How Transgenic Organisms Are Actually Made

A transgenic organism carries a gene that people copied from one species and put into another. That is the whole meaning of the word. Everything else is detail: how the gene gets in, what it does once it arrives, and what nobody is sure about yet.

This article covers the method first, then what it has been used for, and then the problems. The problems get their own section, because an article that lists only benefits has not told you what is known.

What Transgenic Means

The World Health Organization calls an organism genetically modified when its DNA has been changed in a way that does not happen through breeding on its own. The key word is not the tool. It is the word "natural".

Ordinary breeding moves genes around too. The FDA points out that the strawberries sold today are a mix of two species, one from North America and one from South America. Nobody calls that engineering. Nobody avoids the fruit.

Genetic engineering is different in how exact it is. Rather than mixing thousands of genes and keeping whatever works well, it copies one gene that has been identified and puts it somewhere it can do its job.

One term needs sorting out. "Transgenic" usually means the gene came from a different species. A gene moved within one species, or between species that can already cross, is often called cisgenic or intragenic instead. Many countries treat those differently.

How the Gene Gets In

The delivery vehicle is usually a soil bacterium called Agrobacterium tumefaciens. It works because it was already doing this job on its own.

In nature, this bacterium attacks a cut stem and makes a tumour called crown gall. It is not an accident. The bacterium pushes a piece of its own DNA into the plant cell. That DNA makes the plant cell divide without stopping, and makes food the bacterium can eat.

Agrobacterium tumefaciens, the soil bacterium used to deliver genes into plant cells. Image: C-M, CC BY-SA 3.0, via Wikimedia Commons

The Part That Was Switched Off

A 2008 review by Lee and Gelvin reports the finding that made the whole field practical. None of the genes inside the transferred DNA is actually needed for the transfer.

So the tumour genes can be cut out. In their place goes something useful, and the bacterium still delivers its cargo. The section being moved is called T-DNA. It is a small part of the plasmid, about 5 to 10 percent.

It is marked at each end by short border sequences, 25 base pairs long. The bacterium cuts at those borders. One protein, called VirD2, then stays attached to the DNA as it travels, which protects it and points the way to the nucleus.

Agrobacterium causes crown gall in nature. Because the tumour genes are not needed to move DNA, they can be removed and a useful gene put in their place. Image: Lkazen, CC BY-SA 4.0, via Wikimedia Commons

Why the Delivery System Was Split in Two

Early attempts were awkward, because the plasmid is very large and hard to handle.

In 1983 two groups worked out a fix. They showed that the DNA being transferred and the genes that move it could sit on separate pieces of DNA. This works as long as both pieces are in the same cell.

That one change is why the field became ordinary. Moving a small piece of DNA that behaves in a known way is a much easier job than rebuilding a bacterium every time.

Bt Corn, Explained

The clearest example is corn that makes its own insecticide.

The gene comes from Bacillus thuringiensis, or Bt. This is a soil bacterium that people have used as an insecticide since long before anyone moved its gene.

Bacillus thuringiensis. Its toxin had been sprayed on crops for decades before anyone put its gene into a plant. Image: Dr. Sahay, CC BY-SA 3.0, via Wikimedia Commons

Bt being sprayed in 1985, well before the gene went into a crop. Image: USDA Forest Service Regional Archive, public domain, via Wikimedia Commons

That history matters, because it is often left out. Bt is not a chemical invented by genetic engineering. It is an old, approved bacterium, and it was already in use including in organic farming.

What engineering changed is the delivery. The plant now makes the toxin all by itself, rather than waiting for a person to spray it.

Bt maize in the field. Each plant makes the toxin itself, so no insecticide spray is applied. Image: Dave Hoisington, CIMMYT, CC BY 2.5, via Wikimedia Commons

The WHO says these crops have been shown to need less insecticide in some situations. It says "in specific situations", not always. That wording is deliberate, and it is the honest version.

Beyond Crops, and How It Is Checked

The first engineered product a consumer met was not food. In 1982 the FDA approved human insulin made by engineered bacteria, to treat diabetes.

Before that, insulin came from pig pancreas, and supply was getting harder. This is the clearest case of the technique doing something hard to do any other way: a human protein, made by a microorganism told to make it.

Who Checks It

Regulation is more specific than "unregulated". Three US agencies divide the work under a framework written in 1986.

