The types of DNA testing

Casey Randall AlphaBiolabs

By Casey Randall, Head of Genetics at AlphaBiolabs

Last reviewed: 22/07/2017

DNA testing is an incredibly useful tool that can help people verify biological relationships between family members.

In this article, we look at what DNA testing is, and the different types of DNA testing available, depending on a person’s circumstances.

Table of contents
  • What is DNA testing?
  • What are the different types of DNA test?
  • What is the difference between a peace of mind DNA test and a legal DNA test?
  • How can I order a DNA test?

What is DNA testing?

DNA testing provides a simple, accurate way of verifying biological relationships between individuals.

DNA relationship tests – the type of DNA tests we offer at AlphaBiolabs – work by analysing and comparing DNA samples to identify matching DNA markers. However, the type of test a person might order depends entirely on their reasons for wanting a DNA test.

For example, if an individual simply wants a DNA test for their own information, they can order a peace of mind DNA test.

Peace of mind DNA tests require you to collect your own samples at home before returning them to the laboratory for analysis. The results can be used to answer any questions a person might have but cannot be used for legal matters.

If an individual requires a DNA test for legal purposes, such as changing the name on a birth certificate, for child maintenance or custody disputes, or for wills and probate, they will need to order a legal DNA test.

For a legal DNA test, samples must be collected under strict chain of custody conditions by a trained sample collector, ensuring samples are collected in the correct way, from the right people.

This ensures that the DNA results will be accepted by a variety of organisations for legal matters including the Family Court, the Child Maintenance Service, the Home Office and UK Visas and Immigration.

What are the different types of DNA test?

There are many types of DNA test available to members of the public looking for peace of mind DNA tests, or tests that can be used for legal matters.

Below is an overview of each DNA test we offer at AlphaBiolabs, direct from our award-winning, UKAS ISO 17025-accredited laboratory.

Paternity DNA Testing

One of our most popular DNA tests, a paternity test is used to verify a biological relationship between an alleged father and child.

The test simply requires cheek (buccal) swabs to be rubbed quickly and painlessly on the inside of the cheek to collect DNA from each person taking part in the test (alleged father and child) and can be performed at any time on a person of any age, including new-born babies and grown-up children/adults.

When testing the biological father of the child, both will share enough DNA markers to confirm a biological relationship. If the tested man is not the biological father, this will not be the case.

Maternity DNA Testing

A maternity test is a DNA test used to verify a biological relationship between an alleged mother and child.

The test simply requires cheek (buccal) swabs to be rubbed quickly and painlessly on the inside of the cheek to collect DNA from each person taking part in the test (alleged mother and child). These samples are then analysed in the laboratory by expert geneticists, to determine whether the individuals share enough DNA to verify a biological relationship.

In most circumstances, it is easy to determine who is the biological mother of a child. However, a maternity DNA test can be useful in several situations, including:

  • When a child is conceived through in vitro fertilisation (IVF) and the parent(s) would like to confirm that the correct embryo was implanted in the woman’s uterus
  • When an adopted child and mother are reunited after years of separation and would like to confirm their biological relationship
  • When there are concerns that baby switching has mistakenly occurred within a hospital

Prenatal Paternity Testing

A prenatal paternity test – also known as a non-invasive prenatal paternity (NIPP) test – is based on the same principle as a standard paternity test, except it is performed while the mother is still pregnant.

The test is non-invasive and 100% risk free for mum and baby, requiring only a blood sample and two cheek swabs from the mother, and two cheek swabs from the alleged father.

The test works by analysing the baby’s DNA, which can usually be found in the mother’s bloodstream from as early as 7 weeks into pregnancy, together with the parents’ DNA.

By doing this, expert geneticists can determine which half of the baby’s DNA is inherited from the mother and which half is from the alleged father.

Baby Gender Testing

A baby gender test is used to determine the gender of an unborn baby while the mother is still pregnant, with only a blood sample required from the mother.

Although there are some rare exceptions, most human beings have a pair of sex chromosomes in each cell. The Y chromosome is present in males who have one X and one Y chromosome, while females have two X chromosomes.

