Co-dominance
Post-Mendelian genetics · Biology
Study notes
AB blood group is co-dominance in action: the person makes both A and B antigens — neither allele hides, both express fully. Roan cattle (red + white hairs intermixed) and the MN blood group work the same way. Sickle-cell heterozygotes (HbA/HbS) make both normal and sickle haemoglobin — visible as two bands on electrophoresis.