Introduction

The study of blood groups of man opened up a new vista in the analysis of the anthropological data. Shattock discovered, as early as 1899, that the horse serum" to which a drop of human blood was added caused clumping together of the red corpuscles. In the year 1900 Landsteiner discovered that the blood of some persons agglutinated immediately after the introduction of the blood of some other persons. In 1901, he divided the human blood into three groups and in 1907, Jansky made it four O, A, B, and AB. Dengern and Hirzfeld, in 1910, discovered that the blood groups followed the Mendelian way of inheritance. In 1910 Hirzfelds examined troops in the Mecedonian Army in Siberia during the First World War and from the result of their vast observations they came to the conclusion that all races possessed high percentage of O group of blood. The American Indians possess O group and also the Australian aborigines show maximum tendency of O group. In Western Europe, A predominates over B, but in East and South the influence of A decreases. B is not commonly found among the primitive people. Ruggles Gates is of opinion that 0 may be considered as a universal Primitive feature and A is older than B. In his paper on Eskimo Blood Groups and Physiognomy (1935- 36), he has shown that the Eskimos 'with pure Eskimo type of - face possess O group whereas those who show the mixed characters have A group of blood. This predominance of certain groups of blood in a particular group of people provides clue to the Raciologists to find out the racial significance of those features that are controlled by the interplay of certain genes. In 1925, Landsteiner and Miller found that the blood of anthropoid apes possessed blood groups like those of man. Recently Nuttall, Sudermann and Zuckerman have done detailed work on the nature of blood groups in apes and have come to the conclusion that the Old World Monkeys have got more close serological relationship than they are related to the New World Monkeys. Gradually it became the ultimate aim of the scholars of those days to analyze their data through the study of blood groups. Lieutenant Commander Marett applied genetical method to the study of prehistory. J. B. S. Haldane on examining the distribution of B blood group on a map of the world has come to the conclusion that it corresponds to a migration outward from Central Asia which never reached America and also Australia. From his census analysis in 1931 Hutton observes that the origin and distribution of B group is to be found in the broad-headed Eurasiatic race. O group is found in all the races which are considered as the most primitive. A group of blood is more frequent than B group and the former may be called as older. On considering the whole affair AB has been considered as the least frequent group

Great stress has been laid by the physical anthropologists to explain the course of human evolution. The transition from a pre-hominid to a hominid stage is characterised by the change to a fully erect gait, the enlargement of the brain, and the prolongation of immaturity. The chief agency of gradual change in the species is thought to be the role of natural selection acting on-the genetic variability provided by mutation and recombination of genes.

Julian Huxley's Evolution: the modern synthesis (1942) and Rensch’s Evolution Above the Species Level (1960) are considered to be the most valuable study in this regard. The Neo-Darwinism as expounded by Huxley and Rensch is adverse to the idea of orthogenetic explanations of the evolution of exact gait and form of the brain as put forward by Weidenreich (1947). Simpson (1949 and 1950) also has put stresses on the neo-Darwinian view in his works and he is of opinion that the phylogenetic changes are the result of mutational changes which ultimately exert their influence on the development and growth. Haldane (1947) has estimated the mutation rates for man. Fisher (1930) and Haldane (1935) have rnathematically treated the action of selective advantages conferred by the different kinds of genotype in changing the genetic constitution of a group of people. This method has been applied in the recent years to find out the present day distribution of the genes belonging to Rh series (Haldane, 1942) and the gene responsible for the sickle cell trait (Allison, 1954). Mourant in his The Distribution: of Human Blood Groups (1954), has pointed out the steady change in frequency of the Rh chromosomes passing from Negroid to the Mediterranean groups.

The study of Race and Racial differentiation has undergone an abrupt change in the present period due to the application of genetics which has been more accurate after the discovery of the new blood group genes and their behaviour patterns. The problem of race has been treated from the different angles, by the anthropologists’ like-Huxley and Haddon (We Europeans, 1935), Dahlberg (Race, Reason and Rubbish, 1942), Ashley-Montagu (Man’s .most dangerous myth, 1945), Wasbburn (The Races of Europe, 1945), Boyd (Genetics and the Races of Man, 1950). The UNESCO statement on the Nature of Race and Race differences (1952) has presented an integrated view of a number of physical anthropologists and geneticists, which has resulted in a publication like The Race Question in Modern Science, in the year1956, in the study and analysis of Race. The genetic method has now superseded the older method for studying the race and its different problems.

The discoveries of blood group antigens of the MNS system and those of the Rh system besides the well-known ABO system have caused a considerable change in the line of study. A detailed account of the blood group system are to be found in the works of Weiner (Blood groups and transfusion,1943 ), Race and sanger (Blood groups in Man, 19S0), Boyd (Genetic and the Races of man, 1950 ) and Stern ( Principles of Human genetics, 1960).

