Recombinant DNA Technology

Recombinant DNA (rDNA)

• Artificially formed DNA is created by combining genetic material from different organisms.
• rDNA is applied in biotechnology, medicine, agriculture, and research.

Tools Used in Recombinant DNA

• Restriction Enzymes (Endonucleases) are used to cut DNA at specific sites.
• Ligases join DNA fragments together.
• Vectors carry foreign DNA, examples include plasmids and bacteriophages.
• Polymerase Chain Reaction (PCR) amplifies DNA.
• Electrophoresis separates DNA fragments.

History of rDNA in the Laboratory

• Paul Berg (1972) was the first scientist to create rDNA by combining bacterial and viral DNA.
• Stanley Cohen & Herbert Boyer (1973) developed genetic engineering by inserting rDNA into bacteria using plasmids.

Steps/Process of Recombinant DNA

• Isolate the desired gene.
• Cut the DNA using restriction enzymes.
• Insert the gene into a vector, such as a plasmid or virus.
• Transformation: Introduce the vector into a host cell.
• Clone and select successfully modified cells.
• Allow expression of the inserted gene.

Process of Insertion of rDNA

• Transformation involves the uptake of foreign DNA by a bacterial cell.

Vectorless Gene Transfer

• Electroporation uses electric pulses to create pores in cell membranes for DNA entry.
• Protoplast Fusion uses enzymes to remove the cell wall, allowing fusion of different cells.
• Microinjection involves directly injecting DNA into the nucleus.
• Transduction is viral-mediated transfer of DNA into a host cell.

rDNA in Health, Medicine, Agriculture, Environment, and Industry

• Gene Therapy is used for correcting genetic disorders, like CRISPR.
• Agriculture is for genetically modified organisms (GMOs) for pest resistance, drought tolerance.
• Environment is for bioremediation through bacteria degrading pollutants.
• Industry is to produce insulin, vaccines, and enzymes.

History of Life on Earth

• Nicholas Steno, the father of geology, proposed the law of superposition.

Nicholas Steno & the Principle of Faunal Succession

• The Principle of Faunal Succession states that fossils appear in a specific sequence in rock layers, helping to date Earth's history.

Geological Eras

• Precambrian (Longest Era) consisted of the formation of Earth and the emergence of the first life (bacteria).
• Paleozoic Era is known as the Age of jawless fishes, including the first land plants, and early reptiles.
• Mesozoic Era is known as the Age of Reptiles: Dinosaurs dominated, first birds and mammals appeared.
• Cenozoic Era is known as the Age of Mammals and modern humans appeared.

Formation of Mountain Ranges

• Mountain ranges are a result of plate tectonics and continental drift, examples include the Himalayas and Andes.

Mechanisms of Evolution

• Genetic Drift occurs due to random changes in allele frequency.
• Mutation is a source of genetic variation.
• Natural Selection describes the "survival of the fittest."
• Gene Flow is the exchange of genes between populations.
• Recombination shuffles genes during reproduction.

Evidences of Evolution

• Fossils show transitional species.
• Comparative Embryology indicates similar embryonic stages that suggest common ancestry.

Anatomical Evidence

• Homologous Structures have similar structure but perform different functions, like a human arm and whale flipper.
• Analogous Structures have different structures but perform the same function, like a bird wing and butterfly wing.
• Biochemical Evidence shows DNA/protein similarities indicate common ancestry.
• Biogeography, the distribution of species, supports evolution.

Scientists with Evolutionary Thought

• Charles Darwin proposed the Theory of Natural Selection.
• Jean-Baptiste Lamarck proposed the Theory of Acquired Characteristics.
• Alfred Russel Wallace independently proposed natural selection.

Taxonomy and Systematics

• Taxonomy is defined as the science of classifying organisms.
• Systematics is the study of evolutionary relationships among organisms.

Carl Linnaeus and His Classification System

• Carl Linnaeus is the father of modern taxonomy.
• He developed the binomial nomenclature (Genus species).

Cladistics and Cladograms

• Cladistics is classification based on common ancestry.
• A Cladogram is a diagram showing evolutionary relationships.

Phylogenetic Tree

• A phylogenetic tree represents evolutionary history and divergence of species.

Three Domains of Life

• Bacteria is prokaryotic, unicellular, and without a nucleus.
• Archaea is prokaryotic and survives in extreme environments.
• Eukarya has a nucleus and includes plants, animals, fungi, and protists.