DNA Testing Glossary: Essential DNA Terms & Clear Definitions

AABB sets standards for DNA testing, ensuring accuracy and reliability in results.

Accreditation signifies the laboratory's adherence to quality and ethical standards.

Admissible refers to evidence or results that are legally acceptable in court.

An affidavit is a sworn statement, often accompanying DNA test results for legal purposes.

The alleged father is the individual identified as the possible biological father.

Allele refers to different forms of a gene inherited from each parent.

Antemortem pertains to events or activities that occurred before death.

At-home tests offer privacy but may lack legal validity. Ideal for personal knowledge.

Sample collected during a postmortem examination.

Autosomal DNA encompasses non-sex chromosomes, providing information about genetic relationships.

The biological father is the genetically related parent.

A method of DNA collection using cheek swabs.

Chain of custody ensures the integrity of DNA samples from collection to analysis.

DNA collected through swabbing the inner cheek for testing.

DNA testing may determine biological parentage in child support cases.

Chromosomes carry genetic information and determine traits.

CPI combines DNA test results to calculate the likelihood of paternity.

Results that meet legal standards for use in court proceedings.

The custodial parent has legal custody of the child.

Custody is a legal term used, most often in a divorce or separation, to describe who will have legal control and responsibility for a minor child. Legal custody may be granted to a single individual or to both parents (called joint or shared custody).

A deceased person.

Twins that are from two separately fertilized eggs. Also called Fraternal twins

Is an interpretation of the test results that the tested relationship does not exist. For example, the tested man is not the biological father of the child.

A biological sibling, parent, or child of an individual.

Fraternal twins, also called dizygotic twins, occur when two separate eggs are fertilized. Fraternal twins may be of the same sex or of two different sexes. Although unusual, it is possible that fraternal twins could have different fathers.

These are tables showing the distribution of different alleles for the same gene. These tables are established for each genetic marker tested that showed the frequency of each allele. They are established for each race and the frequencies are then used to calculate paternity indices.

A gene is the fundamental unit of heredity. It can be a coding gene (one that determines a specific function or physical characteristic) or it can be non-coding. Each gene is located at a specific position (called locus) on a particular chromosome and variations of the same gene are called alleles.

In the context of a paternity test, an alleged father is “included” when he cannot be excluded as the biological father of the child. LabCorp’s paternity results provide a specific probability of inclusion.

Kinship is a connection by blood.

A "legal" test is also called a chain-of-custody or court-ready test. It is completed using DNA samples that have been collected by an unbiased third party with a documented chain of custody.

The plural form of locus.

The singular term for a specific location on a chromosome.

Related through one’s mother.

A test (usually DNA) to determine whether a woman is or is not the biological mother of a child.

Relating to descent through the maternal line.

Also called identical twins, monozygotic twins develop from a single fertilized egg that divides after it is fertilized into two separate embryos. Identical twins have DNA that is exactly the same. They will be of the same sex and will look like each other.

The parent who does not have custody of the child in question.

A non-standard sample is a biological sample used for DNA testing that is not a cheek swab or blood sample.

A parentage test is a biological test performed to determine whether a person is the biological parent of a child.

Related through one’s father.

For an individual locus, this value is a likelihood ratio comparing the chance the tested, mother and alleged father produced the child to the chance the mother and a man selected at random from the population produced the child.

A biological test is performed to determine the probability that a certain man is the biological father of a child.

A biological sample is taken from a person’s body. Pathology samples are often tissue samples.

Relating to descent through the paternal line.

Postmortem means after death. It can also refer to the examination of a deceased individual to determine the cause of death and will often lead to the collection of several biological samples from the deceased.

The ability of a genetic marker system to detect a man who has been falsely accused of paternity.

In the context of paternity testing, a prenatal test is one that is conducted before the birth of a child, using an amniotic fluid sample or piece of the placenta (CVS), from the fetus.

The prior probability can be from 0 to 1. This is a measure of any evidence other than the test. For example, the social evidence surrounding conception. Laboratories routinely use a prior probability of 0.5, which is considered neutral. This means that the weight of the non-test evidence in favor of paternity is equal to the evidence against paternity.

In the context of paternity testing, a random man is a theoretical man, unrelated to the alleged father, to whom the DNA of the alleged father is compared.

A second-degree relative is a grandparent, grandchild, aunt, uncle, niece, or nephew.

A cheek swab sample that is collected by the party to be tested. It is usually obtained in a person’s home.

A test to determine if two or more individuals are biologically related as either full or half-siblings.

STR is an acronym for Short Tandem Repeat. STRs are short sections of DNA that contain a nucleotide sequence that is repeated a number of times in certain sites on specific chromosomes. The number of repeats differs from individual to individual within the population. These sections of DNA are examined in DNA identity testing.

A surrogate mother agrees to become pregnant for the purpose of giving birth to a child for others to raise. She can be the child’s genetic mother or could have been implanted with an egg from another woman and man.

The sex chromosome is associated with female characteristics in mammals. It occurs as a pair in human females and singly in human males.

The sex chromosome is contributed by a father to his son. Y-chromosomes are only found in males.