Ratio of Beneficial Mutations to Others

I beg your pardon, but it is a matter of fact that deleterious mutations are immeasurably more numerous than beneficial ones, a good estimate being one million to one. And if you add to that the fact that beneficial mutations are often reductive in nature, you can see that true constructive mutations are incredibly scarce, not to say elusive. As I said, hardly a good configuration for constructive evolution!

Conveniently ignoring that fact that only holds for a completely static environment where a species is already very close to a local fitness maximum. Of course in the real world environments are constantly changing where previously neutral or even deleterious mutations (or combinations of the two) often become beneficial. Not that any ID-Creationists operate in the real world. :slightly_smiling_face:

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Do you have examples demonstrating what you are saying here.

Consider blind cave animals. In a lighted external environment a loss of sight is virtually always detrimental. In the lightless cave environment mutations which deactivate energy-hungry eyes are a benefit.

Why do ID-Creationists not understand mutations can only be judged deleterious, neutral, or beneficial WRT their current environment?


The rock pocket mice in my post above is a perfect example. Each coat color can be beneficial or deleterious, depending on the environment.


I strongly suspect that mutations that “break” genes do considerably outnumber those that add new function. But where did you come up with the 1,000,000:1 ratio? Is this published somewhere? It would be good to have data supporting your conjecture.


Hold on a sec bro…

First please do me the pleasure of directly addressing my comment instead of dodging and bringing up a different point. We are here to discuss.

For starters, you asserted

Note that in this context, you are talking about mutations that “damage” the biochemical function of a gene but are beneficial for an organism. (note: this is an artificial category that Behe has manufactured but I"ll accept it for now; this would normally just be considered a beneficial mutation because it helps the organism…).

Now you assert that

This is true in an artificial way as defined by Behe, but I’ll work within your definitions for now. This is what you are talking about in your first quote above.

Notice how you have already conceded? You go from saying " immeasurably more numerous" to “often reductive in nature”.

My entire point is that you are completely wrong in your assessment of beneficial mutations when it comes to the frequency of reductive or biochemically “damaging” mutations vs. true “constructive” mutations. In fact, it is these reductive or biochemically “damaging” mutations which are exceedingly rare because they require very specific situations (for example very few animals live year around in white snowly environments so the degradation of color pigments in skin/fur is rarely going to be beneficial). This is why Behe’s devolution argument against evolution fails.

When we talk about adaptive mutations that are beneficial for organisms, they will usually be constructive in some way. Otherwise we would expect all living creatures to slowly lose their color as their pigments genes get damaged and we would loose our ability to smell as smell receptors degrade and color patterns on flowers would become less complex. This isn’t the world we live in. Look outside. Do have you seen an abundance of devolution over the last few decades or centuries?

Arguing that beneficial mutations are immeasurably rare is not going to convince anyone on this site of anything. People who accept modern evolutionary science already believe this and you’ve already begun to concede how often beneficial mutations are reductive. I think you should give this topic some more thought. Maybe I’ve missed the shift in animal and plant colors to dull gray and white over the last few hundred years…


No, that’s not a good estimate, that is in fact among the very lowest ratios in the literature.

More typical ratios are in the 1000:1 to 10:1 range, with some suggesting beneficial mutations being as likely as ~16% of all mutations


No, they technically have to be exactly equal, because any mutation is in principle reversible. For any “damaging” mutation you can imagine, we can imagine the “damaged” state as ancestral and the “reversal” to the descendant as constructive.

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I found this ratio of one million to one for harmful vs beneficial mutations in the book « Genetic entropy » by John Sanford. Based on his expertise in the field, he considers it as a good estimate, as is the case of Richard Lenski.

John Sanford is a Young Earth Creationist. No wonder he picked one of the lowest ratios in all of the literature.


You do understand Sanford’s Genetic Entropy nonsense was the worst kind of Creationist pseudo-science and has been falsified and universally rejected by the actual scientific community, right?

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The rate Lenski identified was the survival rate of beneficial mutations, not the appearance rate of beneficial mutations. As the paper states, only a tiny fraction of beneficial mutations become fixed in an E Coli population in a constant environment due to interference from other beneficial mutations and from drift.

Would you like me to show you where in the paper’s equations these factors appear?



Is Richard Lenski a young earth creationist?

Why did John Sanford pick the lowest ratio in the literature? Why not a literature review citing many different estimates, from many different species, under many different experimental protocols and so on?

Based on his experience in the field? In what field, exactly?

Why did you present the fixation rate as the appearance rate?


On a related note, isn’t it obvious that there is no such thing as the ratio of beneficial to deleterious mutations? That this ratio is probably different for different loci, having evolved for different amounts of time, depends on how many other functions it interacts with, the environmental circumstances, and so on?


Lenski gives his estimation of the ratio of harmful vs beneficial mutations (one million to one) at the end of the section « estimation of parameters: an empirical example »

All what you are saying here is blatantly false. Sanford is a top notch scientist whose thesis formulated in « Genetic Entropy » hasn’t been falsified at all. In fact, the academic community didn’t engage Sanford’s arguments because it has no answers.

Moreover, if it was true that Sanford has been universally rejected by the actual scientific community, how do you explain that he has been very recently invited to give a lecture entitled « can genome degradation be stopped? » at the NIH.