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NCI Dictionary of Genetics Terms

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10 results found for: F



  • false-positive result  listen  (… PAH-zih-tiv reh-ZULT)
    A test result that indicates an individual is affected and/or has a certain gene mutation when he or she is actually unaffected and/or does not have the mutation; i.e., a positive test result in a truly unaffected or mutation-negative individual.

  • familial  listen  (fuh-MIH-lee-ul)
    A phenotype or trait that occurs with greater frequency in a given family than in the general population; familial traits may have a genetic and/or nongenetic etiology.

  • family history  listen  (FA-mih-lee HIH-stuh-ree)
    The genetic relationships within a family combined with the medical history of individual family members. When represented in diagram form using standardized symbols and terminology, it is usually referred to as a pedigree or family tree. Also called family medical history.

  • family medical history  listen  (FA-mih-lee MEH-dih-kul HIH-stuh-ree)
    The genetic relationships within a family combined with the medical history of individual family members. When represented in diagram form using standardized symbols and terminology, it is usually referred to as a pedigree or family tree. Also called family history.

  • FDR 
    The parents, siblings, or children of an individual. Also called first-degree relative.

  • first-degree relative  listen  (first-deh-GREE REH-luh-tiv)
    The parents, siblings, or children of an individual. Also called FDR.

  • FISH  listen
    A technique used to identify the presence of specific chromosomes or chromosomal regions through hybridization (attachment) of fluorescently-labeled DNA probes to denatured chromosomal DNA. Examination through a microscope under fluorescent lighting detects the presence of the colored hybridized signal (and hence presence of the chromosome material) or absence of the hybridized signal (and hence absence of the chromosome material). Also called fluorescence in situ hybridization.

  • fluorescence in situ hybridization  listen  (floor-EH-sents in SY-too HY-brih-dih-ZAY-shun)
    A technique used to identify the presence of specific chromosomes or chromosomal regions through hybridization (attachment) of fluorescently-labeled DNA probes to denatured chromosomal DNA. Examination through a microscope under fluorescent lighting detects the presence of the colored hybridized signal (and hence presence of the chromosome material) or absence of the hybridized signal (and hence absence of the chromosome material). Also called FISH.

  • founder mutation  listen  (FOWN-der myoo-TAY-shun)
    A gene mutation observed with high frequency in a group that is or was geographically or culturally isolated, in which one or more of the ancestors was a carrier of the mutant gene. This phenomenon is often called a founder effect.

  • frameshift mutation  listen  (FRAYM-shift myoo-TAY-shun)
    An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence. Such mutations usually lead to the creation of a premature termination (stop) codon, and result in a truncated (shorter-than-normal) protein product.