Glosario de IVD y diagnóstico molecular

Acetylation involves the covalent linkage of an acetyl group into an organic molecule.

The adhesion of a gas, liquid or dissolved solid chemical of interest onto a solid surface.

The strength of noncovalent chemical binding between two substances as measured by the dissociation constant of the complex.

Mutually exclusive alternative forms of the same gene occupying the same locus on homologous chromosomes, differing in nucleotide sequence and governing the same biochemical and developmental process.

Alternate Splicing is a process in which multiple protein isoforms or products are generated from a single gene as a result of splicing together different nonconsecutive exons during the processing of initially identical nascent transcripts of a gene into mature mRNA transcripts. An exon may be connected to any one of several alternative exons to form the mRNA and generate related proteins, often in a tissue or developmental stage specific manner.

A type of protein made by B lymphocytes in response to a foreign substance (antigen). Each antibody only binds to a specific antigen, helping to destroy the antigen directly or by assisting white blood cells to destroy the antigen.

Any substance, generally a protein, that stimulates the immune system and elicits an immune response. Recognition by the immune system elicits either a T-lymphocyte response, recognizing processed antigens, or a B-lymphocyte response, producing antibodies that bind to unprocessed antigens.

A chromosome not involved in sex determination. The diploid human genome consists of a total of 46 chromosomes which includes 22 pairs of autosomes.

Strength of binding, usually of a small molecule with multiple binding sites by a larger, particularly the binding of a complex antigen by an antibody.

Initiation of DNA base excision repair (BER) involves a DNA glycosylase that binds the altered deoxynucleoside in an extrahelical position and catalyzes cleavage of the base-sugar bond. Subsequently, an AP endonuclease or AP lyase activity incises the abasic site, followed by short-patch gap-filling, excision of the base-free sugar-phosphate residue, and ligation.

The paired nucleotides in a DNA or RNA sequence.

A storage facility of biospecimens that includes tissue samples, fluids, and molecular derivatives such as DNA, RNA, and proteins. The biorepository has stringent guidelines regarding the standardized collection, handling, storage, and documentation of biological specimens.

An ionic compound that resists changes in its pH.

Enzymatic (e.g. dUTP/UNG) and physical measures that stop amplified DNA from contaminating later runs. Labs with high daily volumes usually require dUTP/UNG chemistry in purchased assays; confirm this when comparing kits from different manufacturers.

Single-stranded DNA that is complementary to messenger RNA or DNA that has been synthesized from messenger RNA by reverse transcriptase.

A machine that uses centrifugal force to separate heavier substances from lighter ones, for removing moisture, or for simulating gravitational effects.

The nonstaining primary constriction of a chromosome which is the point of attachment of the spindle fiber; provides the mechanism of chromosome movement during cell division; the centromere divides the chromosome into two arms, and its position is constant for a specific chromosome: near one end (acrocentric), near the center (metacentric), or between (submetacentric).

The genetic material of the nucleus, consisting of deoxyribonucleoprotein, which occurs in two forms during the phase between mitotic divisions: 1) as heterochromatin, seen as condensed, readily stainable clumps; 2) as euchromatin, dispersed lightly staining or nonstaining material. During mitotic division the chromatin condenses into chromosomes.

A structure found in cells that is comprised of a strand of linearized double-stranded DNA plus proteins that package the DNA in a condensed coil form and regulate chromosomal function.

A sequence of single-stranded RNA that forms a covalently closed continuous loop.

Neoplasm-derived DNA fragments found in the bloodstream or other bodily fluids that have been released from cells.

A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid.

A sequence pattern derived from the alignment of multiple sequences that represents the nucleotide or amino acid most likely to occur at each position in a sequence.

Variation in the number of copies of a particular sequence within the genetic material of an individual. Large-scale copy number polymorphisms are common and widely distributed in the human genome.

Preservation of cells, tissues, organs, or embryos by storage at low temperatures.

A substance that is used to protect from the effects of freezing, largely by preventing large ice crystals from forming.

Elimination, especially by blotting out, cutting out, or erasing.

