Synthetic Biology and Manipulating Nature

The recent feat of synthetically creating a mouse embryo from stem cells highlights the result of decades worth of advancements and research in stem cells, and all the while opens a debate in the ethics of the field itself.

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Studies in synthetic biology and bioengineering have underlined advancements in the human potential to manipulate nature and evolution. At the California Institute of Technology, a team of researchers successfully created a mouse embryo solely from different types of stem cells. The embryo matured to have a beating heart and showed early development of the brain, a remarkable feat without the use of mouse gametes. They harnessed the nature of different stem cells in the lab environment to imitate the mechanisms of a mouse embryo.

Though stem research has been an ongoing field of study since the 1960s, this recent achievement marks a pivotal point in stem cell and reproductive research. It is the product of decades of studying the nature and manipulation of embryonic stem cells. Stem cells were first discovered in the 1960s by hematologist Ernest McCulloch and biophysicist James Till when they identified the hematopoietic stem cell, which is capable of differentiating into different types of blood cells. Thus, the foundation of stem cell research is derived from the discovery of multipotent stem cells, which are self-renewing cells that can differentiate into specialized cells pertaining to a specific tissue or organ. Eventually in the 1980s, scientists successfully isolated and cultured embryonic stem cells from mouse blastocysts—an early phase of the embryo when it is a cluster of rapidly dividing cells made by a fertilized egg. The pluripotent nature, or ability to develop into any type of cell of the body, opened opportunities for manipulating the building blocks of organisms.

From the first discovery of hematopoietic stem cells to the recent accomplishment of replicating the development of a mouse embryo, one may notice that research on mice has shown up frequently in studies regarding stem cell lines. In fact, it is the decades’ worth of experimentation on mice that are helping scientists apply the results to humans. Factors such as cost, time, and availability of a large supply contribute to the efficiency of using mouse cell lines over human cells in stem cell research.

The human body has its own reserve of stem cells in the bone marrow. These cells can differentiate into more complex cells with specific functions, from muscle cells to brain cells. In the lab, however, scientists have the ability to grow stem cells by using culture dishes. The dishes contain a medium that optimizes the growth of different types of stem cells. From there, researchers can manipulate the function of these stem cells to mature into the desired type of cell. They can do this by changing the chemical composition of the culture medium in which the original cells are growing or forcing the expression of specific genes.

The interest in stem cell research lies in the plethora of possibilities it provides to advance in different fields of science. The discoveries can lead to major improvements in reproduction research, developmental abnormalities, and regenerative medicine. The recently synthetically created mouse embryo gives scientists a deeper insight into the important role of the integrity of communication between stem cells in an embryo and the mother’s womb. This is vital to the understanding of pregnancy failures and consequential solutions for these prevalent issues. A major goal scientists tried to achieve in the study was to effectively make the three types of stem cells talk to each other under lab conditions. They successfully managed to do this by altering gene expression and manipulating the environment to promote this type of communication. With this, the embryo was able to go through the developmental stages of a normal mammalian embryo and developed not only a beating heart, but also a yolk sac, which provides nutrients for the embryo. Most importantly, a complete brain was generated in the study, which is the most advanced stage of development achieved so far in a stem cell-derived model.

Despite this, the ethics surrounding the far-reaching consequences of stem cell research is a popular and necessary conversation in science. The concept of humans manipulating stem cells to create organisms from scratch is a future difficult to warm up to. Using stem cells for their regenerative properties and helping patients suffering from chronic diseases or conditions is one thing, but exploiting the power of stem cells for reasons that can be considered unethical for what people may defend as “for the sake of science,” is where a line is drawn. For example, CRISPR babies have been a highly controversial topic in synthetic biology due to the implications it has for eugenics, the study of arranging a population with desirable traits, and the considerable risk that comes with the process due to the early stages of research. Overall, stem cells have great potential in medicine and therapy, and because of that, it is important to use their qualities wisely.