A team of researchers found that Atlantic killifish evolve very quickly in order to adapt to polluted environments. The fish are able to do this because of abnormally high genetic diversity. The details are in a paper that was just published in the journal Science.
Killifish are egg-laying fish that are known for being incredibly hardy. The fish can live in tiny pools of water, their eggs can survive dehydration, and they’re found in a wide range of habitats. Many are small and brightly colored, making them popular additions to home aquariums. Interestingly, Atlantic killifish living in highly polluted areas seemed to be thriving while other fish failed to adapt.
Researchers from the University of California studied populations of Atlantic killifish that were living in East Coast estuaries that had become heavily polluted because of human industrial activity. The team first discovered that the killifish could tolerate this type of pollution 8000 times better than other local fish. In an attempt to understand how the killifish were evolving and adapting so quickly, the researchers analyzed 384 genome sequences from both polluted and clean collection sites.
The team found that killifish showed more genetic variation than most other animals, including humans and all previously studied vertebrates. This variation in genes meant more genetic diversity in the population, allowing the fish to evolve at a rapid pace. For most fish, the process of evolving adaptive genes would take many years but the killifish could adapt remarkably quickly. The concept of genetic diversity leading to fast adaptation is sometimes responsible for pest species adapting to the use of pesticides within years. The team believes that studying the killifish could help explain how animals might adapt to chemical pollutants.
The findings are good news for Atlantic killifish, which appear to be capable of living in highly polluted environments. However, the authors are quick to point out that this isn’t true of most species and that environmental pollution should be treated as a serious problem.
Reid et al. The genomic landscape of rapid repeated evolutionary adaptation to toxic pollution in wild fish. Science (2016).