Comments on: Malaria and blood type

By: John Emerson

John Emerson — Thu, 01 Nov 2007 11:02:42 +0000

To me a flat notation would do the job better and be more expandable as more groups are discovered, at least for medicine and transfusion and for population and historical genetics. I suppose that at the molecular gene-chromosome level the present notation would probably be best.

By: p-ter

p-ter — Wed, 31 Oct 2007 23:35:52 +0000

the ABO blood group is determined by one locus, while the rh blood group is determined by another locus. the two are independent.

the duffy blood group is another, so if you wanted to include all the blood groups, you’d have to keep adding letters as you discovered them. probably simpler just to refer to each locus with a different notation.

By: John Emerson

John Emerson — Wed, 31 Oct 2007 20:41:43 +0000

I'm just wondering why we don't say A, B, C (=Rh+) and O. O would be the present O negative, and then you'd have A, B, C (O positive), AB, AC, BC, and ABC (AB positive).

Rh negative / positive do have a fairly uniform distribution, I guess, generally 5:1.

Just an off-hand question, not specific to the maps.

By: p-ter

p-ter — Wed, 31 Oct 2007 19:49:28 +0000

what do you mean? in this study?

By: John Emerson

John Emerson — Wed, 31 Oct 2007 17:46:22 +0000

Is there any special reason why Rh is not classified with A, B, and O? All 8 combinations of presence or absence of A, B, and Rh+ are found: O+, O-, A-, B-, O+, AB, A+, B+. and AB+.

By: mc

mc — Wed, 31 Oct 2007 12:54:02 +0000

“Most of my Mom’s family, as I am, as also lactose intolerant too.”

Would that have anything to do with them being B? According to the “eat for your blood type theory” type B arose 40,000 years ago, give or take a millenium, among pastoralists and are the premier lactose people, able to handle jugs of cream and hard cheese. However, these theories are laughed at by doctors, who as we know from history, are always right.

By: Mikeyes

Mikeyes — Wed, 31 Oct 2007 11:44:40 +0000

David Boxenhorn

That blood type map doesn't look anything like a map of malaria infestation

Malaria used to be world wide. The last malaria epidemic in North America was less than a century ago and it was as far north as MN and WI at one time.

The same is true in Europe but modern vector control and the recognition of the way malaria is passed on eliminated it in these venues.

The last Yellow Fever epidemic (another mosquito born disease) was in New Orleans in 1912. When I was a medical student in the late 1960s I met some of the survivors. People used to move north of NO in the summer to avoid these diseases.

By: windy

windy — Tue, 30 Oct 2007 10:47:57 +0000

Either that, or GNXP people disproportionately have the B allele!

Some closet Finns in the bunch? :)

Apparently, Russian travel agencies have been advertising the city of Turku (SW Finland) to Russians on the basis that blood type B is more common there - iow, they have "Russian blood". (desperate for ideas??) This was attributed to the Russian garrison there in 1800s. A Finnish geneticist did a back-of-the-envelope calculation and said that for this to explain the modest freq increase (17%->20%) each Russian soldier would have needed to beget at least 5 kids during his stay :)

By: David Boxenhorn

David Boxenhorn — Tue, 30 Oct 2007 00:11:43 +0000

Boy, this thread seems to have brought the B (and AB) people out of the closet. Either that, or GNXP people disproportionately have the B allele!

By: John Emerson

John Emerson — Mon, 29 Oct 2007 19:20:19 +0000

I guess that I’m skeptical of “original peoples” maps. My guess is that in the U.S. even the supposedly “pure” tribal members (not always the majority) have some inbreeding somewhere in the last 200 years.

Of course, if actual O predominance were found in actual populations, given that O is recessive it would be a very strong result. But if various corrections and extrapolations and selections had to be introduced it would seem weak. (The Blackfeet might just have interbred early on, while keeping mixed offspring within the tribe.)

By: razib

razib — Mon, 29 Oct 2007 19:05:53 +0000

btw everyone, the paper that p-ter linked to is Open Access (though a PDF). so if you are curious, read it dog!

By: razib

razib — Mon, 29 Oct 2007 19:04:54 +0000

It may be that there was an attempt to survey blood types of "original peoples" in given areas, but at this point in time that attempt would lead to highly conhjectural results.

yeah. that is an original peoples map. i believe the blackfeet have a lot of A. most of the other NAs are O.

By: John Emerson

John Emerson — Mon, 29 Oct 2007 18:56:16 +0000

Rh-negative is recessive, and O is recessive. A and B together produce AB.

O negative, even though doubly recessive, is 7.7% of the U.S. population. O is the most comon single bloodtype, even though recessive. More than a third of all Americans are O, but only less than a sixth are RH negative. The 1/6 proportion seems constant over A, B, AB, O.

The map doesn't make any sense to me. South America is pretty mixed in origin, but overwhelmingly O. The Americas are mixed, but extremely low in B. The Native American component shouldn't be a factor for a recessive gene. The Latin American high-O zone seems to reach up into Georgia, which makes no sense at all. Northern Florida is much like the rest of the South.

It may be that there was an attempt to survey blood types of "original peoples" in given areas, but at this point in time that attempt would lead to highly conhjectural results.

I'd be reluctant to draw any conclusions from these maps.

By: p-ter

p-ter — Mon, 29 Oct 2007 18:51:31 +0000

re: the age of the AB blood type. I'd never heard that 1K years figure, and it seems highly implausible-- this paper suggests B arose (from the ancestral A) several million years ago:
http://mbe.oxfordjournals.org/cgi/content/abstract/14/4/399

By: diana

diana — Mon, 29 Oct 2007 17:23:13 +0000

AB poz here. Mother: Ukrainian Jew (I guess, a B). Father, Polish Jew, A (right on his dog tags). Commingled in mid-20th century US.

Yes, I read that AB is only 1K years old; cooler heads must explain this.

By: mc

mc — Mon, 29 Oct 2007 16:57:29 +0000

I am ab-negative. so rare i don’t exist.
I once read that ab blood type was only 1000 yrs old, but how can this be? Certainly As & Bs have been conmingling for longer than that.

By: Ouassous

Ouassous — Mon, 29 Oct 2007 16:42:18 +0000

Particularly interesting is the splotch of lower frequency in the highlands of Madagascar that presumably corresponds to the Merina.

By: michelle

michelle — Mon, 29 Oct 2007 15:45:54 +0000

David Boxenhorn

That blood type map doesn't look anything like a map of malaria infestation.

Maybe it's changed over time?

By: pconroy

pconroy — Mon, 29 Oct 2007 14:36:17 +0000

I'm O+, my Dad is O-

My Mom is B+ as are most of her family, together with a few of my siblings.

Her family go back to Lancashire originally, to an area where there is > 20% B - supposedly due to the settlement there by the Romans of 5,500 Alano-Sarmatians.

Most of my Mom's family, as I am, as also lactose intolerant too.

Most of my Mom's family have very wide faces, with high cheekbones...

By: Bill

Bill — Mon, 29 Oct 2007 08:22:20 +0000

I’m AB+ and have a B+ wife (all North/Western Euro ancestry) . Two kids are AB+, one’s AB neg, and one’s B+. I guess we’re staying away from the equatorial zones. The good news, being a universal recipient, is that “all your blood are belong to us”.