A nucleotide comprised of either a purine or pyrimidine nitrogenous base bound to a deoxyribose sugar esterified with three phosphate groups. These molecules are essential for DNA synthesis.

A DNA sequencing technique in which a mixture of deoxynucleosidetriphosphates (dNTPs) and chain-terminating dNTPs, which are radioactively or fluorescently labeled, are combined within the reaction mixture. Once the reaction is complete, the DNA strands are separated by size, and the labeled chain terminating dNTPs can be read in sequence by the investigator or by a machine.

A PCR format that partitions each sample into thousands of sub-reactions and calls each partition positive or negative, giving absolute quantification without a standard curve. Useful for low-level targets, copy-number work, and reference material characterization; throughput and per-test cost differ from qPCR.

A type of polymerase chain reaction technique in which the sample is fractionated, within which individual PCR reactions occur in each fraction.

Any liquid or solid material used to lessen the strength or flavor of a solution or mixture of another ingredient.

To reduce in strength or concentration, especially by the addition of water.

A long linear double-stranded polymer formed from nucleotides attached to a deoxyribose backbone and found in the nucleus of a cell; associated with the transmission of genetic information.

Drug-, radiation-induced, or spontaneous injuries to DNA that introduce deviations from its normal double-helical conformation. These changes include structural distortions that interfere with replication and transcription, as well as point mutations that disrupt base pairs and exert damaging effects on future generations through changes in DNA sequence. If the damage is minor, it can often be repaired (DNA repair); extensive damage can induce apoptosis.

A family of enzymes that catalyze the formation of phosphodiester bonds to repair broken strands of DNA.

Enzymatic restoration of DNA structure after chemical, radiation, or spontaneous damage.

An RNA complex consisting of two complementary base-paired strands of RNA.

A 50-150bp DNA sequence that increases the rate of transcription of coding sequences. It may be located at various distances and in either orientation upstream from, downstream from or within a structural gene. When bound by a specific transcription factor it increases the levels of expression of the gene, but is not sufficient alone to cause expression. Distinguished from a promoter, that is alone sufficient to cause expression of the gene when bound.

Changes in the regulation of the expression of gene activity without alteration of genetic structure.

The complete set of epigenetic modifications on the genome of a cell.

The simplest form of an antigenic determinant, on a complex antigenic molecule, which can combine with antibody or T cell receptor.

The sequences of a gene that are present in the final, mature, spliced messenger RNA molecule from that gene.

An Exonuclease is a hydrolase (nuclease) that specifically catalyzes the hydrolysis of terminal phosphodiester bonds of deoxyribonucleotide or ribonucleotide chains, releasing mononucleotides.

A text-based format for storing a biological sequence that encodes the nucleotide calls as well as their quality scores. It is an extension of the FASTA format.

The chemical preservation of a substance to maintain structural and/or molecular features of that substance as they exist in the living entity.

A compound that preserves tissues and cells for microscopic study.

Fluorescence is a luminescence (i.e., optical phenomenon) in cold bodies, in which a molecule absorbs a high-energy photon, and re-emits it as a lower-energy (longer-wavelength) photon. The energy difference between the absorbed and emitted photons ends up as molecular vibrations (heat).

A class of dyes when excited by light of certain wavelengths, emit photons and become fluorescent. Fluorescence gives fluorochromes imaging characteristics and are used to label or stain biological structures.

Refers to a process where a sample is preserved with formalin and then embedded into a paraffin block for sectioning.

A mutation occurring within the protein-coding region of a gene which results in a shift in the reading frame of the encoded protein. Frameshift mutations often result in the premature truncation of a gene product.

Tissue that is not frozen or embedded in preservatives

A tissue sample that has been frozen prior to analysis.

Any DNA sequence rearrangement that results in the gain of one or more copies of a DNA segment that contains at least one gene.

A deletion that results in the loss of a DNA segment encompassing an entire gene sequence.

Typically involves transcription of genetically encoded information into an intermediary message (messenger RNA) and subsequent translation into a functional protein.

