Biotechnology

Biotechnology

Human Genome Project • The HGP achieved the

goal of obtaining a sequence of the human genome

• Began formally in 1990• The project originally was

planned to last 15 years, but it finished in 2003

• Project goals:• To identify all the

approximately 20,000-25,000 genes in human DNA

• To determine the sequences of the 3 billion chemical base pairs that make up human DNA,

• To store this information in databases,

• To improve tools for data analysis.

Researchers have found about 25 000 genes and noticed the important role of the ‘junk’ DNA

Chromosome Y

• Contains over 200 genes

• Contains over 50 million base pairs, of which approximately 50% have been determined

Chromosome X


• Contains over 150 million base pairs, of which approximately 95% have been determined

Chromosome 1


• Contains over 240 million base pairs, of which ~90% have been determined

Genetic engineering

Insulin production• Donor DNA from another species (in this

case form human) is incorporated into a bacterial plasmid (E.coli)

• The bacterium is able to manufacture human insulin

• The DNA for insulin has to be produced from mRNA rather than inserting the DNA gene for insulin directly

Other uses of gentically modified organisms

1. Producing antibiotics2. Producing factor VIII (involved in blood clotting)3. Producing antigens for the manufacture of vaccines 4. Producing anti-thrombin in the goat's milk5. Chymosin (rennin) production used in cheese-making

Restriction endonucleases

• Naturally occurying enzymes in bacteria

• Bacteria use restriction enzymes to defend themselves against viruses

• The restriction enzymes cut up the viral DNA to prevent the virus from being replicated

• These enzymes cut DNA at specific sequences

PCR (The Polymerase chain

reaction)• PCR is a technique that can be used to amplify

small quantities of DNA• PCR involves repeated cycles• The first stage of the cycle involves denaturing of

DNA (separating 2 strands) using heat• The second stage involves annealing with a primer

selected to match a particular target within DNA. This is done at slightly cooler temperatures

• The final stage involves the extension of the primer using the DNA polymerase from a bacterium Thermophilus aquaticus

• These processes take place in a thermal cycler, which alternates between the three required temperatures

DNA profiling (DNA fingerprinting)

Each of us has a unique sequence of nucleotides in our DNA

The length of DNA varies from person to person

The number of repetitive DNA sequence differs between individuals

How can we use these features of the gentic material?

• In paternity cases,• In evolutionary studies,• In criminology

How to do it?1. Take some of a person's DNA,2. Cut DNA up using restriction enzymes into lots

of small parts,3. Because each of us has a unique sequence of

nucleotides in our DNA, the lengths of these fragments will vary from person to person,

4. Separate DNA fragments using electrophoresis according to their size and charge

5. The result is a pattern of bands unique to each of us

Gel electrophoresis• It involves separating

charged molecules in an electric field

• Samples are placed in wells cast in a gel

• The gel is immersed in a conducting fluid and electric field is applied

• The sample of DNA (or proteins) will move a certain distance through the gel according to the charge on the molecule and its size

CloningA clone is…• a group of genetically identical organisms• a group of identical cells from a single parent

cell

How can we clone artificially?1. Firstly, we need cells separated from the

embryo when they are still pluripotent (capable of developing into all types of tissue)

2. Then, we transplant these cells into surrogate mother

Education

Biotechnology