Researchers at Stanford University think that they have figured out why certain species have evolved the same way, over and over again. Some of these species have genes that are fragile and these fragile genes tend to adapt the same way, again and again. The biologists have studied a fish called three-spine sticklebacks (Gasterosteus aculeatus). These fish got trapped into a glacier-filled lake and were cut off from the ocean. The fish then evolved and lost a pair of pelvis fins. This has repeatedly happened to these fish. It is thought that maybe the fish lost their fins because of the low amount of calcium and phosphate or that the lower weight of their body made it easier for them to evade predators. The researchers think that not all sites in our genome are equal. Some are fragile are predisposed to mutate. The scientists think that the genes mutate because they are predisposed to change not just because they are fragile.

Key Takeaways:

  • Scientists have found that there are certain stretches of DNA that exhibit many multiple repetitions. These particular DNA stretches are considered fragile.
  • These repetitive biological strands may hold a provocative answer to a question evolutionary biologists have been posing for a very long time.
  • The question regards why it is that a force, seemingly rife with choices, specifically nature, nonetheless falls prey to repition, creating similar adaptations again and again.

“A mutation from the breakage of fragile DNA is different from the mutations caused by randomly arising single-nucleotide changes.”

Read more: https://www.quantamagazine.org/fragile-dna-enables-new-adaptations-to-evolve-quickly-20190205/

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