For a baby gender test, the mother’s blood sample is analysed by expert geneticists.

If a Y chromosome is detected, this indicates that the baby is a boy. If no Y chromosome is detected, this means that the baby is a girl.

For the highest chance of a conclusive result, the mother should be at least 8 weeks’ pregnant, to ensure that any Y chromosome present in the blood sample is at a detectable level.

Twin DNA (Zygosity) Testing

A twin DNA test – also known as a zygosity test – is used to determine whether children from multiple births are identical or non-identical (fraternal).

For this test, cheek swabs are rubbed quickly and painlessly on the inside of the cheek to collect DNA from each person taking part in the test.

Expert geneticists can then compare the samples in the laboratory to determine whether the individuals share the same DNA profile.

Identical siblings are known as monozygotic. This means that they were formed from a single fertilised egg which went on to split into separate embryos. Identical siblings share the same DNA profile (barring some minor variations that are very difficult to detect).

Fraternal or non-identical siblings are known as dizygotic (twins), trizygotic (triplets) etc., and are the result of separate fertilised eggs. This means that they share DNA in common, as is the case with siblings from different births, but they do not have identical DNA profiles.

Sibling DNA Testing

A sibling DNA test can be used to determine whether two or more individuals are full siblings or half siblings.

When two or more people have the same biological parents, they are classed as full siblings. Half siblings only share one biological parent – the mother or father.

For a sibling DNA test, cheek swabs are used to collect DNA samples from each sibling. For the most conclusive result, the laboratory will also request that the biological mother’s DNA sample be submitted for testing, if possible.

Expert geneticists will then analyse and compare the DNA samples to determine the genetic profile of the possible siblings and calculate a sibling DNA index or likelihood ratio.

  • A likelihood of greater than 10 supports that the tested individuals are either full or half siblings
  • A likelihood of less than 0.1 is not supportive, meaning the individuals are unlikely to be related
  • A likelihood which falls between 0.1 and 10 is considered inconclusive, which means a relationship cannot be determined based on the statistical probability obtained from the analysis

Grandparent DNA Testing

Grandparent DNA testing is used to establish a biological relationship between a child and one or more of their biological grandparents, which in turn will help verify a biological relationship between a child and their father or mother.

These types of tests are most often used in circumstances where the alleged father or mother of a child is unavailable for paternity testing or maternity testing.

Every person inherits half of their DNA from each of their parents, meaning that a grandchild will share DNA markers with their grandparents.

These tests are more likely to be conclusive if both grandparents from either the paternal or maternal side are tested, however, they can also be performed with just one paternal or maternal grandparent.

Aunt and Uncle DNA Testing

Aunt DNA tests and uncle DNA tests – also known as avuncular tests – are used to establish a biological relationship between a child and their alleged aunt or uncle, which in turn will help verify a biological relationship between a child and their father or mother.

These types of tests are most commonly used in situations where the alleged father or mother is unavailable to take a paternity test or a maternity test.

Every person inherits half of their genetic profile from their mother, and half from their father. When a child’s father or mother is unavailable for a paternity test or maternity test, for example if they have passed away or are not around for another reason, avuncular tests can help individuals learn the truth about their parentage.

For an aunt DNA test or an uncle DNA test, the alleged aunt or uncle must be a full biological sibling of the alleged father or mother (not a half-sibling), as this helps increase the likelihood of a conclusive result.

Single Genetic Profile Testing

Single genetic profile testing is a type of DNA test that allows an individual to obtain a record of their DNA profile.

There are several reasons why a person might want to have a copy of their DNA profile, including:

  • If an individual is working in a high-risk environment (e.g. police service, armed forces, fire service). In this instance, having a copy of the person’s DNA profile to hand can help with identification if the person is involved in a fatal incident
  • Where a person suspects that their family members may have a reason to perform DNA testing (e.g. paternity testing) after they have passed away. Having the results of a single genetic profile test on file (e.g. with the person’s solicitor) would remove the requirement for DNA samples to be obtained from the deceased person for the purpose of testing
  • As a novel gift for new parents, friends, or relatives, who may choose to use their DNA profile as a unique piece of wall art

A single genetic profile test simply requires cheek (buccal) samples to be collected using a cheek swab.

