“Genomic technology has helped document rapid evolutionary transformation of threespine stickleback in less than 50 years’
Typically when people think of evolutionary adaptations they are presuming that they take place over a relatively long period of time. However, recent research shows that some species can actually mutate on a much faster scale when they are abruptly forced into a new environment. One such species is the threespine stickleback, a tiny fish that originally lived solely in saltwater, but has developed a “genetic bag of tricks for invading and surviving in new freshwater habitats.’ According to research projects conducted by the University of Oregon, and with help from University of Alaska researchers, the stickleback has not only become capable of thriving in fresh or saltwater since the end of the last Ice Age, but independent populations in Alaska have been shown to have undergone this, as well as several other changes in 50 years or less, which is remarkable in terms of evolutionary progress.
Image Credit: University of Oregon
The first study, conducted in 2010 using rapid genome-sequencing technology affirmed that “stickleback had evolved genetically to survive in fresh water after glaciers receded 13,000 years ago.’ This finding prompted a follow-up study to reveal just how quickly this kind of change could take place. The new study focused on independent populations of threespine sticklebacks that had been trapped in fresh water after the 1964 Alaska earthquake. The massive earthquake “caused geological uplift that captured marine fish in newly formed freshwater ponds’, and the stickleback have since experienced “changes in both their genes and visible external traits such as eyes, shape, color, bone size and body armor.’ According to one of the main authors of the final paper, William Cresko, they have even “found evidence of changes in fewer than 10 years’, leading researchers to wonder if these kinds of rapid evolutionary changes could be “happening with other organisms as well.’
The findings, according to senior researcher, Susan L. Bassham, verify that “organisms – even vertebrates…can respond very fast to environmental change’, an idea that “perhaps opens a window on how climate change could affect all kinds of species.’ Undoubtedly, more research should be conducted, and on a larger number of organisms to predict just how many others may hold the same “hidden genetic diversity’ that has helped the stickleback to adjust so gracefully to a fundamentally altered environment.
The original paper is available online through the Proceedings of the National Academy of Sciences.
Emily A. Lescak, Susan L. Bassham, Julian Catchen, Ofer Gelmond, Mary L. Sherbick, Frank A. Von Hippel, and William A. Cresko. Evolution of stickleback in 50 years on earthquake-uplifted islands. PNAS, December 14, 2015 DOI: 10.1073/pnas.1512020112
University of Oregon. “Small fish species evolved rapidly following 1964 Alaska earthquake: Genomic technology has helped document rapid evolutionary transformation of threespine stickleback in less than 50 years.” ScienceDaily. ScienceDaily, 14 December 2015. <www.sciencedaily.com/releases/2015/12/151214165724.htm>.