Fig. 2. (A) PCR amplification of DNA isolated from copepod embryos using the 16SAR and 16SBR primers, as reported in Materials and methods. The arrow indicates the presence of a single PCR product of approximately 430 bp. The presence (+) or absence (-) of template DNA is shown above. (B) DNA laddering of two DNA samples (6, 18) isolated from copepod embryos treated with 5 µg ml^-1 of DD for 3 and 1 h, respectively. Sample 31 represents an untreated control. Semiquantitative analysis of the fragmentation extent is reported in Table 1. M, markers (DNA Ladder 100; from top to bottom: 1000, 900, 800, 700, 600, 500, 400, 300, 200 bp).