1 2 3 4 5 6 7 8 9
id,pos,chrom m_0,0.12,1 m_1,0.23,1 m_2,0.45,2 m_3,0.67,2 m_4,0.89,3 m_5,1.01,3 m_6,1.12,3 m_7,1.23,4