To pool or not to pool your biological samples Rafael A Irizarry

Design I SubjectmRNA PoolAssay

Design II or Big Mistake I Subjects mRNA Pool Assay

If you pool you see –Truth + (average of individuas 1-3) + (average of meas error 1-3) If you don’t pool you see –Y 1 =Truth + individual 1 + meas error 1 –Y 2 =Truth + individual 2 + meas error 2 –Y 3 =Truth + individual 3 + meas error 3 Each one has more variance than if you pool but average of Y 1, Y 2, Y 3 should also be –Truth + (average of individuals 1-3) + (average of meas error 1-3) But you also get to see variance of Y 1, Y 2, Y 3 !

Problem with pooling everything

Design I SubjectmRNA PoolArray

Design II Subjects mRNA PoolArray

Better than pooling everything

Another Advantage Log(Y 1 + Y 2 + Y 3 ) not equal to Log(Y 1 ) + Log(Y 2 ) + log(Y 3 )

Thanks!