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Blood is life itself. It is the primal force that fuels the power and mystery of birth, the horrors of disease, war, and violent death. Entire civilizations have been built on blood ties. Tribes, clans, and monarchies depend on them. We cannot exist without blood--literally or figuratively.
Blood is magical. Blood is mystical. Blood is alchemical. It appears throughout human history as a profound religious and cultural symbol. Ancient peoples mixed it together and drank it to denote unity and fealty. From the earliest times, hunters performed rituals to appease the spirits of the animals they killed by offering up the animal blood and smearing it on their faces and bodies. The blood of the lamb was placed as a mark on the hovels of the enslaved Jews of Egypt so that the Angel of Death would pass over them. Moses is said to have turned the waters of Egypt to blood in his quest to free his people. The symbolic blood of Jesus Christ has been, for nearly two thousand years, central to the most sacred rite of Christianity.
Blood evokes such rich and sacred imagery because it is in reality so extraordinary. Not only does it supply the complex delivery and defense systems that are necessary for our very existence, it provides a keystone for humanity--a looking glass through which we can trace the faint tracks of our journey.
In the last forty years we have been able to use biological markers such as blood type to map the movements and groupings of our ancestors. By learning how these early people adapted to the challenges posed by constantly changing climates, germs, and diets, we are learning about ourselves. Change in climate and available food produced new blood types. Blood type is the unbroken cord that binds us to one another.
Ultimately, the differences in blood types reflect upon the human ability to acclimate to different environmental challenges. For the most part, these challenges impacted the digestive and immune systems: a piece of bad meat could kill you; a cut or scrape could evolve into a deadly infection. Yet the human race survived. And the story of that survival is inextricably tied to our digestive and immune systems. It is in these two areas that most of the distinctions between blood types are found.
The Human Story
The story of humankind is the story of survival. More specifically, it is the story of where humans lived and what they could eat there. It is about food--about finding food and moving to find food. We don't know for certain when the human evolution began. Neanderthals, the first humanoids we can recognize, may have developed 500,000 years ago. Maybe more.
We do know that human prehistory began in Africa, where we evolved from humanlike creatures. Early life was short, nasty, and brutish. People died a thousand different ways--opportunistic infections, parasites, animal attacks, broken bones, childbirth--and they died young.
Early humans must have had a harrowing time providing for themselves in this savage environment. Their teeth were short and blunt--ill suited for attack. Unlike most of their competitors on the food chain, they had no special abilities with regard to speed, strength, or agility. Initially, the chief quality humans possessed was an innate cunning, which later grew to reasoned thought.
Neanderthals probably ate a rather crude diet of wild plants, grubs, and the scavenged leftovers from the kills of predatory animals. They were more prey than predator, especially when it came to infections and parasitic afflictions. (Many of the parasites, worms, flukes, and infectious microorganisms found in Africa do not stimulate the immune system to produce a specific antibody to them, probably because the early Type O people already had protection in the form of the antibodies they carried from birth.)
As the human race moved around and was forced to adapt its diet to changing conditions, the new diet provoked adaptations in the digestive tract and immune system necessary for it to first survive and later thrive in each new habitat. These changes are reflected in the development of the blood types, which appear to have arrived at critical junctures of human development:
1. The ascent of humans to the top of the food chain (evolution of Type O to its fullest expression).
2. The change from hunter-gatherer to a more domesticated agrarian lifestyle (appearance of Type A).
3. The merging and migration of the races from the African homeland to Europe, Asia, and the Americas (development of Type B).
4. The modern intermingling of disparate groups (the arrival of Type AB).
Each blood type contains the genetic message of our ancestors' diets and behaviors, and though we're a long way away from early history, many of their traits still affect us. Knowing these predispositions helps us to understand the logic of the blood type diets.
O Is for Old
The appearance of our Cro-Magnon ancestors in around 40,000 B.C. propelled the human species to the top of the food chain, making them the most dangerous predators on earth. They began to hunt in organized packs; in a short time, they were able to make weapons and use tools. These major advances gave them strength and superiority beyond their natural physical abilities.
