PATERN 16.09.96 PATERN is a computer program for the calculation of paternity probabilities from multilocus DNA profiles. An appropriate reference to the mathematical model employed is Krawczak M, Bockel B (1992) A genetic factor model for the statistical analysis of multilocus DNA fingerprints. Electrophoresis 13: 10-17. Once the program has been started and the major layout has appeared on the screen, various options are available. These options are activated by hitting the corresponding keys, as indicated in brackets. For example, uit means that, after hitting either the q-key or the Q-key, the show is over. Options dit pattern - Enter and edit the frequency of the position-wise DNA fingerprint patterns. The window for editing is moved up and down using the cursor keys. Within the window, the cursor is moved left or right using the cursor keys as well. Type ^X to finish editing (i.e. press or and X-key simultaneously). Likelihoods and paternity probabilities will be updated automatically. Usually, the total number of gel positions analyzed is determined automatically as the sum of the frequencies of the eight possible DNA fingerprint patterns. However, when the program is started using option S, i.e. when patern s is entered at the DOS prompt, the total number of gel positions can be edited. Then, the number of '---' patterns is calculated automatically. Inconsistencies are eliminated in that the number of '---' patterns is set equal to zero, and the total number of gel positions is determined as the sum of the frequencies of the remaining seven patterns. If the program is started using option A, i.e. entering patern a from DOS, then neither the number of '---' patterns nor the total number of positions can be edited. In this case, the bandsharing between mother and putative father is determined from patterns including at least one '+', and the number of '---' is chosen such that the bandsharing rate equals the probability of appearence of a band (see below). The latter can not be edited. ppearence prob. - Enter or estimate the probability of appearence of a band at a single gel position (i.e. the band sharing probability). This figure can either be estimated from the maternal and paternal DNA fingerprints (), or can be entered and edited manually (). utation prob. - Enter or edit the mutation probability (i.e. the probability of observing an offspring band at a position where a band is lacking in both parental fingerprints). The default value is 0.001 which represents a good estimate for a variety of typing systems in humans. Paternity probabilities of 0.00000% or 100.00000% are due to the fixed decimal format (maximum = 5 digits). The precise probability can be computed from the LOG10(LIKELIHOOD-RATIO) (LR) using the following formula: P x 10^LR W = 100 x ----------------- P x 10^LR + (1-P) where P is the prior probability of paternity. Best wishes MK