sickle-cell anaemia

• homozygous for normal haemoglobin?

  = don't have the disease
• Homozygous for sickle haemoglobin=

  have sickle-cell anaemia

  • all their blood cells are sickle-shaped
• heterozygous-


  have an in-between phenotype, called the sickle-cell trait

  • they have some normal Hb and some sickle Hb
  • the 2 alleles are codominant because they are BOTH EXPRESSED IN THE PHENOTYPE