Genealogy DNA Test
Genealogy is a practice which aims to find the kinship and filiation of people. Genealogy is therefore considered a science of history which allows the memory of a family to be traced based on documents, oral interviews or genetics .
There are generally two types of genealogy:
- Ascending Genealogy
The ascending genealogy starts from an individual and aims to search for his ancestors. It is this person who will be at the base of a family tree and by going back appear the parents, then his grandparents ...
- Genealogy Descent
Descending genealogy is concerned with the descendants of a given person or couple and aims to find all descendants. This can be used to determine cousin ties between people. Mathematically, the further away the ancestor is in time, the more potential descendants he can have.
Classic genealogy is practiced from an archive and document allowing the research of the ancestry or the descent of a person. This research sheds light on any statement that can explain and prove the relationship between members of a family over several generations.
You can thus use acts of civil status, notarial or legal archives, religious registers or any official or unwritten or oral document that can help you in your process. For example :
- Birth certificate
- Family record book
- Marriage certificate
- Property title
- Certificate and notice of death
In addition today you have several institutions and companies providing information and archives to guide you in your genealogy research. For example the Familysearch site gives you access to family trees of individuals and offers you to connect your own. But also Ancestry which helps you create your family tree by keeping your information throughout your research.
Genetic genealogy is a discipline based on the study of an individual's DNA by a genetic laboratory. In order to carry out several tests in comparison with a database which includes anthropological information , but also the genetic fingerprints of all the people tested .
This analysis leads to two types of results:
- An estimate of the geographical origins of the individual
- A list of genetic matches or "matches":
These are people who have performed a test at the same laboratory, who share DNA markers and therefore a genetic link with you. This list is provided with an estimate of the rate of shared DNA, which gives an idea of the relationship.
The interest of DNA tests in genealogy:
DNA tests give you the possibility of having access to a database which is continuously enriched . If during your test you did not find a reliable connection to add to your genealogy, it is possible that in the future new people may be tested and provide you with the missing information for your research.
- Geographical origins :
Know the percentage of ethnic origin of your DNA and its geographic location. Origin predictions allow you to learn more about the origin of your ancestors in history. Depending on the tests you may also have access to historical data on population migrations, which can guide your classic genealogical research.
- Build your genetic tree:
DNA testing will allow you to check whether your family tree merges with your genetic tree. So you can relate the information about your classic genealogy and the genetic matches that the DNA test can bring you.
It can also identify new genetic branches for you by relating your family tree to that of a 3rd, 4th or 5th degree cousin depending on the results.
- Find unknown parents:
In the event that your family tree contains blanks such as an adoption, or child of a foreign soldier for example. Genetic genealogy gives you a chance to fill this void and trace the lineage of your biological ancestors.
There are 3 main types of genealogical DNA test:
- The Autosomal DNA test
- The Mitochondrial DNA test
- The Y Chromosome DNA test
The autosomal DNA test is an analysis of all chromosomes not involved in determining a person's sex. An autosome is therefore a non-sexual chromosome which holds almost the majority of a person's genetic information.
This analysis makes it possible to identify variants in the composition of a gene (NHPs) in order to compare them to a database composed of information concerning all types of known DNA variants . In order to create genetic matches between people with the same variants.
The correspondence between individuals is generally defined in centimorgan (cM) which represents the unit of measurement of a genetic link. This will let you know the relationship estimate that you can share with other people already tested in the lab's database.
Thus, the reliability of the autosomal DNA test depends on:
- Genetic information held by the laboratory on the populations compared
- The number of markers used
- The value of the genetic variations (NHP) tested
- The degree of mixing in the person tested
Previous estimates for this test were often very imprecise, but their accuracy has improved significantly with the increase in the number of participants and the information collected.
The particularity of the autosomal DNA test
This autosomal DNA analysis therefore makes it possible to identify the gene variations (mutation) that you have inherited from your family from generation to generation . But it is quite possible that two people from the same family (siblings) do not share the same results.
The genetic heritage of each human being is composed of half of the genetic heritage of his father and the other half of that of his mother . But each child randomly inherits genes from their parents. Thus each has a different and unique genetic heritage .
Under these conditions, the tiny genetic mutations present on our chromosomes which are used to establish the results of the autosomal DNA test will not necessarily be the same for two children of the same siblings.
To improve the reliability of your research, it is therefore recommended that several people from the same family participate in this test in order to always refine the accuracy of the information.
X Chromosome DNA Test
Analysis of the X sex chromosome is often included in the autosomal DNA test. All men and women receive an X chromosome from their mother, but only women receive a second X chromosome from their father.
