CHR14

What is Biotechnology?

• Definition: Biotechnology is the use of technology to modify organisms, cells, and their molecules to achieve practical benefits.

• Primary Areas of Application:

  • Agriculture

  • Human health

  • Forensic science

Important Processes in Biotechnology

• Various underlying processes are essential for many biotechnology applications, though not all tools are used in every application.

• Key Processes:

  1. Chop:

  • Cutting DNA from donor species that exhibit a desirable trait.

  1. Amplify:

  • Increasing small DNA samples to usable quantities.

  1. Insert:

  • Inserting DNA pieces into bacterial cells or viruses.

  1. Grow:

  • Culturing separate colonies of bacteria or viruses, each containing donor DNA.

Isolating a Gene of Interest Using Restriction Enzymes

• Chop Process:

  • Restriction enzymes are key tools to isolate a gene of interest.

  • For instance, an enzyme recognizes the sequence ATCGAT and cuts between A and T.

  • Steps in the Chop Process:

  1. Identify a gene of interest in donor DNA.

  2. Introduce restriction enzymes to target specific base-pair sequences surrounding the gene.

  3. Enzymes bind and cut the DNA strand, separating the gene of interest from the donor DNA.

  4. The gene of interest is now isolated.

Polymerase Chain Reaction (PCR)

• Amplify Process:

  • A method to amplify DNA segments.

  • Steps in PCR:

  1. Heat the solution containing isolated DNA, which separates double-stranded DNA into single strands.

  2. Add DNA polymerase, primers, and free nucleotides to the solution and cool it.

  3. DNA polymerase adds complementary bases to each single strand, resulting in two identical copies of the original DNA segment.

  4. This cycle can be repeated multiple times, creating billions of copies of the target DNA sequence.

Using Plasmids to Transfer DNA

• Insert Process:

  • Transfer of DNA from one organism to another using plasmids.

  • Steps in Insert Process:

  1. Isolate the target DNA segment using restriction enzymes.

  2. Make a single cut in a bacterial plasmid using the same restriction enzyme.

  3. The cut plasmid and the DNA segment share complementary ends, allowing them to fit together.

  4. Insert the plasmid containing the gene of interest back into the bacterial cell.

Creating a Gene Library

• Grow Process:

  • A method to preserve different DNA fragments.

  • Steps to Create a Gene Library:

  1. Chop a large amount of DNA using restriction enzymes.

  2. Insert each DNA fragment into a plasmid.

  3. Introduce each plasmid type into different bacterial cells.

  4. Allow bacteria to multiply, each producing a clone of the foreign DNA fragment they carry.

  • All bacterial cells together will contain various fragments of the original DNA.

Key Takeaways of Modern Molecular Methods

• Modern molecular methods enable cutting and copying DNA from one organism and delivering it to another.

• Included Techniques:

  1. Naturally occurring restriction enzymes for cutting DNA.

  2. Polymerase chain reaction for amplifying small DNA amounts.

  3. Insertion of DNA into bacterial or viral vectors.

  4. Cloning and identification of cells with transferred DNA.

CRISPR Technology in Biotechnology

• Definition: CRISPR stands for clustered regularly interspaced short palindromic repeats and is a powerful tool for editing DNA with high precision and efficiency.

• Applications:

  • Enables modification of almost any gene in virtually any organism.

  • Naturally occurring in many bacteria, serving to record viral DNA encounters for defense.

Mechanism of CRISPR

• Process Overview:

  • Researchers synthesize an RNA guide molecule with a sequence that matches the target gene.

  • Introduce RNA sequences and the Cas9 enzyme to target cells via a plasmid.

  • RNA guides the Cas9 enzyme to the intended DNA location where it makes a cut.

  • After cutting, a new DNA sequence can be inserted, which could repair or modify the host cell’s DNA.

Potential Applications of CRISPR

• Modifying mosquito DNA to prevent malaria transmission.

• Using CRISPR-altered human white blood cells to combat cancer cells.

• Engineering beagles to have increased muscle mass.

Risks and Ethical Concerns of CRISPR

• Legal Issues:

  • Disputes regarding the invention and profit from CRISPR technology.

• Ethical Issues:

  • Concerns about editing human embryos and germline cells (sperm and eggs).

• Scientific Concerns:

  • Difficulties in predicting the consequences of introducing altered genes into natural populations.

Summary of CRISPR Technology

• CRISPR represents a significant breakthrough in biotechnology, allowing targeted modification of DNA sequences in numerous species.

Advancements in Agricultural Biotechnology

• Biotechnology enhances food nutrition, farming efficiency, and environmental sustainability.

• Genetic Engineering:

  • Manipulation of a species' genome in ways not occurring naturally.

  • Recombinant DNA Technology:

  • Accelerates genetic engineering and combines DNA from different sources.

• Example: Historical selection of desirable corn traits.

