Fig 1.
Chromosome spreads of D. antarctica.
(A) Giemsa C-banded chromosomes of the specimen from Galindez Island. (B) Inverted image of the DAPI/C-banded karyotype and (C) localization of 45S (green) and 5S (red) rDNA sites on chromosomes of the specimen from Galindez Island. (D) Ag-NOR staining patterns (dark segments) of chromosomes of the specimen from Skua Island. (E) Localization of telomeric repeats (green), 45S (green) and 5S (red) rDNA loci and in the karyotype of the specimen from Skua Island. Arrows point to the intercalary loci of telomere repeats detected on the largest chromosome pair. (F) Distribution of 5S rDNA sites (red) and GAA microsatellite sequence (green) on chromosomes of the specimen from Skua Island. Scale bar—5 μm.
Fig 2.
Karyograms and idiograms of D. antarctica chromosomes.
Karyograms after (A) Giemsa C-banding and (B) FISH with 45S (green) and 5S (red) rDNA probes (the same metaphase plate as in Fig 1A). Karyograms after (C) DAPI/C-banding (inverted image) and (D) FISH with 45S (green) and 5S (red) rDNA (the same metaphase plate as in Fig 1B and 1C). (E) Idiograms of D. antarctica showing relative sizes and positions of DAPI/C-bands (black segments), 45S (green) and 5S rDNA (red).
Fig 3.
Chromosome spread of D. antarctica specimen from Darboux Island.
Chromosome localization of 45S (green) and 5S (red) rDNA sites and inverted image of DAPI/C-banded B-chromosomes (bottom right). Arrows point to the B-chromosomes. Scale bar—5 μm.
Fig 4.
Chromosome spread of the triploid D. antarctica specimen from Great Jalour Island.
(A) The merged fluorescent image: multicolour FISH with telomeric repeats (red), 45S (purple) and 5S (light blue) rDNA probes and sequential rapid GISH with genomic DNA of D. caespitoza (yellow). (B) Localization of chromosome markers revealed by rapid GISH (light green) in relation to 45S (blue) and 5S (red) rDNA loci. Arrows indicate the brightest green signals detected on chromosomes 5 (grey arrows), 8 (short arrows) and 12 (long arrows). (C) Chromosome markers revealed by rapid GISH (yellow) in relation to telomeric repeat signals (red). (D) Inverted image of DAPI/C-banded chromosomes. Long arrows indicate chromosome 12 and a Robertsonian translocation between two homologous chromosomes 12. (E) Karyograms of metaphase chromosomes after multicolour FISH (left) and DAPI/C-banding (inverted image) (right). Scale bar—5 μm.
Table 1.
Cytogenetic analysis of D. antarctica specimens from Great Jalour Island.