- Genetic engineering is the manipulation of DNA to modify genes, transfer them between organisms, or alter gene expression.
- Because the genetic code is universal, genes from one organism can function in another to produce useful products like human insulin and growth hormone.
- This technology is used to create transgenic organisms and genetically modified crops with improved traits such as disease resistance and better nutrition.
Definitions [2]
Define genetic engineering.
Genetic engineering is the manipulation and transfer of genes from one organism to another organism to create a new DNA called recombinant DNA (rDNA). Genetic engineering is also called recombinant DNA technology.
Definition: DNA Fingerprinting
The technique of identifying an individual by analysing the unique DNA sequence present in each person, similar to fingerprints, is called DNA fingerprinting.
Key Points
Key Points: Green Revolution
- Green Revolution refers to the collective methods used to obtain maximum agricultural yield from minimum land to overcome food scarcity caused by population explosion.
- Development of high-yielding dwarf varieties of wheat and rice, along with proper use of fertilizers, pesticides, and water management, greatly increased food grain production.
- Dr. Norman Borlaug and Dr. M. S. Swaminathan played key roles in the Green Revolution, supported by research institutes like IARI, New Delhi, and other national agricultural research centers.
Key Points: Animal Husbandry (Livestock) > Animal Breeding
- Meaning — Breeding & raising livestock to increase yield and improve desirable qualities (milk, meat, eggs).
- Inbreeding — Closely related individuals bred for 4–6 generations → increases homozygosity, eliminates harmful genes. Demerit: reduces fertility.
- Outbreeding — Unrelated animals, no common ancestor for 4–6 generations → removes inbreeding depression.
- Types of Outbreeding — Outcrossing (same breed), Crossbreeding (different breeds), Interspecific hybridisation (different species).
- Examples — Hisardale sheep = Bikaneri ewe × Marino ram | Mule = Horse × Donkey.
- Artificial Insemination (AI) — Semen from a superior male → frozen/preserved → injected into the female's genital tract.
- MOET — FSH given to cow → superovulation (6–8 eggs) → blastocysts (8–32 cell stage) transferred to surrogate mothers.
Key Points: Genetic Engineering
Key Points: DNA Fingerprinting
- DNA fingerprinting is a technique used to identify an individual by analysing the unique DNA pattern present in every person (except identical twins).
- It is based on satellite DNA, especially VNTRs (Variable Number Tandem Repeats) - short sequences repeated in tandem, whose number varies among individuals and creates DNA polymorphism.
- Principle: the differences in VNTR repeat number produce DNA fragments of different lengths, which appear as a unique banding pattern.
- Steps: DNA isolation → PCR amplification → restriction digestion → gel electrophoresis → Southern blotting → probe hybridisation → autoradiography → comparison of band patterns.
- Applications: forensic identification, paternity/maternity testing, pedigree studies, medical research, conservation biology, and evolutionary/anthropological studies.
