rDNA loci and heterochromatin positions support a distinct genome type for ‘x = 9 species’ of section arachis (arachis, leguminosae)
Fecha
2014Autor
Silvestri, María Celeste
Ortíz, Alejandra Marcela
Lavia, Graciela Inés
Metadatos
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Most species of the genus Arachis (Leguminosae;
80 spp.) are diploid with x = 10 and only four
species have x = 9 chromosomes. Three of these x = 9
species belong to section Arachis and are morphologically
and chromosomally similar. To study the homeology of the
genomes of x = 9 species and their relation to other genomes
in section Arachis, we applied fluorescence in situ
hybridization (FISH) of 18S–26S and 5S rDNA and 40,6-
diamidino-2-phenylindole (DAPI) banding. FISH revealed
for these three species one pair of 5S rDNA sites interstitially
within the short arm of the metacentric pair 6 and one
pair of 18S–26S rDNA sites in the proximal region of the
long arm of the SAT chromosomes. Conspicuous DAPI?
bands were detected pericentromerically in all nine chromosome
pairs of A. decora and A. praecox and in all but
one pair of A. palustris. Our results suggest that all three
species with x = 9 of section Arachis share the same
genome type and are different from the other genome types
A, B, D, F, and K described for this section. Apparently,
the x = 9 species of section Arachis form a monophyletic
group characterized by a genome type, that we propose to
call G genome.
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