Answer :
The probability that if this couple has a child, the child will have sickle-cell disease is P=1/9.
What is sickle cell disease caused by?
The sickle cell gene is inherited and results in sickle cell disease. You cannot catch HPV from an infected person because it is not brought on by whatever the parents did either before or during the pregnancy.
Briefing:
Parents of Keisha and Jerome carried the sickle cell allele.
Keisha and Jerome had a 1/4 likelihood of contracting the illness (XX), a 1/2 likelihood of being a carrier (Xx), and a 1/4 likelihood of not contracting the illness (XX).
Since Keisha and Jerome don't have the illness, we can conclude that they are either XX or XX. Accordingly, each of them has a 2/3 chance of being a carrier (Xx).
Given that if a kid has the disease, then both parents must be carriers, the likelihood that both parents were carriers is 2/3 x 2/3, or 4/9.
One of their progeny will be XX (non-carriers) out of the 4 chances they have out of 9, two will be Xa (carriers), and one will be xx (disease).
It indicates that if these parents produce a child, the likelihood that the infant will have sickle-cell disease is 1 in 9.P=1/9
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