Note4Students
From UPSC perspective, the following things are important :
Prelims level: HERVH and 'Jumping Genes'
Mains level: NA
Central Idea
- Recent breakthroughs in genetic research have shed light on the complexities of early embryonic development, particularly focusing on the inner cell mass, a key component in forming the human body.
Embryonic Development Explained
- Life’s Commencement: Life begins with the fusion of sperm and egg, creating a zygote, the first cell of a new individual.
- Cellular Multiplication: The zygote undergoes rapid cell division, marking the onset of embryonic development.
- Diverse Cell Differentiation: As the embryo develops, cells differentiate into various types, leading to the formation of organs and tissues.
- Journey to Birth: This intricate process culminates in the birth of a newborn after nine months of gestation.
Early Stages of Development
- Inner Cell Mass Formation: Early embryonic cells cluster around the inner cell mass, vital for the embryo’s development.
- Pluripotency of Cells: These cells are pluripotent, meaning they can develop into any cell type in the body.
- Scientific Focus: The inner cell mass is a primary subject of study due to its critical role in human development.
Gene Expression in Embryonic Cells
- Analyzing Gene Activity: Researchers study the proteins produced by genes to understand cell-specific gene expression.
- Deciphering Cell Development: This research provides insights into the active genes in each cell, revealing the mechanisms of cell development.
Discoveries in the Inner Cell Mass
- 2016 Research Insights: Manvendra Singh’s reanalysis of gene expression data identified a new group of non-committed cells in the inner cell mass.
- Enigma of Cell Death: These cells, unlike others, do not progress to later developmental stages and are eliminated early on.
HERVH Gene and Cell Survival
- HERVH’s Crucial Function: A 2014 study revealed that HERVH, a gene with virus-like properties, is essential for maintaining pluripotency in embryonic stem cells.
- Gene Expression Variations: Singh’s research showed that while most inner cell mass cells express HERVH, the non-committed cells that eventually die do not.
- Independent Confirmation: This discovery was corroborated by researchers at the University of Spain in lab-fertilized embryos.
Understanding ‘Jumping Genes’
- Transposons in Non-Committed Cells: The non-committed cells express transposons, or ‘jumping genes’, which can cause DNA damage and lead to cell death.
- HERVH’s Protective Role: HERVH protects most cells from the harmful effects of transposons, but cells lacking HERVH expression are vulnerable.
- Natural Selection in Embryos: The early human embryo acts as a selection ground, favoring cells with HERVH expression.
- HERVH’s Unique Nature: Interestingly, HERVH itself is a transposon but functions protectively rather than destructively.
Implications for Placenta and Beyond
- Placental Development: Cells that form the placenta also exhibit transposon activity but manage to survive without HERVH expression.
- Impact on Regenerative Medicine: Understanding HERVH’s role in cell pluripotency has profound implications for regenerative medicine and could influence embryo viability in fertility treatments.Top of Form
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