Data QC with plink: Whole genome association analysis plink toolset.
Added sex info into files.
Get allele frequencies.
Merge hapmap samples CEU, YRI, JPT, CHB (failed due to strand error).
Cross merge hapmap samples YRI, JPT, CHB with CEU (failed, but we got missing snps).
Flip dna strand for missing snps.
Re-cross merge hapmap samples (finished successfully).
Merge all hapmap samples: CEU with the flipped-stand versions of YRI, JPT, CHB (failed due to strand error).