Random Mutation as Driver of Evolution

@Thomas,

Thomas wrote:

Brandon9000 wrote:
The mechanism for introducing new traits into the genepool is accidental mutation. Evolution requires both selection and the introduction of new traits.

What about crossover?

And what about simple sexual reproduction?

Mutation is required at some point in evolutionary history in order to generate new genes. But now that billions of years worth of genetic variation has accumulated in most gene pools, all that is required for extensive variation is the mixing and re-ordering of existing genes. No mutation required for that. True mutation continues to trickle into the system and always will, but the bulk of the variation is being done by mixing existing genes into new combinations.

1 Reply

@Brandon9000,

Brandon9000 wrote:

Evolution couldn't do what it does without the introduction of new traits into the gene pool.

Actually, I just remembered an interesting article by Olivia Judson on this very topic. She asks, if mutation were to stop, how long would it take until natural selection runs out of variation to work on? Her answer is that the question is undecided. Absent mutation, it's a tug of war between some processes increasing diversity and other processes decreasing it. Nobody knows which side would prove stronger in the end. The examples she gives of both kinds of processes is quite interesting.

Here's the article

0 Replies

@parados,

parados wrote:

There will always be variations. It's just that some of the variations will disappear because they may become fatal if the environment changes.

Where do completely new traits come from?

0 Replies

@Thomas,

Thomas wrote:

Brandon9000 wrote:
The mechanism for introducing new traits into the genepool is accidental mutation. Evolution requires both selection and the introduction of new traits.

What about crossover?

Crossover error is one source of mutations.

0 Replies

@rosborne979,

rosborne979 wrote:

Thomas wrote:
Brandon9000 wrote:
The mechanism for introducing new traits into the genepool is accidental mutation. Evolution requires both selection and the introduction of new traits.

What about crossover?

And what about simple sexual reproduction?

Mutation is required at some point in evolutionary history in order to generate new genes. But now that billions of years worth of genetic variation has accumulated in most gene pools, all that is required for extensive variation is the mixing and re-ordering of existing genes. No mutation required for that. True mutation continues to trickle into the system and always will, but the bulk of the variation is being done by mixing existing genes into new combinations.

A tree dwelling tarsier-like creature cannot turn into a human by mixing existing genes. Any appreciable development requires the introduction of new traits.

3 Replies

@Brandon9000,

The term "natural selection" is a term that combines the entire affects of sexual selection, drift, environmental "drivers " , adaptation, mutation, etc. Now we will have to add epigenesis and pseudogene activity to the mix.
This is an argument about the "infield fly rule" .

0 Replies

@Brandon9000,

Brandon9000 wrote:

A tree dwelling tarsier-like creature cannot turn into a human by mixing existing genes. Any appreciable development requires the introduction of new traits.

Are you sure of that? How do you know that the requisite traits didn't already exist in the Tarsier genome, just not in the right combinations?

I would agree that there are probably a few actual mutations between us and our Tarsier ancestors, but I would bet that the VAST bulk of the differences occur through re-ordering of existing genes.

I think genetic studies are showing that the actual *unique* genes which differentiate species like monkeys and man (or even mice and men) are very few.

2 Replies

@rosborne979,

so would most evolutionary biologists.

Geologists not so much, we like to make up stories about unique fossils

1 Reply

@farmerman,

farmerman wrote:

so would most evolutionary biologists.

Geologists not so much, we like to make up stories about unique fossils

You can't trust those geologists, they're always digging around in the dirt and turning over rocks...

0 Replies

@Brandon9000,

Brandon9000 wrote:

A tree dwelling tarsier-like creature cannot turn into a human by mixing existing genes. Any appreciable development requires the introduction of new traits.

"A bunch of random musical notes cannot turn into Beethoven's Ninth merely by mixing existing notes. Any appreciable development requires the introduction of new melodies, harmonies, and rhythms."

The answer, both to your statement and to my parody of it, is "yes we can". On the physical level, "new traits" are merely new combinations of DNA, just as new melodies are merely new combinations of existing notes. Because mutations aren't even close to being the most prevalent, or most important, shuffler of genetic information. For example, I already mentioned crossover during meiosis; it's a much more powerful at mixing up genes. (And it doesn't depend on "errors" to do it.)

0 Replies

@rosborne979,

Sorry, rosborne, but it's no less than preposterous to think that a species of little tarsiers can be changed into humans just by weeding out the bad genes.

1 Reply

@Brandon9000,

Brandon9000 wrote:

Sorry, rosborne, but it's no less than preposterous to think that a species of little tarsiers can be changed into humans just by weeding out the bad genes.

Our current understanding of genetics and the various genomes related to primates indicates that it's more than possible; it's exactly what happened (which just a few minor mutations). Most of the variation is a result of reorganizing existing genes.

0 Replies

Random Mutation as Driver of Evolution

Related Topics

Quick Links

My Account

able2know