The FDA covers most human and animal food. The Environmental Protection Agency rules on the protective substances built into the plants. The Department of Agriculture checks whether an engineered plant could harm other plants.

One detail is worth stating plainly. Food safety consultation in the United States is voluntary. A developer decides whether to consult the FDA. If it does, the data are submitted and the finished consultation is published.

Engineered plants under laboratory conditions. The first ones made are far smaller than anything grown for a field trial. Image: Jucember, CC BY-SA 3.0, via Wikimedia Commons

DNA separated on an agarose gel. A gel like this is how a lab confirms the inserted gene is really there. Image: Ajay Kumar Chaurasiya, CC BY-SA 4.0, via Wikimedia Commons

The FDA describes the testing plainly. The modified plant is grown in a greenhouse, then in small field plots, then in larger ones.

The FDA also notes that engineering is usually combined with ordinary breeding, and that the crop sold today was rarely built in one step.

The Documented Limits

Three health concerns are named by the WHO. They are real enough that leaving them out would make this article useless.

Three Named Health Concerns

The first is allergenicity. So far, no allergic effects have been found in the genetically modified foods on the market today.

The rule applied is caution. A gene from a plant or animal that often causes allergies is not moved into one that does not. The exception is when the protein it makes can be shown not to be an allergen.

The second is gene transfer. DNA from an engineered food could, in principle, move into bacteria living in the gut.

This mattered most when antibiotic resistance genes were used as markers, to pick out the cells that had taken up the new DNA. The WHO calls the probability low, and encourages methods that avoid those markers altogether.

The third is outcrossing. Engineered genes can escape into ordinary crops or into wild relatives.

The WHO records cases where crops approved only for animal feed or industry turned up in small amounts in food meant for people. Some countries now require GM and ordinary fields to be kept apart.

For the environment, the WHO lists escape into wild populations, the gene still being present after harvest, harm to insects that are not pests, and reduced crop variety. All are judged case by case, because they depend on local conditions.

What People Commonly Get Wrong

Any trait that kills something creates pressure, because whatever varies to survive will breed more. This is not a side effect of genetic engineering. It is how evolution works on any population under any steady pressure.

A 2019 review by Vila-Aiub describes herbicide resistance in weeds. It comes from random DNA mutations, which spread under repeated spraying.

Two ways of resisting are known. In target-site resistance, a mutation changes the shape of the enzyme the herbicide fits onto. The herbicide no longer fits.

In non-target-site resistance, the plant changes how much herbicide reaches that enzyme. It may break the chemical down faster, or trap it away in compartments of the cell.

The review is careful about the cause, and the distinction is the point. It blames decades of repeated herbicide use for the selection pressure. Herbicide-tolerant crops are part of that system, not its origin. Calling them the cause misdescribes the evidence.

There is a second finding, and it is not a hopeless one. Resistance usually costs something.

One mutation in the glyphosate target enzyme gives resistance at no measurable cost to the plant. A different double mutation gives more resistance, but badly reduces fitness when glyphosate is not present. That trade-off is what makes managing resistance possible.

What Is Genuinely Unsettled

The WHO is blunt: there is no single verdict on "genetically modified foods" as a group. Different organisms carry different genes, inserted in different ways.

Any article claiming the whole category is safe, or the whole category is dangerous, is making a claim the evidence does not support.

The international position is case-by-case testing under Codex guidelines, which began in 2003. The Cartagena Protocol, an environmental treaty, also took effect that year. It requires exporters to get consent before the first shipment of a living modified organism meant for the environment.

Whether that framework is good enough is a fair thing to argue about. But it is the framework that exists. Describing these organisms as either unchecked or as a solved problem is not accurate.

Key Terms in Plain English

These are the words in this article that would send you to a dictionary. Each one is given here the way it is actually used above.

Term	What it means here
Transgenic	Carrying a gene deliberately put in from a different species.
Recombinant DNA	DNA joined from two sources in a laboratory.
T-DNA	The piece of bacterial DNA moved into a plant cell by Agrobacterium.
Plasmid	A small ring of DNA that bacteria carry apart from their chromosome.
Transformation	Getting foreign DNA into a cell and getting the cell to use it.
Marker gene	A gene used to pick out the cells that took up the new DNA.
Bt	Bacillus thuringiensis, a soil bacterium whose toxin gene is used in insect-resistant crops.
Outcrossing	Engineered genes getting into ordinary crops or wild relatives.
Target-site resistance	Resistance from a mutation that changes the shape of the enzyme a herbicide fits onto.

