DNA paternity testing is the use of
DNA profiles to determine whether an individual is the
biological parent of another individual. Paternity testing can be especially important when the rights and duties of the father are in issue and a child's
paternity
Paternity may refer to:
*Father, the male parent of a (human) child
*Paternity (law), fatherhood as a matter of law
* ''Paternity'' (film), a 1981 comedy film starring Burt Reynolds
* "Paternity" (''House''), a 2004 episode of the television seri ...
is in doubt. Tests can also determine the likelihood of someone being a biological grandparent. Though
genetic testing is the most reliable standard, older methods also exist, including
ABO blood group typing, analysis of various other
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
s and
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s, or using
human leukocyte antigen
The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...
antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respons ...
s. The current techniques for paternity testing are using
polymerase chain reaction
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) ...
(PCR) and
restriction fragment length polymorphism (RFLP). Paternity testing can now also be performed while the woman is still pregnant from a blood draw.
DNA testing is currently the most advanced and accurate technology to determine parentage. In a DNA paternity test, the result (called the 'probability of parentage) is 0% when the alleged parent is not biologically related to the child, and the probability of parentage is typically 99.99% when the alleged parent is biologically related to the child. However, while almost all individuals have a single and distinct set of genes, rare individuals, known as "
chimeras", have at least two different sets of genes, which can result in a false negative result if their reproductive tissue has a different genetic make-up from the tissue sampled for the test.
Paternity or maternity testing for child or adult
The DNA test is performed by collecting buccal (cheek) cells found on the inside of a person's cheek using a buccal or cheek
swab. These swabs have wooden or plastic stick handles with a cotton on synthetic tip. The collector rubs the inside of a person's cheek to collect as many buccal cells as possible, which are then sent to a laboratory for testing. Samples from the alleged father or mother and the child would be needed.
Prenatal paternity testing for unborn child
Invasive prenatal paternity testing
It is possible to determine who the biological father of the fetus is while the woman is still pregnant through procedures called
chorionic villus sampling or
amniocentesis
Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is n ...
. Chorionic villus sampling retrieves placental tissue in either a transcervical or transabdominal manner. Amniocentesis retrieves amniotic fluid by inserting a needle through the pregnant mother's abdominal wall. These procedures are highly accurate because they are taking a sample directly from the fetus; however, there is a small risk for the woman to miscarry and lose the pregnancy as a result. Both CVS and Amnio require the pregnant woman to visit a genetic specialist known as a maternal-fetal medicine specialist who will perform the procedure.
Non-invasive prenatal paternity testing
Advances in genetic testing have led to the ability to identify the biological father while the woman is still pregnant. There is a small amount of fetal DNA (
cffDNA) present in the mother's blood during pregnancy. This allows for accurate fetal DNA paternity testing during pregnancy from a blood draw with no risk of miscarriage. Studies have shown that cffDNA can first be observed as early as 7 weeks gestation, and the amount of cffDNA increases as the pregnancy progresses.
DNA profiling
![DNA paternity testing en](https://upload.wikimedia.org/wikipedia/commons/5/55/DNA_paternity_testing_en.svg)
The
DNA of an individual is the same in every somatic (nonreproductive)
cell
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...
.
Sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
brings the DNA of both parents together to create a unique combination of genetic material in a new cell, so the genetic material of an individual is derived from the genetic material of each parent in equal amounts; this genetic material is known as the nuclear
genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...
of the individual, because it is found in the
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
* Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucl ...
.
Comparing the DNA sequence of one person to that of another can prove if one of them was derived from the other, but DNA paternity tests are not currently 100% accurate. Specific sequences are examined to see if they were copied verbatim from one individual's genome; if so, then the genetic material of one individual could have been derived from that of the other (i.e. one is the parent of the other). This is called Autosomal DNA testing. It is currently the gold standard in paternity testing as it allows a comparison of the child’s DNA to that of the mother and alleged father. The genetic contribution to the child from the mother can be evaluated, resulting in possible genotypes for the true father. If the alleged father cannot be excluded as the true father, then statistical calculations can be conducted to determine how likely the alleged father is the true father compared to if another random man was the true father.
