CHARACTERIZATION OF HUMAN LYMPHOID-CELL LINES GM9947 AND GM9948 AS INTRALABORATORY AND INTERLABORATORY REFERENCE-STANDARDS FOR DNA TYPING

The incorporation of reference DNA is crucial to the validation of any DNA typing protocol. Currently, reference DNA standards are restricte d to molecular size DNA ladders and/or tumor cell line DNA Either of t hese, however, presents some limitations. We have rigorously character ized two Epstein-Barr virus (EBV)-immortalized human lymphoid cell lin es-GM9947 (female) and GM9948 (male)-to determine their suitability as alternative in-line standards for three widely employed allele profil ing strategies. Twenty-one highly polymorphic VNTR-based allelic syste ms (7 RFLPs, 2 AmpFLPs, and 12 STRs) distributed over 12 chromosomes w ere scrutinized along with 3 gender-based discriminatory systems. The genetic stability of each locus was confirmed over a period of 225 in vitro population doublings. Allele size estimates and degree of inform ativeness for each of the 21 VNTR systems were compiled. The reproduci bility of allele scoring by traditional RFLP analyses, using both cell lines as reference standards, was also verified by an interlaboratory validation study involving 13 analysts from two geographically distin ct forensic laboratories. Taken together, our data indicate that GM994 7 and GM9948 genomic DNAs could be adopted as reliable reference stand ards for DNA typing. (C) 1995 Academic Press, Inc.