Question

Gene for sickle cell anaemia is carried by

• A. Sex cells
• B. Sex chromosomes
• C. Autosomes
• D. Bone cells

Answer 1

Answer: (C)

Autosomes

Sickle cell anaemia is an autosomal recesive disorder.

Autosomal recessive inheritance means that the gene in question is located on one of the autosomes (which are not sex chromosomes). "Recessive" means that 2 non-working copies of the gene are necessary to have the trait or disorder. One is inherited from the mother, and one from the father. If you have only 1 recessive gene, you are a "carrier" for the trait or disease, but you do not have any health problems from "carrying" 1 copy of the gene. Once parents have had a child with a recessive trait or disease, there is a 1 out of 4, or a 25%, chance that with each subsequent pregnancy, another child will be born with the same trait or disorder. This means that there is a 3 out of 4, or a 75%, chance that another child will not have the trait or disease.

So, the correct answer is 'Autosomes'.