Re: Blood Type Ratios?

In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] (Daryle Walker) wrote:
>I don't have the exact numbers, but I don't think the distribution of
>blood types is even.  (Quick recap: there are three standard blood type
>factors, binary on their absence or presence.  This leads to eight
>combinations.)

Not quite. There are 3 alleles for red blood cell type - A, B & O. 
Thanks to dominance and codominance of these alleles there are only 4 
resulting types: A, AB, B and O. To get 8 blood types you need to 
include the Rh factor gene, which is ether positive or negative. This is 
an extreme simplification of blood typing, however. There are many 
different factors other than rh and when giving a transfusion one needs 
to be aware of all of them. These days, only in an emergency does one 
give a transfusion based only on ABO & Rh.

I note that ABO blood type is used as a common example on Mendelian 
genetics in science classes in early high school in North America. Also 
note that there are actually two different type of A alleles, discovered 
only through genetic typing of indivduals.

>The aliens had missed: B- AB+
>(So they got: O+ O- A+ A- B+ AB-)
>(They also missed the few people with non-standard types.)

>Does anyone know the exact distrubtions of blood types, so we can
>estimate the percentage killed.  (Only the B-, AB+, and non-standard
>people would be spared.)

Distributions of basic blood types is as follows:

O+      38.5%
A+      32.3%
B+      9.4%
O-      7.7%
A-      6.5%
AB+     3.2%
B-      1.7%
AB-     0.7%

Thus, with the two missing types the Xindi viri would still have been 
able affect 95.1% of Humanity. The question then is whether any of the 
other blood factors beyond Rh, either singly or in combination, would 
give immunity to the virus.

I can easily see how the Xindi could have known blood types but not 
distribution, as that knowledge only comes after sampling a significant 
number of subjects across the globe.

Nor is that distribution something one could reasonably expect T'Pol to 
know, making her three quarters comment perfectly reasonable. Besides, I 
doubt that her intent in making that statement was scientific accuracy, 
rather to impress upon Archer that a lot of people would die even with 
incomplete coverage.

--
Cory Albrecht
http://www.sentex.net/~corya/