Cytotoxic and genotoxic effects of mercury in house fly Musca domestica (Diptera: Muscidae).

Mercury, one of the most widely diffused and hazardous environmental contaminants, induces oxidative stress in organisms, which ultimately leads to genotoxicity and cytotoxicity. House fly Musca domestica L. was used as a model for assaying the genotoxic potential of mercury with the help of micronucleus assay, chromosomal aberration assay as end points and cytotoxicity by assaying the mitotic index and the extent of tissue damage by trypan blue dye exclusion. Late third instar larvae were exposed to different dietary concentrations of mercury (0.0001 mg/ml- 10 mg/ml) for various time intervals. A dose dependent increase in chromosomal aberrations, micronucleus frequency and mitotic index was observed. Micronucleus frequency increases with time while mitotic index decreases showing decreasing rate of cell proliferation due to an increase in cell death. Trypan blue staining gives the visual manifestation of cytotoxicity at higher concentrations of mercury (1 mg/ml- 10mg/ml). The present study suggests that the house fly model may be used to assay the genotoxicity and cytotoxicity of mercury as well as other environmental pollutants.

Seasonal genetic variation in house fly populations, Musca domestica (Diptera: Muscidae).

Seasonal genetic variation was assessed in the common house fly Musca domestica. Allozymes at six gene enzyme system viz., ACPH, EST, G6PD, ME, AO and XDH were analyzed. Fourteen loci with twenty seven alleles were unraveled. The genetic variations were found to be affected to a great extent by environmental influence .F statistics has been used to calculate genetic variation which revealed that very little genetic variation has occurred among the house fly populations analyzed in the present study. Further, except ACPH-2, G6PD-2 and XDH-1 all the other loci show inbreeding (Fis>Fst). Thus it appears that the house fly populations analyzed are characterized by high level of inbreeding. Nei's genetic identity (I) and distance (D) values reveal a close similarity between summer and rainy season collections.