Hi, I have isoform-level deep RNA-seq data from stringtie on about 800 people. I have created gene-level and isoform-level data using tximport. I have just looked at the voom mean-variance trend plots. At the gene level, the plot looks as usual (decreases at low expression levels and then levels off). For the isoform data, the plot looks different, the fit curve continues to decrease all along the x-axis without ever leveling off (so no variance stabilization). I have done this both with loose and quite stringent filtering (requiring at least 15 reads in 75% of individuals for the stringent filtering), and in both cases the plot looks the same. We do not need variance stabilization since we use the voom weights in subsequent analyses, but is this type of plot of any concern? Has this been seen for other isoform data? As expected the isoform data points cluster strongly on the left side of the graph, while the gene-level data cluster more in the middle. Thank you for any comments.