Single-celled organisms called Lokiarchaeota are making headlines as missing links in our supposed single-celled ancestry. A small fraction of their genes resemble those normally associated with more complex cells. Some claim this discovery clinches the case for archaeans, rather than bacteria, as our closest single-celled ancestor.
“Loki” is short for the genus Lokiarchaeum and its phylum Lokiarchaeota. The organisms were identified in frigid sediment sampled near the mid-Atlantic Ridge, 1½ miles deep in the Arctic Ocean between Greenland and Norway, about 9½ miles from the hydrothermal vent known as Loki’s Castle. Like Loki—a mercurial character from Norse mythology—Lokiarchaeota are difficult to pin down, having never been cultured. The Lokiarchaeum composite genome was pieced together from genetic components of the sparse cells found in the sediment. And like the mythological Loki, they held some surprises.
From people to protozoans, millions of organisms are made of eukaryotic cells. Eukaryotic cells are powered by mitochondria, wrap their DNA in a nuclear membrane, and have many intracellular organelles. Evolutionary scientists believe eukaryotic cells evolved from prokaryotes—single-celled organisms without nuclei, mitochondria, or other organelles. They confidently believe this despite distinctive differences and the unbridgeable chasm in their complexity. Evolutionists have however long debated which prokaryotes evolved into us. The team that discovered Lokiarchaeota notes, “The origin of the eukaryotic cell remains one of the most contentious puzzles in modern biology.”1
There are two sorts of prokaryotes: bacteria and archaea. Like bacteria, archaea lack nuclei and intracellular organelles such as mitochondria. Both have circular DNA, and neither processes information in the same way as eukaryotic cells. Initially thought to be bacteria, archaea are genetically different enough to be considered a separate group of prokaryotes.
Archaeans endure some of the harshest conditions on earth, including extreme temperatures. However, like some bacteria they are difficult to identify and culture in the laboratory. Many microbes, including some that secretly share our world and our bodies, have only been identified from a study of their genetic fragments—they have never been grown in a culture dish to be studied in detail. Likewise, our newest putative cousin Loki is known only from genomes pieced together by computer. Scientists reconstructed one nearly complete plausible genome and two partial ones from genetic material isolated from the mud in core samples.
“When we started to have a more in-depth look at the genes of this new Loki genome, we found that something was strange about it quite early on,” says lead investigator Thijs Ettema of Sweden’s Uppsala University, describing the team’s observations. Although Lokiarchaeota lack eukaryotic essentials like mitochondria, Ettema’s team “found genes that were much more like eukaryotes” and confirmed by observing their linkage to other uniquely archaean genes that they were not eukaryotic contaminants.2
Veering from observations into the realm of worldview-based evolutionary conclusions, Ettema explains, “The implication is that these genomic tools were present in the lost [sic] common ancestor, and it had this genomic starter kit that helped eukaryotes become complex. Some 2 billion years ago, we took a right turn, and Loki's ancestors took a left. Loki remained in these sediments, and it never made it into a complex organism. Instead it specialized in living in these deeply buried sediments.”3 Evolutionists think such common designs are necessarily the result of either common ancestry or convergent evolution rather than a Common Designer. Accordingly Ettema adds, “We'd like to obtain more genomes of more distant cousins, and some of those might actually be closer to us or to the common ancestor than Loki is. We could maybe start to get gradual buildup, to build a road map of the journey from single-celled life towards cellular complexity.”4
Like those of many archaeans, Loki’s protein-coding genes include many (about 29%) that are similar to those in bacteria and many (about 26%) that are unique to archaeans. Nearly one-third are not similar to any known protein.5 But about 3% of the genes, though surrounded by clearly archaean genes, resemble the eukaryotic genes that produce the contractile protein actin, proteins that participate in intracellular transport, or proteins that enable membranes to engulf things.6 Scientists don’t know how these genes function in Lokiarchaeota because they’ve never observed them. Nevertheless they maintain that, equipped with such genes, some intrepid archaean ancestor like Loki could have taken the first step to becoming a eukaryote.
One Small Step, One Giant Leap?
Only eukaryotic cells have mitochondria, little powerhouses that generate a lot of energy. Many evolutionists cling to the notion that eukaryotes evolved mitochondria by assimilating bacteria—a process called endosymbiosis. While endosymbiosis is an observable symbiosis in which a microorganism lives inside its host, endosymbiosis cannot bridge the evolutionary gap between prokaryotes and eukaryotes, despite its popularity among evolutionists.7
Mitochondria have their own supply of DNA, but some of the DNA required for their function is also located in cellular nuclei. The evolutionary endosymbiosis tale cannot steer around this irreducible complexity. Mitochondria depend on proteins coded for by genes already present in their cells’ nuclei. Yet such necessary nuclear genes would have no evolutionary reason to exist in an ancestral prokaryote before the mitochondria evolved, and the mitochondria could not function without them. (Read more about problems with the notion of endosymbiosis in eukaryote evolution in “‘Non-evolution of the Appearance of Mitochondria and Plastids in Eukaryotes: Challenges to Endosymbiotic Theory.”) Nevertheless, evolutionary scientists like Ettema believe Loki’s ancestors answered this critical gap in evolutionary dogma.
