GENETIC ENGINEERINGGENETIC ENGINEERING

INTRODUCTIONINTRODUCTION

For thousands of years people have changed For thousands of years people have changed the characteristics of plants and animals.the characteristics of plants and animals.– Through selective breedingThrough selective breeding– Through the exploitation of mutationsThrough the exploitation of mutations

Since breeders have been able to take Since breeders have been able to take advantage of naturally occurring mutations, advantage of naturally occurring mutations, they have dreamed of being able to they have dreamed of being able to artificially create mutations. artificially create mutations.

The ability to design new varieties of plants The ability to design new varieties of plants and animals has now become a reality and animals has now become a reality through genetic engineeringthrough genetic engineering

Genetic engineering involves the Genetic engineering involves the manipulation of genes within a cell or manipulation of genes within a cell or organism to bring about a change in the organism to bring about a change in the genetic makeup of an organismgenetic makeup of an organism

There are several methods of gene There are several methods of gene manipulation currently used, most of which manipulation currently used, most of which include the removal and insertion of genetic include the removal and insertion of genetic material into organismsmaterial into organisms

GENE MAPPINGGENE MAPPING

One of the most important processes in gene One of the most important processes in gene manipulation is that of finding the location of manipulation is that of finding the location of genes on the chromosomesgenes on the chromosomes

gene mapping involves the finding of the gene mapping involves the finding of the particular location on the strand of DNA that particular location on the strand of DNA that contains the genes that control certain traitscontains the genes that control certain traits

The arrangement of the nitrogen bases (A,T,C,G) The arrangement of the nitrogen bases (A,T,C,G) on the molecule of DNA determine the genetic on the molecule of DNA determine the genetic codecode

The process of mapping the genes on the The process of mapping the genes on the strands of DNA involves the use of strands of DNA involves the use of molecules that act as probesmolecules that act as probes– The probes attach themselves to certain parts of The probes attach themselves to certain parts of

the DNA where the nucleotides join each otherthe DNA where the nucleotides join each other– The probe looks for combinations of where the The probe looks for combinations of where the

nitrogen bases join in certain sequencesnitrogen bases join in certain sequences– Once the probe locates the nucleotides, the Once the probe locates the nucleotides, the

sequences of Adenine(A), thymine(T), sequences of Adenine(A), thymine(T), Cytosine(C) and Guanine(G) can be listed in a Cytosine(C) and Guanine(G) can be listed in a map map

Although coding is extremely complex, the Although coding is extremely complex, the code is the same in all organisms.code is the same in all organisms.– The nucleotides only pair with certain other The nucleotides only pair with certain other

nucleotides.nucleotides.– The pairing of nucleotides is the phenomena The pairing of nucleotides is the phenomena

that makes genetic engineering possible.that makes genetic engineering possible.

Gene splicingGene splicing

Once the location of the DNA sequence has Once the location of the DNA sequence has been located, scientists can use restrictiion been located, scientists can use restrictiion enzymes to separate the DNA at a particular enzymes to separate the DNA at a particular location on the genelocation on the gene

Once the pieces of DNA are removed other Once the pieces of DNA are removed other DNA canbe spliced in or recombined with DNA canbe spliced in or recombined with the remaining DNAthe remaining DNA– This results in recombinant DNA This results in recombinant DNA

– The new form of DNA will reproduce with the new The new form of DNA will reproduce with the new characteristics of the introduced DNAcharacteristics of the introduced DNA

The first genetic splicing was done using bacteriaThe first genetic splicing was done using bacteria– Bacteria has plasmids (circular shaped pieces of DNA) Bacteria has plasmids (circular shaped pieces of DNA)

that float freely in the cell’s fluidthat float freely in the cell’s fluid

– By selection the proper enzyme, scientists cut out part By selection the proper enzyme, scientists cut out part of the plasmid DNA and insert DNA from another of the plasmid DNA and insert DNA from another organismorganism

– The DNA replicates and the new bacteria produced The DNA replicates and the new bacteria produced from the spliced DNA holds the desired characteristicsfrom the spliced DNA holds the desired characteristics

One of the first uses of gene splicing was One of the first uses of gene splicing was the manufacture of human insulinthe manufacture of human insulin– Scientists isolated the DNA sequence that Scientists isolated the DNA sequence that

regulates the production of insulinregulates the production of insulin– The DNA segment is spliced into the DNA of The DNA segment is spliced into the DNA of

the E.coli bacteriathe E.coli bacteria– The bacteria carrying the DNA for insulin The bacteria carrying the DNA for insulin

production reproduces and passes the capability production reproduces and passes the capability along to the next generationalong to the next generation

– The bacteria are produced in large quantities through a The bacteria are produced in large quantities through a process called fermentationprocess called fermentation

– When the proper number of bacteria are reproduced, When the proper number of bacteria are reproduced, they are removed from the fermentation tanks and are they are removed from the fermentation tanks and are taken apart to retrieve the insulin produced.taken apart to retrieve the insulin produced.

– The insulin is then separated, purified, and the remains The insulin is then separated, purified, and the remains of the bacteria are destroyedof the bacteria are destroyed

– This procedure provides a ready relatively inexpensive This procedure provides a ready relatively inexpensive supply of insulin for those people who need itsupply of insulin for those people who need it

Bacteria have become the manufacturing Bacteria have become the manufacturing centers for many substances that have made centers for many substances that have made the lives of humans better and more the lives of humans better and more productiveproductive– VaccinesVaccines– HormonesHormones

Bovine somatotropin (BST)Bovine somatotropin (BST)– A relatively recent agricultural innovation using A relatively recent agricultural innovation using

genetic engineeringgenetic engineering

– A hormone composed of protein that that is A hormone composed of protein that that is produced by the animal’s pituitary gland produced by the animal’s pituitary gland

– Helps control the production of milk by Helps control the production of milk by assisting the regulation of nutrients into the assisting the regulation of nutrients into the production of milk or fatproduction of milk or fat

– Supplementary BST causes the cow to produce Supplementary BST causes the cow to produce less fat and more milkless fat and more milk

– By splicing genetic material into E. coli By splicing genetic material into E. coli bacteria the hormone can be produced at bacteria the hormone can be produced at relatively low costrelatively low cost

Tissue cultureTissue culture

Tissue culture- the process of regenerating Tissue culture- the process of regenerating plants from a single cellplants from a single cell

Through the introduction of new DNA into Through the introduction of new DNA into a single cell, a completely new plant of a single cell, a completely new plant of different genetic makeup can be growndifferent genetic makeup can be grown