Any hybrid gene formed from two previously separate genes. Such fusions occur as a result of translocation, intersititial deletion or chromosomal inversion, and often result in gene products with functions different from the two fusion partners. Gene fusions are associated frequently with hematological cancers, sarcomas and prostate cancer.

Genetic Variation consists of deviation(s) in the nucleotide sequence of the genetic material of an individual from that typical of the group to which the individual belongs, or deviation(s) in the nucleotide sequence of the genetic material of offspring from that of its parents.

The complete genomic content of an organism, and possibly the full DNA sequence of that organism. It is contained in a set of chromosomes in eukaryotes, a single chromosome in bacteria, or a DNA or RNA molecule in viruses.

The determination of the DNA sequence of an individual.

Any mutation that appears in the gametes and which will therefore be transmitted to the progeny with some frequency.

The covalent chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, by glycosyl transferases.

A way of denoting the collective genotype of a number of closely linked loci on a chromosome.

Having two different allelic forms of a gene, one inherited from each parent, on each of the two homologous chromosomes.

Placeholder definition before migration.

Major protein component of chromatin. Highly conserved basic proteins, originally classified into classes based on the relative amounts of arginine and lysine in each protein. The various classes are now termed H1, H2A, H2B, H3, and H4. In chromatin, they are found in an octamer, containing two each of H2A, H2B, H3, and H4, complexed with DNA in nucleosomes. The histones in the octamer complex are also known as the core histones. The H1 class of histones, termed the linker histones, is loosely associated with the nucleosome.

The process of exchange of genetic material between autonomous replicons, which depends on regions of extensive sequence homology between the participating DNA strands. This process involves double-strand breakage of one participant, resection of the break, and strand invasion, followed by formation, displacement and resolution of the Holliday junction. This process is involved in repairing broken DNA and creating combinations of genes that may be unique from the parent duplexes. Disruptions in this process can result in inviability, premature aging and predisposition to cancers and degenerative diseases.

Having two identical allelic forms of a gene, one inherited from each parent, on each of the two homologous chromosomes.

The X or Y chromosome in human beings that determines the sex of an individual. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome. The sex chromosomes comprise the 23rd chromosome pair in a human karyotype.

A mutation class that includes insertion mutations, deletion mutations and mutation events where both an insertion and a deletion has occurred.

A non-target amplification built into a reaction to prove the assay chemistry worked even when the sample is negative. It helps distinguish a true negative from inhibition or setup failure, which matters when interpreting single-target assays on difficult matrices.

Non-coding, intervening sequences of DNA that are transcribed, but are removed from within the primary gene transcript and rapidly degraded during maturation of messenger RNA.

The act of turning inside out, upside down, or end-for-end.

The weighted concentration of ions in solutions.

The chromosomal morphology and number in somatic cells of an individual.

Major class of enzymes that catalyze the linking together of two molecules (EC class 6) for example DNA ligases that link two fragments of DNA by forming a phosphodiester bond.

A molecule of RNA 200-17000 nucleotides in length that is transcribed by non-protein coding areas of DNA. These ribonucleotides may play a role in a variety of biological processes.

A genetic variation where gain, loss, or exchange of DNA results in monoallelic loss of function mutations in a diploid cell. In the context of tumor suppressor genes, where a single copy is sufficient for functionality, loss of function for the second allele is associated with tumorigenesis.

A class of RNA molecule containing protein-coding information in its nucleotide sequence that can be translated into the amino acid sequence of a protein.

The quantity and identity of all of the low molecular weight molecules in a biological entity or sample that are products of or participants in various metabolic processes.

Metabolomics is the study of the biological metabolic profile of a cellular specimen in a specific environment at an isolated timepoint. This discipline depicts the physiological states of cells and organisms by focusing on carbohydrates, lipids, and other metabolites. Several analytical techniques are utilized to quantify the metabolic content of specimens such as mass spectrometry and electrophoretic applications.

