Due to the science behind DNA testing, results for a relationship test have to be worded in a certain way that isn’t always easily understandable. Here are the interpretations of common statements in a report and what they mean for the results of your test.
PATERNITY and MATERNITY
Paternity and maternity testing will typically return one of two results: “cannot be excluded” or “excluded”.
If your report contains the statement, “…[name] cannot be excluded as the biological mother / father of [name]”, this means the genetic evidence determined that the tested parent is the biological parent of the tested child.
If your report contains the statement, “[name] is excluded as the biological mother / father of [name]”, this means that there is no direct parent-to-child biological relationship between the tested parent and tested child.
FULL SIBLINGS
Full siblingship is a first order relationship similar to paternity and maternity but, due to the decreased likelihood of the participants sharing an allele, the results for full sibling testing are not as straightforward as paternity or maternity tests. There are several results you could receive from a full siblingship test. Please look at the list below for the statement in your report to determine your results:
“…the relationship is highly likely…”
This result occurs when the Calculated Relationship Index (CRI) is greater than 100.0. The statement means the genetic evidence significantly favors the probability that the tested participants are full siblings.
“…the results support the relationship…”
This result occurs when the CRI is between 10.0 and 99.9. The statement means that the genetic evidence indicates that the tested participants may be full siblings, but further testing with a parent is strongly suggested.
“…it is uncertain that [name] and [name] are related as first degree relatives.”
This result occurs when the CRI is between 0.1 and 10.0. This is called the “grey area” where analysts are unable to say one way or the other whether or not the tested participants could be full siblings. Further testing with a parent is strongly suggested.
HALF SIBLINGS, UNCLE- or AUNT-TO-CHILD, and GRANDPATERNITY
Half siblingship, avuncular (uncle- or aunt-to-child), and grandpaternity testing are not direct relationships like that of a parent to a child or potential full siblings. Due to the degree of separation in the relationship, it is strongly recommended to include a parent that is directly related to one or both participants. There are several results you could receive from a second degree relationship test. Please look at the list below for the statement in your report to determine your results:
“…the relationship is highly likely…”
This result occurs when the CRI is greater than 100.0. The statement means the genetic evidence significantly favors the probability that the participants share the biological relationship that was tested.
“…the results support the relationship…”
This result occurs when the CRI is between 20.0 and 99.9. The statement means that the genetic evidence indicates that the participants may share the biological relationship that was tested, but certain alleles in the tested DNA are very common in the population and therefore give less weight to the alleged relationship. It is strongly recommended to include a parent that is directly related to one or both participants to improve the clarity of this result.
“…it is uncertain that [name] and [name] are related as second degree relatives.”
This result occurs when the CRI is between less than 20.0. This is called the “grey area” where analysts are unable to say one way or the other whether or not the participants share the biological relationship that was tested. Further testing with a parent that is directly related to one or both participants is strongly suggested. The lower the CRI value, the less likely that tested participants share the biological relationship that was tested.
Y-STR MALE LINEAGE
Y-STR testing between two males will return one of two results: “consistent” or “not consistent”.
If your report contains the statement “The DNA profile produced from the sample labeled as [name] is consistent with the profile produced from the sample labeled as [name]”, this means that the tested participants are likely to have come from the same male lineage. If testing two brothers, this can indicate that they share the same father.
If your report contains the statement “The DNA profile produced from the sample labeled as [name] is not consistent with the profile produced from the sample labeled as [name]”, this means that the two participants did not come from the same male lineage.
If your results were not listed here, please contact us to discuss your results.