Scaling laws in enzyme function: "Another Weak Link in Evolutionary Theory"

Fascinating abstract at

. . . but The Christian Post sees it as more fodder against the Theory of Evolution because of implications for Universal Common Ancestry:

Paul Nelson wrote on this topic for Evolution News:

The weakest link in evolutionary theory is still stronger than the strongest link in ID theory.


So if I understand this, re-use of components implies design, but non-re-use of components also implies design.


I haven’t read the paper but it seems to me that the points raised cut against another ID argument - that enzymatic function is sparsely distributed in sequence space.

Whether design or evolution is the better explanation I can’t say. Naive views of evolution would lead us to expect otherwise, but so would naive ideas of design.


And somehow we wouldn’t expect that novel genes would evolve independently in different lineages to carry out the same or similar functions. Why? We aren’t told why, they just assert this.


Of course, if this paper supports design, it supports the “many designers” theory, not the common designer theory. Does Paul Nelson know that?

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Good point. However, that’s not a real argument, just a misrepresentation of the evidence itself.

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Full text preprint:

Scaling laws in enzyme function reveal a new kind of biochemical universality

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If I understand correctly, the suggestion being made in the paper is that there may be certain processe crucial to life that are under extreme constraint in terms of the molecules that are capable of carrying the out. Therefore, the existence of these molecules across various species would not be due to common ancestry, but due to this chemical constraint. That is to say, if life originated on other planets we would expect to find the same chemicals performing these functions, whereas the chemicals performing other functions that are not so constrained would vary according to the historical contingencies of how evolution occurred there.

Is that correct? If so, I am not seeing an argument for design here.


That’s not exactly what this paper is arguing. Specifically they are talking about the distribution of different enzyme functions as a proportion of total number of enzyme functions an organism has.

Apparently they find that there are systematic relationships to total number of enzyme functions, for each of the individual enzyme functions, such that as the total number of enzyme functions an organism has grows, the smaller the proportion of them will consist of (for example) oxireductases.

And for other types of enzyme functions the relationship is the opposite. That as the total number of enzyme functions an organism has increases, the higher the proportion of them that will consist of (for example) transferases. It’s basically all in figure 2.

Interesting, and really might have implications for life that might exist elsewhere in the universe. It says absolutely nothing about common ancestry, or design, or anything of the sort, however.


I was also struck by the way Paul Nelson describes the findings in his Evolution News article.

If there are so many possible ways that different enzymes can perform similar functions, then that would appear to go against the core premise of the Intelligent Design argument that it is difficult to make molecules with new functions. If there are so many paths to achieving similar functions, that should mean that evolution is easier than ID proponents claim.

Also, the fact that there are many different ways to achieve a certain function does not go against the theory of common descent. Certain functions could have evolved after two different organisms evolved from a common ancestor. As other more complicated examples of functional structures: different types of eyes in different organisms, or different structures of thumbs in people and pandas do not challenge the theory of evolution. Textbook convergent evolution.


Right. After quickly scanning the paper (thanks for posting @RonSewell) it seems to me that it is about something very different than how Paul Nelson describes it.

The authors affirm common descent in life as we know it on earth, and are looking for ways to detect other possible chemistries within life on alien worlds. They consider that synthetic life could be influenced by different physical constraints.

A consensus model of the enzyme functions in the last universal common ancestor (LUCA) is demonstrated to be consistent with the scaling behavior of extant life for all but the ligases and transferases, suggestive that some features of the universality classes of modern biochemical systems may have emerged early on in the evolution of life on Earth. Taken as a whole, the results indicate the universality classes identified are not a direct result of the existence of component universality in the more traditional biochemical sense, and therefore is more akin to universality classes in the physical sense where the specific scaling exponents arise due to optimization against hard physical limits that would be expected to similarly constrain other examples of life in the universe, including application to synthetically designed life.


Isn’t it great, then, that @pnelson is a member of this group? He’ll realize that he misunderstood the article, correct or delete his EN article and the authors of this study won’t have to spend years explaining that their article does not support creationism.

Very fortunate.


And if it really sounded like ID, why didn’t @pnelson advance a hypothesis that predicted these empirical results?

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Somewhere on Paul Nelson’s computer is a template opening paragraph:

[insert test here] - sounds like design.


Now THAT is funny.


I’ve emailed Sara Walker so she is aware of this and can respond as she sees fit.


I would be very interested to hear her reaction


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