Problem: Sickle cell anaemia is a condition in which red blood cells can change their shape and flexibility from flexible discs to rigid crescent (sickle) shaped cells. The shape and rigidity of the sickle cells make them block up microvasculature, causing pain, infection and organ damage.
For the following families determine the genotypes of parents and offspring. If the possible genotype is more than one type then list both.
1. Two normal parents have four normal children and one with sickle cell anaemia;
2. A normal male and a female with sickle cell anaemia have six children, all normal;
3. A normal male and a female with sickle cell anaemia have six children, three normal and three have sickle cell anaemia.
Draw a pedigree chart for families in (ii) and (iii).