What Blood Types Should Not Have Babies Together?
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I have heard that certain combinations of blood types in parents cannot possibly give rise to particular blood types in their offspring - indeed, several plays and stories have used this as a plot device to reveal at some point that a person's social father could not have been his/her biological father. Is this true, or a myth? And if true, what are the "impossible" combinations?
Peter Wardley-Repen, Ashford-in-the-Water UK
- You can have any combination of A and B - i.e. you can have A (just A), B (just B), AB (both) or O (neither), and you can pass either of these "letters" on to your children. But you can't pass on a letter you haven't got, so if I'm AB and my mum is B then my dad must be either A or AB - because otherwise where would my A come from?
Peadar Mac Con Aonaigh, Brixton, UK
- If I remember my biology from many years ago the ABO system is governed by classic Mendalian genetics. The blood types are determined by the reaction of a blood sample to antibodies added to them.
A is dominant to O
B is dominant to O
A&B are co-dominantYou get one gene, A, B, or O, from your father and one from your mother. What you get from each is your genotype, what is expressed in your blood is your phenotype. The possible genotypes for an individual are (the order is not really relevant):
AA: Phenotype - A
BB: Phenotype - B
OO: Phenotype - O
AO: Phenotype - A
BO: Phenotype - B
AB: Phenotype - ABSo two pure breeding individuals of A B or O can only give rise to A B or O children. However, using normal blood tests it is impossible to tell the genotype of an individual who has an A or B blood group.
Hence a person with one parent with A blood group and one person with B blood group with genotype AO & BO can produce children of any blood group, so nothing can be proved. If a person of O blood group breeds with a person of B group all the children must be either B or O. If the child is A or AB one of the individuals cannot be the parent. An O and B crossing can not produce an A or AB child. An AB with an O can produce A children or B children but not O.
In short the ABO system can prove you are not a parent but not that you are, as there are millions of other people with the same blood group.
Glyn Baker, South Ockendon, UK
- Most blood types are caused by the presence or abscence of certain proteins (called "compatibility antigens") on the surface of our blood cells. If both parents have the genes that produce proteins A and B, their blood type is called AB. (An additional compatibility antigen provides the Rh Factor.) Such parents could have children with blood types A, B, and AB, but never O. Even with, shall we say, the assistance of a third party, the child could never have blood type O. In a similar vein (and I didn't intend the pun), parents who do not have the genes to produce proteins A or B are said to have blood type O. These parents can have children who have only blood type O. With the hypothetical third-party assistance, other blood types would be possible. If the assistant were of blood type AB, then the indiscreet parentage would be indubitable.
Arthur Earl Davidson, Sylmar, California United States of America
- my blood type is A+ and my father's (deceased) blood type is AB+. which blood type would my mother (deceased) have to have had to prove my father is my birth father? Please send answer as soon as possible to my e-mail address. Thanks!!
b. stevenson, detroit, michigan america
What Blood Types Should Not Have Babies Together?
Source: https://www.theguardian.com/notesandqueries/query/0,5753,-18843,00...