We have been preparing a new version of Gitools with many improvements, amongst which there is a new IGV search, the use of categorical scales and new data aggregation methods that can be used to annotate the heatmap.
Gitools is an interactive heatmap viewer which can also perform various analysis over the data. Heatmaps in Gitools can be multidimensional, with various values per cell, which is very practical for cancer genomics data analysis and visualization (read more).
Let us introduce the new features step by step.
New data visualization features (screenshot)
IGV search (1 in screenshot)
Integrative Genomics Viewer (IGV) is a very powerful genomic browser that provides a complementary visualization of multidimensional genomics data to that of interactive heatmaps. Often it is useful to explore this type of data with the two tools at the same time. With that idea in mind we did a first step to integrate the two types of views. Using the IGV interface for other applications to send commands, Gitools can now locate any position within the human chromosome in your opened instance of IGV. In the screenshot we have the focus on the gene CPM (with the Ensembl id ENSG00000135678). If you click the link “Locate Id in genomic viewer (IGV)” in the left details panel, Gitools will locate the gene within IGV. If you have many genes selected, then Gitools will tell IGV to show them in split screen view.
Display name in color labels (2 in screenshot)
Adding data header from aggregated values (3 in screenshot)
A new type of header can be added now to columns or rows: Aggregated heatmap from matrix data. In the screenshot we can see at (3) the mean expression values, calculated with the mean aggregation method for each row. The aggregation of the values can be calculated for the whole row, just for some selected columns or according to column annotations, as it is the case in the screenshot. Note that even though the mean expression values are shown in the rows annotations, the main heatmap is displaying alteration events.
The aggregated values are represented by the color scale (chosen by the user) and optionally by value text labels. We can see that, in the highlighted gene, the expression mean between the classical and mesenchymal subtype of the glioblastoma brain tumour differ substantially.
Categorical scale and scale drawing (4 in screenshot)
We have added a new color scale to Gitools: the categorical scale. It is designed to visualize categorical data, as shown in the screenshot. Each different data value is assigned to a color, which can be set by the user. The way that the color scales are drawn has been redesigned to be more intuitive.
Color scale memory: Gitools remembers to what data dimension which color scale has been selected. After having actively selected or modified a color scale, this very color scale will be selected after switching back to the data dimension.
Save analysis: When you perform an analysis “on the fly” in Gitools by selecting the menu Analysis -> Your analysis the save button on the top will be activated to let you save the analysis data and results to the hard disk.