Y Chromosome Test (Y-STR)

When one wishes to determine whether two or more male relatives share the same paternal line they can do this by doing a Y chromosomes test.

Results of Y chromosome testing

A Y Chromosome test can tell you:

  • Whether two alleged male siblings share the same father (irrelevant of whether they have a different mother or same mother). In this way they can determine whether they are full siblings or half siblings
  • If uncles, grandfathers and male first cousins share a common paternal line

The second point above needs some further elaborating. The Y-Chromosome test will confirm whether there is a biological relationship between males, however, the specific nature of that relationship cannot really be determined based on solely the test. Determining exact relationship might require genealogical research.

The Y chromosome, a chromosome found only in males, remains relatively unchanged as it is passed on from father to son. This works in favor of Y-chromosome testing as it makes the test reliable.

In cases where alleged brothers wishes to establish that they share the same father, we only suggest a Y chromosome test in cases when it is not possible to directly test the father. A paternity DNA test would be the option that provides stronger results.

You can order Y-chromosome test for two males at the cost of €299.

Visit our page for more information about our relationship DNA testing.

Order your X or Y Chromosome Test from homeDNAdirect today!


X Chromosome Test

The X chromosome test is a DNA test done between females who suspect they share the same biological father.If the alleged sisters do not have the same mother, then it is possible to carry out the X chromosome test with just their own DNA samples.

How the X chromosome test works

The X chromosome test is based on the fact that a female will inherit one X chromosome from the mother and another one from the father. Having different mothers therefore means that they will be half-sisters only if they have an X chromosome in common (which would be the one from the father). In case the X chromosome does not match then they will not be related at all.

In cases where the sisters share the same mother, we will need to carry out an X chromosome test with the mother’s sample so as to have a clear idea which common X-chromosome make up the sisters’ share with the mother. Once we have established this, we will then be able to determine whether they share the same father or not. If the mother in common is not available for testing, then we recommend that you do an STR siblings test.

Paternal grandmother and granddaughter

The X chromosome test can be used between paternal grandmother and granddaughter as they must share one X chromosome. This shared X chromosome is the one that the grandmother passed to her son and he, in turn, passed to his daughter. We only need DNA samples of the paternal grandmother and granddaughter for this test. We require no other samples in this particular case.

The X chromosome test from homeDNAdirect Ireland can be purchased starting at €399 for two females to be tested. Results will be available in 15 working days.

You may keep reading about our relationship DNA tests or click on one of the below options to proceed.

Order your X or Y Chromosome Test from homeDNAdirect today!  Have Us Call You!  Contact homeDNAdirect today!
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