Conditional Probability and Databases
Calculations may also be performed to determine the probability of seeing a certain profile given that it has been seen once already, which is a factor to be considered in regard to the integrity of database information.
This type of conditional probability uses the equations 4.10a and 4.10b from NRC II report.
Click here to read about equation 4.10a in NRC
Click here to read about equation 4.10b in NRC
For homozygotes use:
P(AiAi|AiAi) = [2θ+(1-θ)pi][3θ+(1-θ)pi]/[(1+θ)(1+2θ)]
For heterozygotes use:
P(AiAj|AiAj) = 2[θ+(1-θ)pi][θ+(1-θ)pj]/[(1+θ)(1+2θ)]
where θ is the average of the parameters of θ over all genotypes
As with forensic samples, a five event minimum allele frequency should be used for rare alleles.
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