The words in this article that would otherwise send you to a dictionary.

Key Takeaways

• Transgenic means a gene was copied from one species and inserted on purpose. That is more exact than the shuffling done by normal breeding.
• Agrobacterium moves DNA into plants naturally, where it causes crown gall. None of the moved genes is needed for the move, so the tumour ones can be deleted.
• Bt was sprayed on crops for decades before its gene went into a plant. Engineering changed how the toxin arrives, not the toxin itself.
• The first engineered consumer product was human insulin, approved in 1982.
• Each case is judged on its own. The WHO says no single ruling covers the whole category.
• Allergens, gene transfer to gut bacteria, and outcrossing are the three named health concerns. None is being waved away.
• Herbicide-resistant weeds come from decades of spraying. That is evolution under pressure, not a side effect of engineering plants.

Frequently Asked Questions

Is genetic engineering the same as selective breeding?

No. Both move genes between plants. Ordinary breeding mixes them at random and keeps whatever turns out well. Genetic engineering copies one gene that has been identified and puts it in.

Do genetically modified foods have to be labelled?

In the United States, yes. The National Bioengineered Food Disclosure Standard took effect in 2022. A label is needed for foods with modified genetic material that normal breeding could not produce.

Can a gene from one species really work in another?

Yes. DNA is read the same way in every cell. A gene works by making a protein, and the machinery that reads it is much the same across species.

Are genetically modified organisms bad for the environment?

It depends on the organism and where it is grown, which is why each case is judged separately. Escape into wild populations, harm to insects that are not pests, and reduced crop variety are all real questions that get looked at one at a time.

Is gene editing the same thing?

Related, but not the same. Tools like CRISPR can make exact changes, sometimes without adding DNA from another species at all. How a given edited plant is treated depends on the change made.

Key references
• FDA: how GMOs are regulated
• FDA: the GMO timeline
• WHO: food, genetically modified
• Lee and Gelvin 2008: T-DNA vectors
• Vila-Aiub 2019: resistant weeds

Images: Wikimedia Commons, with the author and license named in each caption. Safety statements follow the World Health Organization, which judges each case on its own rather than ruling on the whole category.

The Evolution of Biological Classification: From Appearance to Genes and Domains

During the 17th century, the arrival of new plant and animal species in Europe sparked the need for classification systems. In 1735, Carl Linnaeus, an influential figure in the field of taxonomy, created a hierarchical system of biological nomenclature that included two kingdoms: animal and vegetable (plant), where the highest rank encompassed all the lower levels. As the understanding of unicellular organisms grew, Ernst Haeckel recognized the need for a third kingdom, Protista, which he proposed in 1866.

The colors of Grand Prismatic Spring in Yellowstone National Park are produced by thermophilic microbes residing within it. These extremophiles, belonging to the Kingdom Archaea, thrive in temperatures ranging from 1,880°F (870°C) at the center to 1,470°F (640°C) at the rim, resulting in a stunning display of rainbow hues.

During the 1960s, Roger Y. Stanier and C.B. van Niel created a classification system consisting of four kingdoms, which was based on the differentiation between prokaryotic and eukaryotic cells. Eukaryotic cells have a cell membrane surrounding their nucleus, while prokaryotic cells do not. They also proposed a higher rank known as superdomain or empire, which consisted of two empires - Empire Prokarya and Empire Eukarya. The Kingdom Monera (bacteria) was included in Empire Prokarya, while Kingdoms Plantae, Animalia, and Protista were grouped together in Empire Eukarya.

Prior to the mid-1970s, taxonomic classifications were primarily based on observable traits such as morphology, anatomy, embryology, and cell structure. However, in 1977, Carl Woese and George E. Fox at the University of Illinois at Urbana-Champaign revolutionized the field by classifying organisms based on a molecular level comparison of their genes. They focused on the nucleotide sequences in a subunit of ribosomal rRNA, which undergoes evolutionary changes. The outcome was the proposal of three domains of cellular life: Domain Archaea, a diverse group of prokaryotic organisms among the oldest on Earth capable of adapting to extreme environments (extremophiles); Domain Bacteria; and Domain Eukarya, which was further divided into the Kingdoms Fungi (yeasts, molds), Plantae (flowering plants, ferns), and Animalia (vertebrates, invertebrates). Woese and Fox’s Protista Kingdom has also undergone further subdivisions. Taxonomic systems containing between two to eight kingdoms have been proposed, highlighting the fact that the final chapter on classification has yet to be written.

