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Archiver > Melungeon > 2001-01 > 0980348211


From: Celia Millington-Wyckoff <>
Subject: Re: [Melungeon] Genetics of Blood Types
Date: Wed, 24 Jan 2001 09:56:51 -0500
References: <53BEE7C509AFD211B63B00A0C9EA04A4A0A967@exchange.acld.lib.fl.us>
In-Reply-To: <53BEE7C509AFD211B63B00A0C9EA04A4A0A967@exchange.acld.lib.fl.us>


Thanks, Mike--excellent information!

Celia in PA

At 9:34 AM -0500 1/24/01, Mike Nassau wrote:
>There are proteins in the cell membranes of animals including humans. If
>these proteins will cause another animal to produce antibodies, the proteins
>are called antigens. There are several types of antigens found in the
>membranes of human blood cells. These are tested for by putting a drop of
>blood with antibodies produced in some other animal. If the antibodies
>clump the blood cells, that is a positive test. If it is for a paternity
>suit or some such test of parentage, many different antigens are tested for.
>But for medical use, testing compatibility for blood transfusions or
>pregnancy/neonatal problems, only the Landsteiner series (ABO) and the rH
>series (named for the Rhesus monkey which has the same antigens) are tested.
>
>
>Landsteiner blood types are A (either Ao or AA alleles), B (either Bo or BB
>alleles), AB (AB alleles only) and O (oo only). So if an A type person has
>children, they can pass on either the A allele or the o allele if they are
>Ao, but only A alleles if they are AA. A B type person can pass on either B
>or o if they are Bo but only B if they are BB. An AB person can pass on
>either A or B. An O type person can only pass on the o allele.
>Average numbers of progeny for matings of blood type alleles in different
>matings:
>AA X AA -> all AA, all type A
>AA X Ao -> 1/2 AA, 1/2 Ao, all type A
>Ao X Ao -> 1/4 AA, 1/2 Ao, 1/4 oo, 3/4 type A, 1/4 type O
>AA X BB -> all AB, all type AB
>Ao X BB -> 1/2 AB, 1/2 Bo, 1/2 type AB, 1/2 type B
>AA X Bo -> 1/2 AB, 1/2 Ao, 1/2 type AB, 1/2 type A
>AA X AB -> 1/2 AA, 1/2 AB, 1/2 type A, 1/2 type AB
>Ao X AB -> 1/4 AA, 1/4 AB, 1/4 Ao, 1/4 Bo, 1/2 type A, 1/4 type AB, 1/4 type
>B
>AA X oo -> all Ao, all type A
>Ao X oo -> 1/2 Ao, 1/2 oo, 1/2 type A, 1/2 type O
>BB X BB -> all BB, all type B
>BB X Bo -> 1/2 BB, 1/2 Bo, all type B
>Bo X Bo -> 1/4 BB, 1/2 Bo, 1/4 oo, 3/4 type B, 1/4 type O
>BB X AB -> 1/2 BB, 1/2 AB, 1/2 type B, 1/2 type AB
>Bo X AB -> 1/4 Ao, 1/4 AB, !/4 BB, 1/4 Bo, 1/4 type A, 1/4 type AB, 1/2 type
>B
>BB X oo -> all Bo, all type B
>Bo X oo -> 1/2 Bo, 1/2 oo, 1/2 type B, 1/2 type O
>AB X AB -> 1/4 AA, 1/2 AB, 1/4 BB, 1/4 type A, 1/2 type AB, 1/4 type B
>AB X oo -> 1/2 Ao, 1/2 Bo, 1/2 type A, 1/2 type B
>oo X oo -> all oo, all type O
>
>Note the peculiarity of the AB X oo mating (type AB and type O),
>that none of their children are like either of them, they must
>either be type A or type B.
>
>Of the three Native American waves, the Amerind wave, coming from Asia some
>16,000 years ago, including all American Indians except the Na-Dene, is
>almost
>all type O. I don't know about the Na-Dene, coming from Asia some 8,000
>years
>ago and closer to the Chinese than to the Amerind (includes Navajo, Apache,
>Athpaskan, Tlingit, etc.), or the Eskaleut (Inuits and Aleuts) who came some
>
>4,000 years ago.
>
>Type B appeared in Central Asia or North Asia as a mutation of the A allele
>after the Amerind wave came to America. It was brought to Europe in a big
>way by the Mongol conquest of Russia, Poland, Rumania, etc. It is very
>rare among the Basques and makes a neat gradient from high in eastern
>Russia to low in Iberia. Shows the way all European peoles have mixed, that
>it has gone everywhere. I wonder if the Hun invasion earlier also brought
>it to
>a lesser extent?
>
>I hadn't heard that B was prevalent in Africans before. That strikes me as
>very
>interesting and very peculiar. I don't believe there has been any big
>movement of genes from Central Asia to Sub-Saharan Africa, but the
>Ottoman Turks did conquer Egypt, Lybia, Tunesia and Algeria, so I can see
>it being in North Africa in a pretty big way. Otherwise, there must have
>been a second mutation from A to B in Africa, which would be most unusual
>though quite possible.
>
>The rH series is intriguing in that there are four loci (rHa, rHb, rHc, rHd)
>with eight alleles,
>+ or - at each locus. Only one is medically important, thank goodness. All
>four can be
>used for paternity/ancestry testing, however. If you have an rH+ allele,
>you are positive,
>if you don't, you are negative. Here are the possible matings:
>rH+rH+ X rH+rH+ -> all rH+rH+, all positive
>rH+rH+ X rH+rH+ -> 1/2 rH+rH+, 1/2 rH+rH-, all positive
>rH+rH+ X rH-rH- -> all rH+rH-, all positive
>rH+rH- X rH+rh- -> 1/4 rH+rh+, 1/2 rH+rH-, 1/4 rH-rH-, 3/4 positive, 1/4
>negative
>rH+rH- X rH-rH- -> 1/2 rH+rh-, 1/2 rH-rH-, 1/2 positive, 1/2 negative
>rH-rH- X rH-rH- -> all rH-rH-, all negative
>
>Both parents give genes for each locus to their children, blood type is not
>inherited
>from just one parent. BUT, if the mother is rH negative, the child's type
>will
>depend on whether the father passes rH+ or rH- to the child. The only way
>the
>medical problems ("blue-baby syndrome", etc.) occurs is if the mother is
>negative and the baby is positive. For this to happen, the father must be
>positive and must pass the rH+ allele to the child. The mother will produce
>
>antibodies to the rH+ antigens in the baby's blood and if she does this
>early
>enough and enough of them enter the baby's blood stream, they will clump
>the baby's blood cells and prevent them from carrying enough oxygen.
>
>I am A+.
>
>Mike Nassau
>
>
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>http://www.melungeonhealth.org


Celia Millington-Wyckoff, M.A.
Instructional Materials Designer
Department of Distance Education/The World Campus
Penn State University
210 Rider II Building
University Park, PA
16802
814-863-8293


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