Here is how it works; every one has two parts of their chromosomes (genotype) that decide weather the blood will be + or -. The (big) D is dominant and positive; and the (little) d is negative and recessive. Each person has two that make up a genotype. If someone has positive blood they are either DD (homozygous dominant), or Dd (heterozygous dominant), if they have negative blood it's dd (homozygous recessive). For two positive blood typed people to produce a negative blood type child they have to both be Dd. That would give them a 25% chance of having a negative blood typed child.
So both my parents are Dd. The dominant D makes them both positive Rh, but when I got one from each of them the ones I have are both d's, so I am negative.
---D d
D DD Dd
d Dd dd (me)
Red - MomBlue-Dad
Yellow-possible positive child types (75%)
Green - possible negative child types. (25%, me)
ABO Type Rh Type How Many Have It
O positive 37.4% 44%
O negative 6.6%
A positive 35.7% 42%
A negative 6.3%
B positive 8.5% 10%
B negative 1.5%
AB positive 3.4% 4%
AB negative .6%
1 comment:
We always knew you were unique and like to do things your own way. I suppose now we should have Jon and Naomi tested to see if they are also rebels. :)
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