Skillful and formidable hunters, the Cro-Magnons soon had little to fear from any of their animal rivals. With no natural predators other than themselves, the population exploded. Protein--meat--was their fuel, and it was at this point that the digestive attributes of Blood Type O reached their fullest expression.
Humans thrived on meat, and it took a remarkably short time for them to kill off the big game within their hunting range. There were more and more people to feed, so competition for meat became intense. Hunters began fighting and killing others who were impinging on what they claimed were their exclusive hunting grounds. As always, human beings found their greatest enemy to be themselves. Good hunting areas became scarce. The migration of the human race began.
By 30,000 B.C., bands of hunters were traveling farther and farther in search of meat. When a shift in the trade winds desiccated what had been fertile hunting land in the African Sahara, and when previously frozen northern areas grew warmer, they began to move out of Africa into Europe and Asia.
This movement seeded the planet with its base population, which was Blood Type O, the predominant blood type even today.
By 20,000 B.C. Cro-Magnons had moved fully into Europe and Asia, decimating the vast herds of large game to such an extent that other foods had to be found. Searching each new area for anything edible, it is likely that the carnivorous humans quickly became omnivorous, with a mixed diet of berries, grubs, nuts, roots, and small animals. Populations also thrived along the coastlines and the teeming lakes and rivers of the earth where fish and other food were abundant. By 10,000 B.C., humans occupied every main landmass on the planet, except for Antarctica.
The movement of the early humans to less temperate climates created lighter skins, less massive bone structures, and straighter hair. Nature, over time, reacclimated them to the regions of the earth they inhabited. People moved northward, so light skin developed, which was better protected against frostbite than dark skin. Lighter skin was also better able to metabolize vitamin D in a land of shorter days and longer nights.
The Cro-Magnons eventually burned themselves out; their success was anathema. Overpopulation soon exhausted the available hunting grounds. What had once seemed like an unending supply of large game animals diminished sharply. This led to increased competition for the remaining meat. Competition led to war, and war to further migration.
A Is for Agrarian
Type A blood initially appeared somewhere in Asia or the Middle East between 25,000 and 15,000 B.C. in response to new environmental conditions. It emerged at the peak of the Neolithic period, or New Stone Age, which followed the Old Stone Age, or Paleolithic period, of the Cro-Magnon hunters. Agriculture and animal domestication were the hallmarks of its culture.
The cultivation of grains and livestock changed everything. Able to forgo their hand-to-mouth existence and sustain themselves for the first time, people established stable communities and permanent living structures. This radically different lifestyle, a major change in diet and environment, resulted in an entirely new mutation in the digestive tracts and the immune systems of the Neolithic peoples--a mutation that allowed them to better tolerate and absorb cultivated grains and other agricultural products. Type A was born.
Settling into permanent farming communities presented new developmental challenges. The skills necessary for hunting together now gave way to a different kind of cooperative society. For the first time, a specific skill at doing one thing depended on the skills of others doing something else. For example, the miller depended on the farmer to bring in his crops; the farmer depended on the miller to grind his grain. One no longer thought of food as only an immediate source of nourishment or as a sometime thing. Fields needed to be sown and cultivated in anticipation of future reward. Planning and networking with others became the order of the day. Psychologically, these are traits at which Type As excel--perhaps another environmental adaptation.
The gene for Type A began to thrive in the early agrarian societies. The genetic mutation that produced Type A from Type O occurred rapidly--so rapidly that the rate of mutation was comparable to four times that of Drosophila, the common fruit fly and current record holder!
What could have been the reason for this extraordinary rate of human mutation from Type O to Type A? It was survival. Survival of the fittest in a crowded society. Because Type A emerged as more resistant to infections common to densely populated areas, urban, industrialized societies quickly became Type A. Even today, survivors of plague, cholera, and smallpox show a predominance of Type A over Type O.
