Biotechnology and Genomics chap 17
Chapter Overview
This chapter focuses on Biotechnology and Genomics, elucidating the techniques and concepts used in the study and manipulation of DNA across different organisms.
Genomics
Definition: Genomics involves comparing the DNA of various organisms, enabling scientists to construct maps for navigating the genetic material of different species.
Figure Credit: Image attributed to NASA.
Antibiotics
Source: Fungi, bacteria, and other organisms with antimicrobial properties are capable of producing antibiotics.
First Antibiotic: Penicillin, noted as the first antibiotic discovered.
Current Practices: Pharmaceutical companies engage in the commercial production and testing of antibiotics specifically aimed at inhibiting bacterial growth.
Figure Credits: Images modified from NIH and Don Stalons/CDC; scale-bar data from Matt Russell.
DNA Extraction Method
Description of the basic process used for the extraction of DNA.
The procedural details are illustrated within the corresponding diagram.
Figure Credit: Based on OpenStax guidelines.
Polymerase Chain Reaction (PCR)
Purpose: PCR is a method used to amplify a specific sequence of DNA.
Components:
Primers: Short DNA sequences complementary to the ends of the target sequence.
Genomic DNA: The DNA from which the target will be extracted.
Taq Polymerase: A thermostable DNA polymerase derived from the bacterium Thermus aquaticus, capable of surviving the high temperatures utilized in PCR.
Habitat: Thermus aquaticus is found in the Lower Geyser Basin of Yellowstone National Park.
Deoxynucleotides: The building blocks for DNA synthesis.
Variant: Reverse Transcriptase PCR (RT-PCR), where cDNA (complementary DNA) is synthesized from an RNA template before the PCR process.
Figure Credit: Based on OpenStax guidelines.
Blotting Techniques
Southern Blotting:
Definition: A method used to locate a particular DNA sequence within a sample.
Process:
DNA fragments are separated via gel electrophoresis.
Transferred to a nylon membrane.
Incubated with a complementary DNA probe targeting the sequence of interest.
Northern Blotting: A similar process to Southern blotting, but it involves RNA instead of DNA.
Western Blotting: Involves running proteins on a gel and detecting them with antibodies.
Figure Credit: Based on OpenStax guidelines.
Molecular Cloning
Diagram illustrating the fundamental steps involved in molecular cloning.
Figure Credit: Based on OpenStax guidelines.
Cloning Example
Dolly the Sheep: First mammal cloned.
Process:
Remove the nucleus from a donor egg cell.
Introduce the nucleus from a second sheep into the egg cell.
Allow the cell to divide to the blastocyst stage.
Implant the blastocyst in a surrogate mother.
Figure Credit: Based on modification of work by "Squidonius".
Gene Therapy
Mechanism: Gene therapy utilizing an adenovirus vector to address certain genetic diseases wherein a defective gene is present.
Figure Credit: Attributed to NIH.
Agricultural Biotechnology
Example: Corn, as a key agricultural crop, is often modified through plant biotechnology for diverse product creation across industries.
Figure Credit: Image attributed to Keith Weller, USDA.
Chromosomal Crossover and Recombination
Concept: Crossover may occur at different locations on a chromosome during meiosis.
Recombination Insights:
Frequency of recombination between genes A and B is greater than between genes B and C, due to the greater distance between genes A and B, which increases the likelihood of crossover.
Cytogenetic Maps
Definition: A cytogenetic map illustrates the appearance of a chromosome after staining and examination under a microscope.
Figure Credit: Based on data from the National Human Genome Research Institute.
Dideoxynucleotides
Structure: Dideoxynucleotides resemble deoxynucleotides but lack the 3' hydroxyl group.
Impact: The incorporation of a dideoxynucleotide into a DNA strand results in the termination of DNA synthesis.
Figure Credit: Based on OpenStax guidelines.
Sanger's Chain Termination Method
Method Details: Frederick Sanger's dideoxy chain termination method allows the termination of DNA fragments at varying lengths using dideoxynucleotides.
Processing: The separated DNA fragments are analyzed based on their sizes, which can then be read to infer genetic information.
Figure Credit: Based on OpenStax guidelines.
PCA3 Gene Test
Gene: PCA3, expressed in prostate epithelial cells, is significantly overexpressed in cancerous cells.
Clinical Relevance: A high PCA3 concentration in urine serves as a more reliable indicator of prostate cancer compared to the PSA test, which measures prostate-specific antigen levels in blood.
Metagenomics
Definition: Metagenomics entails isolating DNA from multiple species inhabiting a specific environmental niche.
Figure Credit: Based on OpenStax guidelines.
Two-Hybrid Screening
Purpose: This technique is employed to determine the interaction between two proteins.
Methodology:
A transcription factor is divided into:
DNA-binding domain (BD): capable of binding to a promoter but inactive in transcription without an activator domain.
Activator domain (AD): required for transcription to occur.
Working Principle: A protein termed the bait is attached to the BD, while a prey protein is linked to the AD. Transcription is initiated only if the prey successfully interacts with the bait.
Figure Credit: Based on OpenStax guidelines.
Chapter Overview - This chapter is about Biotechnology and Genomics. It explains techniques to study and change DNA in different organisms.
