The data file must be tab("\t"), space(" ") or semi-colon(";")-delimited, with column names
(if exist) in the first row. Alleles should be separated with a slash "/", and column names
cannot begin with a number.
Missings can be codified either with string "NA", NULL (empty) values, or a new specified string.
An example of a data file could be the following:
id snp1 snp2 snp3 snp4 status sex age cat.bmi
1 C/C G/G A/G C/C Co Female 74 [25.9,29.0)
2 C/C G/G A/A C/G Co Male 50 [16.0,23.6)
3 C/C G/G A/G C/G Co Female 64 [16.0,23.6)
4 C/C G/G A/A C/C Ca Male 67 [16.0,23.6)
5 C/C G/G G/G C/C Co Female 80 [29.0,52.2]
6 C/C G/G A/G C/C Co Male 79 [29.0,52.2]
7 C/C G/G A/G C/G Ca Male 83 [16.0,23.6)
8 C/C G/G G/G C/C Co Male 53 [23.6,25.9)
9 C/C NA G/G C/G Ca Male 70 [25.9,29.0)
10 C/T G/G G/G C/G Ca Male 62 [25.9,29.0)