A rapid chromosome preparation technique without metaphase arrest for ploidy determination in Nile tilapia, Oreochromis niloticus

Figures & data

Figure 1. Diagram protocol of simple and rapid fish chromosome preparation.

Figure 2. Chromosome spreads (arrows) observed at 400 × magnification; prepared without (a) and with (b) metaphase arrest treatments.

Table 1. Chromosome spreads and mitotic index of different fish age groups in tilapia.

Fish age (months)	Cell number	Chromosome spreads	Mitotic index
	(cell)	(cell)
1	54,288 ± 1690	419 ± 99	0.008 ± 0.002 ^a
2	37,216 ± 1845	386 ± 83	0.010 ± 0.002 ^a
3	51,872 ± 3492	240 ± 66	0.005 ± 0.001 ^b

Note: Different superscripts in the same column indicate significant difference (p < 0.05).

Figure 3. Silver stained diploid (a) and triploid (b) chromosomes and Giemsa stained diploid (c) and triploid (d) chromosomes prepared without metaphase arrest treatment compared with Giemsa stained diploid (e) and triploid (f) chromosomes prepared with metaphase arrest treatment (arrows indicate giant chromosomes).