The Comet assay: A biomarker of DNA damage and adaptation in water hyacinth plants under climate change

Raghad S. Mouhamad

Abstract

Aquatic organisms are exposed to various environmental stressors or contaminants that can induce DNA damage. These include physical factors (such as temperature, radiation, or mechanical stress), chemical factors (such as pollution, pesticides, or metals), or biological factors (such as pathogens, parasites, or eDNA sources). The alkaline comet assay is a technique that measures the degree of DNA strand breaks in aquatic organisms. The comet assay provides indicators of DNA damage, such as the percentage of DNA in the tail (%DNA in Tail), tail moment, and tail length. In this study, we used the comet assay to evaluate the DNA damage parameters in aquatic organisms from eight sites along a river at two time points: 1/12/2022 and 1/7/2022. The environmental factors, such as temperature and rainfall, for each month were also evaluated. The results showed that there were significant variations in DNA damage parameters among the sites and over time, which may reflect the influence of various environmental factors or biological processes on the DNA integrity of the samples. The results with previous studies were compared which employed comet assay to assess DNA damage in aquatic organisms. It was found that different factors, such as temperature, pollution, pesticides, or eDNA sources, can affect the DNA integrity of aquatic organisms. Therefore, it is important to consider these factors when interpreting comet assay.