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Summary Lectures 11-14 Global Food Security
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This document contains an extensive summary of the lectures of week 3 of the course (11-14) that prepares you for the exam.
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Lecture 11: GMO and Food Security: The Technologies and the Debate (MajaSlingerland)
● We want to change plants (plant breeding), because of:
○ Improved yield (both quantity and quality).
○ Stability of performance.
○ Resistance to abiotic stress (thermo tolerant, drought, salinity, frost, cold,
etc.).
○ Resistance to biotic stress (diseases and insect pests).
○ With value-added traits.
● Plants are adapted to the growing conditions and cultivation system.
● Plant breeding takes a lot of time.
● Plant breeding is very imprecise, as all the offspring has to be checked individually →
many, many plants needed.
● 1920: F1 hybrid breeding was applied in maize.
- F1 Hybrid breeding: there are 2 parents and the offspring. The offspring is better
than the parents. These are the seeds for the farmers that want to sell the better
seeds.
- This process of the 2 parents making the offspring is redone over and over →
farmers always buy the F1.
● 1930s: mutation breeding → seedless fruits.
● 1950s: Tissue culture techniques.
● 1960s: Dwarfing traits in the Green Revolution → shorter crops with more grains.
● 1980: Genetic Modification (GM) of plants was invented.
● 1990s: DNA markers used for Marker-Assisted Selection.
- GMO: Genetically Modified Organism.
● GMOs are organisms that have had their characteristics changed through the
modification of their DNA.
- Genome: an organism’s complete set of genetic instructions.
Each genome contains all of the information needed to build that
organism and allow it to grow and develop. A genome is made
up of DNA.
- Gene: a small section of DNA within the genome that codes for
proteins. Genes contain the instructions for our individual
characteristics (traits) → eye colour, hair colour, etc.
● DNA is a long molecule that contains our unique genetic code.
Like a recipe book it holds the instructions for making all the
proteins in our bodies.
● DNA consists of 4 bases that can form pairs (A&T + C&G):
○ Adenine.
○ Thymine.
○ Cytosine.
○ Guanine.
● The order, the sequence, of these base pairs, forms the instruction in the genome.
,● To create a GMO, we change specific characteristics by using lab techniques to
delete or alter particular sections of DNA. Or, by introducing new pieces of DNA into
genomes.
● These pieces of DNA could be:
○ DNA taken from the same species.
○ DNA taken from a different species.
○ DNA made synthetically in the lab.
- Genetic modification / Genetic Engineering: the process of making GMOs. People
that are against creating GMOs call it genetic manipulation.
● Techniques to modify a genome:
1. ‘Agrobacterium-mediated’ genetic modification is a technique used to introduce
new DNA into a plant genome using a modified bacteria.
● A bacteria that transfers DNA from itself to a plant → if you change the DNA
of the bacterium, you can change the DNA of the plant.
● Rather natural technique.
2. ‘Gene gun’: shooting modified DNA with gold particles into a cell, hoping it hits the
nucleus.
● Causes harm to the cell + hard to control.
3. ‘Genome editing’ is a technique used to change selected regions of a genome using
enzymes designed to cut specific DNA sequences.
● Very precise technique.
● Insulin, used by people with diabetes, is mostly insulin that was created by
genetically modified bacteria.
● The US was one of the first countries to start with the development of GM crops.
● 4 key crops that are often genetically modified:
○ Soybean → almost all soybeans are genetically modified. Mainly used in
animal food, so not that much concern.
○ Cotton → almost all cotton is genetically modified.
○ Maize → less often genetically modified → used more for human
consumption than soybeans.
○ Canola.
● GMO generations:
● 1st generation → mainly used to improve agronomic traits:
○ Farmers’ interest in developed countries was central.
○ Reduction of labour and pesticide use.
○ In-built resistance against pesticides, herbicides and fungicides.
● The 2nd and 3th generation are much more concerned about food quality.
○ Enhancing or inserting vitamins and other substances naturally present in
certain crops → golden rice.
○ In-built mechanisms.
, ● GMO controversies:
- Farmers: higher yields, reduced costs, improved fit of crops in local conditions.
- Versus: increasing farmer’s dependence on large agro-chemical companies,
endangering organic food production.
- Consumers: reduced hunger, improved adaptations to consumer demands.
- Versus: unexpected toxins in food, new allergenic proteins (peanut protein in
tacos), antibiotic resistance.
- Environment: reduced use of pesticides and less pressure on remaining natural
areas.
- Versus: reduction of (agro-)biodiversity, gene pollution, creation of
superweeds.
● Gene editing is much less
precise than genetic
modification.
○ Potato blight arose
around the mid 19th
century and is still a
problem nowadays. By
adding a resistance gene,
potato blight can be
solved. Will this be
allowed in the EU?
○ Bacterial blight in rice → addition of a resistance gene.
○ Scab in apple → addition of a resistance gene → there has been made use of
dwarf species for experimenting (takes less time).
● The big question is: is this GM?
● Gene editing has great opportunities for plant breeding, as it is a fast process and
targeted. It specifically works for vegetatively propagated varieties and crops with
complex genomes.
● It’s a way of expanding the ‘toolbox’ of breeders.
● US-EU controversy:
- EU: we want labelling → we must know how the food is made. The US goes against
it → there is no evidence that genetically modified corn is different from regular corn.
Labelling increases costs and it increases threats for hunger.
- The US argues that no specific measures for GM foods are required, only for the
changed elements. There does not have to be segregation in the chains → no
labelling.
- The EU argues that GM foods are fundamentally different and therefore they require
labelling.
● The WTO argues that in crops such as BT cotton or Roundup-ready soy you can find
the modified part coming from another species, hence the crop is substantially
different and recognizable as a GMO.
○ Cis-genesis → add a gene from the same species → resembles a natural
process → not different.
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