CROSSFIND: software for detecting and displaying well-characterised meiotic breakpoints in human family data

An algorithm for detecting well-characterised breakpoints in human family data has been developed and implemented as a computer program. The well-established program CRI-Map is used to perform the necessary likelihood analysis and generate the individual chromosomes, and then a set of user-defined parameters is used to detect the breakpoints, sort them by their position and classify them according to their support. A further program produces PostScript figures giving a visual representation of the breakpoints. The programs can be applied to data from human chromosomes, and the resulting breakpoint panels used to place new markers rapidly on to the map by typing only a few key individuals and their ancestors. A service has been established on the World Wide Web for chromosome 9, allowing workers to fill in an on-line form requesting a suitable panel of breakpoints to facilitate the mapping of new markers. A key feature of this approach is that all of the computing is done whilst detecting the breakpoints, after which new markers can be positioned without any need for a computer. CROSSFIND has been used to generate all the meiotic breakpoint panels shown in the preceding paper by members of the Eurogem Collaboration (Cox et al 1996).