Genes arising from nothing?

I have been asked me to clarify a recent piece of news that has hit the popular science press with headlines like the following:

New genes found that can arise from nothing. (Phys.org, 12/8/2023)

The tenacity of the media (and some scientists) to abuse the concept of nothing is unbelievable. They don’t know that nothing does not exist, and that nothing can arise from what does not exist. This is something that pre-Socratic Greek philosophers did know. (The first to assert this was Parmenides). Twenty-five centuries later, modern man, so proud of the advancement of science and technology, makes the same mistake once and again. In these posts I have often criticized the phrase, common today, that the universe arose spontaneously from nothing, which atheists often formulate to deny the creation and, therefore, the existence of God. This phrase does not belong to science (because current theories do not let us go back to the moment of the Big Bang). As philosophy, it’s just a flagrant proof of ignorance.

As a first clarification, I must say that the discovery associated with the previous headlines has nothing to do with the origin of life or the beginning of the genetic code. What has been discovered is a mechanism that, starting from a DNA molecule (which could belong to any living species), can lead to the appearance of new genes that did not exist before. In some cases, this could accelerate the pace of evolution.

What does this mechanism consist of? The attached figure, which I took from the Phys.org article, explains it.

1. Mutations can occur in the DNA of a living being, and sometimes gives rise to the alteration of a single purine or pyrimidine base (adenine, guanine, cytosine or thymine), which becomes an incorrect base, equal to none of the four. When this happens, if the DNA molecule in question is replicating (i.e. reproducing), upon reaching the wrong base the replication mechanism does not know what to do.
2. When replication stops, the piece of DNA that had just been reproduced separates from the strand that until then had acted as a template and shakes aimlessly.
3. Its random movements can take it to the opposite strand of DNA, which is made up of correct bases. It could then attach to that strand by one of its complementary bases and continue the process of replication. But since it now grows in the opposite direction, the chain that is formed is the mirror and complementary image of the one that had just been replicated, with a few bases in between. That is why it is said that a palindrome of bases is formed, although in fact it is a chain like this: XYX'^-1, made by a piece X, followed by another piece Y, and by the mirror image of the complementary chain of X (X'). In other words, it is not exactly a palindrome.
4. The part of the strand being replicated ends up detaching itself from the opposite strand and returns to its original position. The “palindromic” piece does not fit what comes next, so it cannot form the usual hydrogen bonds, and the two strands become separated, starting at the incorrect base, but the process has bypassed the mistake, so the generation of the new thread continues as if nothing had happened.
5. The “palindromic” part of the new strand can pair with itself, since in addition to being inverted, both parts are complementary, forming a hairpin structure, from which a small RNA molecule of about 22 bases (microRNA) can emerge, that functions as a new gene, and could have beneficial effects for the organism that may be favored by natural selection.

As can be deduced from the above, the new gene has not arisen from nothing, but from a pre-existing DNA molecule, through a mechanism that now seems to have been elucidated. This would explain the way in which a quarter of microRNA molecules have appeared. Furthermore, by studying the presence or absence of these “palindromic” molecules in different primates, the date of their appearance over the last few million years can be deduced. The corresponding figure can be seen at Phys.org.

The same post in Spanish

Thematic Thread on Evolution: Previous Next

Manuel Alfonseca