TECHNICAL INFORMATION:

During a DNA sibling test, a buccal swab (mouth swab) is collected from each of the alleged siblings to obtain cells containing genetic information in the form of DNA (deoxyribonucleic acid). Each person’s DNA represents a unique “genetic blueprint,” similar to a fingerprint. In the laboratory, the DNA is extracted from the cells, and specific DNA regions are amplified through a process called PCR (polymerase chain reaction) for thorough examination. The siblings’ DNA patterns are then compared to each other. A statistical analysis is conducted based on the match type typically expected for true biologically related sibling pairs, generating a “full sibling index” and “half sibling index.” True biologically related full sibling pairs (with the same mother and father) usually have a full sibling index value greater than 1.0 in their DNA sibling test report. Conversely, individuals who are not full siblings typically have a full sibling index value less than 1.0. True biologically related half sibling pairs (with only one parent in common) usually have a half sibling index value greater than 1.0 in their DNA sibling test report. Conversely, individuals who are not related typically have a half sibling index value less than 1.0. The higher the sibling index value over 1.0, the greater the likelihood that the two individuals are biologically related as siblings. Similarly, a half sibling index value of 1.5 indicates that the siblings share more genetic material than would be expected by chance alone. Conversely, the lower the sibling index value is below 1.0, the lower the probability that the two individuals are biologically related as siblings.