• UGI USER
  • Sep 13, 2023
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Without sperm or egg, how scientists grew whole model of human embryo

Relevance

  • GS Paper 3Science and Technology- developments and their applications and effects in everyday life.
  • Achievements of Indians in science & technology; indigenization of technology and development new technology.
  • Tags: #humanembryo #stemmcells #ethicaldilemma #currentaffairs #upsc.

Why in the News?

A Lab Has Created a Synthetic Human Embryo Without a Fertilized Egg.

Understanding the early stages of embryo development is a formidable challenge due to ethical constraints and difficulties in studying implanted embryos.However, scientists have achieved a groundbreaking feat by cultivating a “human embryo” in a laboratory environment, devoid of both egg and sperm. This achievement relied on a combination of stem cells—precursor cells capable of differentiating into various cell types—that autonomously organized into an embryo-like structure, faithfully replicating the molecular characteristics of an early-stage embryo.

How was the embryo model created? 

  • This innovative research has given rise to one of the most comprehensive models of a 14-day-old human embryo.
  • Several research teams have joined the quest to develop embryo-like models, with approximately six such models published in the current year.
  • While none fully replicate the intricate processes of early embryo development, each contributes valuable insights to the field.

Creating the Lab-Grown Embryo Model

  • Researchers from Israel accomplished this feat by combining stem cells with chemical compounds.
  • A fraction of this mixture spontaneously organized into different cell types, including those forming the fetus, providing nourishment, orchestrating body development, and constructing vital structures like the placenta and umbilical cord. Notably, only 1% of the mixture exhibited spontaneous assembly, rendering the process relatively inefficient.

The Significance of Embryo Models in Scientific Research

  • The inability to ethically study early embryo development after implantation in the uterus has driven scientists to explore alternative models.
  • These models hold immense importance because the initial days of embryo development are when most miscarriages and birth defects occur.
  • Investigating these early stages can enhance our understanding of genetic and hereditary diseases.
  • Moreover, comprehending why certain embryos develop normally, retain correct genetic coding, and implant successfully in the womb can contribute to improving the success rates of in vitro fertilization.
  • Debojyoti Chakraborty, a principal scientist at the Institute of Genomics and Integrative Biology, emphasized the significance of embryonic research in shedding light on genetic, epigenetic, and environmental influences on developing embryos.

Can Lab-Grown Embryos Lead to Pregnancy?

  • It’s important to note that lab-grown embryo models are strictly intended for studying the early stages of fetal development. Attempts to implant these models are prohibited, and they are typically destroyed after 14 days of study.

The 14-Day Limit and Its Ethical Foundations 

  • The 14-day limit on embryo research traces its origins to a UK committee’s proposal in 1979, following the birth of the first test tube baby, Louise Brown, which demonstrated the potential for keeping embryos alive in laboratory settings.
  • This timeframe corresponds to when embryos naturally complete implantation and individualization occurs. The concept of the “Primitive Streak” marks this transition from radial to bilateral symmetry, symbolizing a critical ethical threshold in embryo development.

Insights Gained from Embryo Models

  • Embryo models, such as the one pioneered by the Israeli team, have yielded valuable insights into the early stages of development.
  • They have illuminated the origins of errors in DNA duplication, revealing that these anomalies arise much earlier in the process than previously assumed.
  • Additionally, these models enable scientists to unravel the roles played by various genes in fetal development, facilitating gene manipulation for a deeper understanding of developmental processes.

In the words of biologist Magdalena Zernicka-Goetz, these developments allow researchers to manipulate genes and explore their developmental functions within a controlled model system, a task that proves challenging with natural embryos.

 

Understanding Synthetic Human Embryos (SHE)

· Formation Process: Synthetic Human Embryos (SHE) do not result from the traditional fusion of egg and sperm cells. Instead, they are crafted from pluripotent stem cells, which possess the capability to develop into nearly any cell type within the body.

· Stem Cell Sources: These stem cells can be obtained from embryos or reprogrammed from adult cells, such as skin or blood cells.

· Creating SHE: Researchers manipulate the culture conditions and signaling cues that guide cell differentiation to induce stem cells to self-organize into three-dimensional structures resembling early embryonic development. This can include forming blastocyst-like cavities, placenta-like tissues, and primitive streak-like structures marking the onset of gastrulation.

