Induction of adaptive response in Drosophila after exposure to low doses of UVB.

Purpose: The aim of this study was to assess the adaptive response induced by low doses of ultraviolet-B (UVB, 290-320 nm) radiation in the Drosophila wing spot test. Materials and methods: The adaptive response of Drosophila larvae to UVB light was studied by using a somatic mutation and recombination test (SMART). The SMART system used was the wing spot test, which uses morphological markers of the wing blade. This in vivo test has shown to be very useful to study the induction of genetic damage in somatic cells, measuring loss of heterozygosity (LOH) resulting from gene mutation, mitotic recombination, chromosomal rearrangements or chromosome loss. Results: To determine the induction of adaptive response, two-day-old Drosophila larvae were first irritated with an adaptive dose (58.3 J/m²), followed by different challenge doses (178, 224, 288, 338, and 386 J/m²). When the results obtained in the different challenge doses were compared with those obtained following the application of adaptive plus challenge doses, significant decreases (74.7-80.8%) in a first experiment, and (65.6-78.4%) in a second experiment, were observed in the frequency of mutant spots on the wing blades. Conclusions: Our results show that in Drosophila the adaptive response can be stimulated in vivo by UVB exposure. [ABSTRACT FROM AUTHOR]