In India a number of works on blood groups have been conducted by the scholars in this line who have attempted to determine the distribution of percentage of the different blood types and of their gene frequencies. In this particular field of work the names of Malone and Lahiri (1927), P. N. Mitra (1932), A. Aiyappan (1936), A Choudhury (1936) and E. W. E. Macfarlane (1937) may be noted as the early workers. P. N. Mitra's work on "the influence of Blood Group in certain Pathological states" (1933), threw a different light as it depicted the reaction of the people belonging to the different blood groups to various types of infection. In order to solve the problem of racial identification and the racial migration, a number of persons have come forward to test the blood which has provided them a way out. In this particular field of study the names of E. C. Buchi, U A. Krishna Iyer, D. N. Majumdar, S. S. Sarkar, N. Seshadrinathan, B. Timothy, D. K. Sen, N. Kumar, and S. C. Tiwari are important. K W. E. Macfarlane forwarded his idea on the distribution of blood groups in India (1938) and there she attempted to bring the picture of Bengal in the forefront. Two years later she, along with S. S. Sarkar, put forward a more elaborate discussion on the blood groups in India published in the American Journal of Physical Anthropology (vol. 28, No.4). Majumdar conducted a large range of study on the problem and gave an overall picture on the distribution of various blood types in India. He in collaboration with S. Bahadur prepared a blood map of India where he showed the distribution of B blood type. According to him, the concentration of B group was commonly met with the social groups that passed from tribal to caste groups. From his works in Bengal he came to the conclusion that the castes occupying the lowest status showed highest frequency of B. The tendency of B increased among the tribal groups who mixed with all the neighboring caste and tribal groups and allow inter-tribal or extra-marital union; but it brought forth a debatable issue. D. K. Sen's work deserves mention in this context. He utilised the blood group studies in understanding the racial composition of Bengalis and he was quite successful in his work on establishing the trend of relationship between the study on blood typing and that of anthropometry. B. K. Chatterjee and A. K. Mitra in their joint study had also contributed a large mass of data on blood group distribution of the Bengalis (1941-42). They, in a separate paper, attempted to find out the position of the Mundari speaking tribes after examining them in the background of the Dravidian and Monkher speakers. In doing so they successfully utilised the anthropological and serological procedures for the determination of ethnic set up. E. W. E. Macfarlane should be congratulated on her study on the inheritance pattern of the blood groups, and her article on "Mother and Child combination of blood groups and blood type and their development in Bengalis" (1939) opened a new, vista in the study of serology in India. In recent years special emphasis has been laid by the physical anthropologists on the fundamental problems of human genetics with the help of bio-statistical tool. This new trend has brought a profound change in the horizon of physical anthropological study and research. The works of L D Sanghvi (1953) and S. R. Das (1956) are to be mentioned here with due importance, The former has studied the group distance within a caste level, with the help of multiple genetic factor whereas the latter has thrown a considerable light on the pattern of inheritance, of P. T. C. in human groups.

Blood is a specialized tissue of the human body. One of the main functions of blood is to supply nourishment, especially oxygen to the cellular elements of the tissues of the other parts. Another function is to help in removing the waste products of the metabolic activities, especially carbon dioxide. Moreover, it helps in maintaining the required temperature of the body and also the proper balance of fluid substances in the human body.

Blood is composed of two types of material – a faintly yellow fluid called the plasma in which numerous minute particles termed as the blood corpuscles are suspended. The two parts can easily be separated . When a sample of blood taken with anticoagulant is centrifuged or kept in a tube for a considerable time, the red cells settle at the bottom of the tube leaving the white cells to form a thin layer above. On the top lies the plasma

The Plasma is a coagulable fluid. It contains a variety of substances like fibrinogen (which causes clotting in whole blood), albumin, globin , amino-acid, fat. When the coagulating and coagulable elements are removed from the plasma, a clear fluid is obtained this is serum.

There are three kind of blood –corpuscles: red blood corpuscles (RBC) or erythrocytes; white blood corpuscles (WBC) or leukocytes; and blood platelets.

Genetic Markers in red blood cells

The genetic markers in red blood cells can conveniently be discussed under three major heads , namely

1. Red Cell Antigens: Blood Group Polymorphisms

2. Hemoglobin

3. Enzymes

Red Cell Antigens: Blood Group Polymorphisms

The ABO system

IN 1900-1902 Landsteiner discovered that all human beings fall into four principal blood groups according to their composition. The groups are denoted by the letter A,B, AB, and O . There are several sub-groups of A and B. The four main groups are determined by the fact that blood corpuscles of certain individuals react upon the serum or plasma (fluid part of blood) of certain other individuals and thereby causing agglutination or clumping together of the red blood cells. These substances in the red corpuscles are called antigens. Two types of antigens, denoted by the letters A and B, have been distinguished. Again the substances present in the serum with which antigens react are also of two different natures, and they are distinguish as anti-A and anti-B. The two antigens A and B may be present together as in blood group AB, or be altogether absent in blood group O, or be present singly as in blood group A or in blood group B.

To which group a person belongs can easily be found out by mixing a drop of his blood known blood sera A and B. If the red blood corpuscles agglutinate in A serum he belongs to group B; if the red corpuscles agglutinate in B serum he belongs to group A ; if agglutination occurs in both A and B , he belongs to group AB and if agglutination does not take place either in A or B , he is member of group O.

People of O group are known as ‘universal donor’, as O blood can safely be transferred to person of any blood group; while people of AB group are called ‘universal recipient’, as they can easily receive blood of any group. A blood can be given only to persons of A or AB groups and B to persons of B or AB groups only. AB can be transfused safely to AB person only.

The heredity of blood groups are fully known. The allelic genes which can occupy the same locus on a certain chromosome are responsible for hereditary mechanism. It seems that O is recessive to both A and B. Hence out of six genotypic combinations OO, AA, BB, BO, AO, AB, four phenotypic blood groups O, A, B, AB, are distinguished, Applying some formulae gene frequencies of blood groups can also be calculated.

Genotypes and Phenotypes of Blood groups

Genotypes	Phenotypes
OO	O
AA , AO	A
BB, BO	B
AB	AB

The relative frequencies of the four main blood groups among different populations have been found out to use it as a racial criterion.

According to Boyd there are some advantages in using the blood group as a racial criterion.

1.They are inherited in a known way according to Mendelian principles.

2.They are not altered by differences in climate, food, illness to medical treatment.

3.Their frequency in a population is a very stable characteristic.

4.They probably arose very early in the course of man’s evolution.

5.There is a considerable correlation between geography and the distribution of the blood group.

6.The blood groups are sharply distinguish “all-or none” characters which do not grade into each other.