# Data preparation - Genetic Map (.map)

The map file, which name has to end with .map, is supplied by the user to specify the information regarding markers, and is very similar to the Flapjack format.

mrk | chr | pos
--- | --- | ---
Marker1 | 1 | 42.2
Marker2 | 1 | 64.0
Marker3 | 1 | 72.5
Marker4 | 1 | 90.8
Marker5 | 2 | 37.1
Marker6 | 2 | 52.2
Marker7 | 2 | 59.5
Marker8 | 2 | 74.8

mrk: name of markers, without blank in character chain.

chr: index (numerical value) of the chromosome where the marker is located.

pos: relative chromosomal position of loci (cM). Positions of the different loci must be obtained using the Haldane's mapping function (i.e. by assuming no interference).

#### Note:

- Never change the header field names (mrk/chr/pos).
- Check that decimals are 0.00 and not 0,00 for the markers positions column ("pos").
- The map files must be in plain-text, tab-delimited format. So, use tabulation and not spaces between fields (e.g. marker1{tab}1{tab}42.2).