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Orchid utilizes a network of over 5000 collection sites worldwide.
Orchid utilizes a network of over 5000 collection sites worldwide.
Accreditations
Orchid Cellmark holds multiple accreditations from various organizations and adheres to the standards of each accrediting organization. Compliance by our laboratories to these accreditation requirements provides assurance to our clients that test results provided by Orchid Cellmark are of the highest quality. Clink on the links above to learn more about our accreditations.
Orchid Cellmark holds multiple accreditations from various organizations and adheres to the standards of each accrediting organization. Compliance by our laboratories to these accreditation requirements provides assurance to our clients that test results provided by Orchid Cellmark are of the highest quality. Clink on the links above to learn more about our accreditations.
DNA Testing Resources
DNA Glossary
From aaBB to X and Y chromosomes, all the DNA terms you need to know.
Click a letter and maybe you'll learn something new!
A B C D E F G H I K L M N P R S X Y
A
aaBB - (formerly known as American Association of Blood Banks) Accrediting agency for paternity testing.
Accreditation - The recognition by a third party accrediting agency that the company's services consistently conform with the standards set by the accrediting agency.
Admissible - A document or expert testimony is considered to be "admissible" when it is accepted as evidence in a judicial matter.
Affidavit - A sworn statement in writing made especially under oath or on affirmation before an authorized magistrate or officer.
Alleged Father - The man who may be the biological father of a child.
Allele - Any of the variations of a gene that may occur at a given locus.
Antemortem - Preceding death.
At-home Paternity DNA test - A DNA test where biological specimens are collected in a non-clinical setting without the usual Chain of Custody procedures. An at-home test result will not be accepted as proof in legal matters.
Autopsy sample - An autopsy DNA sample is one which is collected by a coroner or medical examiner during the examination of a body after death. Such samples usually consist of a blood sample.
Autosomal DNA - Autosomal DNA is the DNA derived from all of the chromosomes (22 pairs in total) except the sex chromosomes. A routine STR test involves the examination of a small percentage of the total autosomal DNA. The autosomal DNA examined in a DNA paternity test is non-coding i.e. it is not responsible for the generation of any physical characteristics or any physical functions.
B
Biological Father - Sometimes called Birth Father or the Natural Father. The Biological Father contributes 50% of his DNA to the child.
C
Chain of Custody - This term refers to the paper trail showing the collection, possession, control, transfer, analysis and disposition of physical evidence.
Cheek Swab sample - This type of sample is collected using cotton-tipped applicators that are rubbed inside a person’s mouth on the inner lining of the cheek. The samples which are collected are cheek cells, not saliva samples. Also known as a Buccal Swab.
Child Support - Child support is a court-ordered payment by one parent to the custodial parent of a minor child after divorce or separation of the parents.
Chromosome - Chromosomes are long pieces of DNA present in the nucleus of cells of living beings. A human has 46 chromosomes in total with 23 from each parent. The DNA in a chromosome is organized as a long chain called a "double helix" and further composed of four nucleotides: A (adenine), T (thymine), C (cytosine) and G (guanine).
Combined Paternity Index - The Combined Paternity Index is the product of individual paternity indices at each genetic locus that is tested in a paternity test. The Combined Paternity Index indicates the possibility of the alleged father being the biological father relative to any other man selected at random from the population.
Court Ready Paternity test - Commonly referred to as legal test.
Curiosity test - Commonly referred to as at-home test.
Custodial Parent - Parent who has custody of the child.
Custody - 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 (i.e. joint or shared custody).
D
Decedent - A deceased person.
Deoxyribonucleic Acid - A complex naturally occurring organic chemical that is found in all cells. This compound is responsible for coding the genetic information that is passed on to offspring. Its acronym is "DNA".
Direct Exclusion - A direct exclusion, in a paternity test, is when a child and alleged father both have two alleles and both of the child’s alleles are different from those of the alleged father's alleles. This type of result is concluded as an exclusion, regardless of whether the mother is tested.
Dizygotic twins - Twins which come from two different zygotes (=union of egg and sperm). Also called Fraternal twins.
DNA - An acronym for Deoxyribonucleic acid.
E
Exclusion - The named alleged father is not the biological father.
F
First degree relative - A biological sibling, parent or offspring of an individual.
Fraternal twins - Fraternal twins, also called dizygotic twins, are derived from two different zygotes (i.e. unions of egg and sperm). Fraternal twins may be of the same sex or of two different sexes. Although unusual, fraternal twins may also have different fathers.
G
Gene - A gene is the fundamental unit of heredity. It can be coding (i.e. code for a specific function or physical characteristic) or it can be non-coding. Each gene is located at a defined position (i.e. locus) on a particular chromosome and variations of the same gene are called alleles.
Genetic Marker - A gene that is phenotypically associated with a specific, easily identified trait and one which is used to identify an individual when compared to unrelated individuals.
Genotype - The alleles present at a specific locus. In autosomal DNA, at each locus, there will be one allele from the child’s mother and one from the child’s father.
