Evidence is rapidly growing to link adverse health effects in divergent natural species and humans located in similar exposure areas. Our objective is to provide a mechanistic understanding of variables associated with environmentally-induced mutation in laboratory and alternative/environmental sentinel models. The biological complexity can be reduced by using the same gene marker in a variety of models, independent of expression, growth or selection. We have used a bacteriophage as a transgenic indicator in different animals and cells; there is no expression of the phage and recovery of the sequence from each cell means that the use of animals can be greatly reduced. Initially, the approach has been developed and tested using a selective mutant detection. We have produced transgenic fish and human/hamster cells in vitro and demonstrated that the spontaneous mutation frequencies for in vitro cells and tissues of fish were similar to mice and ranged between 1.8-3.7x10-7. Significant increases were observed in mouse cells after exposure to EMS, and in mouse tissues after exposure to ENU. We have now produced two transgenic aquatic species Oryzias latipes (medaka, freshwater), and Fundulus heteroclitus (mummichog, saltwater); both species are used extensively for environmental and laboratory studies. Spontaneous mutation frequencies among phage recovered from F. heteroclitus founders are in the range of 2-4x10-7 and similar to the frequencies observed in mice and cultured mouse cells. Transgenic in vitro goldfish, human and hamster cells have also been produced and preliminary analysis indicates spontaneous mutation frequencies of 1-3x10-7. Significant increases have been observed in fish treated with ENU. Taken together, these results indicate an identical gene target can be used in aquatic species, laboratory mammals and a variety of cultured cells in studies designed to provide a sound scientific basis for extrapolation between various animal and alternative models.