Polymerase Chain Reaction (PCR): A Revolutionary DNA Replication Technique

The Polymerase Chain Reaction (PCR) is a groundbreaking method that enables the production of millions of purified DNA copies from a small or impure sample within hours. Developed by American biochemist Kary Mullis in 1983, PCR replaced traditional DNA reproduction methods, which were time-consuming and required cloning in bacterial cells. The procedure, which involves basic reagents, a test tube, and a heat source, allows DNA to be replicated rapidly and efficiently.

PCR Process

The PCR process consists of three primary steps carried out at different temperatures:

1. Denaturation: The double-stranded DNA sample is heated to split it into two single strands.
2. Annealing: A primer is added to each single strand to help initiate replication.
3. Extension: The Taq polymerase enzyme moves along the template, assembling a copy of the DNA strand. This cycle is repeated multiple times, exponentially increasing the number of copies.

Applications of PCR

PCR has a wide range of applications across various fields, from molecular biology research to forensic science. It has been instrumental in creating transgenic animals, diagnosing genetic disorders, detecting viruses like AIDS, establishing paternity, and linking suspects to crime scenes. Moreover, evolutionary biologists have utilized PCR to analyze DNA from ancient fossils, revealing insights into species' evolutionary relationships. For instance, PCR analysis showed that red pandas are more closely related to raccoons than to giant pandas.

The Southern blot method, a common laboratory procedure, is used for the detection of a specific DNA sequence in a DNAcontaining sample. Applications include showing genetic relationships, such as to establish paternity, or DNA fingerprinting. The method was named after its inventor, the British biologist Edwin Southern (b. 1938).

Cracking Life’s Code: The Discovery of the Genetic Blueprint

The fundamental question in biology has long been how genetic information directs protein synthesis. While Watson, Crick, and Franklin uncovered the double-helix structure of DNA in 1953, the mechanism by which DNA instructs cells to build proteins remained a mystery. Scientists needed to determine how the four DNA bases—adenine (A), thymine (T), cytosine (C), and guanine (G)—were translated into 20 amino acids, the building blocks of life. This led to the unraveling of the genetic code, a monumental achievement in molecular biology.

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The Three-Letter Code: Gamow’s Hypothesis

Physicist George Gamow theorized that a three-letter sequence (codon) of nucleotides could encode amino acids. Since there are four bases, this triplet system would allow for 64 unique codons, more than enough to specify all 20 amino acids. This idea laid the groundwork for experimental breakthroughs in genetic coding.

Nirenberg and Matthaei’s Groundbreaking Experiment

In 1961, at the National Institutes of Health, Marshall Nirenberg and J. Heinrich Matthaei conducted a landmark experiment:

• They introduced a UUU codon (three uracil nucleotides) into a reaction and observed the production of phenylalanine, cracking the first piece of the genetic code.
• Soon, they found that CCC coded for proline, marking further success in decoding codons.

Khorana’s Contributions to Complex Sequences

Building on their work, Har Gobind Khorana at the University of Wisconsin-Madison took the research further:

• He synthesized repeating two-nucleotide sequences, such as UCUCUC, which translated as serine-leucine-serine-leucine...
• His work helped decode the entire 64-codon genetic code, confirming that each codon corresponds to a specific amino acid.

Holley and the Role of tRNA in Protein Synthesis

The final step in understanding protein synthesis came in 1964, when Robert Holley at Cornell University discovered transfer RNA (tRNA). His findings clarified the role of messenger RNA (mRNA) and ribosomes:

1. tRNA reads mRNA codons inside a ribosome.
2. Each tRNA binds to one specific amino acid, ensuring accurate protein assembly.
3. Proteins are formed one amino acid at a time, creating complex biological structures.

The Nobel Prize and the Universal Genetic Code

For their pioneering work, Nirenberg, Khorana, and Holley were jointly awarded the 1968 Nobel Prize in Physiology or Medicine. Their discoveries confirmed that the genetic code is universal, with only minor variations across species. This strongly supports the theory of evolution, suggesting that the genetic code was established early in life’s history and preserved across all organisms.

