What kinship testing does
Kinship analysis evaluates genetic evidence for proposed relationships when direct parentage testing is unavailable or when a more complex pedigree must be assessed.
Key principles for kinship testing
Common relationships
Analyses may include full siblings, half siblings, grandparent-grandchild, aunt/uncle-niece/nephew and other specified relationships.
Likelihood ratios
The laboratory compares competing relationship hypotheses. For example, the evidence may be evaluated under a full-sibling hypothesis versus an unrelated hypothesis. The resulting likelihood ratio indicates how much more probable the DNA evidence is under one hypothesis than the other.
Pedigree accuracy
The calculation is only as appropriate as the relationship hypotheses supplied. Undisclosed relatives, endogamy, consanguinity or an incorrect pedigree can materially alter interpretation.
Additional relatives
Testing an available parent, known sibling, grandparent or other informative relative can substantially increase the power of the analysis.
Limitations
More distant relationships share less DNA and can produce overlapping distributions with unrelated individuals. Some cases remain inconclusive despite technically successful testing.
Forensic/legal use note: This material is educational. Evidentiary admissibility, collection authority, consent and procedural requirements are jurisdiction- and case-specific. Follow applicable law, court directions and the requesting authority’s requirements.
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