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A segregating F2 population was made and the segregation pattern of in total 589 SNP markers were determined. Markers that were difficult to score of had identical segregation patterns were removed. From this dataset a genetic linkage map with molecular markers was calculated using JoinMap 4.1. Markers that were difficult to score were removed from the dataset and markers that showed an identical segregating pattern were considered as derived from the same place (locus) on the chromosome and only one was taken. Finally, 589 markers could be used to construct a genetic or molecular linkage map. An example of a linkage map of chromosome 6 of potato is given below.
linkage map of potato chromosome 6 is according to van Os et al. (2006).
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First count the recombinants between two markers and calculate the recombination frequency per marker combination. Do this for each marker combination possible. Finally draw a molecular linkage map based on the recombination frequencies.
From recombination frequency to cM (centimorgans)
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