Electrophoresis

- A method of separating large molecules (such as DNA fragments or proteins) from a mixture of similar molecules. An electric current is passed through a medium containing the mixture, and each kind of molecule travels through the medium at a different rate, depending on its electrical charge and size. Separation is based on these differences. Agarose and acrylamide gels are the media commonly used for electrophoresis of proteins and nucleic acids.
Definition from:
http://linkage.rockefeller.edu/wli/glossary/genetics.html
 

- A technique that separates DNA fragments on the basis or their size by running them through a viscous material. The fragments move through the material due to the application of an electric current which attracts the negatively charged DNA to the positive terminal, and the fragments are separated due to the fact that the smaller fragments will move through the matrix faster than the larger fragments and will thus arrive sooner at the positive terminal.
Definition from:
Glossary of Forensic DNA terms

Elongation or extension

-Phase of PCR cycle following annealing of primer during which the Taq polymerase synthesizes a strand of DNA. The optimum temperature depends on the enzyme used but is usually between 68-72° C.
Definition from:
http://www.wellscenter.iupui.edu/MMIA/htm/pcr.htm#4

- Refers to the elongation of the DNA chain that is being synthesized using the parent DNA strand as the template for synthesis of that daughter strand. This is a natural process that occurs during DNA replication. Extension occurs during the PCR process with DNA polymerases.
Definition from:
Roche Diagnostics,PCR Glossary

Ethidium Bromide ( EtBr )

- Intercalates within the structure of nucleic acids in such a way that they fluoresce under UV light. Ethidium bromide staining is commonly used to visualize RNA or DNA in agarose gels placed on UV light boxes. Proper precautions are required, because the ethidium bromide is highly mutagenic and the UV light damaging to the eyes.
Definition from:
A Glossary of Terms commonly used in Molecular Biology

Exon
- Part of a gene whose sequence is present in a mature mRNA after splicing.
Definition from:
ZFIN Glossary

Expressed Sequence Tag ( EST )
- A small sequence from an expressed gene that can be amplified by PCR. ESTs act as physical markers for cloning and full length sequencing of the cDNAs of expressed genes. Typically identified by purifying mRNAs, converting to cDNAs, and then sequencing a portion of the cDNAs
Definition from:
Bioinformatics Glossary

- A partial sequence of a randomly chosen cDNA, obtained from the results of a single DNA sequencing reaction. ESTs are used to identify transcribed regions in genomic sequence, to characterize patterns of gene expression in the tissue that was the source of the cDNA and as markers for genetic mapping.
Definition from:
ZFIN Glossary