Eventually, the gene for Type A blood spread beyond Asia and the Middle East into western Europe, carried by the Indo-Europeans, who penetrated deeply into the pre-Neolithic populations. The Indo-European hordes originally appeared in south-central Russia, and between 3,500 and 2,000 B.C. pushed southward into the top of southwestern Asia, creating the populations and peoples of Iran and Afghanistan. Ever burgeoning, they moved further westward into Europe. The Indo-European invasion was really the original Diet Revolution. It introduced new foods and lifestyle habits into the simpler immune systems and digestive tracts of the early hunter-gatherers, and those changes were so profound that they produced the environmental stress necessary to spread the Type A gene. In time, the digestive system of the hunter-gatherers lost its ability to digest its carnivorous pre-agricultural diet.
Today, Type A blood is still found in its highest concentration among western Europeans. The frequency of Type A diminishes as we head eastward from western Europe, following the receding trails of the ancient migratory patterns. Type A peoples are highly concentrated across the Mediterranean, Adriatic, and Aegean seas, particularly in Corsica, Sardinia, Spain, Turkey, and the Balkans. The Japanese also have some of the highest concentrations of Type As in eastern Asia, along with a moderately high number of blood Type Bs.
Blood Type A had mutated from Type O in response to the myriad infections provoked by an increased populace and major dietary changes. But Blood Type B was different.
B Is for Balance
Blood Type B developed sometime between 10,000 and 15,000 B.C., in the area of the Himalayan highlands--now part of present-day Pakistan and India.
Pushed from the hot, lush savannahs of eastern Africa to the cold, unyielding highlands of the Himalayas, Blood Type B may have initially mutated in response to climactic changes. It first appeared in India or the Ural region of Asia among a mix of Caucasian and Mongolian tribes. This new blood type was soon characteristic of the great tribes of steppe dwellers, who by this time dominated the Eurasian plains.
As the Mongolians swept through Asia, the gene for Type B blood was firmly entrenched. The Mongolians spread northward, pursuing a culture dependent upon herding and domesticating animals--as their diet of meat and cultured dairy products reflected.
Two distinct Type Bs sprang up as the pastoral nomads pushed into Asia: an agrarian, comparatively sedentary group in the south and the east; and a nomadic, warlike society conquering the north and the west. The nomads were expert horsemen who penetrated far into eastern Europe, and the gene for Type B blood is still in strong evidence in many of the eastern European populations. In the meantime, an entire agriculturally based culture had spread throughout China and southeast Asia. Because of the nature of the land they chose to till, and climates unique to their areas, these peoples created and employed sophisticated irrigation and cultivation techniques that displayed an awesome blend of creativity, intelligence, and engineering.
The schism between the warlike tribes to the north and the peaceful farmers to the south was deep, and its remnants exist to this day in southern Asian cuisine, which uses little if any dairy foods. To the Asian mind, dairy products are the food of the barbarian, which is unfortunate because the diet they have adopted does not suit Type Bs as well.
Of all the ABO types, Type B shows the most clearly defined geographic distribution. Stretching as a great belt across the Eurasian plains and down to the Indian subcontinent, Type B is found in increased numbers from Japan, Mongolia, China, and India up to the Ural Mountains. From there westward, the percentages fall until a low is reached at the western tip of Europe.
The small numbers of Type B in Old and Western Europeans represents western migration by Asian nomadic peoples. This is best seen in the easternmost western Europeans, the Germans and Austrians, who have an unexpectedly high incidence of Type B blood compared to their western neighbors. The highest occurrence of Type B in Germans occurs in the area around the upper and middle Elbe River, which had been nominally held as the dividing line between civilization and barbarism in ancient times.
Modern subcontinental Indians, a Caucasian people, have some of the highest frequencies of Type B blood in the world. The northern Chinese and Koreans have very high rates of Type B blood and very low rates of Type A.
The blood type characteristics of the various Jewish populations have long been of interest to anthropologists. As a general rule, regardless of their nationality or race, there is a trend toward higher-than-average rates of Type B blood. The Ashkenazim and the Sephardim, the two major Jewish sects, share strong levels of Type B blood, and appear to have very few differences. The pre-Diaspora Babylonian Jews differ considerably from the primarily Type O Arabic population of Iraq (the location of the biblical Babylon) in that they are primarily Type B, with some frequency of Type A.
