Ch 1.8, 8th PP - Biotechnology Applications

DNA and Proteins

Biotechnology Applications

Biotechnology incorporates various techniques utilizing bacterial enzymes and plasmids as vectors, which play a pivotal role in genetic engineering and molecular biology. Techniques such as gel electrophoresis, bacterial transformations, and PCR (Polymerase Chain Reaction) are fundamental in analyzing and manipulating DNA. These methods enable the amplification, separation, and identification of specific DNA sequences, facilitating various applications in research and medicine.

Biology Subject Outline Expectations

Biotechnology Techniques:

  • Use of Bacterial Enzymes and Plasmids:Bacterial enzymes help in the manipulation of DNA, while plasmids serve as vehicles for gene transfer. Together, they enable researchers to clone, express, and study specific genes.

  • Techniques:

    • Gel Electrophoresis: Separates DNA fragments based on size, allowing for analysis of genetic material.

    • Bacterial Transformations: Introduces DNA into bacterial cells, facilitating the replication and expression of genes.

    • PCR: Amplifies specific DNA segments, making countless copies for analysis.

  • Gene Manipulation:Selection and removal of genes can be efficiently accomplished using probes and restriction enzymes.

  • Gene Transfer:The transfer of genetic material across species using plasmids, viruses, or microinjection techniques enables the development of transgenic organisms.

  • CRISPR Technology:Short for Clustered Regularly Interspaced Short Palindromic Repeats, this cutting-edge technology allows for precise gene editing and transfer using the Cas9 protein, revolutionizing genetic engineering.

DNA Profiling

Basis of DNA Profiling:

DNA profiling relies on variations found in non-coding regions of the genome, particularly within introns. These variations include unique repeating sequences known as Variable Number Tandem Repeats (VNTRs) and Short Tandem Repeats (STRs).Humans inherit a total of 46 chromosomes (23 from each parent), and individuals can exhibit different combinations of alleles at gene loci, leading to homozygous (same alleles) or heterozygous (different alleles) genetic expressions.

Gene Probes

Definition:

Gene probes are segments of single-stranded DNA or RNA specifically synthesized to identify and locate genes of interest.

Function:

Equipped with radioactive or fluorescent markers, gene probes bind complementary to target genes through hybridization, allowing scientists to map and identify specific genes with greater accuracy.

Restriction Enzymes

Overview:

Restriction enzymes are naturally occurring enzymes isolated from bacteria, crucial for cutting DNA at specific sequences throughout genetic engineering applications.

Specifics:

  • First discovered in 1970, these enzymes can isolate or remove genes by recognizing unique restriction sites in the DNA sequence.

  • For example, EcoRI distinguishes and cuts DNA at staggered sequences, resulting in “sticky ends” that facilitate the binding of donor DNA.

  • Essential for creating recombinant DNA, these enzymes provide a foundation for numerous biotechnological advancements.

Plasmids

Definition:

Plasmids are small, circular DNA molecules found in bacteria that replicate independently of chromosomal DNA. They often carry genes conferring antibiotic resistance.

Usage:

In genetic engineering, plasmids serve as vectors to splice desired genes for further studies and replicate the inserted gene during plasmid division.

Genetic Engineering (GE)

Historical Context:

Genetic engineering reflects a longstanding practice of modifying plant and animal genetics through selective breeding.

Definition:

Genetic engineering represents the direct manipulation of an organism's genome, allowing for precise modifications across species lines.

Advantages:

  • Enables the precise transfer of genes, resulting in genetically modified organisms (GMOs) that exhibit enhanced traits.

  • Facilitates the production of vital proteins, like insulin, using engineered microorganisms, offering medical advancements.

Steps in Gene Selection

  1. Identify the gene of interest using gene probes.

  2. Utilize plasmids for isolating and replicating the desired gene.

DNA Cloning Steps

  1. Extract DNA from target cells.

  2. Cut with restriction enzymes and prepare plasmids accordingly.

  3. Insert and ligate the gene into the plasmid.

  4. Transform plasmids into bacteria using electroporation or a gene gun technique, followed by bacterial culture to replicate the gene of interest.

  5. Use fluorescent probes to identify positive clones.

  6. Harvest proteins or isolate desired genes for various applications.

Transgenesis

Definition:

Transgenesis involves transferring genetic material from one organism into another, resulting in transgenic organisms that exhibit characteristics of the donor organism.

Methods:

Various methods include chemical techniques, physical insertion (microinjection), or the use of vectors such as viruses and bacteria.

Example - Microinjection:

In microinjection, multiple copies of a gene are directly injected into the nuclei of fertilized egg cells, producing organisms with desired traits.

Gene Manipulation in Plants and Animals

Plants:

Utilizing Agrobacterium or electroporation methods allows the integration of plasmids carrying desired genes into plant cells.

Animals:

In animal genetic engineering, plasmids are injected into reproductive cell nuclei post-fertilization, ensuring stable incorporation into the animal's germ line.

Viral Vectors and Gene Therapy

Viruses can be genetically modified to act as carriers for desired genes, facilitating their delivery into host cells. This approach has significant implications for gene therapy, offering potential cures for genetic disorders.

Benefits of Transgenesis

The advantages of transgenesis include improving crop resilience, developing treatments for genetic diseases, and producing pharmaceuticals through recombinant DNA technologies.

Genetic Engineering Issues

Ethical and ecological considerations encompass the impact on biodiversity, potential loss of genetic diversity, and the long-term implications of modified organisms on human health and the environment.

Ethical Considerations

Genetic engineering raises numerous ethical questions related to social, individual, and economic ramifications, particularly regarding genetic manipulation and cloning practices.

CRISPR Technology

Definition:

CRISPR is a powerful bacterial defense mechanism involving Clustered Regularly Interspaced Short Palindromic Repeats that safeguards bacteria from viral infections.

Applications:

Using the Cas9 protein, CRISPR technology allows for precise DNA cuts at specific sequences, guided by RNA. Its applications range from creating genetic mutations to repairing defective genes, and it offers a quick, cost-effective approach to gene editing.

Specific Protein Design

Utilizing computational methods enables the design of novel proteins based on specific amino acid sequences. This process supports targeted functions, including developing vaccines or delivery systems for pharmaceuticals. The incorporation and purification of these designed proteins are typically facilitated by genetically modified bacteria.