This image depicts the relationship between the codon (the three-letter nucleotide consisting of adenine, thymine, cytosine, and guanine or uracil) and the encoding of amino acids.

The Pioneering Discovery and Transformative Role of Plasmids in Molecular Biology

In 1952, Joshua Lederberg, a renowned geneticist at the University of Wisconsin-Madison, introduced the term "plasmid" to describe a unique category of DNA molecules distinct from the chromosomal DNA. Lederberg’s goal was to create a general term that could encompass a diverse array of genetic elements that had previously been referred to by various names such as parasites, symbionts, organelles, or genes. This new classification paved the way for a deeper understanding of genetic material outside the chromosomal structure and its significant role in various biological processes.

The Rise of Plasmids in Molecular Biology

The significance of plasmids took a dramatic leap forward in the 1970s when they were found to be invaluable tools in the burgeoning field of molecular biology and genetic engineering. This breakthrough was largely thanks to the combined efforts of geneticist Herbert Boyer and biologist Stanley Cohen, who made a landmark discovery in 1973. They demonstrated the potential of plasmids as vehicles for genetic transfer by successfully transferring a gene from one species (frog) to another (bacterium Escherichia coli). Their work revealed that not only could a gene be transferred, but it could also function normally within the new host, proving the concept of gene transfer across species and laying the foundation for modern genetic engineering.

Beyond their use in gene transfer, plasmids also play a critical role in the evolution of microbial resistance and in enabling microorganisms to become pathogenic. Their ability to carry genetic information that confers survival advantages makes them crucial players in microbial adaptability.

Understanding Plasmid Structure and Function

Plasmids are small, circular DNA molecules that replicate independently of the chromosomal DNA within a cell. Their structure typically consists of two main types of genes: backbone genes and accessory genes.

• Backbone genes are essential for the plasmid’s replication and maintenance within the host cell.
• Accessory genes, on the other hand, are not vital for the survival of the host but provide it with certain advantages. These advantages may include the ability to degrade environmental pollutants, resist the toxic effects of heavy metals or antibiotics, or even enable the host to use specific nutrients as a carbon and nitrogen source.

Moreover, plasmids are not confined to a single bacterial species; they can be transferred between different bacterial species, which facilitates the rapid spread of beneficial traits. This gene transfer mechanism is a key factor in bacterial evolution, enabling them to adapt quickly to changing environments and acquire traits such as antibiotic resistance or virulence factors.

Plasmids as Tools in Genetic Engineering

The role of plasmids in genetic engineering cannot be overstated. They are foundational in techniques such as gene cloning, gene therapy, and recombinant protein production. One of the earliest and most influential applications of plasmids was in the production of synthetic human insulin, a breakthrough achieved by Herbert Boyer in 1978. By inserting a gene for insulin into a plasmid and introducing this recombinant plasmid into bacterial cells, Boyer was able to harness the bacterial replication machinery to produce large quantities of insulin. This method revolutionized the production of proteins for medical use, leading to the mass production of human insulin for diabetic patients.

The Future of Plasmid-Based Biotechnology

The use of plasmids in biotechnology continues to evolve, with applications ranging from targeted gene therapies to the production of complex biologics and vaccines. Their ability to transfer and replicate foreign genetic material makes plasmids indispensable in the development of novel therapeutic strategies and in advancing our understanding of genetics at the molecular level.

Final Words: The Lasting Impact of Plasmids on Science and Medicine

From their initial discovery as separate genetic elements to their role in modern genetic engineering, plasmids have proven to be indispensable in the fields of molecular biology and biotechnology. Their ability to carry and transfer genetic material has not only deepened our understanding of gene function and microbial evolution but has also paved the way for innovations in medicine, such as recombinant protein production and gene therapy. As we continue to explore and harness the potential of plasmids, their impact on science and medicine will undoubtedly grow, offering new possibilities for treating diseases and advancing biotechnology.

Joshua Lederberg at work in his laboratory at the University of Wisconsin, 1958. In addition to his discovery that bacteria can exchange genes, he is also well known for his contributions to artificial intelligence and space exploration.

The Evolution of Biological Classification: From Linnaeus to Molecular Phylogenetics

Understanding how living organisms are related has been a central question in biology for centuries. Over time, the tools and theories used to answer this question have changed dramatically—from simple visual comparisons to complex DNA analysis. This journey began with Carl Linnaeus and took a revolutionary turn with Charles Darwin, eventually giving rise to modern phylogenetics.

