# Question #88b5b

Jan 10, 2018

Blood group A can suggest any of the two genotypes
IaIa(Homozygous)
IaIo(Heterozygous)
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

Jan 11, 2018

#### Explanation:

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.