The covalent chemical or biochemical addition of a methyl group(s) to a compound. (NCI)

A sequence of single-stranded RNA, that is 20-25 nucleotides in length, which is transcribed from DNA but is not translated into a protein. This nucleic acid may regulate the transcription or translation of other genes.

Genomic instability associated with the presence of hypermutability in specific genetic marker regions resulting from defective DNA mismatch repair.

A variety of simple di-, tri-, tetra-, and pentanucleotide tandem repeats that are dispersed in the euchromatic arms of most chromosomes.

The mismatch repair (MMR) system promotes genomic fidelity by repairing base-base mismatches, insertion-deletion loops and heterologies generated during DNA replication and recombination. This function is critically dependent on the assembly of multimeric complexes involved in mismatch recognition and signal transduction to downstream repair events.

A point mutation occurring within the protein-coding region of a gene, and which codes for a different amino acid than expected.

Amplification of several targets in a single reaction using multiple primer pairs, each distinguishable by fluorescent channel or melting profile. Multiplexing raises information per sample but makes channel allocation, dye compatibility, and competition between targets key selection criteria.

Any transmissible change in the genetic material of an organism, which can result from radiation, viral infection, transposition, treatment with mutagenic chemicals and errors during DNA replication or meiosis. The effects of mutation range from single base changes to loss or gain of complete chromosomes. As many of the simpler alterations to DNA may be repaired, such changes are only heritable once the change is fixed in the DNA by the process of replication. Mutations may be associated with genetic diversity or with pathologies including cancer.

A control sample where a negative result is expected, to help correlate a positive result with the variable being tested.

Polymerase chain reaction that uses two sets of primers, in two sequential runs of amplification, with the second set intended to amplify a target within the first run product.

Technologies that facilitate the rapid determination of the nucleotide sequence of large numbers of strands or segments of DNA or RNA.

A point mutation occurring within the protein-coding region of a gene, and which codes for a stop that can truncate the protein.

A reaction that contains all reagents except sample nucleic acid. Amplification in the NTC signals contamination of reagents or the environment, so NTC behavior is one of the first run-validity checks in any qPCR run log.

Any of various amplification and detection strategies applied to detection of virus contamination in donor blood. Specifically designed to detect recently infected individuals during the latency period before seroconversion.

Laboratory procedure in which single stranded nucleic acids are allowed to interact so that complexes, or hybrids, are formed by molecules with sufficiently similar, complementary sequences. By this means the degree of sequence identity can be assessed and specific sequences detected. (From Biology-online)

A subunit of DNA or RNA consisting of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA).

Nucleotide Excision Repair (NER) mends DNA regions that contain chemical adducts, such as UV-induced thymine dimers or carcinogenic adducts, which distort the DNA helix and interfere with replication and transcription. NER is targeted to actively transcribed regions of the genome. During NER in eukaryotes, shape irregularities are detected by protein complexes that slide along the DNA molecule and induce cuts on each side of a lesion several nucleotides away. Removal of the damaged 25-30 nucleotide fragment is followed by repair synthesis and ligation.

A DNA polymer made up of a small number of nucleotides.

Short DNA oligonucleotide chains used to prime DNA (and in some cases RNA) synthesis.

A sequence of nucleotides in that contains no termination codons and so can potentially translate as a polypeptide chain.

The concentration of osmoles of solute per kilogram of solvent present in a sample.

Quantity of dimension one used to express on a scale from 0 to 14 the amount-of-substance concentration of hydrogen ion of dilute aqueous solution, calculated as the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter.

The assemblage of traits or outward appearance of an individual. It is the product of interactions between genes and between genes and the environment.

A score reported on a logarithmic scale representing the probability that a nucleotide base was incorrectly called by the base caller.

A small-scale mutation in which a single nucleotide is exchanged for another. Mutagenic chemicals and mistakes in DNA replication may result in point mutations.

Encoded by Polymerase Genes, Polymerase enzymes catalyze polymerization reactions, especially of nucleotides to polynucleotides. (NCI)

A control sample that is known to produce a positive result if the test is working as expected.

