It’s evolution in action seen in unprecedented detail. Genome sequencing of hundreds of killifish in the eastern US has revealed dozens of the evolutionary changes that allow them to survive in extremely polluted waters that would normally kill such fish.
(From New Scientist / by Micheal Le Page)– “They can survive thousands of times the usual lethal levels,” says team member Andrew Whitehead at the University of California, Davis.
Another striking thing is that they managed to evolve this extraordinary ability in just half a century or so, since the estuaries they live in started getting polluted.
Although many people think evolution is a slow process, it can in fact happen extremely fast. There are thousands of examples of evolution in action, from the famous peppered moths that turned black to camouflage themselves on soot-covered trees to the ever-growing numbers of antibiotic-resistant bacteria.
In most cases of contemporary evolution, the genetic changes involved have never been identified. The mutation that turned the first few peppered moths black in about 1819 was identified only earlier this year, for instance.
With DNA sequencing getting ever cheaper, biologists in the US have now been able to sequence the genomes of nearly 400 individual Atlantic killifish (Fundulus heteroclitus), a small fish also known as the mummichog that lives in estuaries along the east coast. They compared the genomes of killifish in four highly polluted areas with those from four unspoilt sites.
“I have never seen an ecological study in which people sequenced the genomes of so many individuals,” says Isaac Wirgin at New York University School of Medicine, who studies how another fish, the tomcod, has adapted to pollution. “We really are going through a revolution.”
Read the full article here: https://www.newscientist.com/article/2115635-fish-rapidly-adapt-to-pollution-thousands-of-times-lethal-levels/