PHYSICAL LOCALIZATION OF REPETITIVE DNA-SEQUENCES IN ALSTROEMERIA - KARYOTYPING OF 2 SPECIES WITH SPECIES-SPECIFIC AND RIBOSOMAL DNA

Fluorescence in situ hybridization (FISH) was used to localise two spe cies-specific repetitive DNA sequences, A001-I and D32-13, and two hig hly conserved 25S and 5S rDNA sequences on the metaphase chromosomes o f two species of Alstroemeria. The Chilean species, Alstroemeria aurea (2n = 16), has abundant constitutive heterochromatin, whereas the Bra zilian species, Alstroemeria inodora, has hardly any heterochromatin. The A. aurea specific A001-I probe hybridized specifically to the C-ba nd regions on all chromosomes. The FISH patterns on A. inodora chromos omes using species-specific probe D32-13 resembled the C-banding patte rn and the A001-I pattern on A. aurea chromosomes. There were notable differences in number and distribution of rDNA sites between the two s pecies. The 25S rDNA probe revealed 16 sites in A. aurea that closely colocalised with A001-I sites and 12 in A. inodora that were predomina ntly detected in the centromeric regions. FISH karyotypes of the two A lstroemeria species were constructed accordingly, enabling full identi fication of all individual chromosomes. These FISH karyotypes will be useful for monitoring the chromosomes of both Alstroemeria species in hybrids and backcross derivatives.