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DNA - A Prosecutor’s Practice Notebook Inventory

Match Description

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The DNA analyst should describe what constitutes a match under their laboratory protocols. They should explain that for each and every typed site (i.e. loci) that yielded a conclusive result, both from the evidence sample taken from the victim/suspect/scene and the control sample, the results compared were found to be identical and therefore a "match." When a 13 loci STR typing is performed on an evidentiary sample and each of the 13 sites typed yielded conclusive results, the resulting match is based on 26 points of comparison (2 alleles at each loci X 13). If all 26 points (alleles) from the evidence sample match all 26 points from the control sample, a "match" is declared. The DNA analyst should also explain that in this example, if one site had not matched, the result would have been a definite exclusion. The typing results will also include amelogenin results.

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