Tracking the inherited lineage of the X chromosome is helpful in dramatically reducing the possibility of a relationship and improving the accuracy of the autosomal DNA test report . Because a match of the X chromosome with a man can only come from his maternal side. Like autosomal DNA, DNA from the X chromosome is passed down randomly in each generation, with the exception of the X chromosomes from father to daughter, which are passed on unchanged .
Mitochondria is an autonomous structure present in all human cells . This component has the particularity of having its own DNA, and its function is to provide energy to the cell allowing it to become completely autonomous in turn.
The mitochondria and therefore its mitochondrial DNA is transmitted only by the mother to all her children . This transmission is completely identical from generation to generation because mutations in mitochondrial DNA are extremely rare.
The mitochondrial DNA test consists of analyzing the markers of this DNA, in order to define your maternal line with great precision. It can be done by men and women for genealogical research as well as for relationship testing.
DNA relationship test
Mitochondrial DNA testing can also be used to confirm the biological relationship between two people, since all individuals of the same lineage are assumed to have an identical copy of that DNA.
The mitochondrial DNA test allows with great certainty to confirm a relationship of maternity, fraternity or filiation between two or more people.
On the other hand, the analysis of Mitochondrial DNA cannot distinguish a specific relationship between women belonging to the same maternal line.
The mitochondrial DNA Haplogroup
Haplogroups are large groups of people with common characteristics and correspond to the great waves of migrations through prehistory and history . Belonging to one group rather than another will help guide your genealogical research to people or parts of the world who share your haplogroup.
The story of the Mitochondrial Eve:
It is the name given to a hypothetical woman considered to be the most recent common ancestor by maternal line of Humanity. Its existence is attested by the demonstration that there is a unique lineage of mitochondria in the cells of all humans. Indeed by going up the chain of events of a maternal line, we inevitably arrive at a woman who still has today an exceptional line of female descendant . Although this person could not have been identified during his lifetime.
The Y chromosome is one of two sex chromosomes in humans. It is part of the XY sex determination system, which every person has in the cells of their body.
- Men have one Y chromosome and one X chromosome - (XY) -
- Women have two X chromosomes - (XX) -
The peculiarity of the Y chromosome is that only men have it because it is only transmitted from father to son during fertilization. In addition, this transmission is such that the possibility of mutation is rare, so the Y chromosome remains unchanged over the generations.
The Y chromosome DNA test consists of analyzing the markers of this DNA, in order to define your paternal line with great precision. It can be done by men for genealogical research as well as for relationship testing.
DNA relationship test
The Y chromosome DNA test can also be used to confirm the biological relationship between two people, since all individuals of the same lineage are assumed to have an identical copy of that DNA.
The Y chromosome DNA test allows with great certainty to confirm a relationship of paternity, fraternity or filiation between two or more people.
On the other hand, the analysis of the DNA of the Y chromosome cannot distinguish a specific relationship between men belonging to the same paternal line.
Y chromosome DNA Haplogroups
Haplogroups are large population groups with common characteristics and correspond to large waves of migrations through prehistory and history . Belonging to one group rather than another will help guide your genealogical research to people or regions of the world who share your haplogroup.
The Autosomal DNA Test
The Mitochondrial DNA Test
The Y Chromosome DNA Test
We have selected 4 laboratories that we recommend because of the quality of the service and the reliability of the results they offer. But each laboratory has its advantages and disadvantages, the choice of a test will depend on your profile, your situation and your objectives.
We start from the principle that if you want to have as much information as possible about your genealogy, then it is recommended to do genetic tests on all the databases that exist. This will allow you to increase the rate of identifiable genetic relationships in order to speed up your research.
The laboratories we recommend for a Genealogy test:
You want to know your ethnic and geographical origins:
- We recommend that you start by doing a test at 23andMe which offers greater precision on the estimation of geographical origins. Geographic areas even target your home regions within a country, with fairly convincing results.
You want to complete your family tree:
- If your research concerns your origins around the world and especially in America, Ancestry is the best choice because they have the largest database. You can also create your family tree and have access to the correspondence association of your relationships.
- If your research concerns European origins, we advise you to use the MyHeritage databases which brings together more information on the origins of peoples' countries in Europe . You can also create your family tree and associate corresponding relationships (matches).
You are looking for an unknown relative:
- We recommend that you start by doing DNA testing of the Y chromosome or mitochondrial DNA at FamilytreeDNA . This type of test which is not offered elsewhere, and is much more reliable in the precision of the relations found.
Genealogical research often involves having to relate, but also record, exchange and merge the data of the results of genetic tests. In order to deepen your analyzes and increase the chances of matches, the laboratories allow you to transfer raw information from one database to another.
In this transfer policy, most laboratories accept that raw data can be downloaded by the person concerned. But not all of them give you the option to add the information from a third party lab.
Today MyHeritage FamilyTreeDNA and laboratories are the most flexible and allow the addition of genetic information from any other competitor laboratory.