AB Is for Modern
Type AB blood is rare. Emerging from the intermingling of Type A Caucasians with Type B Mongolians, it is found in less than 5 percent of the population, and it is the newest of the blood types.
Until ten or twelve centuries ago, there was no Type AB blood. Then barbarian hordes sliced through the soft underbelly of many collapsing civilizations, overrunning the length and breadth of the Roman Empire. As a result of the intermingling of these Eastern invaders with the last trembling vestiges of European civilization, Type AB blood came to be. No evidence for the occurrence of this blood type extends beyond nine hundred to a thousand years ago, when a large western migration of eastern peoples took place. Blood Type AB is rarely found in European graves prior to A.D. 900. Studies on exhumations of prehistoric graves in Hungary show a distinct lack of this blood group into the Longobard age (fourth to seventh century A.D.). This would seem to indicate that up until that point in time, European populations of Type A and Type B did not come into common contact, or if so, did not mingle or intermarry.
Because Type ABs inherit the tolerance of both Type A and Type B, their immune systems have an enhanced ability to manufacture more specific antibodies to microbial infections. This unique quality of possessing neither anti-A nor anti-B antibodies minimizes their chances of being prone to allergies and other autoimmune diseases such as arthritis, inflammation, and lupus. There is, however, a greater predisposition to certain cancers because Type AB responds to anything A-like or B-like as "self," so it manufactures no opposing antibodies.
Type AB presents a multifaceted, and sometimes perplexing, blood type identity. It is the first blood type to adopt an amalgamation of immune characteristics, some of which make them stronger, and some of which are in conflict. Perhaps Type AB presents the perfect metaphor for modern life: complex and unsettled.
The Blending Grounds
Blood type, geography, and race are woven together to form our human identity. We may have cultural differences, but when you look at blood type, you see how superficial they are. Your blood type is older than your race and more fundamental than your ethnicity. The blood types were not a hit-or-miss act of random genetic activity. Each new blood type was an evolutionary response to a series of cataclysmic chain reactions, spread over eons of environmental upheaval and change.
Although the early racial changes seem to have occurred in a world that was composed almost exclusively of Type O blood, the racial diversifications--coupled with dietary, environmental, and geographical adaptations--were part of the evolutionary engine that ultimately produced the other blood types.
Some anthropologists believe that classifying humans into races invites oversimplification. Blood type is a far more important determinant of individuality and similarity than is race. For example, an African and Caucasian of Type A blood could exchange blood or organs and have many of the same aptitudes, digestive functions, and immunological structures--characteristics they would not share with a member of their own race who was Blood Type B.
Racial distinctions based on skin colors, ethnic practices, geographical homelands, or cultural roots are not a valid way to distinguish peoples. Members of the human race have a lot more in common with one another than we may have ever suspected. We are all potentially brothers and sisters. In blood.
Today, as we look back on this remarkable evolutionary revolution, it is clear that our ancestors had unique biological blueprints that complemented their environments. It is this lesson we bring with us into our current understanding of blood types, for the genetic characteristics of our ancestors live in our blood today.
* Type O: The oldest and most basic blood type, the survivor at the top of the food chain, with a strong and ornery immune system willing to and capable of destroying anyone, friend or foe.
* Type A: The first immigrants, forced by the necessity of migration to adapt to a more agrarian diet and lifestyle ... with a more cooperative personality to get along in crowded communities.
* Type B: The assimilator, adapting to new climates and the mingling of populations; representing nature's quest for a more balanced force between the tensions of the mind and the demands of the immune system.
* Type AB: The delicate offspring of a rare merger between the tolerant Type A and the formerly barbaric but more balanced Type B.
Our ancestors left each of us a special legacy, imprinted in our blood types. This legacy exists permanently in the nucleus of each cell. It is here that the anthropology and science of our blood meet.