Evolution: species pre-planning identified (Evolution)

by David Turell @, Friday, February 01, 2019, 14:57 (550 days ago) @ David Turell

In a stickleback fish study:


"Genetic analysis of sticklebacks shows that isolated populations in similar environments develop in comparable ways. The basis for this is already present in the genome of their genetic ancestors.


"On the Scottish island of North Uist, sticklebacks can be found in bodies of water with extremely varied pH values. While the lakes to the west contain alkaline water, the high moorland lakes in the east are acidic and low in nutrients.

"Studies of five populations from both the western and eastern lakes showed that the fish adapted to their alkaline or acidic habitat independently of each other, but in comparable ways. All five populations in the acidic lakes, for example, displayed a greatly reduced skeleton and stunted growth -- probably as an adaptation to the lack of nutrients.

"In addition to the shared external characteristics, the researchers were also able to establish that changes in the genetic pool proceeded in very similar ways: the populations within the same type of habitat showed the same genetic variants in dozens of regions of the genome. This makes it possible to predict where in the genome changes will take place under the influence of a particular habitat -- evolution becomes predictable to some extent.

"Genetic analysis of the marine ancestor also showed that the genetic variants that are beneficial for adapting to acidic or alkaline water are all present in the ancestor. Similar life forms, therefore, didn't occur randomly, but independently of each other through the predictable sorting of advantageous genetic variants that were already present in the genome. "

Comment: It certainly looks as if the existing genome can guide future adaptations, but in case within related species. Note the bold statement

I'm surprised there is no comment on this obvious evidence of pre-planning

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