A new discipline that emerged thanks to the democratization of genetic testing as early as 2000, genetic genealogy is of interest, passion, sometimes worrying, controversial. What does this have to do with classical genealogy? How is it organized? What exactly is genetic genealogy? Definition.

How is genetic genealogy practiced?

A genetic test carried out in a genetic genealogy laboratory forms the basis of this discipline. Several different tests are available, the most common being the autosomal test. This test can be used to determine ethnic origins but also to identify common ancestors, shared with genetic cousins, up to 8 previous generations.

Analysis of the Y chromosome, present only in men, allows to identify a male family lineage, even in archaeological times.

The mitochondrial test, present in men and women, can identify an archaeological ancestor.

Depending on the commercial offers of the laboratories, certain tests may be associated.

The genetic genealogy laboratory allows us to carry out one/several tests but above all to give access to a database of other genetic tested sharing segments of DNA (called matches or matches) with us, thus being genetic cousins with one or more common ancestors.

The 4 main laboratories are, in order of seniority from the oldest to the most recent: FamilyTree DNA, Ancestry DNA, 23andMe and MyHeritage.

Classical genealogy and genetic genealogy

Classical genealogy is practised from the acts of civil status or religious registers. In order to complete this research, the notarial archives can be consulted, but also any official or not documents, any written traces to trace the life of his ancestors, from the judicial archives to the land registries of the properties. A genealogist soon became a local historian, a historian of the daily life of his ancestors.

For my part, I call classical genealogy, declarative genealogy as opposed to genetic genealogy to determine all biological cousins (within the temporal limits evoked) beyond our borders.

The practice of a genetic test will confirm, supplement or disprove all or part of the family tree.

Confirm the family tree

By identifying genetic matches as genealogical cousins, the genetic genealogist will confirm the discoveries of the classical genealogist.

Complete the family tree

Also by identifying genetic matches, the genealogist will be able to find genetic genealogical cousins "lost" including:

  • identify an undyed natural father from his genealogy
  • find unknown descendants of his genealogy (immigration of an ancestor in France or abroad, unfamiliar remarriage, unknown child of an ancestor, etc.)
  • identify an ancestor with certainty (cases of names, ancestor with pseudonym, change of identity of a French or foreign ancestor, etc.)
  • for babies born under X, born from a gamete donation or adopted, identify the biological family (father and/or mother)

Infiring the family tree

Generally the subject of recurring fantasies, non-filiative events such as the child born of adultery represent an average of 1% in genealogies. It can also be a hidden adoption, a child linked to an adulterous affair or a biologically foreign child, a child from a rape or rape of war, but also a baby exchange as this American discovered through a genetic test.

Our Canadian friends, having launched a large study since 2000 involving more than 8,500 descendants of French couples, have estimated these non-filiative events at 0.5%.

If this percentage is minimal, the risk of a non-filiative event increases over generations. For example, it is estimated that in the previous 6 generations, there is a risk in two (very exactly 40%) that one of your ancestors among the 64 ancestors is not your biological ancestor, including women and men.

The genetic genealogist

The promise of genetic genealogy laboratories is often staggering: from genetic testing, your family tree will "build" itself, partly thanks to your DNA matches, but also and above all thanks to the family trees put online by your genetic cousins.

This service allowing you to complete your family tree from the other trees is also available for the "classic" genealogist, assuming that a heap of names and dates of birth, marriage and death is considered genealogical work. Like any serious and passionate genealogist, this is not enough.

This commercial promise of laboratories has created the fantasy of an independent discipline called genetic genealogy.

Genetic genealogy is complementary and inseparable from declarative genealogy. It is based on classical genealogy to be able to confirm, or not, the data found.

A genetic genealogist, without a family tree of matches, can do nothing and find!

Many people who have been tested have little or no knowledge of their ancestry, so you may make the family tree of your genetic correspondent in order to identify the common ancestor.

Genetic genealogy is also time-limited as the autosomal test can only identify in the previous 8 generations (more in case of endogamy).

As I have titled my book, DNA, a genealogical tool, the genetic genealogist is above all a genealogist who has acquired an additional specialty, genetic genealogy.

The genetic genealogist's missions

This discipline requires a mastery of genealogy, basic notions of genetics, the various commercial offerings and tools existing on the internet (these evolving, disappearing or new tools appearing), a minimum of mastery of excel.

Advice mission

The genetic genealogist must clearly identify the research and needs of his "client" in order to advise him the most appropriate genetic test (s) according to the commercial offers of the laboratories as well as possibly for other members of his family. A good knowledge of the different laboratories of genetic genealogy as well as their fields of action is necessary.

He must inform on ethical aspects and ensure the protection of his client's data in foreign laboratories.

Mission of achievement

From the delegation given by his client, the genetic genealogist performs the work of identifying common ancestors with genetic and therefore ethnic correspondents of all ancestry or part of ancestry according to the client's request.

The genealogist will be able to create one or more surname groups and manage them for his client.

The mastery of the various tools available according to the genetic genealogy laboratories, but also the external tools is essential.

Although rare, applications may relate to the archaeological aspect of an ancestry on which the genetic genealogist should be able to inform his client.

Educational mission

It must inform about the results obtained by contextualizing them, including ethnic outcomes.

Technological and documentary monitoring mission

In order to offer the best service to its clients, the genetic genealogist must carry out an important documentary watch corresponding to each of his clients, in the permanent evolutionary framework of this discipline.

Genetic genealogist specializing in genetics

I hope this article will have enlightened you on genetic genealogy. As always, I count on my savvy readers to supplement this article with their thoughts and suggestions. This definition of genetic genealogist is not exhaustive but presents the essential elements of this new specialization.