Genetic engineering

Genetic engineering is the process of taking genes and segments of DNA from one species and putting them into another species, thus breaking the species barrier and artificially modifying the DNA of various species.

• These changes in DNA result in an alteration of reproductive and hereditary processes of the organisms since the process is irreversible and the organism's offspring will also possess this unique DNA (Levine).

• Genetic engineering can be done on any living organism because all living organisms contain DNA within each cell nucleus.

• Genetic engineering involves the manipulation of DNA and the transfer of gene components in order to encourage replication of desired traits.

Process

1. Determination of the gene

• it is important first to understand the structure of deoxyribonucleic acid, or DNA. DNA stores the information that determines an organism's hereditary or genetic properties. Genetic engineering is based on this genetic information.

recombinant-DNA formation, or gene splicing.

• Genetic manipulation

• This procedure whereby segments of genetic material from one organism are transferred to another.

• The basis of the technique lies in the use of restriction enzymes that split DNA strands wherever certain desired sequences of nucleotides, or specific genes, occur.

• This desired segment of DNA is referred to as donor DNA. The process of gene splicing results in a series of fragments of DNA, each of which express the same desired gene that can then combine with plasmids (Rubenstein).

3. Insertion of plasmid

• Plasmids are small, circular molecules of DNA that are found in many bacteria.

• The bacteria act as vectors in the process of genetic engineering. The desired gene cannot be directly inserted into the recipient organism, or host, therefore there must be an organism that can carry the donor DNA into the host.

• Plasmid DNA is isolated from bacteria and its circular structure is broken by restriction enzymes (Dworkin). The desired donor DNA is then inserted in the plasmid, and the circle is resealed by ligases, which are enzymes that repair breaks in DNA strands.

4. Cell replication (division)

• This reconstructed plasmid, which contains an extra gene, can be replaced in the bacteria, where it is cloned, or duplicated, in large numbers.

• The combined vector and donor DNA fragment constitute the recombinant-DNA molecule. Once inside a host cell, this molecule is replicated along with the host's DNA during cell division.

• These divisions produce a clone of identical cells, each having a copy of the recombinant-DNA molecule and thus permanently changing the genetic makeup of the host organism (Steinbrecher).

• Genetic engineering has been accomplished.

Types of Genetic Engineering

• Negative• Positive

Negative Genetic Engineering

• Correct a genetic defect

Positive Genetic Engineering

• Make a life-form better.

Eugenics

• Eugenics- make improvements upon organism.

Genetic Therapy

Types of Genetic Therapy• Somatic Therapy

• Germ line Therapy

Somatic Therapy

• Somatic therapy is a type of genetic therapy that only affects the individual.

• Changes are not passed on to any subsequent generations or off spring.

Germ line Therapy

• Germ line therapy is a type of genetic therapy that not only affects the individual but also the off spring.

• Changes are passed on to subsequent generations.

Splicing

• Splicing is a method where genes from one organism are “spliced” into the DNA of another organism. This is the most common method of genetic engineering.