The coelacanth, which was thought to be extinct was seen at a fish market in South Africa in 1938. This fish resembles the lungfish, a fresh water fish that can breath air. The coelacanth has fleshy fins that look like limbs. The genome of the coelacanth was decoded Wednesday in the Journal of Nature. This lead scientist that the lungfish is the closer ancestor to the rise of tetrapods. But further research shows that the coelacanth has 2.8 billion units of DNA which is like a human genome, it is decodable. The lungfish is 100billion units of DNA and at this time is not able to be decoded.
Lobed-fin fish are said to be the link between fishes and tetrapods. You can see the thicker portion of the fin closest to the body. It looks more like a limb compared to most fish.
ReplyDeleteThe size of the lungfish genome at 100 billion units of DNA is remarkable. The current environments that the coelacanth reside in are deep sea environments, as opposed to more shallow waters. This supports the evidence from the genome sequencing that the lungfish are more close in ancestry to the first tetrapods which descended upon the land in prehistoric times. With future technology, perhaps the lungfish genome will be decodable and researchers will finally be able to determine which fish gave rise to tetrapods.
ReplyDeleteCoelacanths are one of my favorite fish. They are so unique and I love the way their fins can move independantly. It is so amazing how little they have changed in millions of years. I wonder why their evolution stopped while others evolved into lungfish and then eventually tetrapods. I always thought lungfish would be the closest link to tetrapods rather then the coelacanth do to the fact that they can breath air while the coelacanths can't even come up to shallower water, they stay in deep waters and now that the coelacanth genome has been mapped it can be proven.
ReplyDeleteI also look at an article that discussed this phenomena. They concluded that the coelacanth’s genome will be used to help better understand how we evolved even though the lungfish may be a closer relative to vertebrates on land. If they are able to decode the lungfish like the 2nd comment states, then scientists can draw a conclusion amongst the two fish. Further researcher definitely needs to be accomplished.
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