Gestational Surrogacy - A process designed for women who cannot carry their own children. An embryo formed from a woman and man is carried by another woman who is unrelated to either the mother or father. The woman who carries the child is the gestational surrogate. The donors of the egg and sperm are called the biological or natural parents.
H
Heterozygote - Two different alleles at a specific locus on a chromosome is said to be heterozygous at that locus.
Homozygote - The same allele at a specific locus on a chromosome is said to be homozygous at that locus.
I
Inclusion - In the context of a paternity test, the alleged father cannot be excluded as the biological father of the child.
Indirect Exclusion - An indirect exclusion, in a paternity test, is when the child and alleged father match at one of their two alleles, but after accounting for the maternal contribution to the child, the alleged father is excluded. This type of exclusion must be confirmed by a second indirect or direct exclusion.
Infidelity - Unfaithfulness to a sexual partner, especially a spouse.
K
Kinship - Kinship is a connection by blood. Orchid Cellmark refers to a kinship as any relationship other than paternity or maternity.
L
Legal DNA test - A "legal" test is also called a Chain of Custody or Court Ready test. It is completed using biological specimens that have been collected by an unbiased third party with a documented Chain of Custody.
Loci - The plural form of locus.
Locus - The singular term for a specific location on a chromosome.
M
Maternal - Related through one’s mother.
Maternity Test - A test (usually DNA ) to determine whether a woman is or is not the biological mother of a child.
Matrilineal - Relating to descent through the maternal line.
Mitochondria - The energy-producing organelle in the cell of a living organism. Each cell has multiple mitochondria.
Mitochondrial DNA - DNA present in the mitochondria of a living organism.
Monozygotic twins - Also called identical twins, monozygotic twins develop from a single fertilized egg which then divides and develops as two separate embryos. Their DNA is therefore exactly the same, they will be the same sex and they are more likely to look like each other.
Motherless - A DNA test conducted without any DNA from the child’s mother.
Mutation - A change of the DNA sequence within a gene or chromosome of an organism resulting in the creation of a new allele not found in either of the parents. If the mutation takes place in a non-coding part of the DNA, this change will not affect the physical appearance or functions of the offspring.
N
Non-Custodial Parent - The parent who does not have custody of the child in question.
Non-standard sample - A non-standard sample is a biological sample used for DNA testing that is not a cheek swab or blood sample.
P
Parentage Test - A parentage test is a biological test performed to determine whether a person (male or female) is or is not the biological parent of a child.
Paternal - Related through one’s father.
Paternity Index - This value equals the odds that the alleged father is the biological father rather than any other man selected at random from the population.
Paternity Test - A biological test performed to determine whether a man can be the biological father of a child.
Pathology sample - A biological sample taken to study the presence and/or progression of a disease, such as cancer. It is often a tissue sample.
Patrilineal - Relating to descent through the paternal line.
Phenotype - The visible form of a genotype. There may be more than one genotype that presents itself as the same phenotype.
Population Database - A statistically significant set of data comprised of allele combinations for randomly selected individuals. Population databases are used to determine the variety and frequency of alleles at a specific locus in that specific population. They are used in paternity testing to calculate the Combined Paternity Index leading to the Probability of Paternity.
Postmortem - 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.
Power of Exclusion - The ability of a genetic marker system to properly exclude a man who has been falsely accused of paternity.
Prenatal - 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.
Prior Probability (of Paternity) - The prior probability is a number anywhere from zero to one, that is assigned as the chance of a certain man being the father of a child, without any DNA testing. In a paternity test, the standard Prior Probability is 0.50 which is 50%. That means that, without testing any of the parties, there is a 50% chance that any untested man is the father and a 50% chance that he is not the father (i.e. same chance as flipping a coin). The Probability of Paternity obtained as a result of an actual DNA test can be compared to this Prior Probability.
Putative Father - The man who may be the biological father of a child.
R
Random Man - 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.
Recombination - The natural formation in offspring of genetic combinations not present in parents. This happens through genetic events called crossing over or independent assortment.
S
Second degree relative - A second degree relative is a grandparent, grandchild, aunt, uncle, niece, or nephew.
Self collection - A cheek swab sample that is collected by the party to be tested. It is usually obtained in a non-clinical setting such as a person’s home.
Semen screen - A biological test conducted to detect the presence of acid phosphatase and Prostatic Specific Phosphatase that are present in seminal fluid.
Sibship Test - A test to determine if two or more individuals are biologically related as either full or half siblings.
STR - STR is an acronym for Short Tandem Repeat. STR’s are short sections of DNA that contain a nucleotide sequence which is repeated a number of times in certain sites on specific chromosome s. The number of repeats differs from individual to individual within the population. These sections of DNA are examined in DNA identity testing.
Surrogate mother - A surrogate mother agrees to become pregnant for the purpose of gestating and giving birth to a child for others to raise. She can be the child’s genetic mother or could have been implanted with a zygote from another woman and man.
X
X-chromosome - The sex chromosome associated with female characteristics in mammals. It occurs as a pair in females and singly in males.
Y
Y-chromosome - The sex chromosome that is contributed by a father to his son. Y-chromosomes are only present in males.