Endosymbiosis Under the Microscope

Do microbes get married and become one?
Is this an example of evolution?

 

Some science reporters go overboard with headlines to get clicks. A recent example claims a once-in-a-billion-year event occurred to glorify Darwin.

Two lifeforms merge into one for first time in a billion years (The Independent UK, 29 April 2024). Reporter Anthony Cuthbertson believes everything evolutionists tell him. Like most mainstream science reporters, he cannot bring himself to criticize Darwinians or ask any hard questions.

For the first time in at least a billion years, two lifeforms have merged into a single organism.

The process, called primary endosymbiosis, has only happened twice in the history of the Earth, with the first time giving rise to all complex life as we know it through mitochondria. The second time that it happened saw the emergence of plants.

He has learned his Darwinese well. In evolutionary imagination, Stuff Happens, “giving rise to” the “emergence” of progress. They may as well think that hats give rise to the emergence of rabbits (22 Aug 2023). But aside from matters of lingo, the claim, even if true, would do nothing to offer “new insights into the process of evolution,” as Cuthbertson and his chosen experts claim. Why? Because the merging of two genomes adds no new information. When two people get married, the relationship changes, but they are still the same individuals.

At best, the new “single organism” combines the genetic information of two pre-existing microbes, but doesn’t add new genes. At worst, it represents a loss of genetic information, because like two drunks leaning on each other, each prior organism loses the stamina it had as a standalone cell. Yet the reporter and his evolutionary experts talk like this the launch of a whole new glorious era of Stuff that might Happen in the drama of evolutionary progress.

“The first time we think it happened, it gave rise to all complex life,” said Tyler Coale, a postdoctoral researcher at University of California, Santa Cruz, who led the research on one of two recent studies that uncovered the phenomenon.

“Everything more complicated than a bacterial cell owes its existence to that event. A billion years ago or so, it happened again with the chloroplast, and that gave us plants.”

Stuff happened! Launch the fireworks! This time, the Darwin propagandists promise, whatever happened might hold “the potential to fundamentally change agriculture.” Where would we be without Darwin giving us understanding?

The Endosymbiosis Narrative

The new claim relies on treating the theory of “primary endosymbiosis” as fact. Endosymbiosis theory, originally scorned by evolutionists when Lynn Margulis proposed it in the 1960s, has become an accepted truth in the Darwin Party today, even though Margulis herself was a nonconformist regarding Darwinism. She proposed that one microbe married (engulfed? enslaved?) another microbe, and it turned into a mitochondrion—an essential organelle in all eukaryotes. The other alleged example is an alga engulfing a cyanobacterium which turned into a chloroplast, the organelle responsible for photosynthesis in higher plants. These claims and their associated problems have been discussed in our previous posts which interested readers can check:

• How Well Do Evolutionists Understand Endosymbiosis? by David Coppedge, 16 Feb 2016.
• Bad News for Plant Origins, by Dr Margaret Helder, 10 Feb 2020.
• Diatoms Defy the Evolutionary Endosymbiosis Theory, by Dr Margaret Helder, 29 June 2020.
• Origin of Eukaryotes: Still Wishing and Hoping Endosymbiosis Is True, by Dr Jerry Bergman, 24 Oct 2022.

The new claim is that a marine alga (a eukaryote) engulfed a bacterium millions of years ago, and turned it into a nitrogen-fixing organelle that the evolutionary scientists are calling a ‘nitroplast.’ The claim, however, has even less support than the other cases of alleged endosymbiosis. It is written up in two journal papers:

• Coale et al., Nitrogen-fixing organelle in a marine alga, Science, 11 April 2024.
• Cornejo-Castillo et al., Metabolic trade-offs constrain the cell size ratio in a nitrogen-fixing symbiosis, Cell, 11 March 2024.

Ramon Massana also beat this drum in a Perspective article in the same issue of Science, “The nitroplast: A nitrogen-fixing organelle,” 11 April 2024. The alleged endosymbiont-turned-nitroplast is called UCYN-A, and its host is the unicellular alga Braarudosphaera bigelowii. But despite the celebration, Massana admits that this kind of union, if it truly “happened,” was rare and hard to explain, having occurred allegedly 100 million years ago, over a billion years after the other cases.

