Animal Science Chapter 10: Biotechnology and Genetic Engineering

Biotechnology

is the development of products by a biological process

Traditional biotechnologies

began in 1953 when James Watson and Francis Crick proposed the double-helix structure of DNA

New Biotechnologies

owes its existence to the understanding of the cell and its components, and especially the genetic code

Recombinant DNA technology

is the combination of DNA molecules from different biological sources

The discovery of what two essential components made gene cloning and DNA recombinant techniques possible?

restriction enzymes and plasmid DNA

Restriction enzymes

are DNA cutting enzymes

Plasmid DNA

is a circular form of self-replicating DNA that scientists can manipulate to carry and clone other pieces of DNA

Cloning

in biotechnology refers to the process of creating copies

Cloning is the process of creating copies of:

-DNA fragments (molecular cloning)

-Cells (cell cloning)

-Whole organisms

Products of biotechnology

-used in disease research

-food production

-waste management

Cloning of DNA fragments involves four steps:

1. Fragmentation

2. Ligation

3. Transformation

4. Screening/Selection

Fragmentation

cutting and separating a piece of DNA

Ligation

gluing together pieces of DNA using DNA ligase and vectors

Transformation

insertion of the newly formed DNA pieces into cells

Screening/Selection

selection of cells successfully transformed with the new DNA

Polymerase Chain Reaction

is a rapid and versatile method for amplifying target DNA sequences

The basic mechanism of PCR relies on a 3-step process:

1. Denaturation

2. Annealing

3. Elongation

Denaturation

causes separation of the template DNA into single strands

Annealing

allows primers to bind to the complementary bases at opposite ends of the target sequence

Elongation

allows DNA polymerase to copy the template DNA and to synthesize a complementary strand

Why is gene mapping so important?

it is a critical step in the understanding of any genetic trait including genetic disease or an economically important trait in livestock

Gene Mapping

refers to the creation of a genetic map by identifying genes at specific locations on chromosomes

There are two different ways of mapping:

1. Genetic mapping

2. Physical mapping

Genetic mapping

which uses crossbreeding experiments to determine the relative position of genetic markers or genes within a genome

Physical Mapping

which uses molecular techniques to determine the absolute position of these markers or genes within the genome.

Genetically manipulated organisms

is the result of a laboratory process where genes from the DNA of one species are extracted and artificially forced into the genes of an unrelated plant or animal

Transgenic plants are being created that have:

-enhanced nutritive value

-resistance to various pests and diseases

-ability to withstand adverse growing conditions

-resistance to herbicides

-unique ornamental value

-edible vaccines

Micropropagation

is a biotechnology that takes cells of a desired plant and uses them to generate another plant

Clone

is a transgenic animal whose DNA was cloned from another organism and injected into the pro-nucleus of a fertilized ovum

What species have we cloned?

sheep

What are the uses of clones?

-enhance growth rates

-improve carcasses

-improve milk production

-enhance reproductive efficiency

-gene pharming for human medicine

-resistance to diseases

Nuclear Transfer from somatic cells

involves transplanting the nucleus from a somatic cell of the animal into an egg with the nucleus removed

Cloning is considered to be:

extremely inefficient

For what use have most transgenic animals been developed to date?

-modification of milk composition or production

of novel milk proteins

-understanding control of growth and of carcass composition

-producing environmentally friendly pigs

Gene Pharming

the production of pharmaceutical proteins in the blood or milk of transgenic animals

Xenotransplantation

companies are actively pursuing the development of transgenic animals that could donate organs to humans that would not be rejected by the human recipient

Genetic tests

involve direct examination of DNA molecules from blood or other tissues to find genetic disorders

Gene Therapy

is a technique for correcting defective genes responsible for disease development

Pharmacogenomics

is the study of how an individual's inherited variation in different genes affects drug response

Recombinant bovine somatotropin (rBST)

has been among the most successful products of genetic engineering made available to agriculture

What are some of the uses that microorganisms have been genetically harnessed to perform in terms of producing drugs and vaccines?

• Hormones and growth factors such as insulin

• Antibodies such as TNF used to treat arthritis

• Blood-related proteins

• Some vaccines

How is BST produced commercially?

by being administered to dairy cows, which causes greater milk production

Biotechnology and Pest Management

several bacteria have been genetically altered to improve their ability to kill or repel pests

Bacteria Engineered for the Food Industry

genetically altered microorganisms are used to facilitate food production, including cheese making and reduced timing for baking bread

Nutraceuticals

which are products that have both nutrient and pharmaceutical properties

Agricultural Biotechnology

is a broad term that describes the use of biological processes other than genetic engineering, such as micropropagation, plant and animal health diagnostics, vaccines, and biopesticides