Besides nuclear DNA,
mitochondria also have their own genetic material called
mitochondrial DNA. Mitochondrial DNA comes only from the mother, without any shuffling. Proving a relationship based on comparison of the mitochondrial genome is much easier than that based on the nuclear genome. However, testing the mitochondrial genome can prove only if two individuals are related by
common descent through maternal lines only from a common ancestor and is, thus, of limited value (i.e., it could not be used to test for paternity).
In testing the paternity of a male child, comparison of the
Y chromosome
The Y chromosome is one of two sex chromosomes (allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or abse ...
can be used, since it is passed directly from father to son. However, similar to mitochondrial DNA, the Y chromosome is passed through the paternal line. Meaning two brothers share the Y chromosome of their father. Therefore if one brother is the suspected father, his biological brother could also be the father based on Y chromosomal data alone. This is true with any male related to the suspected father on the paternal line. For this reason autosomal DNA testing would be a more precise paternity testing method.
In the US, the
AABB has regulations for DNA paternity and family relationship testing, but AABB accreditation is not required. DNA test results are legally admissible if the collection and the processing follows a chain of custody. Similarly in Canada, the SCC has regulations on DNA paternity and relationship testing, but this accreditation, while recommended, is not required.
The Paternity Testing Commission of the
International Society for Forensic Genetics has taken up the task of establishing the biostatistical recommendations in accordance with the
ISO/IEC 17025 standards.
Bio-statistical evaluations of paternity should be based on a likelihood ratio principle - yielding the
Paternity Index, PI. The recommendations provide guidance on concepts of genetic hypotheses and calculation concerns needed to produce valid PIs, as well as on specific issues related to
population genetics
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as Adaptation (biology), adaptation, ...
.
History
The first form of any kind of parental testing was blood typing, or matching
blood types between the child and alleged parent, which became available in the 1920s, after scientists recognized that blood types, which had been discovered in the early 1900s, were genetically inherited. Under this form of testing, the blood types of the child and parents are compared, and it can be determined whether there is any possibility of a parental link. For example, two O blood type parents can produce a child only with an O blood type, and two parents with a B blood type can produce a child with either a B or an O blood type. This often led to inconclusive results, as 30% of the entire population can be excluded from being the possible parent under this form of testing. In the 1930s,
serological
Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given mic ...
testing, which tests certain proteins in the blood, became available, with a 40% exclusion rate.
In the 1960s, highly accurate genetic paternity testing became a possibility when
HLA typing was developed, which compares the genetic fingerprints on white blood cells between the child and alleged parent. HLA tests could be done with 80% accuracy but could not distinguish between close relatives.
Genetic parental testing technology advanced further with the isolation of the first
restriction enzyme
A restriction enzyme, restriction endonuclease, REase, ENase or'' restrictase '' is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. Restriction enzymes are one class o ...
in 1970. Highly accurate DNA parental testing became available in the 1980s with the development of
RFLP. In the 1990s,
PCR became the standard method for DNA parental testing: a simpler, faster, and more accurate method of testing than RFLP, it has an exclusion rate of 99.99% or higher.
[
]
Legal evidence
The DNA parentage test that follows strict chain of custody
Chain of custody (CoC), in legal contexts, is the chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of materials, including physical or electronic evidence. Of particula ...
can generate legally admissible results that are used for child support, inheritance, social welfare benefits, immigration, or adoption purposes. To satisfy the chain-of-custody legal requirements, all tested parties have to be properly identified and their specimens collected by a third-party professional who is not related to any of the tested parties and has no interest in the outcome of the test.
The quantum of evidence needed is clear and convincing evidence
In a legal dispute, one party has the burden of proof to show that they are correct, while the other party had no such burden and is presumed to be correct. The burden of proof requires a party to produce evidence to establish the truth of facts ...
