Genetic Engineering

Quipper - Topic 2.2: Genetic Engineering

General Overview

  • Selectivity in Breeding:

    • Selective breeding has been the primary method for the improvement of crops in the Philippines such as rice, corn, cabbage, and sugarcane.

Historical Context of Selective Breeding

  • Domestication of Gray Wolves to Dogs:

    • This process employed selective breeding techniques beginning thousands of years ago.

Limitations of Classical Breeding

  • Difficulties in Trait Acquisition:

    • Some traits, like disease resistance (e.g., stem rust in wheat), are hard to obtain through classical breeding.

Recombinant DNA Technology vs. Traditional Breeding

  • Power of Recombinant DNA Technology:

    • A question posed about the advantages of recombinant DNA technology over traditional breeding methods leads into a discussion of its significance.

Learning Competencies

  • Objectives of the Lesson:

    • Discuss general principles of recombinant DNA technology.

    • Explain the techniques involved in recombinant DNA technology.

    • Discuss applications in producing transgenic organisms like corn, mice, and bacteria.

Introduction to Genetic Engineering

  • Challenges in Trait Acquisition:

    • There are cases where organisms with desirable traits cannot reproduce with those that need them.

  • Foreign Gene Introduction:

    • The concept of directly introducing foreign genes to organisms to achieve desirable protein expressions is introduced.

Definition and Explanation of Genetic Engineering

  • What is Genetic Engineering?

    • Direct manipulation of genes in organisms in a laboratory setting to express desired traits.

Modification of Traits

  • Types of Modifications:

    • Introduction of new traits into an organism.

    • Enhancement of existing traits by increasing gene expression.

    • Enhancement of existing traits by disrupting the inhibition of desired gene expression.

Genetically Modified Organisms (GMOs)

  • Definition of GMO:

    • A genetically modified organism (GMO) is any plant, animal, or microbe whose DNA has been altered to express desirable traits like disease resistance or nutritional improvements.

  • Non-Natural Modification:

    • The genetic material of GMOs is intentionally altered in a manner that doesn’t occur through natural mating or recombination.

Characteristics of GMOs

  • Modification Techniques:

    • Involves adding, removing, or changing genes.

    • GMOs are utilized in agriculture, medicine, and scientific research.

Recombinant DNA Technology

  • Primary Technique in Genetic Engineering:

    • Involves the use of enzymes and laboratory techniques to manipulate and isolate DNA segments.

Steps in Creating Recombinant DNA

  1. DNA Cutting:

    • DNA and plasmid are cleaved using restriction enzymes.

  2. Gene Insertion:

    • The gene of interest is inserted into the open plasmid by DNA ligase.

  3. Recombinant Plasmid Transformation:

    • The recombinant plasmid is inserted back into the bacterial cell.

  4. Gene Isolation and Insertion:

    • Gene copies are isolated and inserted into other organisms.

Comparison of Techniques: Classical Breeding vs. rDNA Technology

  • Classic Breeding Example:

    • Guapple is cited as an improved variety of guava achieved through traditional methods.

  • rDNA Technology Example:

    • Genetically engineered E. coli producing human insulin signifies advancements in technology.

  • FlavrSavr Tomato:

    • A tomato engineered to maintain flavor and extend shelf life via manipulation of the ripening process.

Notable Applications and Developments in Genetic Engineering

  • Transgenic Animals and Crops:

    • Historical figures in genetic engineering like Ralph Brinster and Richard Palmiter—their creation of 'Supermouse'—and the creation of the first transgenic crop using Agrobacterium tumefaciens is documented.

Brief Historical Timeline

  1. 1972: Cohen and Boyer introduced plasmid segments into bacteria.

  2. 1974: Rudolf Jaenisch created the first transgenic mouse by inserting human growth hormone genes.

  3. 1982: Genentech produced human insulin through GM E. coli, marking the first FDA-approved GMO.

Principles of Recombinant DNA Technology

  • Role of DNA:

    • Recognized as the blueprint of life, influencing phenotypes via proteins.

  • Gene Identification:

    • Understanding gene identification and host organisms is critical in rDNA technology.

Methods of Introducing Foreign DNA

  1. Microprojectile Bombardment (Gene Gun):

    • Physical method that propels DNA-coated metal particles into target cells.

  2. Electroporation:

    • Uses electric pulses to increase cell membrane permeability, allowing DNA entry.

  3. Agrobacterium tumefaciens-mediated Transformation:

    • Utilizes the natural ability of Agrobacterium to transfer DNA into plant genomes.

Challenges in Genetic Engineering

  • Isolation of Genes:

    • Issues during the isolation of genes of interest and the role of crown gall formation in plant genetic engineering.

Conclusion

  • Innovative Potential of Genetic Engineering:

    • Enables overcoming limitations of traditional breeding and represents a crucial advancement in biotechnology.

  • Future Prospects:

    • Continuous development and applications of genetic engineering in various fields, including agriculture and medicine, with the aim to improve efficiency and efficacy in crop production and health solutions.