Question #88b5b

2 Answers
Jan 10, 2018

Blood group A can suggest any of the two genotypes
Similarly B blood group can be
either IbIb or IbIo
As you have blood group O you have the genotype IoIo which is the only one genotype that codes for blood group O
So it means you had received those two gametes from your parents,both of which had Io allele in it.
Whereas your brothers and sisters received Ib from your dad and Io from your mom,hence became IbIo i.e the genotype for blood group B

Jan 11, 2018

Your blood group (and those of your sisters) depend on the respective genes received from your parents.


Your mother having the phenotype A+ could have four possible genotypes: AA-DD, AO-DD, AA-Dd, or AO-Dd, where A codes for the blood cell marker A, O means that there is no marker, D codes for the presence of the rhesus factor, and d indicates its absence.

Your father having the phenotype B- could have two possible genotypes: BB-dd, or BO-dd,where B codes for the blood cell marker B, O means that there is no marker, and d indicates the absence of the rhesus factor.

From the above genotypes, and examining your and your sisters' blood groups, it is apparent that your mother's blood group genotype is AO-Dd and your father's blood group genotype is BO-dd.

From these genes, the following combinations are possible:

  1. AB-Dd=AB+ and AB-dd=AB-
  2. AO-Dd=A+ and AO-dd=A-
  3. BO-Dd=B+ and BO-dd=B-
  4. OO-Dd=O+ and OO-dd=O-

You mentioned that your blood group is O+ with negative Rh factor; I presume what you mean is that your blood group is O-.

As you can see from the eight possibilities, your blood group and those of your sisters are possible when we consider the deduced genotype of your parents.