Lost DNA Clues Reveal How Fish Evolved Into Land Animals

Vertebrates made a huge leap when they moved from water to land. This shift changed their bodies and how their genes work. Scientists now study this using genomes from fish and land animals.

A new study looked at missing pieces of DNA. These are called conserved non-coding elements, or CNEs. Some CNEs exist in fish but are gone in land animals. They may have been lost or changed too much to find.

Researchers used zebrafish as a model. They compared these missing CNEs to ones shared across all jawed vertebrates. The goal was to see what changed during the move to land.

The biggest changes were in genes for pigment and muscle development. These systems had to adapt for life on land. Also, parts of Wnt and Hedgehog signaling pathways were found near CNEs kept in fish.

These findings show how gene networks were rewired. Losing old DNA helped vertebrates reach new forms. It shows how evolution works at the genetic level.