Flow cytometry measurement of the DNA contents of G0/G1 diploid cells from three different teleost fish species

Background: Although there is a lot information in the literature about genome size in fish, a high variability among data for the same species is reported, being mainly related to methodological aspects. Flow cytometry-based fluorescence measurements of intercalating dyes is the most attractive approach due to its precision, objectivity, high speed, and relative simplicity. Methods: We analyze the DNA content of G0/G1 diploid nuclei of three teleost species (Carassius auratus, Tinca tinca, and Danio rerio) using flow cytometry. Forty-three animals were used and up to 50,000 retinal cells were analyzed per sample. Propidium iodide-associated fluorescence was assessed using a FACSCalibur flow cytometer. Standard human leukocytes were used as a reference. Results: Our results show that C auratus (3.584 +/- 0.058 pg per nucleus) and D, rerio (3.357 +/- 0.074 pg per nucleus) showed similar DNA contents per cell, whereas it was significantly lower (2.398 +/- 0.038 pg per nucleus) in T Mica. Interestingly, a low intraspecies variability was observed, the coefficient of variation being 1.608%, 2.198%, and 1.573% for C auratus, D. rerio, and T tinca, respectively. Conclusions: The methodology used in this study provides an accurate and easy measurement of the genome size of a species. (C) 2002 Wiley-Liss, Inc.