Application of a nonisotopic southern hybridization method for sex determination from bloodstains found in criminal spots

: Bloodstains collected from criminal spots were submitted to the nonisotopic Southern hybridization (NISH) method for sex identification (Kobayashi et al., J. Forens. Sci., 33, 613-620, 1988). A RNA probe, transcripted from a Y-chromosome specific DNA sequence (Nakahori et al., Nucl. Aci. Res., 14, 7569-7580), was used for this series of investigations. Among the 95 bloodstain specimens studied, in which the sex of each was previously known, 54 (88.5%) of 61 male stains were appropriately determined to be male by the NISH method, and 28 (82.4%) of 34 female bloodstain specimens were estimated to be female. The sex of the 13 remaining stain specimens were unable to be determined by this method, but no specimen was erroneously misidentified. With regard to 12 specimens, in which the sex of each was unknown at the time of the NISH test, 5 were determined as being male and 3 were estimated as being female, though the sex of the remaining 4 specimens could not be determined. The causes in the stains that made determination impossible were analyzed using patterns of ethidium bromide fluorescence of electrophoresed gel and/or NISH, and it was concluded that this could be due to an insufficient quantity of extracted DNA (12 cases), the resistance against a restriction enzyme (EcoRI) (3 cases), and the depolymerization of the Y-chromosome specific fragment (2 cases).