The use of lod scores for the determination of the order of loci on a chromosome.

A method is given for calculating the probabilities of the possible gene orders for a group of syntenic loci using lod scores calculated for each pair of loci in the group. Applying it, we find the most probable gene order for the five loci on chromosome 1 to be PGM1; Rh; PGD; PEP-C; Fy. However, the probabilities for other orders such that Rh lies between PGM1 and PGD with PEP-C and Fy outside these three are of a similar order of magnitude and no firm conclusions can be given. The probability for other possible orders is negligible.