Clinch the Case?
“The acquisition of mitochondria really got things started,” explains Ettema. “The genes we find in Loki provide some pointers.” He says, “In Loki we also find genes that are related to those that encode actin proteins. Although we don't know what they do in Loki, we can infer that the last common ancestor had these genes.”8 Believing that discovery of genes that could presumably have equipped a prokaryote for endosymbiotic evolution into a eukaryote, Ettema declares, “Archaea and eukaryotes are sister groups, sharing a common ancestor.”9
Ecstatic about the discovery that Lokiarchaeota might be equipped to use their membranes to engulf things, Eugene Koonin of NIH’s National Center for Biotechnology Information commented, “These findings clinch the case for the origin of eukaryotes from within the archaeal diversity and point to a specific part of the archaeal evolutionary tree where eukaryotes belong. Equally important, Lokiarchaeota combine a number of ‘eukaryotic-like’ features that previously have been found scattered among different archaeal genomes. Taken together, these findings give credence to the evolutionary scenario in which the eukaryotes evolved from an archaeon with a complex cellular organization that might have been capable of engulfing bacteria.”10
“Humans have always been interested in trying to find an answer to the question, ‘Where do we come from?’” Ettema says. “Well, now we know from what type of microbial ancestor we descend. . . . Essentially, Lokiarchaeota represent a missing piece of the puzzle of the evolution from simple cells—bacteria and archaea, prokaryotes—to complex cells—eukaryotes, which includes us humans.”11
Even though, as University College London’s Nick Lane explains, Lokiarchaeota “lack the large genome and energy-producing mitochondria of true eukaryotic cells” and are only “a thousandth of the way towards the complexity of a eukaryote,”12 evolutionary scientists contend Loki’s phylum represents a missing link, one small step in the evolution of increasingly complex life-forms, illustrating a mechanism by which such evolution could occur.
The evolutionary authors of “Evolution: Steps on the Road to Eukaryotes,” a news-and-views article in Nature, agree that Lokiarchaeota have the toolkit that could enable ancient archaea to evolve into a more eukaryotic-like organism. They also assert that the methodology used to compare Lokiarchaeota to eukaryotes “provides a powerful toolkit for testing ideas about the origins of the component parts of eukaryotic cells,” adding that “the investigation of eukaryotic origins can now enter the realm of testable science.”13
But how can that be? Can any scientist ever perform a test to objectively show the evolutionary origin of a life-form that supposedly sprang into being 2 billion years ago? No. Claims that life evolved from non-living matter through natural processes 4 billion years ago and later into more complex eukaryotes are riddled with worldview-based assumptions and are completely untestable and unobservable. Such vast ages are themselves presumptions grounded in circular reasoning, as is the unverifiable notion that organisms can acquire new information to evolve into more complex organisms. Such a process has never been observed in the laboratory. Eukaryotes do not even process information in the same way as prokaryotes, and evolution of one from the other would demand a complete and virtually simultaneous re-working of the entire organism and its numerous complex, interdependent systems.
Common Designer, Our Creator Jesus Christ
So what should we make of a few similarities amidst a sea of differences, such as those eukaryotic-like genes in a prokaryotic organism? A few genetic similarities between very different kinds of organisms is not proof of common ancestry but rather is an example of common design such as we would expect from a Common Designer, the Creator God to whom all living things, even microbes, owe their origins. Neither archaea nor bacteria are the ancestors of eukaryotic cells or the many organisms, including human beings, composed of them. If Lokiarchaeota are eventually observed to have the ability to engulf material, that in no way demonstrates that an ancestral prokaryote evolved into a eukaryote by engulfing bacteria. Such an ability would not get around the many problems with evolutionary endosymbiotic claims. It would instead simply be an example of the biodiversity we find in the world God created. God supplied the information needed for the complex features found in each created kind of organism, be it microbe or man.
Ettema says humans want to know where we come from. But we will never discover our origins in the genomes of prokaryotes. The speculative claims of evolutionary origins remain not only unverifiable but outside the realm of plausibility based on experimental biology. Despite evolutionary claims, living things only come from living things, and living things—whether plants, animals, or microorganisms—reproduce and vary only within their created kinds. Microorganisms fulfill many important roles in our world, and some even live inside other organisms and interact with them. (Read about a great example of this in “Just Endosymbiosis”!) But this does not mean they are on the road to becoming a new kind of organism or reveal any way to overcome the difficulties inherent in the endosymbiotic theory of eukaryotic evolution.
God’s eyewitness account of our origins in the Bible’s book of Genesis are, however, consistent with observable science. We can trust what the Bible tells us about our past, our present, and our future: the creation of a very good world about 6,000 years ago, the deterioration of many things in this world in the wake of man’s sin, and the saving grace available for life now and forever through the Lord Jesus Christ, through whom the world was created (Colossians 1:16–17) and by whom our salvation was purchased (John 3:16–18).
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