Incomplete Dominance- Sickle Cell Anemia


  • Incomplete Dominance is when one allele is not completely dominant over another
  • Heterogeneous phenotype is a blending of the two homozygous phenotypes
  • Josef Kolreuter was the discover of incomplete dominance by doing the study of crossing a white and red flower and producing pink
  • Which is dominant and which is recessive alleles don't matter in this case
  • The third generation could have the result of either of the parents or the new attribute


  • A disease in which the hemoglobin protein is produced incorrectly example- the red blood cells have became sick shaped (crescent moon)
  • People with heterozygous have a fitness advantage; also resistant to severe malaria
  • The cells are stiff and sticky which blocks blood flow in the vessels
  • Causes pain, organ damage, and puts at risk of infection
  • Normal blood cells live for 120 days then die but sickle cells 10 to 20 days which is a problem because the bone marrow is not producing replacement fast enough
  • Inherited form of anemia based down by parents (both parents have to have the allele)

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