1    snp1   0   1000
X    snp2   0   1000
Y    snp3   0   1000
XY   snp4   0   1000
MT   snp5   0   1000
20   snp6   0   551234
20   snp7   0   -551235
20   snp8   0   567890
0    snp9   0   1234321
10   snp10  0   987456
10   snp11  0   5672341