Monday, December 10, 2018

From Fins to Feet

What was once believed to be extinct by 70 million years, the coelacanth, an ancestral fish thought to be one of the first specimens that gave rise to the formation of tetrapods 400 million years ago, has made its comeback after being found in a fish market in 1938 in South Africa.  With this recent discovery, scientists have been able to decode the coelacanth genome, noting that it has 2.8 billion units of DNA, remarkably the same size of the human genome.  This information aids in this study of what genetic alterations had to be undergone to transform from a deep-sea fish to a land-loving tetrapod.  What is peculiar about this fish is its fins - they are fleshy, limb-like structures which is why the coelacanth is believed to be one of the first to make its way onto land.  Fish with these types of fins, including the lungfish, are known as sarcopterygians and are ancient ancestors of tetrapods.  Some scientists say that humans and all other tetrapods are evolutionarily advanced sarcopterygian fish.
Being able to decipher genome sequences and date back to prehistoric times gives great insight to how species actually evolved into the ones that are present on Earth now.  Just like how some scientists are trying to undergo backwards evolution and turn a chicken into a dinosaur, I believe that this process of decoding the gene and tracing back to which traits were adapted or discarded over the course of hundreds of millions of years will only better our understanding of the past.

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