Biotechnology
Easy Overview
If regular biology is understanding nature, biotechnology is hacking it. We're talking transgenic animals (pigs with human genes), gene therapy (fixing broken DNA), RNA interference (silencing bad genes), and the ethical firestorm around all of it. This is biology's wild side.
Transgenic animals — animals with borrowed genes
Animals that have a foreign gene deliberately inserted into their genome are transgenic. Rosie the cow produced human protein in her milk. Mice with human genes are used to study diseases. Goats that spin spider silk protein in their milk. It's like giving animals a side job making drugs or materials for us.
Gene therapy — fixing the unfixable
Some diseases are caused by a single defective gene. Gene therapy tries to fix it. A working copy of the gene is delivered into patient cells using a vector (usually a modified virus). The first success was for SCID (severe combined immunodeficiency) — 'bubble boy' disease. It's still risky, but the potential is insane.
RNA interference (RNAi) — silencing bad genes
RNAi is a natural mechanism where small RNA molecules bind to specific mRNA and prevent it from being translated. It's like finding a bad recipe and hiding it before anyone can cook from it. Scientists use RNAi to silence disease-causing genes. It's also being used to make pest-resistant plants without genetic modification.
Molecular diagnosis — spotting diseases early
PCR can amplify tiny amounts of pathogen DNA to detect infections. ELISA uses antibodies to detect antigens or antibodies in blood. Both can find HIV, hepatitis, or genetic disorders before symptoms appear. Early detection = better treatment. These tools have revolutionized medical testing.
Ethical issues — just because we can, should we?
Genetic modification raises real questions. Is it okay to patent a gene? Should we edit human embryos? What about the environmental impact of GM crops? Different countries have different rules. India allows Bt cotton but not Bt brinjal. The science is powerful — and with power comes responsibility. Boards love asking about this.
Key Points
- •Transgenic animals: foreign gene inserted into genome (e.g., Rosie cow, transgenic mice for research)
- •Gene therapy: deliver functional gene to correct genetic defect; in vivo (direct) or ex vivo (cells modified outside)
- •SCID was the first disease successfully treated with gene therapy
- •RNAi: dsRNA → siRNA → binds complementary mRNA → blocks translation
- •PCR can amplify DNA from a single cell for disease detection (HIV, hepatitis, genetic disorders)
- •ELISA: enzyme-linked immunoassay detects antigens or antibodies; used for HIV diagnosis
- •Cry genes from Bt are used in transgenic plants (Bt cotton) for pest resistance
- •Ethical debates: GM food safety, gene patenting, germline editing, environmental impact
Practice Questions
- What are transgenic animals? Describe any two applications with examples.
- Explain the principle of gene therapy. How was it used to treat SCID?
- What is RNA interference? How can it be used to protect plants from pests?
- Compare PCR-based diagnosis with ELISA. When would you use each?
- Discuss any two ethical concerns related to biotechnology. What is India's position on GM crops?