The enzymatic processing of a polypeptide chain after translation from messenger RNA and after peptide bond formation has occurred. Examples include glycosylation, acylation, limited proteolysis, phosphorylation, isoprenylation.

Chemicals that are added to drug products to prolong shelf life and maintain sterility. Protection of formulations, especially aqueous solutions, against microbial growth requires use of either antibacterial or antifungal preservatives. Generally, such agents are active against either bacteria or fungi but a few are active against both. The antimicrobials include but not limited to chlorobutanol, benzyl alcohol, sodium benzoate, sorbic acid, and phenol. The antioxidizing agents include butylated hydroxytoluene, hydroxyanisole, propyl gallate, and sulfites. The necessary addition of preservatives for both safety and economy sometimes has been associated with significant adverse effects in certain patient populations.

General term for a piece of DNA or RNA corresponding to a gene or sequence of interest, that has been labelled either radioactively or with some other detectable molecule, such as biotin, digoxygenin or fluorescein. As stretches of DNA or RNA with complementary sequences will hybridize, a probe will label viral plaques, bacterial colonies or bands on a gel that contain the gene of interest.

A DNA sequence at which RNA polymerase binds and initiates transcription.

Refers to the total protein-encoding capability of an organism's genome. It is also used to refer to the actual total expressed protein complement of an organism or to the identifiable proteins of a single tissue or cell type or subcellular compartment.

The global analysis of cellular proteins. Proteomics uses a combination of sophisticated techniques including two-dimensional (2D) gel electrophoresis, image analysis, mass spectrometry, amino acid sequencing, and bio-informatics to resolve comprehensively, to quantify, and to characterize proteins. The application of proteomics provides major opportunities to elucidate disease mechanisms and to identify new diagnostic markers and therapeutic targets.

Nonfunctional DNA sequences that are very similar to the sequences of known genes. Many seem to have arisen as functional gene duplications that subsequently underwent mutation and loss of function. Others are structurally similar to mRNA and seem to have arisen by a reverse transcription event followed by integration into the genome. Some pseudogenes are transcribed and may play a role in regulation of its homologous gene.

The number of times a particular locus (site, nucleotide, amplicon, region) was sequenced.

One of the three possible ways of reading a nucleotide sequence. As the genetic code is read in nonoverlapping triplets (codons) there are three possible ways of translating a sequence of nucleotides into a protein, each with a different starting point.

The number of nucleotides successfully ordered from each side of a nucleic acid fragment obtained after the completion of a sequencing process.

Any natural or synthetic substance used in a chemical or biological reaction in order to produce, identify, or measure another substance.

An application of PCR that measures the products generated during each cycle of the polymerase chain reaction process in order to determine the starting amount of template in the reaction.

A PCR method that measures amplification as it happens using fluorescent reporters, so target quantity is estimated from the amplification curve rather than by post-run handling. qPCR is the workhorse format for viral load, pathogen detection, and GMO or food testing workflows.

Enzymes that exhibit endonuclease activity at a specific short nucleotide sequence to cleave strands of DNA.

A sequence in DNA that can be recognized by a specific restriction enzyme.

An RNA-dependent DNA polymerase that is involved in the replication of retroviruses an in the maintenance of telomeres.

A two-step setup in which RNA is first copied into complementary DNA by a reverse transcriptase and then amplified by PCR. Used for RNA viruses such as influenza, RSV, SARS-CoV-2, and HCV. In procurement documents, confirm whether "RT-PCR" refers to real-time (quantitative) or endpoint (qualitative) reading.

The action of copying RNA into DNA by reverse transcriptase.

Ribonuclease inhibitor (461 aa, ~50 kDa) is encoded by the human RNH1 gene. This protein plays a role in the inhibition of ribonucleases.

Single-stranded long chain of nucleotides containing ribose. It is the end product of DNA transcription by the enzyme RNA polymerase. It is essential in protein synthesis.

An RNA molecule that does not contain protein-coding sequence information and constitutes the majority of the cellular RNA (~80%). This nucleic acid associates with multiple proteins to form ribosomes, which are the organelles that drive mRNA-directed protein synthesis.

