Stickleback fish exist in both freshwater and saltwater forms. The saltwater varieties also have armor plating and defensive spines, but many scientists believe that since the Ice Age they have repeatedly shed their armor and spines and adapted to the smoother freshwater varieties found in streams and lakes around the world. Evolutionary biologist David Kingsley’s Stanford-based team has identified the genetic changes underlying this so-called “rapid evolution.”
By completely sequencing the genomes of 21 stickleback varieties from three continents and comparing the results, they have determined the characteristics for which the genetic codes differ and the sorts of changes that make the phenotypic alterations possible. They report that about 150 DNA sequences distinguished the freshwater varieties from the saltwater ones. Those distinctive freshwater sequences were similar in other freshwater species from all over the world. The genes affecting armor plating and salt-processing by the kidney—an essential adaptation for switching environments—were among those that differed.
Because the freshwater genomes tended to have similar genetic characteristics, the researchers believe “the fish do not evolve new features from scratch each time” but instead “may retain ancient genetic adaptations to freshwater living that allow them to colonize new sites.”
“On a genome-wide scale, we’ve found a whole set of regions being used over and over to adjust to new environments,“ says Kingsley. “We’re able to study the molecular basis of vertebrate evolution.”
They believe the evolution of this fish is accelerated by the use of pre-existing genetic information.
It appears, Kingsley’s team reports in its paper in Nature, that about 80% of the genetic differences arise from alterations in regulatory DNA and about 20% in actual coding DNA. They believe the evolution of this fish is accelerated by the use of pre-existing genetic information. They believe the freshwater divergences happened about 10,000 years ago in “an evolutionary blink of an eye.”
What the researchers have documented here is not the evolution of a new kind of creature but simply variation within a created kind. In fact, freshwater and saltwater sticklebacks are able to successfully interbreed in the laboratory, clearly demonstrating they are of the same created kind. The “ancient genes” the fish seems to switch on and off are the genetic information God provided in order to enable this fish to adapt to various environments, with the ultimate variety in each environment regulated by natural selection and other factors. We should not be surprised at the speed of this adaptation.
God has designed organisms to vary within their kinds. This variation is not accomplished by acquiring new information but by reshuffling, regulating, and sometimes losing old information. That the same information is offering survival advantages in certain ecosystems worldwide is evident from the similarity of the freshwater genomic distinctives from around the world and by similarities in regional varieties, whether saltwater or fresh. This research supports the biblical concept of biological creation and variation within kinds and provides no support applicable to molecules-to-man sort of evolution or evolution of any new kind of organisms.
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