| dc.description.abstract | Corydoras aeneus is a freshwater ornamental fish native to the waters of
South America. It is exhibiting unique behavior of cleaning aquarium walls with its
mouth. C. aeneus locally known as the mouse fish, and it has been widely cultivated
in Indonesia. This research aims to determine the karyotype characteristics of mouse
fish distributed in Indonesia, specifically from two different cultivation locations:
Medan and Bogor. This research used a descriptive method with fish samples
obtained from ornamental fish sellers in Medan, acclimatized for 4 days. The fish
were immersed in a 0.007 % colchicine solution for 8 hours to obtain chromosomes
at the metaphase stage. Chromosome preparations were made using the solid tissue
technique from fish gills, stained by 5% Giemsa solution, and observed under a
AmScope microscope. Karyotype analysis was performed using Adobe Photoshop
CS3 and IdeoKar 1.3 software. The analysis results show that Corydoras
aeneus from Medan and Bogor have the same diploid chromosome number of 2n =
56, but there are differences in chromosome size and shape. C. aeneus from Medan
has the largest chromosome measuring 11.62 µm, with a total complement
chromosome length of 202.43 µm, a total form percentage of 44.08 %, a karyotype
asymmetry index of 55.91 %, and an average centromeric index of 0.42 µm.
Meanwhile, C. aeneus from Bogor has the largest chromosome measuring 13.29 µm,
with a total complement chromosome length of 214.31 µm, a total form percentage
of 44.22 %, an asymmetry index of 55.77 %, and an average centromeric index of
0.42. C. aeneus from Medan has 23 pairs of metacentric chromosomes, 4 pairs of
submetacentric chromosomes, and 1 pair of telocentric chromosomes. In contrast,
those from Bogor has 24 pairs of metacentric chromosomes, 2 pairs of
submetacentric chromosomes, and 2 pairs of telocentric chromosomes. The
differences in chromosome size and shape indicates genetic variation between
populations. Corydoras aeneus from Medan shows a more advanced evolutionary
level with a slightly higher karyotype asymmetry index compared to those from
Bogor. Although there is genetic variation between populations, it does not cause
morphological differences in C. aeneus. | en_US |