· First SHE Milestone: The University of Cambridge and the California Institute of Technology reported the creation of the first synthetic human embryos, which were developed to a stage equivalent to just past 14 days old. This aligns with the legal limit for studying natural human embryos in many countries.

Regulations Surrounding Synthetic Human Embryo Development

· Global Variability: Laws and regulations pertaining to synthetic human embryo research exhibit significant variation across different countries and regions.

· Prohibition in Some Nations: Certain countries, such as Germany, Italy, Ireland, Poland, and Slovakia, impose stringent regulations that either prohibit or severely restrict human embryo research of any form.

· Research Allowed in Others: Conversely, countries like Australia, Canada, France, Japan, Singapore, South Korea, Sweden, the UK, and the US have more lenient regulations that permit specific forms of human embryo research under defined conditions and stringent oversight.

· Lack of Explicit Regulations: Notably, many of these regulations do not explicitly address synthetic human embryos or other types of stem cell-based embryo models, creating a regulatory gap.

The Indian Perspective on Synthetic Human Embryos

· No Specific Legislation: In India, there is no dedicated legislation governing synthetic human embryo research. Nevertheless, some guidelines are applicable to stem cell research in a broader context.

· ICMR Guidelines: The Indian Council of Medical Research (ICMR) issued the National Guidelines for Stem Cell Research in 2017, providing ethical principles and norms for conducting stem cell research involving humans or animals.

 

 

International Agreements Related to Synthetic Human Embryo (SHE) Development:

No Binding Treaty: There is no binding international treaty or convention specifically regulating synthetic human embryo (SHE) research.

Universal Declaration on the Human Genome and Human Rights (UNESCO, 1997):

· Prohibition of Reproductive Cloning: It prohibits practices contrary to human dignity, such as reproductive cloning of human beings.

· Genome Interventions: It allows interventions on the human genome only for preventive, diagnostic, or therapeutic purposes, with the informed consent of the person concerned.

Universal Declaration on Bioethics and Human Rights (UNESCO, 2005):

· Human Dignity and Rights: It emphasizes the full respect of human dignity, human rights, and fundamental freedoms in any scientific research involving human beings.

· Individual Welfare Priority: It prioritizes the interests and welfare of individuals over the sole interests of science or society.

Guidelines by the International Society for Stem Cell Research (2021):

· Ethical Stem Cell Research: These guidelines, issued in 2021, offer detailed recommendations for conducting ethical and responsible stem cell research.

· Scope: They cover various aspects, including human embryos, stem cells, organoids, and other related models.

 

Understanding Stem Cells

· Nature of Stem Cells: Stem cells are unique human cells with the remarkable ability to differentiate into various cell types.

· Diverse Potential: Stem cells can transform into a wide range of cell types, including muscle cells, brain cells, and more.

·Tissue Repair: In certain instances, they possess the capacity to repair damaged tissues.

· Cell Division: Under appropriate conditions, either within the body or a controlled laboratory environment, stem cells divide, generating daughter cells.

· Daughter Cell Fate: These daughter cells can take one of two paths: becoming new stem cells or specializing into distinct cell types through a process called differentiation. This specialization leads to the formation of specific cells, such as blood cells, brain cells, heart muscle cells, or bone cells.

·Unique Regenerative Ability: Stem cells are unparalleled in their natural ability to generate new cell types, a characteristic not shared by any other cell in the body.

Sources of Stem Cells

· Embryonic Stem Cells: Derived from embryos typically 3 to 5 days old, referred to as blastocysts, consisting of approximately 150 cells. These are pluripotent stem cells, capable of evolving into any cell type in the body. This versatility makes them valuable for regenerating or repairing diseased tissues and organs.

· Adult Stem Cells: Found in limited numbers within various adult tissues, such as bone marrow and fat. Compared to embryonic stem cells, their potential is more restricted, leading to the development of closely related cell types. These cells are referred to as multipotent, meaning they can differentiate into specific, closely related cell types. For example, stem cells residing in bone marrow were initially believed to only produce blood cells.

Sources: The Hindu

Mains Question

“Analyze the 14-day limit on embryo research and its ethical foundations. Discuss the insights gained from lab-grown embryo models and their relevance to understanding genetic and developmental processes. 250words.