What is the Y chromosome?

The Y chromosome is one of the two sex chromosomes present in humans. Unlike the X chromosome, which can be inherited by both men and women, the Y chromosome is exclusively passed from father to son.

It plays a key role in determining male sex and contains specific genes related to male development. More generally, a chromosome is a structure composed of DNA that contains an individual's genetic information.

Why perform a genetic profile test of the Y chromosome?

The Y chromosome genetic profile test provides a unique genetic signature of your Y chromosome. Unlike a paternal lineage search, this test does not aim to trace ancestors or genealogical matches. It simply establishes a profile that you can compare with other Y profiles to determine if they are identical or not.

This type of test is useful in several situations

Confirmation of family links: Two men can compare their Y profiles to verify if they share a direct paternal lineage, for example, in cases of adoption or family separation.
Legal and judicial testing: It can be used in certain legal cases, particularly to confirm kinship in paternity recognition or disputed inheritance cases.
Genetic identification in forensic medicine: Law enforcement and forensic experts sometimes use the Y profile to identify unknown individuals or establish family links between human remains.
Historical and archaeological research: The test can be used to analyze ancient human remains and identify genetic connections between different male lineages.
Genealogy and ethnic studies: It helps trace the origin of certain male family lines and understand human migrations.
Detection of specific genetic mutations: Certain rare medical conditions transmitted by the Y chromosome can be studied through this test.

What does a Y chromosome genetic profile look like?

The results of a Y chromosome genetic profile are presented in a table indicating the analyzed markers (STR loci) and their corresponding alleles. Here is an example of how results are presented:

This table allows for comparing genetic profiles between individuals to determine if they are identical or not. Each individual has a unique profile based on their Y-STR markers, which are passed from father to son.

How is the Y chromosome profile test conducted?

The test is simple and non-invasive. It is performed using a saliva sample, but other non-standard samples can be used if necessary. Here are the main steps of the process:

Ordering the kit: You receive a home sampling kit containing all the necessary materials.
Collecting the sample: A saliva sample is collected using a buccal swab.
Sending it to the laboratory: Once the sample is taken, it is sent back using the provided envelope.
Laboratory analysis: The sample is analyzed to establish your Y chromosome genetic profile.
Receiving results: Within a few weeks, you receive a detailed report with your genetic profile.

How long does it take to get the results?

Results are available within 5 days for a buccal sample and within 10 days for a non-standard sample after the laboratory receives it. You will be informed of your test’s progress at each step.

What types of samples can be used, and how reliable are they?

The Y chromosome profile test can be performed using various sample types, each offering a different level of reliability:

Buccal swab (saliva sample): The most commonly used method due to its simplicity and reliability. It provides accurate and reproducible results within 5 days of laboratory reception.
Hair with root bulb: This type of sample can be used if a saliva sample is unavailable. However, it requires more complex extraction, and DNA quality may vary.
Dried blood (on filter paper): A reliable alternative that allows for long-term storage and effective analysis, though with a slightly longer processing time.
Cut nails: Contain DNA, but in varying quantities depending on sample quality.
Used razor: May contain skin cells and hair follicles that can be analyzed.
Toothbrush: May contain saliva traces and serves as an alternative in the absence of a buccal sample.
Semen: A rich and reliable source of DNA for analysis.
Earwax (used cotton swab): Contains shed cells that can be used for DNA extraction.
Used tissue: May contain saliva and shed cells.
Cigarette butts: Can contain saliva and serve as a viable DNA source.

Each sample type is processed rigorously to ensure the highest possible reliability of results, although non-standard samples may require more extensive analysis, leading to a processing time of up to 10 days.

There are several ways to use a Y chromosome test depending on the needs:

Comparison of Y profiles: If two men wish to verify whether they belong to the same paternal lineage, they can compare their Y-STR chromosome results. If their profiles are identical or very similar, they share a common paternal ancestor.
In-depth paternal lineage search: To go further, a genealogical Y chromosome test can be conducted. This test searches for matches in a genealogical database to find individuals with similar profiles and potentially identify a common ancestral lineage.

These analyses help refine family link research and explore the genetic history of a paternal lineage with greater precision.