Genetic%20Engineering%20and%20Biotechnology

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Genetic Engineering and Biotechnology

• IB topics 4.4.1-4.4.5
• PCR and Introduction to DNA Profiling

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What is genetic engineering

• Genes from one organism are transferred to the
  genome of another
• Also known as recombinant DNA
• This can happen because remember, the genetic
  code is universal
• Triplet code ? amino acid
• Important applications
• Biotechnology
• Pharmaceuticals, medicine, agriculture, forensics

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The steps of genetic engineering

• 1. Isolating the gene from the source gene
• 2. Cutting up of DNA
• 3. Isolating DNA
• 4. Vectors for cloning
• 5. Using plasmids as vectors

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Isolating the gene from the gene source

• DNA is divided into genes (units of inheritance)
• Average of 2200 genes/chromosome
• vary in length, but typically thousands of bases
  long
• Each gene codes for a particular protein
• For genetic engineering, genes need to be
  isolated and identified.

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Isolating continued

• DNA may be extracted from tissue by
• Mechanically breaking up the cells
• Filtering off the debris
• Breaking down the cell membranes by treatment
  with detergent
• The protein framework is removed by incubation
  with a protein digesting enzyme (protease)
• DNA can be isolated using ethanol

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Cutting up of DNA

• Genetic engineering began with the discovery of
  restriction enzymes
• Occur naturally in bacteria
• They protect against the activity of viruses by
  cutting up viral DNA
• Many different restriction enzymes have been
  discovered and purified to use today
• They cut at particular base sequences

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Isolating DNA fragments

• Electorphoresis
• Process used to separate particles
• DNA, RNA, proteins, and amino acids
• Done in agarous gel (sugar)
• Contain tiny pores (acts like a sieve)
• Small particles move quicker than larger ones
• Also use an electric field
• The molecules separated also carry an electrical
  charge (P in DNA is negative)

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Electrophoresis Animation

• http//www.dnalc.org/ddnalc/resources/electrophore
  sis.html

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Vectors for cloning

• Vector an agent that transports between one
  organism and another
• Vectors are commonly found in bacteria
• Plasmids (type of DNA)
• Easily isolated and easily re-introduced
• Plasmids replicate independently of the
  chromosome, so any gene added to the plasmid is
  replicated many times

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Plasmids as vectors

• Restriction enzyme cuts open the plasmid
• The same restriction enzyme cuts out the gene
• Segments are sealed back up using the enzyme
  ligase

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DNA Profiling

• Exploits techniques of genetic engineering to
  identify a person or organism from a sample of
  their DNA
• Forensic science
• Crime scenes
• Fingerprints, fluids, hair, skin
• Paternity cases

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Homework

• Due Monday, April 19
• Go to http//www.dnai.org/d/index.html
• Click on human identification
• Take notes on all four applications
• Profiling
• Family
• Murder
• Innocence