Example of Golden Rice

• Definition: Golden rice is enhanced white rice with beta-carotene-producing genes, resulting in increased vitamin A content by nearly 25-fold.

• Process:

  • Beta-carotene genes are obtained from other species and inserted into the white rice genome.

Usage of Genetically Modified Crops in the U.S.

• Common Usage: Many U.S. citizens consume genetically modified crops unknowingly.

• Prominent Factors for Adoption:

  • Insecticide-engineering in crops.

  • Herbicide-resistant gene engineering.

• Statistics of GMO Usage:

  • Corn, Cotton, and Soybeans:

  • % of genetically modified crops: 7%, 7%, and 14% respectively.

  • % of non-genetically modified crops: 86%, 93%, and 93% respectively.

Insect Resistance in Crops

• Example: Corn plant genetically modified with a bacterium gene (Bacillus thuringiensis) that produces Bt crystals poisonous to caterpillars.

• Advantages:

  • Eliminates the need for pesticides while protecting crops from insect predation.

Faster Growth in Aquaculture

• Example: Genetically engineered larger salmon possesses a growth hormone gene enabling year-round growth.

Impact of Biotechnology on Agriculture

• Biotechnology contributes to improved agricultural productivity through transgenic plants and animals.

• It significantly reduces the environmental and financial costs of food production through herbicide- and insect-resistant crops.

• Potential ecological and health risks of widespread transgenic species usage are not fully understood.

Risks of Genetically Modified Foods

• Concerns Raised:

  1. Indestructibility of targeted organisms.

  2. Accidental death of non-target organisms.

  3. Inadequate testing and regulation of genetically modified crops.

  4. Safety of consuming genetically modified foods.

  5. Genetic diversity loss among crop plants.

  6. Hidden costs decreasing financial benefits.

Genetically Modified Foods Overview

• Continuous development in genetically modified foods based on recombinant DNA technology brings legitimate public fears about potential catastrophic risks and long-term financial benefits.

Biotechnology in Disease Treatment

• Biotechnology enhances disease management and medicine production through:

  • Disease prevention

  • Disease cure

  • Disease treatment

• Example: Insulin production using recombinant DNA technology has influenced a biotech revolution in treating diabetes.

Other Achievements in Biotechnology

• Human Growth Hormone (HGH):

  • Can treat dwarfism.

  • Now produced by transgenic bacteria.

• Erythropoietin:

  • Key for blood doping scandals; produced from hamster ovary cells.

Takeaways in Disease Treatment

• Biotech advancements provide notable successes in treating diseases more efficiently than traditional methods.

Gene Therapy and Its Challenges

• Biotechnology aids in diagnosing and preventing genetic disorders but has limited success in curing them.

• Areas of Screening Focus:

  1. Likelihood of parents conceiving a baby with genetic disease (E.g., Tay-Sachs disease, significantly reduced incidence since 1969).

  2. Probability of babies being born with genetic diseases (e.g., cystic fibrosis, sickle-cell anemia).

  3. Risk of individuals developing diseases later in life (e.g., breast cancer).

Gene Therapy Limitations

• Reasons for Limited Success:

  1. Difficulty in targeting specific cells with the working gene.

  2. Challenges in introducing the gene into sufficient cells.

  3. Issues with the gene entering unintended cells.

  4. Problems regulating gene expression.

Conclusion on Gene Therapy

• Despite developments aimed at reducing diseases and suffering, gene therapy faces technical difficulties in curing inherited disorders.

Cloning

• Cloning encompasses genes, organs, and individuals. It poses both opportunities and ethical challenges.

• Cloning Steps:

  1. Isolate an egg cell from one sheep and a mammary cell from another.

  2. Remove each cell's nucleus and implant the mammary cell nucleus into the egg cell.

  3. Induce division to grow cells to the embryo stage and implant into a surrogate sheep.

  4. Surrogate mother gives birth to cloned sheep.

Ethical Considerations in Cloning

• While cloning offers potential benefits, ethical questions persist regarding its implications in agriculture and medicine.

Forensic Biotechnology

• DNA as an Identifier:

  • DNA fingerprinting has revolutionized criminal justice. Colin Pitchfork was the first criminal convicted using DNA evidence.

• Forensic Techniques:

  • Identical DNA sequences account for 99.9% among individuals, but approximately three million base-pair differences exist.

  • Short Tandem Repeats (STRs) are crucial for genetic fingerprinting; they are variable in repeat lengths among individuals.

DNA Fingerprinting Process

• Creation Process:

  1. Determine alleles for 13 STR regions for comparison.

  2. Amplify STR regions with PCR.

  3. Sort sized DNA fragments through electrophoresis to identify individuals.

Conclusion on DNA Fingerprinting

• DNA comparisons help identify tissue specimens and ascertain individual identities, but they are not infallible.