Cool news about evolution
I love evolutionary theory, it's testable and very dynamic, and evolution has lead to the presence of the world as we know it - birds, trees, people, etc. I got my BS degree it it at University of Arizona seemingly a lifetime ago.
ANYWAY. Now scientists have found evidence for a key concept in evolution (story here), but before I talk about that, I must discuss with the laypeople readers about the central dogma of biology, else you won't understand this new breakthrough. THe central dogma has it that that DNA replicates itself, and also gives rise to proteins through an 'intermediate' called RNA. So the chain goes like this: DNA -> RNA -> protein. DNA is inheritable, and DNA mutations lead to heritable changes, which cause evolution on a scale of thousands of generations. DNA mutations lead to protein mutations, which cause the proteins to change function, or not function at all.
So, the new data talks about the idea that once a mutation has occured to change a gene function, it's hard to go back to it's original function. Why? Two reasons.
First, a subsequent mutation in the original gene or something that the gene product interacts with is required to keep the existing function. Think of it as a lock and key mechanism - If you change the lock, the key no longer fits. You must use a new key to fit the lock, or change the lock to fit the old key.
Second - and this is what the researchers focused on, once the mutation occurs, the protein pathway can be free to mutate to a new function, becaues the old function is no longer being used. Think of it this way; if a car's engine suddenly changes into something different, like a computer, then the car will stop working. Since the car no longer works, the other parts are no longer required, and can aquire new functions; the battery can change into a keyboard , for example.
That's what happened in the case of the morning glory. Here's a quote from the story.
ANYWAY. Now scientists have found evidence for a key concept in evolution (story here), but before I talk about that, I must discuss with the laypeople readers about the central dogma of biology, else you won't understand this new breakthrough. THe central dogma has it that that DNA replicates itself, and also gives rise to proteins through an 'intermediate' called RNA. So the chain goes like this: DNA -> RNA -> protein. DNA is inheritable, and DNA mutations lead to heritable changes, which cause evolution on a scale of thousands of generations. DNA mutations lead to protein mutations, which cause the proteins to change function, or not function at all.
So, the new data talks about the idea that once a mutation has occured to change a gene function, it's hard to go back to it's original function. Why? Two reasons.
First, a subsequent mutation in the original gene or something that the gene product interacts with is required to keep the existing function. Think of it as a lock and key mechanism - If you change the lock, the key no longer fits. You must use a new key to fit the lock, or change the lock to fit the old key.
Second - and this is what the researchers focused on, once the mutation occurs, the protein pathway can be free to mutate to a new function, becaues the old function is no longer being used. Think of it this way; if a car's engine suddenly changes into something different, like a computer, then the car will stop working. Since the car no longer works, the other parts are no longer required, and can aquire new functions; the battery can change into a keyboard , for example.
That's what happened in the case of the morning glory. Here's a quote from the story.
Said Rausher, "These findings provide a concrete example of what biologists have believed -- that such ecologically important characters as flower color are the result of a developmental process that involves many genes. And if you knock out any one of those genes, the other genes in the pathway are essentially free to decay or to take on new functions."
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