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From: werner@aecom.yu.edu (Craig Werner)
Newsgroups: sci.bio
Subject: Re: Are blood types inherited?
Keywords: bloodtype, parents, genes, whatever...
Message-ID: <2406@aecom.yu.edu>
Date: 17 Aug 89 23:51:12 GMT
References: <4250@orca.WV.TEK.COM>
Distribution: usa
Organization: Albert Einstein Coll. of Med., NY
Lines: 44

In article <4250@orca.WV.TEK.COM>, kris@maui.WV.TEK.COM (Kristen McCormick) writes:
> 
> I'm posting here because I didn't know who else to ask.
> I am probably the only person on earth who never had 
> biology in high school, or anywhere else (I may take it next
> term though). So my question is, are blood types inherited?
> 
> Can a father with type A positive blood and a mother
> with AB negative (I think) have a child with O positive blood?
> If it helps any, the other child has A positive.
> 
	In general, if a father has AB blood and the child has type O
blood, that is taken as evidence in most states as legal proof of
non-paternity.  However, cases of mistaken maternity (as above) are pretty 
rare. And although the probability of faulty recall is the best explanation
of the above, there is a way for an AB mother to have a phenotypically
type O child. It's called the Bombay blood group.

	All blood group markers are genetically determined. There are
several dozen of them in all, only a few of which are well known: ABO,
Rhesus, MNSs, Duffy, and a few others.  ABO is the only one to which
people are naturally immune to.  The gene (designated I) can be in one 
of three forms: A, B, or inactive. There are two copies. Hence, OO gives
O blood group, AA or AO give A, BB or BO give B, and AB gives AB.  The
mechanism is that either the A-modification or the B-modification is made
to another blood antigen (the H antigen). O is defined as the absence of
A and the absence of B, not the presence of anything.  Hence, if one
lacks the H antigen, one has the A/B enzymes, but nothing to modify, and
appears O.  This was first described in a family in Bombay, hence is called
the Bombay blood group.   Note well, however, that if this is really the
case and the offspring received multiple transfusions, the child is in 
trouble.  Normal O blood contains the H antigen, Bombay O blood does not.
Persons with O(Bombay) can only receive other O(Bombay) blood for 
transfusions.

	And, by the way, my father was type A, my mother was type B. I'm
type O.  My family is thus one of the few combinations where both genotypes
and phenotypes are known.

-- 
	        Craig Werner   (future MD/PhD, 4.5 years down, 2.5 to go)
	     werner@aecom.YU.EDU -- Albert Einstein College of Medicine
              (1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517)
      "... Has Determined That Cigarette Smoking Is Dangerous To Your Health"