Effect of sex on ratios and concentrations of DNA and RNA in three marine species

The aim of the present study was to quantify differences in RNA:DNA ratios between male and female fishPomatoschistus microps, crustaceansCrangon crangon, and bivalvesRuditapes decussatus. RNA:DNA ratios were greater in females than in males, especially because of a greater RNA content per unit dry weight in females. Sexual dimorphism in addition to physiological and behavioural differences between males and females may account for these results. RNA:DNA ratios of adult marine organisms should be interpreted with caution, because the effect of sex on nucleic acid concentrations may bias results if the sex ratio in the sample from which results were derived is not representative of the population.