Storspigg. Foto: Johan Lind
Three-spined stickleback. Photo: Johan Lind
 

“It has been fascinating to see how three-spined sticklebacks have undergone convergent evolution both outside paper pulp mills and in strongly eutrophic areas along the coasts of Sweden and Finland.” 

Using methods in population genomics, Emma Lind determined that the genetic composition of three-spined sticklebacks is clearly altered in those living outside pulp mills. Moreover, the changes are similar, convergent, outside several pulp mills along the coast of Sweden. But it is not only pulp mills that affect the genetic composition of these fish; eutrophication can have a similar, though weaker effect.

DNA sequences mutated in sticklebacks

The dissertation shows which DNA sequences have mutated in fish living in the polluted environments compared with fish living in cleaner areas. Several of the DNA sequences identified proved to lie in or close to functional genes, which is of concern especially because only a little over one percent of the stickleback’s total genome consists of functional genes. What’s more, one of the genetic markers identified, which had previously been discovered by Finnish scientists, was shown to be important for the stickleback’s adaptation to fresh water. 

Storspigg i nedsmutsad vattenmiljö. Foto: Johan Lind
Three-spined stickleback in contaminated aquatic environment. Photo: Johan Lind
 

“I have scientifically demonstrated that the impact of humans on the environment can result in rapid evolution of animal genomes that have enabled animals to survive in these environments. We should not imagine that our emission pass through nature unnoticed,” says Emma Lind. 

Title of dissertation: Genetic response to pollution in sticklebacks; natural selection in the wild

For further information
Emma Lind, Department of Zoology, Stockholm University, and Department of Natural Science, Environment, and Technology, Södertörn University, mobile +46 (0)735 72 66 73, e-mail emma.e.lind@gmail.com