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NCI Dictionary of Genetics Terms


8 results found for: T



  • tagging SNP  listen  (TA-ging snip)
    A single nucleotide polymorphism, or SNP, that is used to “tag” a particular haplotype in a region of the genome. As a subset of all of the SNPs in the genome, tagging SNPs can be extremely useful for testing the association of a marker locus with a qualitative or quantitative trait locus in that it may not be necessary to genotype all of the SNPs. Also called tagSNP.

  • tagSNP  listen  (tag-snip)
    A single nucleotide polymorphism, or SNP, that is used to “tag” a particular haplotype in a region of the genome. As a subset of all of the SNPs in the genome, tagSNPs can be extremely useful for testing the association of a marker locus with a qualitative or quantitative trait locus in that it may not be necessary to genotype all of the SNPs. Also called tagging SNP.

  • transcription  listen  (tran-SKRIP-shun)
    The process of synthesizing messenger RNA (mRNA) from DNA.

  • translation  listen  (trans-LAY-shun)
    The process of synthesizing an amino acid sequence (protein product) from the messenger RNA code.

  • translocation  listen  (TRANZ-loh-KAY-shun)
    A type of chromosomal abnormality in which a chromosome breaks and a portion of it reattaches to a different chromosomal location.

  • trinucleotide repeat  listen  (try-NOO-klee-oh-tide reh-PEET)
    Sequences of 3 nucleotides repeated in tandem on the same contiguous section of chromosome. A certain amount of normal (polymorphic) variation in repeat number with no clinical significance commonly occurs between individuals; however, repeat numbers over a certain threshold can, in some cases, lead to adverse effects on the function of the gene, resulting in genetic disease.

  • triple-negative breast cancer  listen  (TRIH-pul-NEH-guh-tiv brest KAN-ser)
    Triple-negative breast cancer is defined by a lack of expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu). Also called ER-negative PR-negative HER2/neu-negative breast cancer.

  • trisomy  listen  (TRY-soh-mee)
    The presence of an extra chromosome, resulting in a total of three copies of that chromosome instead of the normal 2 copies (e.g., trisomy 21, or Down syndrome).