Products of Partial Digestion with <i>Hae</i> III. Part 1. Characterization, Casework Experience and Confirmation of the Theory of Three-, Four- and Five-Banded RFLP Pattern Origins Using Partial Digestion

The sizes of Hae III partial digestion products at D1S7, D2S44, D4S139, D5S110, D10S28, and D17S26 were evaluated in experimentally generated partial digestions of liquid blood DNA. The partial digestion products were highly predictable, suggesting a very high level of sequence conservation in regions flanking variable number tandem repeat (VNTR) blocks. Partial digestion bands associated with three-or-more-banded patterns were also characterized. Partial digestion of three-banded patterns can be used to determine whether the extra bands arise due to internal Hae III sites in the VNTR block and to identify hidden three-banded patterns. Partial digestion products from forensic casework also conformed to size expectations. Presumed partial digestion bands from 27 forensic samples were compared to the experimentally generated data. The causes of partial digestion are examined and recommendations for interpreting forensic DNA evidence exhibiting partial digestion products are given.