MapChart: Software for the Graphical Presentation of Linkage Maps and QTLs

Over the last 15 years a wealth of linkage maps and quantitative trait loci (QTL) mapping results have become available. The pace of generating this genetic infor-mation is accelerating owing to advances in molecular marker technology and the development of software for linkage anal-ysis and QTL mapping. A graphical presentation of this infor-mation is often needed, both for publica-tion purposes and for easy and intuitive interpretation. However, the development of tools for the graphical presentation of linkage maps and QTLs has lagged behind. DrawMap (Van Ooijen 1994) was an early program capable of drawing genetic link-age maps. However, the output of this pro-gram was not very well suited for use in modern word processors and presenta-tion software. Authors in this field have therefore, of necessity, resorted to the use of general graphics software to compose charts of their linkage and QTL maps. This is always a laborious process, with some-times disappointing results. Also, each time a map is recalculated when new data become available, this process has to be repeated. For this reason I developed MapChart, a software package that takes as input the linkage and QTL data and gen-erates charts of linkage maps and QTLs. These charts can easily be exported to word processing or presentation software. The charts are exported as vector graph-ics (Windows enhanced metafiles) rather than bitmaps, which makes them easy to rescale and to edit further if desired. User Interface MapChart has a standard Windows inter-face, with a main menu, toolbar, and pop-up menus. The manual is available from the Help menu in the form of an HTML file with index and links. Several maps can be opened simulta-neously, each in their own subwindow. A map window consists of two tab sheets. One sheet shows a text editor with the map data, the other shows the chart pag-es. The chart pages can be shown at sev-eral magnifications, from a full-page view to a view at printer resolution. Both the charts and the map data can be printed, saved to files, or copied to the Windows clipboard.