- The succession, or following, of one thing or event after another. [L. sequor, to follow]- Alu sequences in the human genome a repeated, relatively conserved s. of about 300 bp that often contains a cleavage site for the restriction enzyme AluI near the center; about 1 million copies in the human genome.- insertion s. discrete DNA sequences of nucleotides that are repeated at various sites on bacterial chromosomes, certain plasmids, and bacteriophages and that can move from one site to another on the chromosome, to another plasmid in the same bacterium, or to a bacteriophage.- intervening s. SYN: intron.- s. ladder The array of bands, made conspicuous by labeling, when DNA fragmented by endonucleases is subject to gel electrophoresis; corresponds to the nucleotide s..- leader sequences sequences at the end of either nucleic acid s (DNA and RNA) or proteins that must be processed off to allow for a specific function of the mature molecule.- long terminal repeat sequences (LTR) regions of the RNA genome associated with regulation, integration, and expression of retroviruses.- pulse s. in magnetic resonance imaging, a series of changes in the induced magnetic field, which include the phase and frequency-encoding gradients and read-out functions.- regulatory s. any DNA s. that is responsible for the regulation of gene expression, such as promoters and operators.- Shine-Dalgarno s. a purine-rich, untranslated region of mRNA upstream from the initiation codon in prokaryotes; assists in aligning the mRNA on the ribosome.- twin reversed arterial perfusion s. (TRAP) a circulatory anomaly in monozygotic twins wherein there are placental arterioarterial and venovenous anastomoses and umbilical anomalies, with one fetus being perfused with deoxygenated blood; the recipient fetus develops as an acardiac acephalic, and the pump or donor twin is at risk for cardiac failure.
* * *1) a continuous or connected series specif the exact order of bases in a nucleic acid or of amino acids in a protein2) a consequence, result, or subsequent development (as of a disease)sequence vt, se·quenced; se·quenc·ing to determine the sequence of chemical constituents (as amino acid residues in a protein or bases in a strand of DNA) in <sequenced the DNA of the entire genome of an organism>
* * *se·quence (seґkwəns) [L. sequi to follow] 1. a connected series of events or things. 2. in dysmorphology, a pattern of multiple anomalies derived from a single known or presumed prior anomaly or mechanical factor. Called also anomalad and complex. 3. the order of arrangement of residues or constituents in a biological polymer, as the order of nucleotides in DNA or RNA, or of amino acids in a protein. 4. a specific fragment or segment of a biological polymer, with a known arrangement of its residues. 5. to ascertain the order of the residues of a biological polymer.
Medical dictionary. 2011.