Rh Factor

[cloak25]

"The paternity of a royal heir is in dispute. The queen, (known to be the baby's mother) has AB- blood while the king has B-. The baby has A+ blood. The positive or negative Rh factor is transmitted as a classical Mendelian dominant/recessive trait, with + being dominant. Is the child the offspring of the king and queen?" (Note: passage states O blood type is recessive to A and B.)

A. Absolutely
B. Possibly
C. No
D. Unable to tell

Not even sure where to start for this question. help?

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[mcloaf]

Well, as Rh factor is classically dominant, for the baby to be Rh+ then one of the parents must be Rh+ as well. The king and queen are both Rh-, so the royal court should be checking the bloodtype of the mailman, or however you want to think about it.

 

[MedPR]

"The paternity of a royal heir is in dispute. The queen, (known to be the baby's mother) has AB- blood while the king has B-. The baby has A+ blood. The positive or negative Rh factor is transmitted as a classical Mendelian dominant/recessive trait, with + being dominant. Is the child the offspring of the king and queen?" (Note: passage states O blood type is recessive to A and B.)

A. Absolutely
B. Possibly
C. No
D. Unable to tell

Not even sure where to start for this question. help?

C. No.

The question says that Rh is a classical mendelian trait, which means that in order to be Rh-, you must be homozygous recessive. If both parents (or suspected parents, in this case) are Rh-, they cannot have Rh+ offspring together.

Say R is dominant allele and r is recessive allele. The queen is AB-, so she is rr, and the king is B-, so he is also rr. The child is A+, so it must be either RR or Rr. Neither of the parents has an "R" allele to donate, so the child cannot be the king's.

Also notice that the Rh factor is completely unrelated to the ABO type. If this question were about ABO and not Rh - as in, it didn't say anything about Rh +/- - then the child could possibly be the king's.

 

[gettheleadout]

I would say C as well. And here I thought this was going to be a Bombay phenotype problem

 

[cloak25]

Got it. Thanks.

 

[SaintJude]

If both the mother & father are rr, how did the baby get the Rh+ factor then? The queen is "known to be the baby's mother & the Rh factor is supposedly inherited via Mendelian patterns.

 

[gettheleadout]

If both the mother & father are rr, how did the baby get the Rh+ factor then? The queen is "known to be the baby's mother & the Rh factor is supposedly inherited via Mendelian patterns.

The King isn't the only one who's been visiting Her Majesty's chambers.

 

[milski]

How do we know that the queen was the mother? Maybe the king was the cheater? It's such a sexist stereotype to blame it on the woman!

 

[gettheleadout]

How do we know that the queen was the mother? Maybe the king was the cheater? It's such a sexist stereotype to blame it on the woman!

"The paternity of a royal heir is in dispute. The queen, (known to be the baby's mother) has AB- blood while the king has B-. The baby has A+ blood. The positive or negative Rh factor is transmitted as a classical Mendelian dominant/recessive trait, with + being dominant. Is the child the offspring of the king and queen?" (Note: passage states O blood type is recessive to A and B.)

If you mean how does the problem supposedly know, well, it's easy to watch a women give birth, not so easy to see her conceive.

 

[SaintJude]

How do we know that the queen was the mother?

Strangely, the problem explicitly states that "the queen was the mother" That's why I said it's impossible to tell, b/c it's look the queen mother got herself a surrogate to carry a biologically unrelated child.
This is too much scandal for me and I'm saying this question's setup is faulty.

 

[MedPR]

How do we know that the queen was the mother? Maybe the king was the cheater? It's such a sexist stereotype to blame it on the woman!

Well someone probably saw the queen give birth