Genomics Glossary

Browse through our genomics glossary of terms

  • ‘omics
    ‘omics is a suffix that refers to the analysis of all the molecules of one type in a cell or tissue. For example, genomics (investigation of all the DNA molecules in a cell), transcriptomics (all RNA molecules), proteomics (all proteins).
  • Adenine
    A. One of the nucleotides that comprises DNA and RNA, of the purine class
  • Allele
    An alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome.
  • Amino acid
    The monomeric unit of protein. There are 20 different amino acids.
  • Analytical validity
    Refers to how well the test predicts the presence or absence of a particular DNA sequence, which could be a gene or a genetic change.
  • Association (genotype / phenotype)
    The occurrence of a certain genotype in individuals with a specific trait, at a frequency higher than would be expected by random chance.
  • Bioinformatician
    A person who uses data algorithms and specialised software to analyse biological data, such as DNA or RNA sequences.
  • Bioinformatics
    The use of algorithms and software to analyse biological data.
  • Biomolecule
    Any organic molecule produced by a living organism.
  • Carrier
    A person possessing a mutation associated with a disease or condition, who does not show symptoms but can pass it on to their children.
  • Chromosome
    The threadlike structure of DNA and associated proteins to keep the DNA strand tightly supercoiled. Transmits genetic information in cell division. Humans have 23 pairs of chromosomes (46 individuals), two of each numbered 1 to 22, then two sex chromosomes (XX in females and XY in males).
  • Clinical Geneticist
    Doctors who have undergone speciality training in genetics after general professional training (such as paediatrics and oncology) and see referred patients for diagnosis, management, genetic testing and genetic counselling.
  • Clinical genetics
    The medical specialty which provides a diagnostic service and “genetic counselling” for individuals or families with, or at risk of, conditions which may have a genetic basis.
  • Clinical utility
    The usefulness of the genomic test to the patient (i.e. to what extent does it influence the effectiveness of the proposed intervention or clinical decision making).
  • Clinical validity
    How well the genetic variant being analysed is related to the presence, absence, or risk of a specific disease.
  • Coding sequence
    DNA sequence that encodes functional RNA molecules; a gene.
  • Codon
    A three-nucleotide sequence in a gene that encodes an amino acid.
  • Cytosine
    C. One of the nucleotides that comprises DNA and RNA, of the pyrimidine class.
  • Deoxyribose
    The five carbon sugar backbone of DNA; it is a modified form of ribose lacking one oxygen.
  • DNA or deoxyribonucleic acid
    A polymer of nucleotides, of which there are four: A, C, G and T. The substance which encodes the information for which proteins are expressed, and when; and which is inherited by our children. Collectively referred to as the ‘genome’.
  • Encode
    to store information in sequence, as in the DNA code
  • Endobronchial ultrasound-guided transbronchial needle aspiration
    Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) is a procedure which uses a special kind of telescope to see inside the airways. It also uses ultrasound to allow doctors to take samples of tissue just outside the lungs.
  • Endogenous
    having an internal cause or origin
  • Exogenous
    of, relating to, or developing from external influences
  • Exome
    Part of the genome formed by exons, the sequences that when when transcribed, remain within the mature RNA after introns are removed by RNA splicing.
  • Exon
    the coding DNA sequence of a gene, interrupted by introns. After introns are excised from the mRNA in post-translational processing, the exons are translated into protein
  • Expression (of genes)
    the process by which genes encoded by DNA are read to produce RNA, which is then used to produce a protein in the sequence determined by the original DNA code
  • Gene
    A span of DNA that is the basic unit of inheritance; encodes a protein and has surrounding sequence to regulate the expression of this protein.
  • Genetic counsellor
    Healthcare professionals who have undergone speciality training to help individuals, couples and families understand and adapt to the medical, psychological, familial and reproductive implications of the genetic contribution to specific health conditions.
  • Genetic pathologist
    Pathologists who have undergone speciality training in genetics and genomics who provide specialist input to genomic tests including test selection, results and interpretation to aid in the diagnosis, management and treatment of patients with a genetic basis for their disease.
  • Genetic test
    A type of medical test that identifies changes in chromosomes, genes, or proteins.
  • Genetics
    The study of single genes – their structure, function and involvement in heredity.
  • Genome
    The set of genes within an organism.
  • Genomic data
    The data produced from DNA sequencing of a genome. It can be compared with a reference genome.
  • Genomic knowledge
    Includes information about the interpretation of genomic data and the implications of these findings, as well as relevant non-genomic clinical information.
