with emphasis on

Philodendron ornatum, which presented CMA+

/DAPIheterozygous bands in the pericentromeric region of a chromosome. CMA blocks were observed in the species Dracontioides desciscens, Taccarum ulei and Monstera adansoni, the latter corresponding to RONs. The high variability without heterochromatic bands pattern corroborates the importance of dysploidies and subsequent chromosomal rearrangements in the chromosomal evolution of the Araceae family, especially evidenced in the genus Anthurium and Philodendron.