I have noticed that some values in the ENCODE repli-seq wavelet-smoothed signal are negative. Does anyone know how this can occur and what is the relevance? The documentation states the wavelet smoothed signal was calculated as...
formula=(0.917*G1b)+(0.750*S1)+(0.583*S2)+(0.417*S3)+(0.250*S4)+(0*G2)
.
Suggesting as an additive formula that one part of the cell cycle must be a negative value.
As a high value is early replication with low values as late replicating. how late does it have to be to be zero or negative? Is it safe to treat negative values as zero or, if a positive value is required as a very small number, i.e. 0.00001?