New Delhi: A recent research led by US scientists identifies the genetic mechanism which is responsible for evolutionary adaptation to toxic pollution observed in wild Atlantic killifish populations.
The Atlantic killifish is renowned for its ability to tolerate large fluctuations in temperature, salinity and oxygen levels.
However, its rapid adaptation to the normally lethal levels of toxic pollution found in some urban estuaries in the US is unusual, even for such a hardy species.
A report by a collaborative team of research institutions including the University of Birmingham, found that some populations of killifish are up to 8,000 times more resistant than others to highly toxic industrial pollutants such as dioxins, heavy metals and hydrocarbons.
The team analysed the genomes of four wild populations of pollution-tolerant killifish compared with four non-tolerant populations, to identify the mechanism behind this adaptation.
They found that the genes responsible for the trait were those involved in the aryl hydrocarbon receptor (AHR) signalling pathway, which combined with observations of desensitisation of this pathway in tolerant populations, led them to conclude that the AHR pathway is a key target of natural selection.
The team also showed that the potentially negative effects of desensitisation of the AHR pathway were ameliorated through compensatory adaptations in terms of cell cycle regulation and immune system function.