RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM - MOLECULAR-WEIGHT ANALYSIS AND CALCULATION WITH A SCANNER-BASED COMPUTER-SYSTEM

For an exact and reproducible molecular weight calculation, an essenti al requirement in all applications of DNA profiling, we present a new system, called RFLP-MAC (restriction fragment length polymorphism - mo lecular weight analysis and calculation). The system is composed of a sensitive digital gray-scale scanner unit and an Apple Macintosh compu ter supported by a powerful combination of a shareware and self-develo ped software package. Molecular weights are calculated by profiling th e optical density and band particle processing parameters to identify the unknown DNA fragments. Mathematical models were used to interpolat e the transverse and horizontal migration directions of the molecular weight standards, insuring consistent results from gel to gel. All dat a are stored in a relational multi-user database system. Descriptive s tatistics are performed and allele frequencies are analyzed. Procedure s for image-analysis, molecular weight calculation, statistical evalua tions and database management were developed and run,within the multit asking environment of 4th Dimension. Two sets of data, intragel and in tergel measurements, are investigated in order to check the precision of the RFLP-MAC system. All these data are subjected to a standard ana lysis of variance resulting in a maximal 3 SD value of 0.005 (0.288%) for the intragel and of 0.091 (1.654%) for the intergel variation.