From: L638615@LMSC5.IS.LMSC.LOCKHEED.COM (STAFFORD, KD)
Subject: Re: 17 Re: Blood types - Mother&Father
Organization: Lockheed Missiles & Space Company, Inc.
Date: Fri, 31 Jul 92 16:22:52 GMT

Okay, if brown eyes are dominant and blue eyes are recessive....how do
two brown eyed parents get a blue eyed child?  And NO, it wasn't the
postman!! :-)))

Kelly
------------------------- Original Article -------------------------
In article <1992Jul29.050413.33898@ux1.cts.eiu.edu>, cfaks@ux1.cts.eiu.edu
(Alice Sanders) says:
>
>This is slightly off the subject, but my interest has been piqued by this
>thread.  From where does a child get his/her blood-type?  I mean both the
>A,B,0, AB stuff and the +/- factor as well?  Does it come from a specific
>parent, for instance?
>
>Alice
>
Ok, biology lesson.
There are two terms which should be known first.  Dominant and Recessive.
Dominant means, in laymen's terms, that it will come first.  Recessive
means, in laymen's terms, that it will most usually not show up unless
there is no dominant things around.

A and B are both dominant.  Neither is really dominant over the other.
O is recessive.

A child gets one of these blood types from each parent.  Hence a child
could get an A & A, a B & B, an A & B, an A & O, a B & O, or an O & O.
Two A's make an A, two B's make a B, two O's make an O.  The A & B make
AB.  The A & O make A, and the B & O make B.
(Make sure you read that word for word...or letter for letter)

The RH factor works the same way.  You get either the Positive or the
Negative factor from each parent.  The Positive one is Dominant, and the
Recessive one is the Negative.  So, if the child has a + & +, they'll be +.
- & - make a -.  + and - make a +.  Ok so far?

Now, you just take the blood type A (or whatever) and tack the +/- on
the end of it.

The same thing works for eye color.  Where Blue eyes are Recessive and
Brown eyes are Dominant.  So if you get Blue from mom and Brown from dad,
you'll probably have Brown eyes.  Blue from dad and Brown from mom, STILL
makes Brown eyes.  Blue and Blue make Blue, and Brown and Brown make Brown.

The below is a chart which you'd see in generic biology books:

Mom has A+ blood, Dad has A+ blood.  Now, it sounds as though all of their
children will have A+ blood.  But that is not the case.  In order for each
parent to have A blood, they can either be AA or AO.  In order for each
parent to have the Positive RH factor, they can have a +- or a ++.

Let's say for now, that the mom is AA with a ++, and dad is a AO with +-.

  \    A  |  A
    \ ----------
  A  | AA | AA  |   The top row is mom, the side is dad.
-----|----+-----    50% of the children COULD be AA.
  O  | AO | AO  |   50% of the children COULD be AO.
      ----------    They can't be anything else.

  \    +  |  +
    \ ----------
  +  | ++ | ++  |   The top row is mom, the side is dad.
-----|----+-----    50% of the children COULD be ++.
  -  | +- | +-  |   50% of the children COULD be +-.
      ----------    They can't be anything else.

So, the children can NOT be B or BO or AB, nor can they have -- for RH.

As you'll recall, the AA makes A and the AO makes A.
As you'll recall, the ++ makes + and the +- makes +
So, in this case, the children will ALWAYS be A+.

Let's take this senario now (You'll probably be better off to print this
out, take it home, and read it there.  *sigh*)

Mom has A+ blood, Dad has A+ blood.  Now, it sounds as though all of their
children will have A+ blood.  But that is not the case.  In order for each
parent to have A blood, they can either be AA or AO.  In order for each
parent to have the Positive RH factor, they can have a +- or a ++.

Let's say for now, that the mom is AO with a +-, and dad is a AO with +-.
                                   ::::::::::::
  \    A  |  O
    \ ----------
  A  | AA | AO  |   The top row is mom, the side is dad.
-----|----+-----    25% of the children COULD be AA.
  O  | AO | OO  |   50% of the children COULD be AO.
      ----------    25% of the children COULD be OO.
                    They can't be anything else.
  \    +  |  -
    \ ----------
  +  | ++ | +-  |   The top row is mom, the side is dad.
-----|----+-----    25% of the children COULD be ++.
  -  | +- | --  |   50% of the children COULD be +-.
      ----------    25% of the children COULD be --.
                    There is nothing else possible to be, in this case.

So, the children can NOT be B or BO or AB, nor can they have -- for RH.

As you'll recall, the AA makes A and the AO makes A.
  The OO makes O.
As you'll recall, the ++ makes + and the +- makes +.
  The -- makes -.

This is the case where some children could be A+ while some of the
children could be O-.  (This is what I supposedly come from, where BOTH
of my parents are A+, yet I'm supposedly O-.)

If you can compute the rest of the statistics, I'll start by telling you
that in this case, a child has 1 in 16 chances of being O-.  The children
could be A-, O+, or even the PRESUMED A+, as well as the O-.

Does this help?  I sure hope so.  I'm tired now.

-Jennifer

PS.  I know some biology, but I don't know MEDICINE such as RHOGAM!  *sigh*