Genomics - Definition: Genomics is the study of comparing the DNA of different living things to understand their genetic information.
Antibiotics - Source: Antibiotics are made by fungi, bacteria, and other microorganisms.
First Antibiotic: The first antibiotic discovered was Penicillin.
Current Practices: Companies today make and test antibiotics to stop bacterial growth.
DNA Extraction Method - This describes how to extract DNA from cells.
There is a diagram that shows the steps.
Polymerase Chain Reaction (PCR) - Purpose: PCR is used to make many copies of a specific DNA piece.
Components:
Primers: Short DNA pieces that help start the copying.
Genomic DNA: The DNA source we want to copy from.
Taq Polymerase: An enzyme that can work at high temperatures, found in the heat-loving bacterium Thermus aquaticus.
Deoxynucleotides: The building blocks for making DNA.
Variant: Reverse Transcriptase PCR (RT-PCR) changes RNA into DNA before copying.
Blotting Techniques - Southern Blotting: Method to find a specific DNA sequence.
Northern Blotting: Similar but used for RNA.
Western Blotting: Used to find specific proteins.
Molecular Cloning - A diagram shows the basic steps in molecular cloning.
Cloning Example - Dolly the Sheep: First cloned mammal.
Process:
Remove the nucleus from an egg cell.
Add a nucleus from another sheep.
Let it grow until a certain stage.
Implant in a surrogate mother.
Gene Therapy - Mechanism: A method using a virus to fix genetic diseases by delivering new genes.
Agricultural Biotechnology - An example is corn, which is often genetically changed to create better products.
Chromosomal Crossover and Recombination - Concept: During reproduction, pieces of DNA can switch places on chromosomes, leading to genetic variation.
Cytogenetic Maps - Definition: A map showing what a chromosome looks like under a microscope after staining.
Dideoxynucleotides - Structure: Similar to regular building blocks of DNA but stop DNA copying when used.
Sanger's Chain Termination Method - Method: A technique that uses special building blocks to stop the DNA copying process, allowing us to read the DNA sequence.
PCA3 Gene Test - Gene: PCA3 is found more in cancerous prostate cells.
Clinical Relevance: High PCA3 levels in urine can indicate prostate cancer better than other tests.
Metagenomics - Definition: The study of DNA from many different organisms in a specific environment.
Two-Hybrid Screening - Purpose: To see how two proteins interact with each other.
Methodology:
A special protein is split into two parts that must come together to work.
The interaction happens if the two proteins bind, allowing for a response.
Gel Electrophoresis
Definition: A technique used to separate DNA, RNA, or proteins based on their size and charge.
Process: Samples are placed into a gel matrix and an electric current is applied, causing them to migrate through the gel. Smaller molecules move faster, allowing for separation.
Molecular Cloning
Definition: A method for replicating specific DNA sequences.
Steps: Include vector preparation, insertion of DNA fragment, transformation into host cells, and selection of successful clones.
Reproductive Cloning
Definition: A process to create a genetic copy of an entire organism.
Example: The process used in cloning Dolly the sheep, which involved taking the nucleus from a somatic cell and placing it into an egg cell.
Biotechnology Uses in Medicine
Applications:
Development of antibiotics and hormones through recombinant DNA technology.
Gene therapy to treat genetic disorders by inserting healthy genes into patients' cells.
Biotechnology Uses in Agriculture
Applications:
Genetic modification of crops to improve yield, resistance to pests, and environmental adaptability.
Use of biopesticides and biofertilizers to enhance agricultural practices.
Genomics
Definition: The study of genomes, which includes the analysis, comparison, and sequencing of DNA across different organisms.
Genetic and Physical Maps
Genetic Maps: Show the relative positions of genes on a chromosome based on recombination frequency.
Physical Maps: Provide the actual physical distances between genes, often measured in base pairs.
Genomic Mapping Methods
Methods:
Physical mapping through techniques like FISH (Fluorescence In Situ Hybridization).
Genetic mapping using linkage analysis.
Sequencing methods to define complete genetic information.
Three Types of Sequencing
Sanger Sequencing: A method using dideoxynucleotides to terminate DNA synthesis at specific lengths for reading.
Next-Generation Sequencing (NGS): Technologies that allow for rapid sequencing and analysis of large amounts of DNA.
Third-Generation Sequencing: Techniques used for direct sequencing of single molecules of DNA without amplification.
Whole-Genome Sequencing
Definition: A comprehensive method for decoding the complete DNA sequence of an organism's genome.
Pharmacogenomics
Definition: The study of how genes affect a person’s response to drugs, informing personalized medicine approaches.
Polygenic
Definition: Relating to traits that are influenced by multiple genes, often resulting in a continuous range of phenotypes.
Systems Biology
Definition: An interdisciplinary approach that integrates biological data to understand complex biological systems and their interactions.
Proteome
Definition: The entire set of proteins expressed by a genome, cell, tissue, or organism at a certain time.
Protein Signature
Definition: The unique pattern of protein expression within a specific context, such as in disease states, used for diagnostic and therapeutic purposes.
Relevant Terminology Related to Biotechnology
Includes key terms such as recombinant DNA, genetic engineering, bioinformatics, and synthetic biology that underpin the field of biotechnology.