The abbreviation for “logarithm of the odds favoring linkage.” The lod score method is employed in the statistical analyses of linkage. In the calculations, a pedigree is analyzed to determine the likelihood or probability (Pr) that two genes show a specified recombination value (r). Next, the likelihood (Pi) is calculated under the assumption that the genes assort independently. The lod score Z = log10(Pr/Pi). The advantage of using logarithms is that the scores from new pedigrees can be added to earlier Z values as they become available. A Z score of +3 is considered evidence for linkage. A computer program such as LIPED makes laborious manual computations unnecessary and is generally used in analyzing a collection of complex pedigrees. See Chronology, 1955, Morton; 1974, Ott.
Subjects: Genetics and Genomics.