Somatic mutations and recombination test in Drosophila melanogaster used for investigating the genotoxicity of some food additives

Abstract

In the present study, the effects of several food colorings, namely (Ponceau 4R (E 124), Tartrazine (E 102), and Pea green (E 102-E 133), were investigated in vivo using the wing spot test, SMART (somatic mutation and recombination test), in Drosophila melanogaster. Food colorings are the food additives, which are used for improving the appearance of food and beverages. In SMART, multiple wing hair (mwh), flare (flr3), and beaded serrate (BdS) marker genes on the third-largest chromosome of Drosophila are used. The genotoxic effects of the food colorings on the imaginal disc cells that will develop into the wing spot cells during the embryonic development of Drosophila heterozygous larvae and the genotypic changes caused by mutation or recombination in somatic cells also play a role in the formation of mutant spots in the wings. Classes by mutant clones are as follows: small single spots containing 1-2 mwh, large single spots containing ≥3 mwh or ≥4 flr3, and twin spots containing adjacent mwh and flr3 cells (GRAF et al., 1984). Negative control medium was prepared with distilled water, while positive control medium was prepared with 1 mM EMS (ethyl methane sulfonate). According to results obtained from SMART, Ponceau 4R, Tartrazine, and Pea green demonstrated significant results in trans-heterozygous flies (mwh/flr3) for inducing the mutant wing spots compared to control groups at 25 mg/ml, 50 mg/ml, and 75 mg/ml exposure concentrations. On the other hand, Ponceau 4R, Tartrazine, and Pea green yielded significant results for inducing the mutant wing spots in balancer-heterozygous flies (mwh/TM3) at 25 mg/ml, 50 mg/ml, and 75 mg/ml exposure concentrations. The numbers of mutant wing spots were increased by all three colorings depending on the concentration (X2= df=3, P<0.001). It was also determined that these numbers were significantly higher than the flies in the negative control medium and it suggests that these food colorings have genotoxic effects. However, the numbers of mutant wing spot were less than the flies in the positive control medium; this finding indicates that genotoxic effects of the food colorings were not as much as the EMS.