Darwin's biggest blunder-Junk DNA


For 30 years, scientists thought that "junk DNA" was solely represented genetic fossils useful only to prove common ancestry. However, this view has changed as more and more of these "selfish" elements have been found across all living organisms. These elements have adaptive functions, in contrast to what was originally thought.

For example, some "junk DNA" elements help to regulate gene expression, while others play a role in DNA repair. Additionally, some "junk DNA" elements may even be involved in the evolution of new genes.

The discovery of the adaptive functions of "junk DNA" has challenged our understanding of the genome. It is now clear that this so-called "junk" DNA is essential for the proper functioning of cells and organisms.

An international team of scientists has discovered ancient RNA viruses embedded in the DNA of symbiotic organisms living inside reef-building corals. The RNA fragments are from viruses that infected the symbionts as long ago as 160 million years. The discovery, published in the journal Communications Biology, could help scientists understand how corals and their partners fight off viral infections today.

The researchers, led by Adrienne Correa of Rice University, found that the ancient viruses are widespread in the genomes of coral symbionts, known as dinoflagellates. These single-celled algae live inside corals and provide them with their vibrant colors. The viruses are called endogenous viral elements, or EVEs.

EVEs are not uncommon in the genomes of animals and plants. However, most EVEs are derived from retroviruses, which are a type of RNA virus that can integrate its genetic material into the DNA of its host. The viruses found in coral symbionts are not retroviruses, which makes their presence even more surprising.

Most RNA viruses are not known to integrate their genetic material into the DNA of their host organisms. Retroviruses are a special type of RNA virus that can do this, but they are relatively rare. The viruses found in coral symbionts are not retroviruses, so their presence in the coral DNA is a mystery.

One possibility is that these viruses were once retroviruses, but they have evolved to lose their ability to reverse transcribe. Another possibility is that these viruses are a new type of RNA virus that has the ability to integrate into the host DNA.

The researchers believe that the ancient viruses may have helped the coral symbionts to evolve resistance to other viruses. They hypothesize that the viruses may have inserted genes into the dinoflagellates' DNA that gave them the ability to fight off infection.

The discovery of ancient viruses in coral symbionts could have important implications for our understanding of coral health. Corals are under increasing threat from climate change and other environmental stressors. These stressors can weaken the coral-dinoflagellate partnership, making the corals more susceptible to viral infections.

The study's findings suggest that the coral-dinoflagellate partnership may have evolved to include a defense mechanism against viruses. This defense mechanism may be essential for the survival of corals in a changing ocean.

The researchers are continuing to study the ancient viruses in coral symbionts. They hope to learn more about how these viruses evolved and how they may be helping corals to fight off infection. This research could help us to develop new strategies for protecting corals from viral diseases.


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