Assessing allelic dropout.

An assessment of allelic dropout based on 897 PCRs of known heterozygous individuals. The observed dropout rate was calculated for each marker, and the number of reactions showing long allele dropout and short allele dropout are shown. These values were used to estimate the average probability of misidentifying a heterozygote as a homozygote, if applying a multiple PCR repeats approach. Estimated error rates are indicated here for 2–5 PCR repeats. CT mean values (± st.dev.), as a proxy for DNA preservation, were calculated for DNA extracts showing dropout and no dropout respectively. P -values represent the significance of difference in mean values. Overall P-value was calculated with Fisher's approach.