According to a quick Google search, type B blood is significantly more rare (rarer? is that a word?) than type A blood. Specifically, about 39% of the population is either A+ or A-, while only about 11% of the population is either B+ or B-. What gives? If the genes for the A and B blood types are both dominant, then shouldn’t their distributions be much more similar?
The gene for type B appears to be a (relatively) recent mutation; it is virtually non-existent in Amerinds and Na-Denes, generally accepted to have been isolated from the Eastern Hemisphere for thousands of years. The frequency of type B, moreover, seems to form a smooth function as a distance from a locus in Asia, where it is considered to have originated.
The answer, then, is that the type B genotype has not yet had time to spread generally into the human gene pool.
What in the hell are “Na-Denes?”
The Na-Dene peoples are North American natives living along the northern part of the West Coast (BC and up into Alaska). They include Haida and Tlingit tribes, IIRC, and probably more. Their culture and languages are different from most other NA natives, so they get their own group.
Well, Barb and I went to school with a girl named Nadine, but I suspect what Akatsukami is referring to is the Native American/First Nations group called Na-Denes, AKA Athapaskans, who are ethnically and linguistically significantly different from the remainder of NA/FN peoples. (“Lumper” glottochronologists hypothecate a common ancestry for all Western Hemisphere pre-Columbian languages except Innuit/Aleut and Na-Dene groups.) ‘Katsu’ clearly is trying to preserve the distinction, much like someone addressing a common trait in Europe and South Asia by saying “Indo-European peoples and the Basques” – making clear that he’s aware of the distinction but intends to include the Basques in his discussion anyway.
Those American aboriginals who speak (or spoke) Na-Dene languages: primarily Athabaskan, but including other languages of the American and Canadian PNW, and outliers such as Apache and Navajo.
Na-Denes are linguistically and genetically quite distinct from other non-Eskimo Americans (“Amerinds”), and it is generally accepted that they stem from a quite migration, several thousand years after the Amerind expansion into the Americas (probably before 9,000 BCE, from a staging area in Beringia and western Alaska).
“Na-Dene”, incidentally is three syllables: approximately “NAH-dey-nee”.
Groovy.
Ah, that explains it then. On a semi-related note: are there any significant phenotypic (is that a word?) differences between the different blood types? I.e., is there any advantage to being, say, O+, or B-, or whatever, aside from the ability to receive transfusions from a greater or lesser number of people?
No, there is no detectable difference in the A-B-O or Rh blood groups.
When there’s no selective pressure, as in the case of blood type, dominance or recessiveness has absolutely nothing to do with distribution. You could have a dominant trait that remains extremely rare or a recessive trait that is extremely common. They’re totally unrelated.
I am not aware of any advantages, but there may be a disadvantage. Specifically, people with type A blood are more likely to develop various cancers.
There is a disadvantage for a woman who is RH - to have children with a man who is RH +
If the children of an RH - mother have RH + blood it is possible for the mother to build up antibodies against her children’s blood. They screen for this today and the treatment options are very good but it can be very bad for the babies if not detected in time.
Some more GQ Blood type information.
I have type AB- guess I could be doomed if I needed a blood transfusion. They say rh- came from the annunaki. Who knows lol
No, you can safely get a transfusion from anyone without RH factor. Anyone who needs a transfusion and can only get it from you (on a desert island or something) would most likely be screwed, however.
My mom’s B- and I’m B+. Guess we got lucky; I was her first, and she didn’t even see a doctor until after her water broke.
I’ll have to ask if she had any issues with later offspring, as it appears the first pregnancy doesn’t often cause this. I shoulda read first!
I’m Bneg and have been asked a couple times to be a direct donor.
And none of my ancestors came from Asia, to my knowledge. Am I misunderstanding Akatsukami’s post?
From a selfish point of view, AB+ is the ‘best’ blood type - you can receive a transfusion from anyone (generally speaking).
Here’s a map of the ABO situation, for what it’s worth: http://anthro.palomar.edu/vary/vary_3.htm
Just pointing out that this thread is eight years old, and some incredibly handsome intelligent guy explained way back then why a dominant gene could be rare.