Question

Sickle cell anaemia can be lethal in ____________ condition.

Options

• recessive homozygous

• co-dominant

• recessive heterozygous

• dominant heterozygous

Answer 1

Sickle cell anaemia can be lethal in recessive homozygous condition.

Explanation:

The disease sickle-cell anaemia is caused by the recessive Hb^s gene. A marriage between two sickle-cell anaemia carriers (Hb^A Hb^s) will give birth to healthy offspring. sickle cell carriers with (Hb^AHb^A) genotype

(Hb^AHb^s) genotype and sickle-cell anaemia with the Hb5 genotype Sickle-cell anaemia leads to death. Carriers and nonnal are left behind. Consequently, thus the (recessive) gene for sickle-cell anaemia is In homozygous state, it is lethal.