STR Analysis - DNA Testing Methodology

STR testing (Short Tandem Repeat testing) is done between siblings who are brother in cases where they want to determine whether they are full siblings, half siblings or whether they are unrelated. This test is particularly useful in cases where the alleged parents are not available for testing.

An STR DNA test works by locating specific areas on a chromosome called genetic loci and comparing them between the samples of the siblings tested. People who are related share common DNA, due to the fact that we inherit DNA from each of our parents. The greater the degree of relatedness, the greater the amount of genetic material two people will have in common. This method of analysis will allow you to establish if you are full siblings, half siblings or not related at all.

The test involves the comparison of genetic profiles between siblings; for this reason it is recommended that a sample of a known parent is included for testing if this is available. This will help to distinguish between the maternal and paternal DNA inherited by the children, and so enable us to provide you with more conclusive results.

The STR test is priced at £269.00 for the testing of two siblings. Order Here.

Alternatives to STR testing

STR testing is recommended in cases where the siblings to be tested are male and female. This because, in cases of same sex siblings it may be simpler to use alternative tests. In the case of two males we would recommend the use of a Y chromosome test. In the case of two females with different mothers, then the X chromosome test is recommended.

Please note that in cases where both parents are unavailable for testing, and the alleged siblings want to know if they share the same biological mother, mtDNA testing can be considered as a viable alternative.

For more information, return to the Siblings DNA testing page.