Is genetics the unrecognized confounding factor in bioelectromagnetics? Flock-dependence of field-induced anoxia protection in chick embryos

Work in bioelectromagnetics has long been plagued by problems with replicat ion. This includes experiments done on electromagnetic (EM) field-induced e ffects in chick embryos. Our laboratory investigated responses of embryos f rom two flocks of White Leghorn hens. Both flocks were studied simultaneous ly, and it was found that they responded differently to EM field exposures. Embryos were exposed to 60 Hz, 8 mu T EM fields prior to placement in an a noxic chamber. Following re-oxygenation, survival in controls was 34.6%, ex posed flock 1 survival was 62% (P < 0.0001) and exposed flock 2 survival wa s 43% (P < 0.0136). P values are from comparison of data between EM field e xposed embryos (flocks 1 and 2) versus controls. In order to induce maximum protection in flock 2, (approximate to 62% survival), embryos required a l onger exposure time at higher magnetic field strengths. These results reinf orce the concepts that genetics are important in determining whether or not chick embryos will respond to EM field stimulation. A broader look at the role of genetic factors emphasizes that these variations in response to ext ernal stimuli (e.g., drugs, radiation, and EM fields) are found in all area s of biological research (cell culture, chick, rat, and human studies). The present study suggests that genetics may be a prime cause of the difficult ies encountered in replication studies in the field of bioelectromagnetics. We conclude that replication studies should not be undertaken unless care is taken to insure that exactly the same strains of cells or animals are us ed. Researchers should also first confirm that the responses of their model to non-EM field stimuli are similar to that obtained in the original study . (C) 1999 Elsevier Science S.A. All rights reserved.