Exploring the Influence of Intermittent Heat Exposure on Spontaneous Mutations in Drosophila melanogaster: Assessing the Role of Vitamin C in Mitigating Heat Stress and Examining Inheritance Patterns of Induced Mutations

Abstract

Climate change poses a significant threat to the well-being of organisms. It has a detrimental impact on the survival of smaller organisms in response to climatic shifts, posing a substantial danger to biodiversity, which is already under stress due to habitat loss, emerging invasive species, and diseases. This study aimed to assess the influence of fluctuating temperatures on the physiology and behavior of Drosophila melanogaster, as well as to investigate whether such temperature fluctuations have any effect on phenotypic expression through potential spontaneous mutations. Genotypic changes were examined by observing cytological alterations in the salivary gland chromosomes. Drosophila melanogaster were exposed to intermittent heat conditions for a period of two weeks. The experimental setup was divided into four groups: a control group maintained at room temperature (25±2°C), a group at room temperature supplemented with vitamin C, a group exposed to heat at 38±2°C, and a group exposed to 38±2°C with vitamin C supplementation. Revival of the flies was noticeably better in the vitamin C supplemented group. These flies exhibited a higher revival rate even after exposure to the heat stress. Salivary gland chromosome analysis provided intriguing insights. More balbiani rings were observed, indicating elevated mRNA production during the heat exposure. Furthermore, an increase in the number of puffs in polytene chromosomes was noted, suggesting an overall increase in mRNA production in the heat-exposed flies. Additionally, the evaluation of wing mutants yielded important findings. It became evident that these mutations were not related to vestigial or curly wing traits. Instead, they indicated that heat exposure was damaging wing formation, resulting in abnormal wing patterns. These results suggest a substantial impact of temperature fluctuations on insect behavior, which can even lead to the induction of mutations. Generational studies further indicate that these mutations can be inherited.