: that is, more evidence than an ordinary case in civil litigation
Civil law is a major branch of the law.Glanville Williams. '' Learning the Law''. Eleventh Edition. Stevens. 1982. p. 2. In common law legal systems such as England and Wales and the United States, the term refers to non-criminal law. The law ...
, but less than beyond a reasonable doubt
Beyond a reasonable doubt is a legal standard of proof required to validate a criminal conviction in most adversarial legal systems. It is a higher standard of proof than the balance of probabilities standard commonly used in civil cases, bec ...
required to convict a defendant in a criminal case.
In recent years, immigration authorities in various countries, such as the United States, United Kingdom, Canada, Australia, France, and others, may accept DNA parentage test results from immigration petitioners and beneficiaries in a family-based immigration case when primary documents that prove biological relationship are missing or inadequate.
In the U.S., immigration applicants bear the responsibility of arranging and paying for DNA testing. The U.S. immigration authorities require that the DNA test, if pursued, be performed by one of the laboratories accredited by the AABB (formerly American Association of Blood Banks). Similarly, in Canada, the laboratory needs to be accredited by the Standards Council of Canada.
Although paternity tests are more common than maternity tests, there may be circumstances in which the biological mother of the child is unclear: examples include cases of an adopted child attempting to reunify with his or her biological mother, potential hospital mix-ups, and in vitro fertilization
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) f ...
where the laboratory may have implanted an unrelated embryo inside the mother.
Other factors, such as new laws regarding reproductive technologies using donated eggs and sperm and surrogate mothers, can also mean that the female giving birth is not necessarily the legal mother of the child. For example, in Canada, the federal ''Human Assisted Reproduction Act'' provides for the use of hired surrogate mothers. The legal mother of the child may be the egg donor. Similar laws are in place in the United Kingdom and Australia.
In Brazil in 2019, two male identical twins were ordered to both pay maintenance for a child fathered by one of them, because the father could not be identified with DNA.
Legal issues
Australia
Peace-of-mind parentage tests are widely available on the internet. For a parentage test (paternity or maternity) to be admissible for legal purposes, such as for changing a birth certificate, Family Law Court proceedings, visa/citizenship applications or child support claims, the process must comply with the ''Family Law Regulations 1984'' (Cth). Further, the laboratory processing the samples must be accredited by the National Association of Testing Authorities (NATA).
Canada
Personal paternity-testing kits are available. The Standards Council of Canada regulates paternity testing in Canada whereby laboratories are ISO 17025-approved. In Canada, only a handful of labs have this approval, and it is recommended that testing is performed in these labs. Courts also have the power to order paternity tests during divorce cases.
China
In China, paternity testing is legally available to fathers who suspect their child is not theirs. Chinese law also requires a paternity test for any child born outside the one-child policy
The term one-child policy () refers to a population planning initiative in China implemented between 1980 and 2015 to curb the country's population growth by restricting many families to a single child. That initiative was part of a much br ...
for the child to be eligible for a ''hukou
''Hukou'' () is a system of household registration used in mainland China. The system itself is more properly called "''huji''" (), and has origins in ancient China; ''hukou'' is the registration of an individual in the system (''kou'' li ...
'', or family registration record. Family tie formed by adoption can also only be confirmed by a paternity test. A large number of Chinese citizens seek paternity testing each year, and this has given rise to many unlicensed illegal testing centers being set up.
France
DNA paternity testing is solely performed on decision of a judge in case of a judiciary procedure in order either to establish or contest paternity or to obtain or deny child support. Private DNA paternity testing is illegal, including through laboratories in other countries, and is punishable by up to a year in prison and a €15,000 fine. The French Council of State has described the law's purpose as upholding the "French regime of filiation" and preserving "the peace of families."
