BANGALORE: Scientists in Goa have found that pollution of sea waters brings about changes in the DNA of snails.
They have discovered that the changes in the DNA is more along the Goan coast as the level of pollution is higher there. These changes can be used as a marker to predict pollution levels in marine waters in future, they observed.
The scientists said they collected a species of snails called M granulata from different sites such as Arambol, Anjuna, Sinquerim, Dona Paula, Bogmalo, Hollant, Velsao, Betul and Palolem, and measured the extent of DNA changes.
The highest DNA integrity (least alteration) was observed at Arambol, identified as the reference site, whereas the lowest DNA integrity was found at Hollant, situated between two highly contaminated sites — Bogmalo and Velsao.
The paper said, “The extent of DNA damage in snails increases with the increase in the levels of contamination at different sampling sites. The measurement of DNA integrity in M Granulata provides an early warning signal of contamination of the coastal ecosystem of Goa by genotoxic contaminants.”
The main author of the paper, Anupam Sarkar, said, “It is important to study how a continually-changing environment affects the genome and immunological response in marine organisms.”
According to the paper, “Marine organisms are exposed to a variety of genotoxic agents like polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) organochlorine pesticides (OCPs) and heavy metals. These marine pollutants are likely to cause severe damage to the genetic material.”
On why snails were chosen for the study, the scientist said, “The snails, which belong to the group Mollusca, are the most abundant animals after arthropods and 80 per cent of molluscs are represented by gastropods. Gastropods are efficient accumulators of metals, organic pollutants and respond to pollution in a sensitive and measurable manner. They move very slowly, are very useful to study for bio-monitoring of pollution and eco-toxicological studies.”