Contents

Golden Rice

GM Corn

<aside> <img src="https://image.flaticon.com/icons/svg/1828/1828885.svg" alt="https://image.flaticon.com/icons/svg/1828/1828885.svg" width="40px" /> Golden Rice is a genetically modified version of white rice that produces Vitamin-A, which is handy in countries where people (especially children) die from Vitamin-A deficiency.

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<aside> <img src="https://image.flaticon.com/icons/svg/1828/1828885.svg" alt="https://image.flaticon.com/icons/svg/1828/1828885.svg" width="40px" /> Bt-corn is genetically altered to express the bacterial Bt toxin, which is poisonous to insect pests. In the case of corn, the pest is the European Corn Borer. (Kenya)

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References

Biotechnology, the use of technology to allegedly manipulate genes in organisms for the benefit of human beings.

Genetic engineering

• Identification and mapping of genes in the human genome (Human Genome Project)
• Modifying genes
• Transferring genes from one organism to another organism

Genetically modified organisms (GMOs)

Organisms that have had their DNA changed through some form of genetic engineering. In many cases, this results in i.e. better nutrition, longer shelf life, faster growth or even better taste (purely aesthetic).

GMOs are created in order to to produce new gene combinations that result in more favorable traits, such as crops that have:

• Longer shelf life
• Better nutrition
• Herbicide tolerance
• Pesticide tolerance
• Better taste
• Faster growth
• Ability to withstand a variety of temperatures

Gene splicing

Gene splicing has four main steps:

1. Identification of the gene from source genome
2. Cutting up of DNA segment/gene using restriction endonucleases (called restriction enzymes), such as EcoRI, which binds to the sequence GAATTC.
   • Restriction enzymes were developed by bacteria to protect themselves against viral attacks.
   • There are over 3000 known restriction enzymes.
   • Restriction enzymes are used in genetic engineering to isolate specific genes by cutting the DNA molecule at specific base sequences called palindromes
   • Restriction enzymes act like chemical scissors, and the cut leaves ”sticky ends” of DNA, which can then be joined to the complementary bases of other DNA strands.
3. Insert the desired gene into the plasmid of a bacterium.
4. Gene is transferred by the bacterium to the organism to be modified, so that a genetically engineered bacteria with recombinant DNA is created.

Gene transfer techniques

Bacteria

Genes are inserted into the plasmids of bacteria using restriction enzymes to cut the DNA strands and the enzyme ligase to ”glue” the strands back together. The bacteria then produce useful products such as human growth hormone (hGH) or insulin.

Virus

Virus with desired gene is used to tranfer the gene into a living recipient cell, where it produces more copies of the gene.

Injection

DNA is transferred through a microscopic injection into the recipient cell, where it reproduces more copies of the gene.

Particle gun

A microscopic, gold-coated metal ball covered with DNA is shot into plant cells, where it reproduces more copies of the gene.

All plants above are artificially selected from mustard plants. Photo: Britannica.

The insertion of a gene into a plasmid to produce a molecule of recombinant DNA. Photo: Khan Academy.