In this blog post, we’ll examine the background behind the emergence of evolutionary developmental biology (Evo-Devo), its core concepts, and why it’s regarded as a new trend in the future of biology.
Over the past 150 years or so, one of the theories that has most passionately captivated the biological community is, without a doubt, the theory of evolution. The theory of evolution explains that organisms undergo repeated species evolution through natural selection, and that humans, too, may be life forms that emerged as a result of such evolution. When it first appeared, this theory clashed head-on with existing religious worldviews and sparked intense controversy. However, today—more than 150 years after the publication of ‘On the Origin of Species’—Darwin’s theory of natural selection has established itself as one of the most powerful paradigms, at least within the field of biology. Recently, various academic fields bearing the names “Darwin” or “evolution”—including evolutionary psychology, Darwinian medicine, the philosophy of evolution, and evolutionary economics—have been actively developing. Among these trends, one field that deserves particular attention is Evo-Devo (Evolutionary Developmental Biology).
Although evolutionary developmental biology is a relatively new field, it holds great significance in that it integrates developmental biology and evolutionary biology to study both the developmental and evolutionary processes of living organisms. The core research focus of this field is to compare the developmental processes of different organisms and to elucidate the pathways through which these processes have evolved. This research is regarded as a new attempt to integrate various fields within biology, and many researchers predict that Evo-Devo will become one of the major research trends in biology in the future. In this article, we will examine how Evo-Devo—which is leading this integrative research trend within biology—began, what its core research areas are, and why it occupies such an important position in the future of biology.
It is no exaggeration to say that i-bo-di-bo truly began with the discovery of the homeobox. In the late 1970s, German biologists discovered a specific DNA sequence while studying genes that regulate body segment formation in fruit flies; this was the homeobox. Subsequently, these genes came to be commonly known as Hox genes.
As research continued, it was revealed that the homeobox plays a crucial role in regulating the activation of specific genes during development. In other words, even though all cells possess the same genetic information, some cells become muscle cells while others become nerve cells because these regulatory genes selectively turn gene expression on and off. For this reason, the homeobox is often referred to as the “master switch” that determines a cell’s fate.
Even more remarkable is the fact that these homeobox genes have been found not only in fruit flies but also in vertebrates, including mice and humans. It has been confirmed that the gene arrangement used to determine the anterior-posterior axis in fruit flies functions in a very similar way in mammals during the formation of the spine and skeleton. In other words, even among organisms that are evolutionarily very distantly related, similar genes have been conserved over a long period of time and perform similar functions.
Furthermore, developmental regulatory genes such as Hox genes perform remarkably similar functions across different species. A prime example is the gene that regulates eye development. Although the eyes of insects and vertebrates differ greatly in structure, form, and function, the Eyeless gene, which regulates eye development in fruit flies, and the Pax6 gene in mice perform very similar functions even across different species. In fact, studies have reported cases where normal eyes formed even when these genes were introduced into the embryos of different organisms.
The reason these genes perform the same regulatory function even in different organisms is that they act as key regulators that determine which organs cells will develop into. These types of genes are called “master regulatory genes” or “toolkit genes,” and the field of Evo-Devo has developed precisely around these regulatory genes.
To some, this may seem like nothing more than an ongoing process of discovering important genes. However, in reality, i-evo has significantly transformed the existing framework for understanding evolution and holds great significance in that it has presented a new paradigm capable of explaining the unity and diversity of life from a single perspective.
In traditional evolutionary biology, evolution was primarily understood as the process by which the frequency of specific genes within a population changes over generations. In other words, the phenomenon itself—where certain genes gradually become more prevalent or disappear through natural selection—was viewed as the core of evolution. Furthermore, research was centered on structural genes, which directly produce proteins to carry out biological functions.
In contrast, iVoDiVo has significantly broadened the perspective on evolution. It highlights that even when organisms possess the same structural genes, it is when, where, and how strongly these genes are expressed that determines an organism’s form and function. In other words, the core of evolution lies not in the continuous creation of new structural genes, but in changes to regulatory genes that control the timing and location of expression of existing structural genes.