Linnaeus and the Birth of Biological Classification

In the early 1700s, Carl Linnaeus, a Swedish botanist, introduced a system for naming and organizing living organisms known as binomial nomenclature. He gave each species a two-part Latin name (like Homo sapiens for humans) and grouped organisms into categories such as genus, family, and kingdom.

Linnaeus believed that all species were created exactly as they appeared and did not change over time. So, his classification was based purely on physical traits—such as shape, structure, and behavior. While revolutionary for its time, this approach lacked an understanding of how species might be connected through shared ancestry.

Darwin’s Theory and the Challenge to Fixed Classifications

A century later, Charles Darwin introduced the idea of evolution by natural selection, offering compelling evidence that species change over time and share common ancestors. This new perspective meant that Linnaeus’s fixed system of classification needed to be reconsidered.

Darwin's theory highlighted the importance of evolutionary relationships rather than just surface-level similarities. Organisms that looked different might be closely related, while those that looked alike might have evolved similar traits independently. This realization laid the groundwork for a deeper and more accurate approach to classification.

Ernst Haeckel and the Concept of Phylogeny

In 1866, German biologist Ernst Haeckel, an early supporter of Darwin, coined the term phylogeny to describe the evolutionary history of a species or group of organisms. Phylogeny focuses on tracing how different organisms are related through lines of descent—much like a biological family tree.

This new approach required scientists to go beyond appearance and dig into the deeper connections that link all life on Earth.

The Rise of Systematics and Phylogenetic Trees

To better understand these evolutionary connections, a field called systematics emerged. Systematics aims to reconstruct the evolutionary relationships among both living and extinct organisms.

One of the most influential figures in this area was Willi Hennig, a German biologist who, in 1950, introduced phylogenetic systematics—a method that identifies relationships based on shared evolutionary traits. Hennig’s work formalized the idea of using phylogenetic trees to represent how species diverged from common ancestors.

What Is a Phylogenetic Tree?

A phylogenetic tree is a branching diagram that shows how different species are related through evolution. Each branch point represents a common ancestor from which two or more lineages evolved. For example, coyotes and gray wolves share a recent common ancestor, so they appear as branches from the same node on the tree.

It’s important to note that a phylogenetic tree is a hypothesis, not a proven fact. It’s the best current interpretation based on the available evidence and can change as new data emerges.

Moving Beyond Appearances: The Role of Molecular Biology

For a long time, scientists relied on visible traits—like bone structure, body shape, or color—to build phylogenies. But these traits can be misleading. Different species may develop similar features independently through a process called convergent evolution.

Thanks to advances in molecular biology, scientists can now examine DNA, genes, and entire genomes to uncover relationships that were once hidden. By comparing genetic sequences, researchers can determine how closely two species are related—even when they look nothing alike.

How DNA Reveals Evolutionary History

The differences in DNA sequences between two organisms act like a molecular clock. The more differences there are, the longer it’s been since the two species shared a common ancestor. This approach has uncovered surprising connections—such as the close genetic link between birds and certain dinosaurs—and has reshaped our understanding of the tree of life.

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Key Takeaways for Curious Minds

• Carl Linnaeus developed the first standardized system of classification but believed species were unchanging.
• Charles Darwin's theory of evolution challenged fixed classifications by introducing the concept of common ancestry.
• Phylogeny is the study of evolutionary relationships, showing how species are connected like branches on a family tree.
• Phylogenetic trees visually represent these relationships, with each split indicating a shared ancestor.
• Molecular biology has revolutionized classification by revealing genetic links that aren’t visible through external traits.

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Why This Matters

Understanding the evolutionary connections among species helps scientists in fields as diverse as medicine, ecology, and conservation. It allows researchers to trace the origin of diseases, discover new drugs, and protect endangered species by understanding their closest relatives.

In a world where life is constantly changing and adapting, the story of biological classification reminds us that science, too, must evolve. And with every discovery, we get a clearer picture of our place in the intricate web of life.

This image depicts a phylogenetic tree of life, with completely sequenced genomes divided according to the three domains of life: Archaea (green); Bacteria (blue); Eukarya (red), with the red dot denoting Homo sapiens.