Four founders (designated 49-52 OQ) were produced by microinjecting a BAC clone bearing the WT Tmprss6 sequence into single-cell embryos homozygous for the mask mutation. Hemoglobin and serum iron levels in each of the founders, in blood sampled at 4 weeks of age. B6 controls, age-matched C57BL/6J mice, N=4. Non-transgenic controls, Tmprss6msk/msk littermates that lacked the transgene, N=4. Error bars indicate 1 SEM.