GMOs Flashcards

Global Food Production and Security

Optimal Resource Use: Emphasizes making the best use of land and other resources.
Balance: Balancing animal and plant production systems.
Efficiency: Achieving more with less, including feed conversion and reproductive efficiency in animals.
Waste Reduction: Minimizing harmful waste through processing and proper disposal.
Food Distribution: Addressing challenges in food distribution.
GMO Application: Considering the application of GMO technology to these areas.

Definition: A Genetically Modified Organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques.
Varying Definitions: The exact definition varies, but commonly refers to organisms altered in a way that does not occur naturally through mating or natural recombination.
Wide Variety: Includes animals, plants, and microorganisms.

Process:
- Goat DNA stretch containing the lactation regulatory circuit is engineered to include spider gene(s) for silk production.
- This modified DNA is inserted into a goat egg and fused with the goat's chromosomal DNA.
Older Techniques: Previous GMO techniques used ligases and restriction enzymes.
Key Questions:
- What is the role of the spider gene?
- What is the role of the promoter?
- Why is the spider gene fused with the nucleus of the mother goat's cell?
- How is the GMO nucleus encouraged to form a baby goat?

Occurrence: Several native Australian plants contain fluoroacetate (1080), including Acacia georginae, Gastrolobium spp., and Oxylobium spp..
Metabolic Disruption: Fluoroacetate disrupts the Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle) by being converted into fluorocitrate which inhibits aconitase. The inhibition of aconitase prevents the conversion of citrate to isocitrate, disrupting cellular respiration.
Fluoroacetate + Acetyl-CoA \rightarrow Fluoroacetyl-CoA

Glyphosate-Resistant Crops: Crops resistant to Roundup (glyphosate), which inhibits the enzyme EPSP synthase (essential for plant growth but absent in animal genomes).
Golden Rice: Rice enriched with beta-carotene (a precursor to Vitamin A).
AquaAdvantage Salmon: Salmon with a growth hormone (GH) promoter from the ocean pout, a cold-tolerant North Atlantic fish, leading to faster growth.
'Peter Pan' Cane Toads: An allusion to cane toads with modified growth or developmental characteristics (the specific details of this example are not provided in the transcript).

Natural Mutations: Exploiting naturally occurring mutations like MSTN mutant cattle and Callipyge sheep.
Artificial Selection: Selecting the best parents for breeding.
Breed Formation: Developing specific breeds like Piedmontese cattle.
Trait Improvements: Achieving continuous improvements in traits like broiler feed efficiency.
Breeding Techniques: Using hybridization, genome ploidy, and sterility, especially in plants.

Ethical Question: Addresses the fundamental ethical question of whether we should create GMOs simply because we can.
'Natural' Food: What is 'natural' food?.
Line in the Sand: Is there a distinction between foods manipulated through traditional methods (e.g., strawberries) and GMOs created with modern biotechnology?

Desired Traits:
- Higher muscle mass.
- Red muscle fiber composition.
- Polled livestock (animals without horns, a trait controlled by a single locus).
- Disease resistance.

Modifications: Which traits would be modified in humans and wildlife if there were no regulatory or technical barriers?

Random Mutagenesis Screens ('Forwards'):
- Using Chemicals such as ethylmethanesulfonate (EMS).
- UV irradiation.
- Transposons and retroviruses.
Targeted Genomic Modification ('Reverse'):
- CRISPR/CAS9.
- Theoretically create a single nucleotide polymorphism (SNP) at a specific genomic location.

Process: Inducing random mutations in an organism's genome to observe resulting phenotypic changes and identify gene functions.
ENU Mutagenesis: Using N-ethyl-N-nitrosourea (ENU) to induce mutations in mice to study gene functions and model human diseases.
Forward Screen: Identify unknown genes by starting with a phenotype of interest

Impact Assessment: Evaluate the impact of mutations on phenotypes.
Favorable Mutations: Low proportion of random mutations are likely favorable.
Gene Identification: Determine which gene(s) are responsible for an observed phenotype.

Strengths and Weaknesses: What are the strengths and weaknesses of random mutagenesis for agriculturally important species?

CRISPR-CAS9: Localize to the desired target area (among 3 billion base pairs!).
Specific Modification: Make a very specific modification.
Reverse Screen: Manipulate a gene with known function and observe the effect

Definition: CRISPR gene editing stands for "Clustered Regularly Interspaced Short Palindromic Repeats."
Genetic Engineering Technique: It is a genetic engineering technique in molecular biology used to modify the genomes of living organisms.
Origin: Based on a simplified version of the bacterial CRISPR-Cas9 antiviral defense system.
Mechanism:
- Cas9 nuclease (“genetic scissors”) complexed with
- A synthetic guide RNA (gRNA) (the “homing pigeon”) is delivered into a cell to cut the target cell's genome at a desired location.
Outcomes: Allows existing genes to be removed and/or new ones added in vivo.

Strengths and Weaknesses: What are the strengths and weaknesses of CRISPR targeted mutagenesis for agriculturally important species?

Canvas: A 3 billion base pair production animal genome.
Considerations:
- Which genomic region would you select?
- Which class of molecule or regulatory region might you select?
- What type of mutation would you introduce?

Methods:
- Genome-Wide Association Study (GWAS) in the species of interest or another comparable species.
- Reverse engineering of a mouse locus from a random mutagenesis screen identifies a promising locus.
- Inspiration from an existing transgenic mouse, or some other transgenic species.
Cross-Species Application: To what extent can you assume a locus in one species will produce a similar phenotype in another?

Feature	NATURAL MUTATION	GMO RANDOM	TARGETED TO ‘INFLUENTIAL’ REGIONS
Rate	SLOW	FAST?	FAST?
Selection	ONLY THE FIT OFFSPRING SURVIVE	FUNCTIONAL OUTCOME(S) TO ANIMAL UNCLEAR	FUNCTIONAL OUTCOME(S) TO ANIMAL
Ethics	NO ETHICAL DILEMMA	PLAYING GOD?	PLAYING GOD?
Consumer Concern	LITTLE CONCERN OVER CONSUMPTION	SOME CONCERN OVER CONSUMPTION (JUSTIFIED?)	SOME CONCERN OVER CONSUMPTION

Definition: Aimed at improving the genetic merit of a population of humans.
Practices:
- Inhibiting the fertility of those considered inferior (forced sterilization).
- Promoting reproduction of those considered superior.

In Utero Testing:
- Downs syndrome.
- Neural tube defects.
- Morphological screening.
Designer Babies:
Pre-implantation screens: A ‘selection’ process.
- Sex.
- Traits.
GMO: A ‘creation’ process.