Measuring precision in determining the length of restriction fragments within the scope of DNA analysis

Because of the measurement error that is known from the length determination of restriction fragments during DNA analysis, it is necessary to determine the precision by which identical DNA can be evaluated. Besides the collection of frequency data from a certain population this is one of the basic prerequisites to calculate the likelihood ratio of an established polymorphism. By multiple measurement of restriction fragments from different persons indicated by the probes MS1, MS31, MS43A, g3 and YNH24 on different blots the within-laboratory variation was determined in the complete separation area from 1 to 19 kb. The values were compared to procedures used by other laboratories.