Hello, This is my first time using R and HTqPCR package. I'm trying to do a miRNAs expression analysis. I have a problem in the end of the analysis, I want to represent my significant different expression miRNAs in a HeatMap using heatmapSig function, but it isn't work. These is my error: heatmapSig(DCtnorm.ttest, comparison = "all", zero.center = TRUE) Error in x$ddCt : $ operator is invalid for atomic vectors Thank you! Mar??a -- output of sessionInfo(): sessionInfo() R version 3.0.2 (2013-09-25) Platform: i386-w64-mingw32/i386 (32-bit) locale: [1] LC_COLLATE=Italian_Italy.1252 LC_CTYPE=Italian_Italy.1252 [3] LC_MONETARY=Italian_Italy.1252 LC_NUMERIC=C [5] LC_TIME=Italian_Italy.1252 attached base packages: [1] parallel stats graphics grDevices utils datasets methods [8] base other attached packages: [1] HTqPCR_1.16.0 limma_3.18.1 RColorBrewer_1.0-5 [4] Biobase_2.22.0 BiocGenerics_0.8.0 loaded via a namespace (and not attached): [1] affy_1.40.0 affyio_1.30.0 BiocInstaller_1.12.0 [4] bitops_1.0-6 caTools_1.16 gdata_2.13.2 [7] gplots_2.12.1 gtools_3.1.0 KernSmooth_2.23-10 [10] preprocessCore_1.24.0 stats4_3.0.2 tools_3.0.2 [13] zlibbioc_1.8.0 -- Sent via the guest posting facility at bioconductor.org.