Removal of introns from mRNA precursors and the reattachment or annealing of exons.

The act or process of settling particles by mechanical means from a state of suspension in air or water.

A collection of double stranded DNA fragments flanked by oligonucleotide sequence adapters to enable their analysis by high-throughput sequencing.

Area of repetitive DNA within the genome consisting of multiple, end-to-end copies of a short DNA sequence usually comprised of di-, tri-, or tetranucleotide repeat units.

A point mutation occurring within the protein-coding region of a gene, and which codes for the same amino acid as expected.

A variation of a single nucleotide at a specific location of the genome due to base substitution, present at an appreciable frequency between individuals of a single interbreeding population.

A variation of a single nucleotide at a specific location of the genome due to base substitution, which is found at any frequency in the population.

A long linear single-stranded polymer formed from nucleotides attached to a deoxyribose backbone.

A 20 to 25-nucleotide double-stranded RNA which is involved in a sequence-specific messenger RNA degradation process known as RNA interference.

The ability of a particular substance to dissolve in a particular solvent (yielding a saturated solution).

A liquid that dissolves or that is capable of dissolving; the component of a solution that is present in greater amount.

Any mutation with an origin in cells that are not destined to become gametes. As a consequence, such mutations are not transmitted to progeny, though they will be transmitted during any mitosis within the individual. Somatic mutations may contribute to a broad variety of pathologies including cancer.

Any mutation that occurs within the discrete sequences comprising the 5' or 3' splice sites of a gene that has a spliced message. Splice-site mutation may result in a deletion or insertion of extraneous amino acids in the gene product or a change in the reading frame of the spliced message.

A stretch of repetitive nucleotide sequences (TTAGGG repeats in humans) found at both ends of each chromatid arm that plays a role in chromosome stability during replication.

A genetic process in which single-stranded RNA with base sequence complementary to a region of plus strand DNA is synthesized by DNA-dependent RNA polymerases. Following the binding of RNA polymerase on DNA promoter regions, the RNA product is synthesized in a 5' to 3' direction, elongating RNA along the DNA strand as the polymerase proceeds, accompanied by unwinding and rewinding of the DNA template.

The complete set of RNA transcripts that are produced by the genome, under specific circumstances or in a specific cell.

A class of short adaptor RNAs that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. Each transfer RNA comprises a three-nucleotide sequence that is complementary to the triplet nucleotide coding sequence of an mRNA, conferring specificity to the amino acid being incorporated into the assembling protein.

The act or process of rendering from one language into another.

The movement of a physical object from one place to another. (NCI)

A relatively less common point mutation in which a purine is exchanged for a pyrimidine or a pyrimidine is exchanged for a purine.

Ubiquitin is a family of widely distributed proteins found in all eukaryotes that contain a highly conserved sequence of 76 amino acids identical in organisms from humans to insects. It participates in diverse cellular functions by conjugation to other proteins through its carboxy terminus. Ubiquitination is associated with many highly regulated biological events including protein degradation, chromatin remodelling, heat shock, cell cycle progression, differentiation, antigen presentation, retrovirus assembly, apoptosis, signal transduction, transcriptional activation, biological clocks, receptor down regulation, and endocytosis. Protein ubiquitination regulates the half-lives of many proteins by targeting them for degradation. Newly discovered families of ubiquitination and deubiquitination enzymes participate in these processes. Ubiquitination enzymes may provide new therapeutic targets and ways of intervention in many human diseases.

Short random nucleotide sequences that are ligated to each primer molecule during amplification of a nucleotide sample during library preparation to act as a unique tag. Their use helps to identify PCR duplicates in sequencing data.

The product of so-called RNA genes; a functional RNA represents the final product of a gene rather than a transient molecule that will be translated into protein.

The relative rate of occurrence of a specific variant allele compared to the total number of alleles at that locus in the sample. This measurement may be reported as a ratio or percentage.

An alteration or difference from a norm or standard.

A procedure that can determine the DNA sequence for nearly the entire genome of an individual.