DNA Test Glossary

Genetic testing terms and their meanings

Confused by genetic testing terminology? Below you’ll find explanations of some of the most common terms associated with DNA tests. Of course, if there’s anything you don’t understand, our staff will be happy to talk it through with you – just contact us.

Autosome Any human chromosomes that are not the X and Y sex chromosomes.
Cell The ‘building blocks’ that all living things are made from. We extract DNA for testing from the nucleus of a cell.
Chromosomes Structures made up of DNA and protein that are found in the nucleus of a cell. Chromosomes contain the genetic information of the parent that is passed on to offspring.
Collection centre Laboratories or clinics authorised by DNA Diagnostics to collect samples for DNA testing.
DNA Deoxyribonucleic acid, or DNA, is the ‘blueprint’ of life. It carries all the genetic information of an individual, and is unique to the individual (except in the case of identical twins).
DNA extraction The process of extracting the DNA used for testing from a sample – usually a blood sample or mouth swab.
DNA profile Also known as a genetic fingerprint, a person’s DNA profile is a record of the DNA markers that make up their unique biological identity.
DNA test The process of analysing DNA to establish the unique DNA profile of the test subject. DNA testing is carried out for many reasons, such as paternity testing, forensic testing and testing for medical conditions.
Dizygotic twins Non-identical twins (also known as fraternal twins) that have developed from two separate zygotes.
Gene The ‘coding’ part of a DNA molecule that is transferred from parent to offspring and determines some characteristic of the offspring.
Genetic testing See DNA test
Maternity The relation of a mother to her children.
Mitochondrial DNA (mtDNA) DNA that is found in an area of the cell called the mitochondria. mtDNA is inherited from the mother, and can therefore be used to determine maternal ancestry.
Molecular genetics The study of genes at a molecular level.
Molecule The smallest particle of a substance that has the chemical and physical properties of that substance.
Monozygotic twins Identical twins that have developed from one zygote, which has split to form two embryos.
Paternity The relation of a father to his children.
Paternity index A measure of the statistical likelihood of paternity versus non-paternity.
Paternity test A test, usually of DNA, to determine whether a man is the biological father of a particular child.
Sex chromosome A chromosome that determines the sex of an organism. In humans, these are the X and Y chromosomes.
STR (short tandem repeat) Short, repeated sequences of DNA. Analysis of these STRs is especially useful for human identification.
X chromosome The female sex chromosome. Human females have two X chromosomes in each cell – designated XX.
Y chromosome The male sex chromosome. Human males have one Y and one X chromosome in each cell – designated XY.
Zygosity The characteristics of a zygote. In the case of twin testing, whether the twins are from a single zygote (identical twins), or two separate zygotes (non-identical twins).
Zygote The cell produced when an egg and a sperm join together. Essentially, a fertilised egg, which develops into an embryo.

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