Describe the RNA world hypothesis, and discuss specific evidence that supports this scientific hypothesis.
i know part of it is The RNA world hypothesis proposes that self replicating ribonucleic acid molecules were precursors to current life. but i don't know the evidence part.
http://exploringorigins.org/ribozymes.html
The RNA world hypothesis suggests that in the early stages of life on Earth, before the emergence of DNA and proteins, there was an era dominated by self-replicating RNA molecules that served as both genetic material and catalysts for chemical reactions. This hypothesis is based on several key pieces of evidence:
1. Catalytic properties of RNA: One line of evidence is that RNA can act as an enzyme, catalyzing chemical reactions, just like proteins. This was demonstrated by Thomas Cech and Sidney Altman, who independently discovered that certain RNA molecules, called ribozymes, have the ability to perform catalytic functions. These findings opened up the possibility that RNA molecules could have played a dual role as both genetic material and enzymes in the RNA world.
2. RNA can store genetic information: Another important piece of evidence is that RNA can store genetic information. RNA molecules can be both replicated and also undergo mutation, which allows for variation and natural selection. This suggests that RNA could have served as the hereditary material in the early stages of life before DNA took over this role.
3. RNA's ability to self-replicate: Researchers have also demonstrated that certain RNA molecules can self-replicate without the aid of proteins or other molecules. For instance, the RNA molecule known as the "ribozyme" has been shown to be capable of catalyzing its own replication. This provides support for the idea that self-replicating RNA molecules could have been the precursors to modern forms of life.
4. RNA found in modern organisms: Additionally, RNA molecules are still present in all living organisms and play essential roles in gene expression and protein synthesis. This suggests that RNA has remained a fundamental component of life, further supporting the idea that it played a central role in the early stages of life's evolution.
It is worth mentioning that while these pieces of evidence support the RNA world hypothesis, it is still an ongoing area of research, and scientists continue to explore and test this hypothesis using various experimental approaches.