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Genotoxins are capable of multigenerational impacts on natural populations via DNA damage and mutations. Sexual reproduction is assumed to reduce the long term consequences of genotoxicity for individual fitness and should therefore reduce population level effects. However, rather few empirical studies have quantified the magnitude of this effect. We tried to analyse the multigenerational demographic responses of sexual Artemia franciscana and asexual Artemia parthenogenetica due to chronic genotoxicity by a reference mutagen, ethyl methane sulfonate (EMS). A prospective (elasticity analysis) and retrospective (differences and contributions) perturbation analysis was carried out to understand the interactions of life history traits with population growth rate λ by comparing elasticities, differences and contributions of vital rates to λ. None of the previous studies have compared the effects of chronic genotoxicity using prospective and retrospective perturbation analyses in a sexual and asexual species over generations. The behaviour of a population with lower growth rate in the presence of genotoxicants in the field was studied by simulating reduced fertilities in the LTRE design. The results of prospective and retrospective perturbation analyses of effects on λ showed that population growth rate was proportionally more sensitive to juvenile survival whereas the effect of EMS on juvenile fertility contributed more to the variations in population growth rate in both the species and this effect was due to the high growth rate of Artemia. Simulations of lower population growth rate in the model showed that adult fertility and survival are also of importance. Sexual reproduction substantially mitigated the long term consequences of genetic damage, although these would be greater if population growth rate were lower. So multigenerational population level consequences of genotoxicity were much greater in an asexual species. So asexual species, and those with a parthenogenetic phase in their life cycle, may be particularly vulnerable to the effects of environmental mutagens. Ecological risk assessments should include information from multigenerational studies, as responses to genotoxicity may vary depending on the life history strategies and reproductive modes of the species under consideration. Single generation studies may under or over-estimate risks., (Copyright © 2013 Elsevier B.V. All rights reserved.)

There is considerable evidence that genetic damage in organisms occurs in the environment as a result of exposure to genotoxins and ionising radiation, but we have limited understanding of the extent to which this results in adverse consequences at a population level. We used inter-simple sequence repeat (ISSR) markers to quantify genotoxic effects of the mutagen ethylmethane sulfonate (EMS) on a sexual (Artemia franciscana) and an asexual (Artemia parthenogenetica) species of brine shrimp. The method provides information similar to that obtained with assessment of RAPD (random amplification of polymorphic DNA) but is more robust. Genetic damage was transmitted to the F1 generation in both Artemia species, but the sexual species showed a greater degree of recovery, as shown by higher values of genomic template stability. There was a strong correlation between DNA damage and effects on individual fitness parameters: size, survival, reproduction and population growth. These effects persisted into the F2 generation in A. parthenogenetica, but in the sexual A. franciscana only effects on fecundity continued beyond the exposed generation, even though there were substantial alterations in ISSR patterns in the F1 generation. Genetic biomarkers can thus be indicative of effects at the population level, but sexually reproducing species have a considerable assimilative capacity for the effects of genotoxins., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The impact of chronic genotoxicity to natural populations is always questioned due to their reproductive surplus. We used a comet assay to quantify primary DNA damage after exposure to a reference mutagen ethyl methane sulfonate in two species of crustacean with different reproductive strategies (sexual Artemia franciscana and asexual Artemia parthenogenetica). We then assessed whether this predicted individual performance and population growth rate over three generations. Artemia were exposed to different chronic concentrations (0.78mM, 1.01mM, 1.24mM and 1.48mM) of ethyl methane sulfonate from instar 1 onwards for 3 h, 24 h, 7 days, 14 days and 21 days and percentage tail DNA values were used for comparisons between species. The percentage tail DNA values showed consistently elevated values up to 7 days and showed a reduction from 14 days onwards in A. franciscana. Whilst in A. parthenogenetica such a reduction was evident on 21 days assessment. The values of percentage tail DNA after 21 days were compared with population level fitness parameters, growth, survival, fecundity and population growth rate to know whether primary DNA damage as measured by comet assay is a reliable biomarker. Substantial increase in tail DNA values was associated with substantial reductions in all the fitness parameters in the parental generation of A. franciscana and parental, F1 and F2 generations of A. parthenogenetica. So comet results were more predictive in asexual species over generations. These results pointed to the importance of predicting biomarker responses from multigenerational consequences considering life history traits and reproductive strategies in ecological risk assessments., (Copyright © 2013 Elsevier Inc. All rights reserved.)