On March 27, 1964, an earthquake measuring 9.2 on the Richter scale – the second strongest in history – devastated Southeast Alaska. One of its victims was the then spiny saltwater fish ( Gasterosteus aculeatus ), caught in small lakes or ponds formed as a result of the earthquake in the islands of Prince William Sound (Prince William Strait) and the Gulf of Alaska.
And, as scientists at the universities of Oregon and Alaska have discovered, the spiny fish’s body then began a desperate evolutionary race to adapt to its new freshwater habitat. Successfully: In just five decades, this aquatic species underwent remarkable changes in its body shape , eyes, pigmentation, spine size, body coverage, and of course its genome.
This supports the hypothesis that evolution does not take thousands or millions of years to model animal organisms: a catastrophic event or sudden environmental transformation can accelerate the rate on timescales of decades or even years even in vertebrates.
Experts knew that Gasterosteus aculeatus had already adapted to freshwater before, 13,000 years ago, when there was a retreat of glaciers, but now they have proven how quickly it can do so. To do this, they have used a technology called Restriction Site Associated DNA Sequencing (RAD-seq). “The change is not simply cosmetic, like getting tanned by the sun; the genome has been rapidly remodeled. This finding may allow us to better understand how climate change is affecting all kinds of species ”, explained Susan L. Bassham, co-author of the research.
Image: University of Oregon