  • Genomic Medicine
    The medical discipline applying genomic information to clinical care.
  • Genomic services
    Whole genome sequencing and analysis available for research, screening, and diagnostic purposes.
  • Genomic testing
    Is the analysis of hundreds or even thousands of genes from a cell or tissue simultaneously using sophisticated computer-based algorithms.
  • Genomics
    The application of genome-based knowledge through the study of genes and other genetic information, their functions and inter-relationships for the benefit of human health.
  • Genotype
    The genetic characteristics of an organism.
  • Germline cell
    The reproductive cells in multicellular organisms.
  • Guanine
    G. One of the nucleotides that comprises DNA and RNA, of the purine class.
  • Holistic
    consideration of the parts of something as interconnected, explicable only by reference to the whole
  • Intron
    a non-coding DNA sequence between exons in a gene which are excised from the mRNA after transcription and before protein is translated
  • Massively Parallel Sequencing
    or ‘next generation sequencing’; a range of technologies developed in the 1990s allowing simultaneous sequencing analysis of millions of DNA fragments in a specimen or organism
  • Metadata
    A set of data that describes and gives information about other data.
  • Molecular analysis
    genetic testing
  • Mutation
    a change to the DNA sequence or chromosome causing damage to the cell or organism
  • Non-coding sequence
    DNA sequence that does not encode functional RNA molecules. About 80 to 90 per cent of a genome
  • Nucleic acid
    One of the four biomolecules, made up of monomeric nucleotides and forming deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
  • Nucleotide
    the basic monomeric unit of nucleic acids (DNA or RNA), called ‘bases’: adenine (A), guanine (G), thymine (T) cytosine (C). RNA has uracil (U) in place of thymine (T)
  • Pharmacogenetics
    The study of how the actions of, and reactions to, medicines vary with the patient’s genes.
  • Phenotype
    observable characteristics of an organism
  • Polygenic
    pertaining to or determined by several different genes
  • Polymorphism (or SNP, see below)
    a change to the DNA sequence that does not have a harmful effect on the cell or organism
  • Precision (of tests)
    the degree of similarity between the results of repeat tests on the same sample
  • Predisposition
    a latent susceptibility to a phenotype that may be activated under certain conditions
  • Pre-symptomatic
    a person who has a mutation for a condition which has onset later in life
  • Prospective study
    investigators design the study, recruit subjects and collect baseline data before intervention (eg genomic testing) is started, then follows patients through the course of the study (compare to retrospective study)
  • Replication (of DNA)
    when DNA is copied before a cell divides to produce an identical copy of the first
  • Retrospective study
    investigators design the study, select subjects for collection and interrogation of data from the past (compare to prospective study).
  • RNA
    Ribonucleic Acid: a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA to initiate and control the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.
  • Selective advantage
    a reproductive advantage of an organism in their environment, caused by random beneficial genetic changes
  • Sensitivity (of tests)
    the detection limit of the test
  • SNP (or single nucleotide polymorphism)
    a change to the DNA sequence that does not have harmful effect on the cell or organism
  • Somatic cell
    All body cells of an organism – apart from the sperm and egg cells, the cells from which they arise (gametocytes) and undifferentiated stem cells – are somatic cells. Examples of somatic cells are cells of internal organs, skin, bones, blood and connective tissues. In comparison, the somatic cells contain a full set of chromosomes whereas the reproductive cells contain only half.
  • Specificity (of tests)
    the degree to which the test measures the analyte of interest, and is not confounded by other chemicals in the sample
  • Splicing
    Process by which the DNA of an organism is cut and a gene, perhaps from another organism, is inserted.
  • Symptomatic
    a person showing signs of a particular disease or condition
  • Systemic
    relating to a system, as opposed to a particular part
  • Thymine
    T. One of the nucleotides that comprises DNA and RNA, of the pyrimidine class
  • Transcription (of DNA)
    when the DNA molecule is ‘read’ by specialised enzymes to produce RNA molecules
  • Transcriptome
    The sum total of all the messenger RNA molecules expressed from the genes of an organism.
  • Translation
    the process by which RNA molecules are ‘read’ by specialised enzymes to determine the sequence of amino acids linked into proteins
  • Whole Exome Sequencing (WES)
    the simultaneous sequencing and analysis of the entire coding / exonic sequence of a specimen or organism
  • Whole Genome Sequencing (WGS)
    the simultaneous sequencing and analysis of the entire genome sequence of a specimen or organism