Germany
Under the Gene Diagnostics Act of 2009, secret paternity testing is illegal. Any paternity testing must be conducted by a licensed physician or by an expert with a university degree in science and special education in parentage testing, and the laboratory carrying out genetic testing must be accredited according to ISO/IEC 17025. Full informed consent of both parents is required, and prenatal paternity testing is prohibited, with the exception of sexual abuse and rape cases. Any genetic testing done without the other parent's consent is punishable with a €5,000 fine. Due to an amendment of the civil la
section 1598a
in 2005, any man who contests paternity no longer automatically severs legal rights and obligations to the child.
Israel
A paternity test with any legal standing must be ordered by a family court. Though parents have access to "peace of mind" parental tests through overseas laboratories, family courts are under no obligation to accept them as evidence. It is also illegal to take genetic material for a parental test from a minor over 16 years of age without the minor's consent. Family courts have the power to order paternity tests against the will of the father in divorce and child support cases, as well as in other cases such as determining heirs and settling the question involving the population registry. A man seeking to prove that he is not the father of the child registered as his is entitled to a paternity test, even if the mother and natural guardian object. Paternity tests are not ordered when it is believed it could lead to the murder of the mother, and until 2007, were not ordered when there was a chance that the child of a married woman could have been fathered by a man other than her husband, thereby making the child a ''mamzer
In the Hebrew Bible and Jewish religious law, a ''mamzer'' ( he, ממזר, , "estranged person"; plural ''mamzerim'') is a person who is born as the result of certain forbidden relationships or incest (as it is defined by the Bible), or the de ...
'' under Jewish law.
Philippines
DNA paternity testing for personal knowledge is legal, and home test kits are available by mail from representatives of AABB- and ISO 17025-certified laboratories. DNA Paternity Testing for official purposes, such as sustento (child support) and inheritance disputes, must follow the Rule on DNA Evidence A.M. No. 06-11-5-SC, which was promulgated by the Philippine Supreme Court on October 15, 2007. Tests are sometimes ordered by courts when proof of paternity is required.
Spain
In Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
, peace-of-mind paternity tests are a "big business," partly due to the French ban on paternity testing, with many genetic testing companies being based in Spain.
United Kingdom
In the United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
, there were no restrictions on paternity tests until the ''Human Tissue Act 2004
The Human Tissue Act 2004 is an Act of the Parliament of the United Kingdom, that applied to England, Northern Ireland and Wales, which consolidated previous legislation and created the Human Tissue Authority to "regulate the removal, storage, u ...
'' came into force in September 2006. Section 45 states that it is an offence to possess without appropriate consent any human bodily material with the intent of analysing its DNA. Legally declared fathers have access to paternity-testing services under the new regulations, provided the putative parental DNA being tested is their own. Tests are sometimes ordered by courts when proof of paternity is required. In the UK, the Ministry of Justice A Ministry of Justice is a common type of government department that serves as a justice ministry.
Lists of current ministries of justice
Named "Ministry"
* Ministry of Justice (Abkhazia)
* Ministry of Justice (Afghanistan)
* Ministry of Just ...
accredits bodies that can conduct this testing. The Department of Health
A health department or health ministry is a part of government which focuses on issues related to the general health of the citizenry. Subnational entities, such as states, counties and cities, often also operate a health department of their ow ...
produced a voluntary code of practice on genetic paternity testing in 2001. This document is currently under review, and responsibility for it has been transferred to the Human Tissue Authority
The Human Tissue Authority (HTA) is an executive non-departmental public body of the Department of Health and Social Care in the United Kingdom. It regulates the removal, storage, use and disposal of human bodies, organs and tissue for a number ...
.
In the 2018 case o
Anderson V Spencer
the Court of Appeal permitted for the very first time DNA samples taken from a Deceased person to be used for paternity testing.
United States
In the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
, paternity testing is fully legal, and fathers may test their children without the consent or knowledge of the mother. Paternity testing take-home kits are readily available for purchase, though their results are not admissible in court and are for personal knowledge only.