Distinguishing an endosymbiont from an organelle can be challenging, and each reported endosymbiosis may appear at a different stage of a putative endosymbiontorganelle continuum. Nevertheless, the deep cellular integration of UCYN-A into the host and its severe genetic dependency support the view that the nitroplast of B. bigelowii can be added to the short list of endosymbiosis-derived organelles. The evolutionary history of the nitroplast is analogous to that of mitochondria and chloroplasts, including gene loss, coordinated division, and subjugation to the host. Besides the mitochondrion, chloroplast, and nitroplast, there are only a few additional cases of endosymbiosis-derived organelles (10), such as the chromatophore of the amoeba Paulinella. Additionally, the spheroid bodies of freshwater diatoms, which resemble UCYN-A in many ways, may represent another independently evolving nitroplast. Nonetheless, it is still intriguing that so few endosymbiosis-derived organelles are known, which emphasizes how difficult it is to achieve this transition.

Anomalies and Alternatives

What makes this new claim problematic is that none of UCYN-A’s genes have been transported into the nucleus of the alga. Some of the alga’s nuclear genes make proteins that are targeted for UCYN-A, but this makes the “organelle” look more like a parasite than an endosymbiont. Parasitism can exist on a sliding scale from harmful to moderately beneficial to even beneficial, as in the case of mutualistic symbiosis. In many cases of persistent parasitism, the parasite sheds redundant genes and relies on the host to provide their services. Those cases represent devolution, not evolution.

If this was such a monumental evolutionary transition, why don’t plants carry nitroplasts in their own cells? Why do some of them, like legumes, coax nitrogen-fixing bacteria to inhabit their root nodules? Nitroplasts should exist throughout the plant kingdom, but they clearly don’t. Why did this marine alga keep its secret sauce to itself for 100 million years?

Even if one accepted the endosymbiosis narrative for the sake of argument, (1) no new genetic information has been added, and (2) this one is not much different from other cases of parasitism that are prevalent throughout the biosphere. Parasitism involves a loss of genetic information, as our entry from 16 Feb 2016 emphasized. Moreover, no biologist can say when an endosymbiosis occurred without assuming the evolutionary timeline (circular reasoning). And as Michael Denton pointed out, such an event would represent a sudden change—a saltational event—that runs counter to Darwin’s preference for the accumulation of slow, gradual variations instead of dramatic leaps.

Most importantly, an alleged endosymbiosis event has no causal power over subsequent evolution. Marry a mitochondrion, give birth to a giraffe two billion years later? That’s absurd. It’s not clear, therefore, how these papers help Darwinian theory at all.

Readers are cautioned to be wary of flamboyant claims of evolution in action. If Darwinists didn’t have question-begging in their explanatory toolkit, they would have no tools at all.

So what’s an alternative, non-evolutionary way to look at B. bigelowii? We repeat some text from our 16 Feb 2016 commentary:

Creationists have reasons to believe that microbes were created essentially as they are, except for degradation and parasitism that occurred after the Fall. Mitochondria and chloroplasts are too marvelously engineered for their functions to have had an accidental origin. Observations about partial genomes in the organelles and other parts in the nucleus may be puzzling, but remember Nelson’s Principle: “If something works, it didn’t happen by accident” (quoted in Flight: The Genius of Birds). There may be good reasons for the split genomes. The transporters that carry products of nuclear translation into the organelles are also amazingly complex and effective.

Evolutionists have massive puzzles to explain. The ATP synthase motors in mitochondria and the photosystems in plastids are complex almost beyond description; where did they come from? How did the ancestors invent those? The endosymbiont theory doesn’t explain that, nor does it explain any of the subsequent “Great Transformations” natural selection would have to perform with Darwin Flubber to get from the first eukaryote to a kangaroo, a titanosaur or a human brain. Endosymbiosis is just a cute story that makes evolutionists feel good, as if they have made some progress in articulating the Grand Myth.