See below for full questions and answers:

Questions:

Sickle-cell anaemia is an inherited condition caued by a dominant allele.

Sickle cell anaemia is a disorder of the blood caused by an inherited abnormal haemoglobin the abnormal haemoglobin causes distorted (sickled) red blood cells. The sickled red blood cells are fragile and prone to rupture.

The man had a blood sample taken, its showed the sickle cell reb blood cells. 

The man’s mother also has sickle-cell anaemia but his father does not.

The man is heterozygous for sickle-cell anaemia.How the information given above shows that the man is heterozygous for sickle cell anaemia. [3 marks]The man marries a woman who does not have sickle-cell anaemia. What is the probability that their first child will have anaemia? [1 mark]

Answers:

Part I)The man has inherited SC allele from mother as shown on the blood film.

The man will have inherited normal recessive allele from father as he doesn’t have SC alleles at all.

Father homozygous recessive so no SC alleles on either chromosome.

Part II)Father is recessive homozygous

Mother is dominant heterozygous

So, child has a 50% chance