Only a court-ordered paternity test may be used as evidence in court proceedings. If parental testing is being submitted for legal purposes, including immigration, testing must be ordered through a lab that has AABB accreditation for relationship DNA testing.
The legal implications of a parentage result test vary by state and according to whether the putative parents are unmarried or married. If a parentage test does not meet forensic standards for the state in question, a court-ordered test may be required for the results of the test to be admissible for legal purposes. For unmarried parents, if a parent is currently receiving child support or custody, but DNA testing later proves that the man is not the father, support automatically stops. However, in many states, this testing must be performed during a narrow window of time, if a voluntary acknowledgement of parentage form has already been signed by the putative father; otherwise, the results of the test may be disregarded by law, and in many cases, a man may be required to pay child support, though the child is biologically unrelated. In a few states, if the mother is receiving the support, then that alleged father has the right to file a lawsuit to get back any money that he lost from paying support. As of 2011, in most states, unwed parents confronted with a voluntary acknowledgement of parentage form are informed of the possibility and right to request a DNA paternity test. If testing is refused by the mother, the father may not be required to sign the birth certificate
A birth certificate is a vital record that documents the birth of a person. The term "birth certificate" can refer to either the original document certifying the circumstances of the birth or to a certified copy of or representation of the ensui ...
or the voluntary acknowledgement of parentage form for the child. For wedded putative parents, the husband of the mother is presumed to be the father of the child. But, in most states, this presumption can be overturned by the application of a forensic paternity test; in many states, the time for overturning this presumption may be limited to the first few years of the child's life.
Reverse paternity testing
Reverse paternity determination is the ability to establish the biological father when the father of that person is not available. The test uses the STR alleles
An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution.
::"The chrom ...
in mother and her child, other children and brothers of the alleged father, and deduction of genetic constitution of the father by the basis of genetic laws, all to create a rough amalgamation. This can compare the father's DNA when a direct sample of the father's DNA is unavailable. An episode of '' Solved'' shows this test being used to know if a blood sample matches with the victim of a kidnapping.
See also
* Paternity fraud
Paternity fraud, also known as misattributed paternity or paternal discrepancy, occurs when a man is incorrectly identified as the biological father of a child. The underlying assumption of "paternity fraud" is that the mother deliberately miside ...
* Mosaicism
Mosaicism or genetic mosaicism is a condition in multicellular organisms in which a single organism possesses more than one genetic line as the result of genetic mutation. This means that various genetic lines resulted from a single fertilized ...
and chimerism
A genetic chimerism or chimera ( ) is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood ...
, rare genetic conditions that can result in false negative results on DNA-based tests
* Non-paternity event
In genetics, a non-paternity event (also known as misattributed paternity, not parent expected, or NPE) is the situation in which someone who is presumed to be an individual's father is not in fact the biological father. This presumption of NPE is ...
* ''Lauren Lake's Paternity Court
''Lauren Lake's Paternity Court'' (originally known as Paternity Court) is a nontraditional court show in which family lawyer and legal analyst Lauren Lake heard and ruled on paternity cases and rendered DNA test results.
The show was produced ...
'', a television series that debuted in fall 2013
Genetic:
* Heritability
* List of Mendelian traits in humans
Mendelian traits in humans are human traits that are substantially influenced by Mendelian inheritance. Most — if not all — Mendelian triaits are also influenced by other genes, the environment, immune responses, and chance. Therefore no ...
References
External links
UK paternity testing regulations
per the Human Tissue Authority
The Human Tissue Authority (HTA) is an executive non-departmental public body of the Department of Health and Social Care in the United Kingdom. It regulates the removal, storage, use and disposal of human bodies, organs and tissue for a number ...
Paternity Testing Services
for the Hispanic Community.
{{DEFAULTSORT:Parental Testing
Applied genetics
DNA
Family law
Fathers' rights
Forensic genetics
Genetics techniques
Parenting
Testing