Revolutionizing Genetics and Biotechnology
Revolution in Genetics and Biotechnology
Introduction:
Genetic discoveries in the 21st century have led to the development of techniques such as:
- In vitro fertilization
- Cloning
- Gene therapy (curing diseases by manipulating genes)
Genetics has evolved significantly thanks to the discovery of DNA.
DNA and RNA
These are nucleic acids, core components of the cell.
Chemical Composition:
- Functions of DNA: To maintain genetic information and pass it on to daughter cells during cell division.
- Why are we different if we are made of DNA? The difference between humans lies in the order of nucleotides (e.g., ATG is not the same as GAT).
- How does DNA divide (or replicate)?
- It copies itself (natural cloning).
- During mitosis (cell division), the two DNA strands separate, and each serves as a template to form a complementary strand.
- Genetic Information: DNA’s genetic information is contained in genes, which are segments of DNA that make up chromosomes (humans have about 35,000 genes). The set of genes is called the genome.
- Why are genes important? They contain information for producing proteins, molecules responsible for cellular structure and functions.
- What are proteins and what do they do? Proteins are made of amino acids. The order of amino acids determines the protein. Each gene codes for a protein, and each cell produces proteins.
- Codon: A set of rules relating the nucleotide sequence of DNA to the amino acid sequence of a protein. It consists of a three-letter code. We can deduce the mRNA sequence from the DNA.
- Biotechnology allows the production of human proteins in other cells (non-human) because all cells follow the same rules for protein synthesis.
Human Genome Project (HGP)
Biotechnology
Biotechnology: Genetic and biochemical processes that modify organisms and biological processes to obtain useful products.
The part of biotechnology that uses genetic modification is called genetic engineering. It has enabled the production of modified plants, animals, and antibodies.
Genetic Engineering Techniques
- Isolating, combining, copying, and sequencing DNA fragments.
- Combining DNA from different species into a new DNA molecule. This allows inserting a gene for a human protein into bacteria to produce large amounts of the protein.
If a living being receives one or more genes from another species, it is called transgenic.
Applications in Medicine
- Manufacturing pharmaceuticals (human insulin, antibiotics).
- Gene therapy: Locating the gene causing a disease and replacing it with a healthy one.
- Vaccine Production:
- Isolating proteins from the virus or bacterium causing the disease.
- Cloning the protein genes into bacteria to produce large quantities.
- Purifying the protein and introducing it into humans to stimulate antibody production (e.g., hepatitis B vaccine).
- Transgenic Animals: Incorporating genes into animal cells at the zygote stage to create disease-resistant animals or develop drugs.
Applications in Agriculture
In classical genetics, plants were crossed to obtain new ones with desired characteristics. Biotechnology accelerates this process by:
- Inserting specific genes for desired traits.
- Introducing genes from other species.
Goals:
- Delayed fruit ripening.
- Nitrogen fixation (plants capturing nitrogen from the atmosphere).
- Herbicide resistance (transferring resistant genes to plants).
- Insect resistance (inserting genes that produce insecticides harmless to plants and humans).
- Disease resistance (inserting genes that provide resistance to pests or diseases).
- Production of natural substances (e.g., molecules for plastic manufacturing).
Applications in the Environment
- Plants that accumulate heavy metals (lead, mercury) for removal from contaminated areas.
- Bacteria that degrade hydrocarbons (oil spills).
- Bacteria to remove excess nitrates and sulfates from water.