Chapter 8: DNA Applications

Recombinant DNA technology

The process of transferring a gene from a cell of a member of one species to the cell of a different species

Genetically modified organism (GMO)

An organism that has been modified by incorporating a piece of foreign DNA into its genome

Vector

A vehicle used to transfer DNA sequences from one organism to another

Restriction enzyme

An enzyme that cuts DNA at a specific restriction site

Restriction site

A specific nucleotide sequence (usually 4–8 base pairs) that is recognised as a cleaving site for a restriction enzyme

Sticky end

The overhanging end of a DNA fragment that is produced after asymmetrical cleavage by a restriction enzyme

Blunt end

The flat end of a DNA fragment that is produced after symmetrical cleavage by a restriction enzyme

DNA ligase

An enzyme that catalyses the formation of a sugar–phosphate bond between two pieces of DNA

Recombinant plasmid

A plasmid with foreign DNA inserted into it

Polymerase chain reaction (PCR)

A cyclical reaction in which DNA polymerase is used to copy a DNA sample, making millions of copies of the same piece of DNA

Taq polymerase

DNA polymerase from the bacterium Thermus aquaticus; used in PCR because it can withstand the high temperatures used in the process

Primer

A single-stranded DNA molecule that anneals to its complementary sequence on the DNA sample to act as the start of the amplification process

Anneal

To hydrogen bond, as when two single-stranded sections of complementary DNA align to form a double strand

Denaturation

The application of high temperatures to break the hydrogen bonds in DNA, causing the two strands to separate

Gel electrophoresis

A technique that separates DNA fragments according to their size and charge

Agarose gel

A gel matrix used for electrophoresis

Molecular size marker

A set of pieces of DNA of known length that is used to estimate the size of other DNA fragments in a gel

DNA profiling

A process that compares an individual’s genome with another

Short tandem repeat (STR)

A short non-coding region of DNA that is repeated many times in the genome of an organism; it is highly variable between individuals and can be used in DNA profiling to identify individuals