Blood groups and societal history

I often hear that Japanese people have predominantly A blood group, because their ancestors where supposedly farmers, while Europeans are predominantly O, because they were hunters (except Baltic people who are more B - were they fishermen ?).

What I don't understand is that farming came to Japan from China only in the 1st century, while Greek, Romans and other knew it long before that. Agriculture developed first at about the same time, around 5000BC, in Mesopotamia, Egypt and China. From the Middle East, it spread quickly Westwards to Greece, Europe and whole Mediteranean, and Eastward to Persia and India. That happened of course before the rise of the first civilisations (circa 3000BC).

So why do all Japanese believe that blood group difference are based on different ancient life styles ?

It seems that genetical/physiological differences between East Asians and Europeans date back from a separation of two ethnic groups 500.000 years ago. Furthermore, modern human skulls are said not to have evolved much only for the last 50.000 years.
That probably explains the physiological differences between continents, including the blood group repartition.

I need to do more research on this.

What's your opinion ?

I know nearly nothing about the physiological/anthropological background of blood types, but I was always wondering about that blood type hype in Japan. There's a tendency to link a person's character to a specific blood type which has already been proved to have no scientific foundation at all.

Is it true that Japanese schools carry out physical exams in order to determine their pupils' blood type?

All Japanese know their blood group since their early childhood. I've always known mine as well. I am not sure whether schools make the test or if parents already know it since their babies' birth.

@prehistory

I have checked a history atlas ; the first humans arrived in East-Asia 1 million years ago, while they reached Europe only half a million years ago from the Middle-East. So there has been at least 1 million year of separation, except, like some theories suggest it, if modern humans (Cro-magnon) originate in a single place and replaced all other primitive humans (Java men, Neanderthal, etc.) around 100.000 years ago.

It's amazing to think that Japanese/Chinese and Europeans had no contact or intermarriage in 100.000 or 1 million years, then, suddenly, in a few decades so many of us get married together and mix their blood and genes for the first time in hundreds of thousands of years of evolution. That works for Africans or any other ethny in the world as well.

If it took so long to differentiate Caucasians, Asians and Africans physically, how shall we feel that in a few hundred years, all humans might be mixed ? Civilisations exist for less than 6.000 years, but it took maybe a million years for Asians to look Asian, and half that for Europeans to look Caucasian from a supposed common African origin. That lets me marvelling...

What I don't understand is that modern humans are like Cro-magnon, so haven't changed much for only 100.000 to 50.000 years. So if the separation really occured 1 million years ago, how comes all humans on earth have evolved the same way and are still genetically compatible after so long ? Even after 100.000 years, all humans are still a single species, while other species have become distinct in much less time than that.

I'll continue my researches.

Maybe we're an alien lab-experiment after all... :D

Then aliens must be very patient to wait a million years to see how we evolve. ;)

Perhaps the flow of time is a matter of perception. Don't animals perceive time differently then humans?