For example, even with the same genes, the body’s structure and the form of its organs can vary significantly simply based on whether those genes are expressed or not at specific points during development. From this perspective, iBodivo reinterprets evolution not as a mere change in genetic composition, but as a change in the way genes are expressed. In other words, the evolution of living organisms is largely determined not by changes in the structural genes themselves, but by changes in the regulatory genes that act as switches to control those structural genes.
Having proposed this new paradigm, epigenetics is highly likely to lead an important trend in future biology. Above all, this is because it integrates evolutionary biology and developmental biology—fields that had previously developed separately—into a single research framework. Furthermore, as this integration expands into various subfields of biology, it is providing new clues for understanding a variety of long-standing unsolved problems.
How a single fertilized egg differentiates into countless cells and tissues to form a complex adult organism has long been one of biology’s greatest mysteries. However, recent advances in developmental genetics and molecular biology have gradually revealed the various regulatory genes involved in this process, broadening the scope of research to areas that were previously difficult to explain through traditional developmental biology alone.
Today, “Evo-Devo” research involves not only molecular biology, cell biology, and developmental genetics—which study gene expression mechanisms—but also a wide range of other fields, including genomics, proteomics, and systematics. Phylogenetic research is necessary to compare homology among different groups of organisms, and research at the molecular level is also essential for understanding the functions of genes and proteins. Furthermore, paleontology is receiving new clues to understand the process by which ancestral limbs first appeared and how that developmental process evolved. In this way, Evo-Devo today serves as a central axis connecting various fields of biology.
Furthermore, evo-devo has provided an opportunity to take the so-called “Modern Synthesis” of 20th-century biology a step further. With the rapid advancement of genetics in the early 20th century, developmental biology received relatively little attention and was not sufficiently integrated with evolutionary biology. At the time, developmental biology was sometimes underestimated because quantitative research was difficult and the field was considered primarily descriptive. Even Thomas Hunt Morgan (T. H. Morgan), a leading geneticist, had expressed critical views toward developmental biology.
However, Ibodibo subsequently proposed a new perspective—that changes in the developmental process itself are a key driving force of evolution—thereby reintegrating developmental biology and evolutionary biology, which had long been separated, into a single research framework. In other words, it proposed a new approach that seeks to explain how the form and function of living organisms are formed and changed by considering both development and evolution as two interrelated axes. In this regard, the “Evo-Dev” approach is recognized as an integrative research paradigm that encompasses the entire field of biology.
In line with this academic trend, universities around the world have actively moved to consolidate their previously fragmented biology-related departments. The University of California, Berkeley operates a “Department of Integrative Biology,” and several other universities, including the University of Texas and the University of Chicago, have established educational and research systems that link various fields of biology. Harvard University is also actively conducting research in integrative biology, separate from its official departmental structure.
In South Korea as well, the number of universities that have consolidated departments previously divided into biology, molecular biology, and microbiology into a “life sciences” or “School of Life Sciences” structure has steadily increased. Of course, not all of these organizational restructuring efforts were directly driven by Evo-Devo, but it is clear that these changes align with the research trend toward an integrated understanding of biology. Similarly, in the field of education, there is a shift away from the traditional practice of listing disciplines independently toward understanding them as a single, closely interconnected system.
So far, we have examined what “Evo-Divo”—a new trend gaining attention in the biological sciences—is, as well as the key research supporting it. We have also explored how this research is presenting a new paradigm in biology and creating an integrative trend that connects various fields into one.
Recently, the concepts of convergence and integration have established themselves as important research directions not only in biology but also in various fields of science and technology, as well as in the humanities and social sciences. Based on accumulated knowledge and information, disciplines that previously developed independently are now being connected around new theories and technologies, and collaboration across different fields is giving rise to new areas of research.
From this perspective, evolutionary developmental biology—or EvoDev—is establishing itself as a crucial research framework that connects various fields within biology. Furthermore, by laying the groundwork for an integrated understanding of developmental biology and evolutionary biology, it is making a significant contribution to explaining both the diversity and commonality of life. While it is impossible to definitively predict the future direction of biology, Evo-Devo has established itself as a highly significant field of research in modern biology, and it is highly likely to continue developing as one of the core fields driving diverse research and interdisciplinary convergence.
