Context:
Recently, Scientists have achieved a remarkable feat by creating a lab-grown “human embryo” model using stem cells and chemicals, without using an egg or sperm shedding light on early embryo development.
Relevance:
GS III: Biotechnology
Dimensions of the Article:
- Human Embryo
- Creation of the Embryo Model
- Insights from These Models on Early Development
- Use of Lab-Grown Embryos for Pregnancy
- Stem Cell
Human Embryo:
- A human embryo refers to the developing human organism from the moment of fertilization until the end of the eighth week of gestation.
- It undergoes three primary stages of development: the pre-implantation stage, the implantation stage, and the organogenesis stage.
- Comprising various cell types, a human embryo differentiates into the diverse tissues and organs that make up the human body.
- Typically, a human embryo is formed through the fertilization of a human egg (oocyte) by a human sperm, which can occur either in the female reproductive tract or in a laboratory setting.
Creation of the Embryo Model:
- Stem Cells and Chemicals Combination: Israeli researchers employed a combination of stem cells and specific chemicals to fabricate a model resembling a 14-day-old human embryo.
- Crucial Starting Point: This blend of stem cells and chemicals served as a critical initial step in the development of an embryo-like structure.
- Spontaneous Cell Assembly: The model created by the Israeli researchers had the remarkable ability to spontaneously arrange into various cell types necessary for fetal development. This included cells for fetal formation, nutrient provision, embryonic body development, as well as the creation of essential structures like the placenta and umbilical cord to support the developing fetus.
- Efficiency Challenge: A notable challenge faced during this process was that only approximately 1% of the stem cell-chemical mixture naturally organized itself, indicating a need for improved efficiency in the creation process.
Insights from These Models on Early Development:
- Detection of DNA Duplication and Chromosome Distribution Errors: These models have been instrumental in revealing errors in Deoxyribonucleic acid (DNA) duplication and the distribution of chromosomes during early development.
- Early DNA Duplication Abnormalities: Researchers discovered that abnormalities in DNA duplication occur early in the embryonic development process, impacting cell division.
- Study of Gene Functions: These embryo models provide a platform to study gene functions and their roles in the development of the fetus, offering valuable insights into the molecular mechanisms involved in early human development.
Importance of Embryo Models and Research:
- Ethical Challenges in Studying Post-Implantation Embryos: Once implantation in the uterus occurs, studying early embryo development becomes ethically challenging. Therefore, research during the initial stages is crucial.
- Addressing Miscarriages and Birth Defects: Most miscarriages and birth defects occur during the early stages of embryonic development. Understanding these processes is vital for identifying potential causes and developing preventive measures.
- Improving In Vitro Fertilization (IVF) Outcomes: Insights gained from studying embryo development can lead to improved outcomes in IVF procedures, increasing the chances of successful pregnancies.
- Understanding Genetic, Epigenetic, and Environmental Influences: Research on embryo models helps researchers comprehensively study the genetic, epigenetic, and environmental factors that influence embryonic development, providing valuable knowledge about how these processes work.
Use of Lab-Grown Embryos for Pregnancy:
- Exclusively for Research: Lab-grown embryos are intended solely for research purposes. They are typically destroyed after 14 days, and implantation into a uterus is not permitted.
- The 14-Day Limit: The 14-day limit was proposed in 1979 in the UK and is equivalent to the point when natural embryo implantation is completed. It signifies the stage when cells begin forming an “individual,” and the possibility of them splitting into twins no longer exists.
- Ethical Transition from Cells to Individuals: Ethical considerations surrounding embryo research change as embryos progress from clusters of cells to individuals. The emergence of the Primitive Streak, a linear structure in the embryo, marks the transition from radial symmetry (like an egg) to the bilateral symmetry of the human body, with left and right sides.
- The Role of the Primitive Streak: The Primitive Streak is significant because it signifies the moment when the embryo transforms from a mere clump of cells to an individual. Ethical considerations regarding research and experimentation on embryos often hinge on this developmental milestone.
Stem Cell:
- Stem cells are a unique type of cell with the remarkable ability to transform into specialized cell types within the body.
- They hold the potential to replace damaged or lost cells and tissues due to diseases or injuries in the future.
- Stem cells possess two distinctive properties:
- They can undergo multiple divisions, continuously generating new cells.
- As they divide, they have the capability to differentiate into various cell types found in the body, contributing to tissue repair and regeneration.
-Source: The Hindu
