STR Analysis – DNA Testing Methodology

Information about short tandem repeat analysis

STR, or short tandem repeat testing, seeks to locate shared DNA sequences between brother and sister. Full siblings will share a lot of their DNA whilst half siblings will share a smaller amount of genetic material. If they are not related at all, the amount of genetic material shared will be very low (if there happens to be some genetic material shared, it is due to the fact that we all have some DNA in common with each other). Adding the DNA sample of a known parent helps provide a more accurate sibling test result.

You will not need to do an STR analysis test:

• If only female siblings are taking part in the test and have different mothers; in this case we recommend an X-chromosome test;
• If only male siblings are taking part in the test; in this case we recommend a Y-chromosome test;
• To confirm if siblings are related from the maternal side, then an mtDNA test is recommended.

You can either return to our DNA Siblings Testing page for more information or click on on the below options.