F

FAM:

6-carboxy fluorescein. Most commonly used reporter dye at the 5' end of a TaqMan® probe.

Familial:

An inherited trait.

Facultative Heterochromatin:

It describes the inert state of sequences that also exist in active copies.

Fast PCR:

A modified PCR protocol that allows shortening of overall reaction time to less than the typical 90 minutes (usually 40 minutes or less) thanks to recent developments in amplicon design, reagent chemistry, thermocycling conditions as well as the PCR machines with fast ramping rates.

FISH (Fluorescence in Situ Hybridization):

A physical mapping approach that uses fluorescein tags to detect hybridization of probes with metaphase chromosomes and with the less- condensed somatic interphase chromatin.

Flow Cytometry:

Analysis of biological material by detection of the light- absorbing or fluorescing properties of cells or subcellular fractions passing in a narrow stream through a laser beam. An absorbance or fluorescence profile of the sample is produced. Automated sorting devices, used to fractionate samples, sort successive droplets of the analyzed stream into different fractions depending on the fluorescence emitted by each droplet.

Flow Karyotyping:

Use of flow cytometry to analyze or separate chromosomes on the basis of their DNA content.

Fluorescence Resonance Energy Transfer (FRET):

The interaction between the electronic excited states of two dye molecules. The excitation is transferred from one (the donor) dye molecule to the other (the acceptor) dye molecule. FRET is distance-dependent and occurs when the donor and the acceptor dye are in close proximity.

Footprinting:

A technique by which one identifies a protein binding site on cellular DNA. The presence of a bound protein prevents DNase from "nicking" that region, which can be detected by an appropriately designed gel.

Forward Mutations:

It is to inactivate a wild type gene.

Frame-Shift:

A change from one reading frame to another.

Frameshift Mutation:

A mutation (deletion or insertion, never a simple substitution) of one or more nucleotides but never a multiple of 3 nucleotides, which shortens or lengthens a trinucleotide sequence representing a codon; the result is a shift from one reading frame to another reading frame. The amino acid sequence of the protein downstream of the mutation is completely altered, and may even be much shorter or longer due to a change in the location of the first termination (stop) codon:

Asn Tyr Thr Asn Leu Gly His Wild-type polypeptide

AAU UAC ACA AAU UUA GGG CAU mRNA

Asn Thr Gln Ile STOP Mutant polypeptide
Deletion of A from mRNA creates frame-shift mutant

Fusion Protein:

A product of recombinant DNA in which the foreign gene product is juxtaposed ("fused") to either the carboxyl-terminal or amino-terminal portion of a polypeptide encoded by the vector itself. Use of fusion proteins often facilitates expression of otherwise lethal products and the purification of recombinant proteins.