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Genetic Engineering Masterclass

Lisa Milne, Will Cassie

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Contents

  1. Genetic engineering overview

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  • Guess the model organism

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  • Techniques used in genetic engineering

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  • Applications of genetic engineering

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What do you know about genetic engineering already?

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What is Genetic engineering?

-DNA determines the characteristics of an organism. DNA physically is just a molecule.

-Genetic engineers can edit the DNA within a cell, to change how the cell and organism behaves.

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Genetic engineering simple method

Gene= short sequence of DNA that codes for a particular characteristic

  1. Select a gene of interest from a database
  2. Gene is synthesised or taken from another organism and inserted into a vector
  3. Vector is inserted into the chosen organism
  4. (Hopefully) Gene is expressed in the chosen organism

Vector = DNA carrier

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Types of vectors

  • Plasmid= circular strand of DNA within cytoplasm
  • Virus
    • Retrovirus e.g. lentivirus, rhinovirus
    • Phage with integrase
  • Cosmid
  • Bacterial

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Types of vectors 2

Modifying eukaryotic cells on a larger scale:

YACs - yeast artificial chromosomes

BACs - bacterial artificial chromosomes

HACs - human artificial chromosomes

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Advantages: larger, more stable

Disadvantages: only one or two copies per cell

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Methods of building vectors

  • Restriction enzymes and ligases
  • Gibson assembly and Golden gate assembly

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Model organisms

Model organism= non-human species which is extensively studied to understand particular biological principles

  • Short life cycle
  • Cheap
  • Small
  • Well characterised
  • Have little to no rights

“According to the Animal Welfare Act, experiments on invertebrates such as Drosophila melanogaster are not considered animal experiments”

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E. coli

The most commonly used bacterial species [model organism] is E. coli

  • It is very well characterised
  • Not dangerous (unless pathogenic strain)
  • Most labs will have some on hand and they are extremely cheap to keep

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Guess the model organism

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Drosophila melanogaster

Common fruit fly

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Xenopus laevis

African clawed toad

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Mus musculus

House mouse

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Danio rerio

Zebrafish

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C. elegans

Nematode roundworm

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Arabidopsis thaliana

Thale cress

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Saccharomyces cerevisiae

Baker’s yeast

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Guess the flies

Please be gentle with the flies 🙏

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Write of a piece of paper A to F.

We have test tubes of flies A to F, of different varieties.

Pass the test tubes around, and use the sheet to guess which variety of fly is in each test tube.

Winning team gets a 3D printed object.

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Genetics techniques

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DNA

Phosphate is negatively charged

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Gel electrophoresis

This can be done with protein or DNA to identify size of fragments

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Sequencing methods

Polymerase chain reaction (PCR): method to make many copies of a specific sequence of DNA

Sanger sequencing - simplest method to find the exact base sequence in DNA

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Modern sequencing methods

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CRISPR

Clustered Regularly Interspaced Short Palindromic Repeats

Really useful for targeted deletions over regular restriction enzymes

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RNA= similar to DNA but single stranded

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Applications of genetic engineering

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Tomato engineering as a proof of concept

Using CRISPR-Cas technology

  • From wild tomato
  • In one generation, 6 genes were modified resulting in
    • 10x fruit number
    • Shorter
    • 3x fruit size
    • Additional lycopene beta cyclase (more nutritious)

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Applications of genetic engineering

  • Making proteins
    • Lactase
    • Insulin
  • Gene therapy
    • cystic fibrosis
    • Large range of genetic disorders which can be cured
  • Engineered crops
    • Orphan crops

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Regulation slide

Genetic engineering and all of synthetic biology is heavily regulated by about 10 boards in the UK alone.

Transport of genetically modified organisms is especially sensitive.

Work in humans and higher mammals is very sensitive as well and genetic modification of human cells is illegal across the world

There have been cases but they were unsuccessful as far as I know

Gene therapies are fine but they are distinct

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Jobs in genetic engineering

  • Industry research
  • PhD/post-doc researcher
  • Applied in industry
    • Manufacturing proteins
    • Startups in detection and waste processing
  • Policy and regulation
  • Essential research tool so any job which involves providing reagents are in high demand