|
|
In 1900 Landsteiner discovered that all humans may be classified into four groups, depending on the presence or absence of two chemical substances, called A and B, in the red blood cells. Thus a person may have A or B, both or neither, and is said to belong to the blood group A, B, AB or O. Determination of the blood groups is done by the use of agglutinins, substances which can cause the red cells to stick together in clumps or agglutinate. These agglutinins may be produced artificially but they also occur naturally in human serum; the one which combines with the substance A occurring in the serum of a person of group B, and so on. Of course, a person of group AB would have no agglutinins and one of group O would have both. The substances A and B are therefore called agglutinogens. Descriptions of the actual technique for such determinations may be found in any good article on blood groups or in any textbook of immunology.1
After the Hirzfelds discovered, during the World War, that the percentage of persons belonging to each of the four blood groups is different in various ethnic groups, anthropologists had hopes that this method would solve many problems of race. At first there was a period of over optimism, but when it was found that all of the problems of race could not be settled there followed a period of pessimism, and some were inclined to minimize the anthropological usefulness of blood group studies. The facts are that they tell us just as much (and of course no less) as any other single physical anthropological characteristic. Head form, by itself, would be of little use in classifying people into racial groups, but taken in conjunction with numerous other physical characteristics it is of great use. So it is with the blood group distribution. As a matter of fact, the blood groups possess some advantages which the other well known physical characteristics do not have. Their mode of inheritance is completely known, the substances A and B being inherited as Mendelian dominants, the two of them together with the factor O (absence of either) forming a series of triple allelomorphs. Moreover the impossibility of social selection in the case of the blood groups is of great significance. Since it is known that the agglutinogens A and B are remarkably stable, not being destroyed by heat, drying, acids, and other drastic treatments, Dr. William C. Boyd thought of the possibility of detecting them in the tissues of mummified human remains, thus determining the blood group to which the person belonged. In 1933 he found that this could be done with the flesh of corpses, using a technique which had previously been applied to blood.2 Since the agglutinogens occur in practically all parts of the body as well as in the blood, dried tissue from any part of a human mummy seemed suitable. Application of the method to such material was successful and it has been possible to detect the presence of the agglutinogens in the tissue from an Egyptian mummy some 5000 years old. There is one serious disadvantage as yet, namely that a negative test does not tell us whether the person belonged to group O or whether the agglutinogens have deteriorated. In spite of a recent report to the contrary we still feel that there is no certain positive test for group O.
Being interested in American anthropology I collaborated with Dr. Boyd in a study of mummified American Indian remains. Several problems at once presented themselves: the antiquity of the blood groups in the New World, whether prehistoric or resulting from white admixture; the relations between the physically different Basket Maker people and the later Pueblo people of the Southwest; the relation to these of certain peripheral groups of as yet uncertain position; and the relation of the ancient Peruvians to other groups. We tested dried tissue from 226 human burials, 59 from the Southwestern United States, 34 from Alaska or the Aleutian Islands, and 133 from Peru. Of the Southwestern material, 4 were from Lovelock Cave, Nevada, 16 were of Basket Maker horizon from the San Juan drainage, 7 were of Modified Basket Maker horizon, 2 were of Developmental Pueblo horizon, 15 of Great Pueblo, 4 of Regressive Pueblo, 6 from the Big Bend Cave culture of Texas, and 5 of unknown horizon. Many museums, universities and other institutions have been most cooperative and generous in sending us material, and we have had the privilege of testing all the available material in the museum of Mesa Verde National Park. The positive results were as follows: 6 B's, 2 AB's, and 1 A in Peruvian material, nearly all of it prehistoric; 1 A in a Lovelock Cave specimen from a medium depth in the cave; 1 A in a Basket Maker specimen from Canon del Muerto, Arizona: and 1 B in a Big Bend specimen from Goat Cave, Val Verde County, Texas. This demonstration of the presence of the agglutinogens A and B in prehistoric American mummies proves a greater antiquity of these groups in the New World than had previously been supposed. Inasmuch as many blood group studies on living Indians had shown that full-bloods were predominately of group O, the theory that A and B had occurred as recent mutations in the Old World since the last migration of the original settlers of America had been widely accepted. Some recent studies on bloods and Blackfeet, and on Navahos, have shown the presence of more A than can be accounted for on the basis of white admixture, especially in the presence of so little B.3 Remarkably high percentages of B have also been found in the Yahgans of Terra del Fuego and in the Carajas of Brazil.4 Because of these findings and because of our demonstration we must admit that A and B are not especially recent mutations and that these factors were brought to the New World by prehistoric immigrants. Elsewhere we have presented the reasons which lead us to believe that humans have possessed A and B since before the differentiation of the present races of mankind, possibly inherited from our anthropoid ancestors.1
Since our only positive tests in North American material were in specimens from pre-Pueblo or peripheral horizons we might suppose that this finding is another example of the physical distinctness of the Basket Maker and Pueblo peoples and that the first immigrants to the Southwest brought a fair percentage of A, whereas the later round-headed Pueblo immigrants were predominately O. Any hypotheses about the relations and migrations of the ancient Americans based on as few determinations as we have been able to make are highly speculative and are offered solely for the purpose of stimulating discussion. All we claim to have shown is the presence of both agglutinogens A and B in prehistoric Americans. With this qualification in mind one might suppose a relationship between the Lovelock Cave people and the Basket Makers of the Southwest, or a lack of relationship between the Big Bend Cave people and the Basket Makers. Suggested also is the possibility of two A bearing migrations separated by an O bearing migration, the last one bearing A accounting for the high reponderance of A in the living North American tribes mentioned above.3 The preponderance of positive tests for B in South American material is consistent with the findings of much B in certain living South American tribes,4 and might lead us to suggest that some of the earliest immigrants to America, earlier than the Basket Makers, brought B. The single positive test for B in a Big Bend specimen tempts one to suggest that the Big Bend culture represents a station of these early B bearing people who migrated along the eastern periphery of the Southwestern area to populate South America. A more extended discussion of the possible significance of our findings may be found elsewhere.5
Aside from the possible scientific importance of our work there is a touch of romance and certainly a "thrill" in thinking that it is possible to determine at least one physiological characteristic of the people whose houses and belongings amaze us when we visit Mesa Verde. Heretofore we have been able to study only the anatomical characteristics of their remains. Determination of the blood groups is truly a physiological study. In the method substances remaining in dessicated tissues of the ancient people are made to react with other substances obtained from the blood of living people, in some cases ourselves. This brings these ancient people closer to us and makes archeology a thing become alive. | ||||||
| <<< Previous | > Cover < | Next >>> |
vol7-2b.htm
14-Oct-2011