DNA Technology and Biotechnology Lecture

Chapter $12$ focuses on DNA Technology, encompassing a wide range of techniques including DNA Cloning, Genetic Engineering, Gene Therapy, and the CRISPR-Cas9 system.
DNA Cloning is defined as a set of methods that employs live cells to produce many identical copies of a specific DNA fragment.
Restriction Enzymes play a critical role in cloning by cutting DNA at specific nucleotide sequences.
- These enzymes often leave single-stranded tails known as "sticky ends."
Recombinant DNA is a DNA molecule that contains genetic material derived from more than one organism.
A Cloning Vector is a DNA molecule used to accept foreign DNA and carry it into a host cell. Bacterial plasmids are commonly used as cloning vectors in this process.

Humulin is human insulin produced by genetically modified bacteria using recombinant DNA (rDNA) technology.
Product Details for Humulin N (isophane suspension):
- Manufacturer: Lilly
- NDC Number: $0002-8315-01$
- Volume: $10\,mL$
- Concentration: $100$ units per $mL$
- Product Code: $HI-310$
- Classification: NPH human insulin (rDNA origin)
- Concentration Type: $U-100$

CRISPR stands for Clustered Regularly Interspersed Short Palindromic Repeats.
The CRISPR-Cas9 system is a new DNA technology that allows the nucleotide sequence of specific genes to be edited within living cells.
Functional Capabilities of CRISPR-Cas9:
- Removing mutated genes and replacing them with normal genes.
- The system is based on restriction enzymes that are guided to specific locations in the genome by specifically designed RNA molecules.

Gene Therapy is an experimental technique used to transfer a normal or modified gene into a person suffering from a genetic disorder.
Technical Implementation:
- A genetically modified virus is typically used as a vector to deliver the gene.
- This technique is currently being tested to treat various conditions, including AIDS, Alzheimer's disease, cystic fibrosis, and muscular dystrophy.
- The speaker notes that despite its potential, Gene Therapy is still considered an experimental technique and carries inherent risks.

The primary benefit of growing insect-resistant plants is the reduced need for chemical insecticides.
Genetically Modified Plants Examples:
- "Golden Rice $2$ ": A transgenic variety of rice carrying genes from daffodils and corn. It is designed to prevent Vitamin A deficiency and the resulting blindness, particularly in developing nations where rice is a staple crop.
- Modified Strawberry Plants: These plants produce bacterial proteins that act as a natural antifreeze, protecting delicate plants from cold weather damage.
- Engineering for Health: Potatoes and rice have been engineered to produce harmless proteins derived from the cholera bacterium.
- Future Aspirations: Researchers hope to produce edible vaccines against cholera, a disease that causes thousands of deaths among children in developing nations annually.

AquAdvantage Salmon: This genetically modified Atlantic salmon was approved in $2019$ for food production.
Genetic Modifications:
- These fish contain growth hormone genes that allow them to grow all year round.
- Growth Statistics: The AquAdvantage salmon reaches maturity in $18$ months, compared to the $3$ years required for conventional Atlantic salmon.

An overheard conversation between modern sheep notes a humorous resistance to technology: "I don’t need no stinkin’ DNA Technology for improvement. Im purrfect as I am…"

PCR is a technique by which a specific segment of DNA can be amplified by targeting and copying it quickly and precisely.
Utility of PCR:
- It permits scientists to obtain sufficient quantities of DNA from minute amounts of blood or other tissue.
- This amplified DNA is sufficient to construct a DNA profile.
Components required for PCR:
- Target DNA
- Nucleotides
- Taq Polymerase (heat-stable enzyme)
- Primers
- Buffers
The PCR Process involves three main steps performed in a Thermocycler:
1. Denaturation
2. Annealing
3. Elongation

Single Nucleotide Polymorphisms (SNPs) represent the most common DNA variation between people.
Frequency and Distribution:
- SNPs occur approximately once every $1000$ base pairs in humans.
- The average individual has between $4$ million and $5$ million SNPs.
- These variations differ between individuals and different populations.
Applications of SNPs:
- Useful in tracing ancestry.
- Used as markers for identifying specific genes.

DNA Profiling is the analysis of DNA samples to determine if they originated from the same individual.
- This technology transformed the field of Forensics (the scientific analysis of evidence for crime scene investigations and legal proceedings).
Gel Electrophoresis Process:
- A mixture of DNA fragments of different sizes is placed in a gel.
- A power source is applied.
- DNA fragments move through the gel based on size.
- Results: Fragments form bands. The band of longest fragments moves the slowest (stays closer to the start), while the band of shortest fragments moves the fastest (travels furthest).
Forensic Application:
- Amplified crime scene DNA is compared alongside amplified suspect DNA on a completed gel to look for matching fragment patterns.

Genomics is defined as the study of complete sets of genes, known as genomes.
Proteomics is defined as the study of complete protein sets in a species.
The Human Genome Project:
- Completion Date: $2003$
- Total Nucleotides: Approximately $3 \times 10^9$ (three billion).
- Total Genes: Approximately $21,000$ genes.
- Functional DNA: Only about $1.5\%$ of human DNA contains genes that code for proteins.

Sequencing Costs History (NIH National Human Genome Research Institute data):
- In $2001$ , the cost per genome was approximately $100M$ .
- By $2011$ , the cost dropped significantly, outstripping the rate of Moore's Law.
- By $2017$ , the cost reached a threshold near $1K$ .
- The trend shows an exponential decrease in cost from $2001$ through $2017$ .