B chromosomes observed in 100% cells of 12 females and 01 male. No individual carried more than one B chromosome per cell.
Karyological information
Record 1
Geographical area of study
Capivara River, Tieteˆ River basin, Botucatu, Sao Paulo, Brazil.
Source of chromosomes
Kidney tissue, gills.
Number of specimens with sex
50 (18 male, 32 female)
Diploid chromosome number
50
Karyotype formula
8m+12sm+14st+16a
Fundamental arm number
84
Chromosome length
-
Sex chromosome
-
Chromosome staining/banding/FISH
Faint C bands present in some A and in B chromosomes, while strong bands present in terminal region of long arms of acrocentric pairs 18–22. Ag-NORs showed intra-population variation with pair No. 12 showed principal NOR, and pair No. 2 sometimes Ag-NOR positive. No Ag-NORs observed in B chromosomes. 18S rDNA signal present on short arm of chromosome pair No. 12. 5S rDNA located in pericentromeric region of pair nos. 2 and 20.
Reference
Silva DMZdA, Pansonato-Alves JC, Utsunomia R, Araya-Jaime C, Ruiz-Ruano FJ, et al. (2014) Delimiting the origin of a B Chromosome by FISH mapping, chromosome painting and DNA sequence analysis in Astyanax paranae (Teleostei, Characiformes). PLoS ONE 9(4): e94896
Karyotype /Metaphase complement image
Record 2
Geographical area of study
Pindorama and Lopei streams (upper Paraná river basin), Brazil.
Source of chromosomes
Anterior kidney cells.
Number of specimens with sex
26 (10 male, 16 female)
Diploid chromosome number
48
Karyotype formula
8m+20sm+10st+10a
Fundamental arm number
-
Chromosome length
-
Sex chromosome
-
Chromosome staining/banding/FISH
In Pindorama stock, AgNORs present terminally in long arm of chromosomes pairs 3, 5, 18 and in pairs 15, 16, 19 and bitelomerics on pair 4. In Lopei stock, AgNORs found terminally on long arm of chromosome pairs 3, 14 and in short arm in chromosome pairs 15, 19 and in short arm in pair 16. C-bands observed as small centrometric marks in chromosome pairs 3, 4, 5, 8, 13, 15, 16, 18, 19 in Pindorama stock, and pairs 2, 3, 8, 9, 10, 15, 16 in Lopei stock, and associated with NORs in both stocks.
Reference
Yano CF, Filho OM, Margarido VP (2014). Interpopulational comparative cytogenetics analysis among three Astyanax (Characiformes: Incertae Sedis) species of two streams of upper Paraná River basin, Brazil. Biologia (Section Zoology), 69/6: 790—798.
