The lod score reflects the odds that two loci are linked with a given recombination fraction. Lod scores can be summed across families.
For a given recombination fraction (theta) and a family with both nonrecombinant and recombinant offspring and phase known meioses:
lod score for given theta =
= ((total number of children) * LOG10(2)) + ((number of nonrecombinants) * LOG10(1 - (theta))) + ((number of recombinants) * LOG10 (theta))
where:
• theta = recombination fraction = recombination between the disease locus and the DNA marker locus tested
• The values of theta range from 0 to 0.5.
Interpretation:
• A value for theta of 0.5 indicates that the loci are unlinked.
• An lod score >= 3.0 indicates that there is statistically significant evidence of linkage.
• An lod score from -2.0 to +2.9 are inconclusive.
• An lod score < -2.0 is evidence against linkage.
