DNA DNA TechnologyTechnology

Genetic engineering:Genetic engineering:

The application of The application of molecular genetics for molecular genetics for practical purposespractical purposes Examples:Examples:

• Medicine (insulin)Medicine (insulin)• Cures for diseaseCures for disease• Gene therapyGene therapy• Criminal casesCriminal cases• agricultureagriculture

Genetic engineeringGenetic engineering

DNA FingerprintingDNA Fingerprinting

A pattern of bands made A pattern of bands made up of specific fragments of up of specific fragments of a person’s DNAa person’s DNA

Banding patterns of DNA Banding patterns of DNA fragments are compared fragments are compared to establish relatednessto establish relatedness

Can be used to solve Can be used to solve crimes or prove paternity crimes or prove paternity casescases

DNA FingerprintingDNA Fingerprinting StepsSteps:: (1) Collect sample & Isolate DNA (1) Collect sample & Isolate DNA

Only a small amount of tissue, like Only a small amount of tissue, like blood, hair, or skin, is needed. For blood, hair, or skin, is needed. For example, the amount of DNA found at example, the amount of DNA found at the root of one hair is usually sufficientthe root of one hair is usually sufficient

DNA FingerprintingDNA Fingerprinting

(2) DNA is cut using restriction (2) DNA is cut using restriction enzymesenzymes cut the DNA at specific placescut the DNA at specific places For example, an enzyme called EcoR1, For example, an enzyme called EcoR1,

found in bacteria, will cut DNA only found in bacteria, will cut DNA only when the sequence GAATTC occurswhen the sequence GAATTC occurs

DNA FingerprintingDNA Fingerprinting (3) Fragments of DNA are (3) Fragments of DNA are

separated using gel separated using gel electrophoresiselectrophoresis

Sorts according to sizeSorts according to size Samples of DNA being Samples of DNA being

compared are loaded into compared are loaded into wells on gelwells on gel

Electric current is run through Electric current is run through gelgel

DNA is negatively charged and DNA is negatively charged and moves towards positive end of moves towards positive end of gelgel

Smaller DNA fragments move Smaller DNA fragments move faster and will travel further faster and will travel further along the gelalong the gel

DNA FingerprintingDNA Fingerprinting (4) Transfer of DNA to (4) Transfer of DNA to

nylonnylon The distribution of DNA The distribution of DNA

pieces is transferred to a pieces is transferred to a nylon sheet by placing nylon sheet by placing the sheet on the gel and the sheet on the gel and soaking them overnight soaking them overnight

(5) Probing(5) Probing Adding radioactive or Adding radioactive or

colored probes to the colored probes to the nylon sheet produces a nylon sheet produces a pattern called the DNA pattern called the DNA fingerprint. Each probe fingerprint. Each probe typically sticks in only typically sticks in only one or two specific places one or two specific places on the nylon sheet. on the nylon sheet.

DNA FingerprintingDNA Fingerprinting

(6) DNA fingerprints are compared(6) DNA fingerprints are compared

http://www.pbs.org/wgbh/nova/sheppard/analyze.html