Format for the Pedigree file:

1. The pedigree file should contain two lines: one line for each twin.

2. The first two positions should be filled by the individuals identifiers. 
   The first of which should be the family's numeric name, 
   while the second one is the individuals numeric name.

3. The next two positions should be filled by the individuals father's and
   mother's individuals identifiers. If these are unknown, these positions
   should be filled with zeroes (0). Data on an individual's parents need
   not be included in the pedigree file and should not be included if no marker
   data is available.

4. The fifth position should be filled by the individuals sex: MALE=1,
   FEMALE=2, UNSPECIFIED=0.

5. The remaining positions should be filled by the 2m (m = no. of markers) 
   alleles of the individuals genotype, in order by marker. 
   If the genotype is unknown, then 0's may fill the positions.
   Males should be homozygous for X and Y chromosome markers.
   Females should have 0's in the Y chromosome marker posisitons.

For example:

1 1 0 0 1 1 1 2 2 301 301 404 404
1 2 0 0 1 1 1 2 2 301 301 404 404