Construction of integrated genetic linkage maps by means of a new computer package: Join Map

Summary A computerized procedure to construct integrated genetic maps is presented. The computer program (Join Map) can handle raw data from F 2 s, backcrosses and recombinant inbred lines, as well as listed pair‐wise recombination frequencies. The procedure is useful for combining linkage data that have been collected in different experiments; the result is a mathematical alignment of the distinct genetic maps. Data from single experiments can be dealt with as well. In view of the fast growing amount of linkage information for molecular markers, which is often being generated by different research groups, integrated maps provide useful information on the map position of genes and DNA markers. The procedure performs a sequential build‐up of the map and, at each step, a numerical search for the best fitting order of markers. Weighted least squares is used for the estimation of map distances.