Y Chromosome Testing

Y chromosome testing – also known as Y-DNA testing – is used to verify a relationship between alleged male relatives by identifying matching Y chromosomes.

Y-DNA testing is most often used in situations where potential male relatives want to confirm that they share a common paternal line and can be useful if the alleged father is unavailable or unwilling to participate in a paternity test.

A son inherits his Y chromosome from his father, and the chromosome does not change from father to son. This means it is possible to analyse and compare the DNA samples of test participants to determine a biological relationship through the paternal line.

However, the test cannot be used to determine how two people are related (i.e. whether they are father and son, grandfather and grandson etc.). It can only be used to confirm that two males are paternally related.

Viability DNA testing

A DNA viability test – also referred to as a viability study – is often performed where discretion is required when performing the DNA test, or where an individual is not available to provide a cheek swab sample for DNA testing.

DNA relationship tests usually involve collecting cheek swab DNA samples from two or more sample donors and comparing each person’s DNA profile to verify a biological relationship.

However, for a DNA viability test or viability study, DNA samples are extracted from an alternative source. AlphaBiolabs provides two options for peace of mind DNA viability testing:

Toothbrush DNA testing

This involves extracting a DNA profile from a used toothbrush for the purpose of performing a DNA relationship test.

Nail DNA testing

This involves extracting a DNA profile from fingernail clippings or toenail clippings for the purpose of performing a DNA relationship test.

If a DNA profile can be retrieved from the used toothbrush or nail clippings, a DNA relationship test can then be performed by analysing and comparing the DNA profile from the toothbrush or nail clippings with the DNA profiles of the other test participants via cheek swabs.

The main reason that people choose toothbrush DNA testing and nail DNA testing is so that samples can be collected discreetly – usually from older children (under 16 years of age), where collecting a cheek swab sample could lead to awkward questions (e.g. when performing a paternity test).

However, this does not mean that these tests can be performed without the consent of anyone aged 16 or over whose DNA is being submitted for testing.

Any person aged 16 or over must provide consent (a signature) before their DNA samples can be used for testing. For a child under the age of 16, parental consent is required to perform the test. This consent must be given by a person with parental responsibility for the child.

A legal DNA viability test is usually performed when a person has passed away, and a living relative wants to perform a DNA relationship test (e.g. paternity test for wills and probate).

In these circumstances, a sample of the deceased person’s nail clippings (usually toenail clippings) or less frequently, tissue or blood, could be used to obtain a viable DNA profile, provided the next of kin has given consent for the DNA to be used in testing.

These samples are collected by the coroner or funeral director, who will complete a declaration form at the time of sample collection to maintain chain of custody. This helps ensure the test results will be accepted for legal purposes.

How can I order a DNA test?

It has never been easier to get answers to those all-important questions, with peace of mind DNA testing from AlphaBiolabs.

Our award-winning, UKAS ISO 17025-accredited DNA laboratory has been helping people find out the truth about their family relationships since 2004.

We offer a wide range of DNA tests to suit all circumstances including paternity, non-invasive prenatal paternity (NIPP), maternity, sibling, twin, grandparent, and aunt/uncle tests.

Order your test online now and we will ship your kit out to you immediately in discreet, plain packaging, for full confidentiality.

Need a DNA test for court or other private legal/official matters? Call us on 0333 600 1300 or email to discuss your requirements and request a quote.

Order a DNA test

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Casey Randall AlphaBiolabs

Casey Randall

Head of Genetics at AlphaBiolabs

Casey joined the AlphaBiolabs team in 2012 and heads up both the DNA and Covid-19 testing teams.

An expert in DNA analysis and a member of the International Society for Forensic Genetics (ISFG), Casey holds an MSc with Distinction in DNA Profiling and a First-Class BSc with Honours in Forensic Science.

Casey is responsible for maintaining the highest quality testing standards, as well as looking for ways to further enhance the service that AlphaBiolabs provides and exploring new and innovative techniques in DNA analysis.

Connect with Casey on LinkedIn

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