January 9, 2023 | David F. Coppedge

Gene Sharing Is Not Evolution

Microbes in the ocean share genes in tiny bubbles,
but where did the genes come from?

 

Another non-Darwinian mechanism has been found for how microbes in the ocean share genetic information. The article below claims the discovery helps “our understanding of the evolution of bacterial genomes,” but it actually has nothing to do with Darwinism.

Scientists discover a new way of sharing genetic information in a common ocean microbe (MIT News, 5 Jan 2023). “Prochlorococcus, the world’s most abundant photosynthetic organism,” writes press office reporter David L. Chandler, “reveals a gene-transfer mechanism that may be key to its abundance and diversity.” Words like diversity and adaptation are often presented with an evolutionary slant, but this is not Darwin’s mutation/selection method of acquiring information.

Now, new research reveals that these tiny bacteria exchange genetic information with one another, even when widely separated, by a previously undocumented mechanism. This enables them to transmit whole blocks of genes, such as those conferring the ability to metabolize a particular kind of nutrient or to defend themselves from viruses, even in regions where their population in the water is relatively sparse.

The new gene-sharing mechanism begins when blocks of DNA separate out from a bacterium and become encapsulated in membrane “bubbles” that can travel outside the cell.

The findings describe a new class of genetic agents involved in horizontal gene transfer, in which genetic information is passed directly between organisms — whether of the same or different species — through means other than lineal descent. The researchers have dubbed the agents that carry out this transfer “tycheposons,” which are sequences of DNA that can include several entire genes as well as surrounding sequences, and can spontaneously separate out from the surrounding DNA. Then, they can be transported to other organisms by one or another possible carrier system including tiny bubbles known as vesicles that cells can produce from their own membranes.

Lead author of a paper about this in the journal Cell (5 Jan 2023), postdoc Thomas Hackl, named the agents after Greek goddess Tyche, daughter of Oceanus. He considers the bubble-transport mechanism to be efficient in the open ocean, where contact between bacteria is rare.

A prokaryotic cell compared to a eukaryotic cell. From Wikimedia Commons.

No Thanks to Darwin

This mechanism seems anti-evolutionary in the sense that it confers no direct benefit on the donor. It appears altruistic: helping other members of the species but not the donor. This is contrary to the portrayal of evolution by Richard Dawkins, author of The Selfish Gene.  These shared genes, found in “genetic hotspots” in members of the species, are “associated with known key survival processes such as the ability to assimilate essential, and often limiting, nutrients such as iron, or nitrogen, or phosphates.” If the recipient gains a survival advantage this way, it is not arising by Darwin’s Stuff Happens Law of natural selection.

Hackl compares this “plug-and-play” transfer method to building an adaptable genome with Lego blocks.

Hackl describes what they found as being something like a genetic LEGO set, with chunks of DNA bundled together in ways that could almost instantly confer the ability to adapt to a particular environment. For example, a species limited by the availability of particular nutrients could acquire genes necessary to enhance the uptake of that nutrient.

No millions of years needed for this kind of adaptation to occur; it’s instantaneous, and happening everywhere in the ocean.

“It’s kind of a plug-and-play mechanism, where you can have pieces that you can play around with and make all these different combinations,” he says. “And with the enormous population size of Prochlorococcus, it can play around a lot, and try a lot of different combinations.”

A Widespread Mechanism

Is this mechanism limited to Prochlorococcus? That species may be the first of many others to be investigated:

While this study was specific to Prochlorococcus, Hackl says the team believes the phenomenon may be more generalized. They have already found similar genetic elements in other, unrelated marine bacteria, but have not yet analyzed these samples in detail. “Analogous elements have been described in other bacteria, and we now think that they may function similarly,” he says.

A similar phenomenon was discovered in soil bacteria in the past two years. See my articles in Evolution News last 21 October and in 13 Aug 2021 discussing how this kind of “non-Mendelian inheritance” goes on in soils. Scientists found large packets of genes they dubbed “Borgs” that were being generated and “assimilated” among microbes. Perhaps it is the way that antibiotic resistance is transmitted between species: not by Darwinian evolution, but by receiving the information from genetic libraries.

The MIT article mentions that other kinds of horizontal gene transfer occur in higher organisms. Tycheposons represent a new kind of gene sharing that is “different from any of the several other mechanisms that have been observed in other organisms, including in humans.” But should scientists give credit to evolution for these discoveries? Hackl remarks that “future work on tycheposons has wider implications for our understanding of the evolution of bacterial genomes.”

These processes appear designed for robustness, like an engineer would plan for with foresight. Darwin takes credit (24 Aug 2007, 12 Nov 2021) for mechanisms that have nothing to do with his speculations. Notably, some of the research was done by members of MIT’s Department of Civil and Environmental Engineering.

The paper says that this method of gene sharing produces “convoluted evolutionary histories” and that tycheposons “evolved independently over similar [ancient] timescales.” Watch the evolutionists try to rescue Darwin by applying Darwin Flubber to the story with “convergent evolution”—

A subset of the tycheposons appear to be viral satellites similar to PICIs and are the first of their kind described in cyanobacteria. The different evolutionary histories of tycheposon and PICI genes and, in particular, their integrases suggest that their structural similarity could have arisen from convergent evolution.

Then they try to rescue Darwin with futureware in a grand finale of pomp without circumstance:

Tycheposons have left their signatures all over the genomes of marine microbes, implicating themselves as important agents of microbial diversification and adaptation. Though much remains to be learned about tycheposon mobilization, replication, and transfer, their potential for shaping the genetic structure of marine microbial populations opens an exciting new area of inquiry, shedding new light on the processes that govern evolution across the vast oligotrophic oceans and beyond.

Sorry, Charley. Your credit balance was used up long ago.

 

 

 

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