1. The term “lineage” consists of all descendants in one line of a particular person through a determinate number of generations. Where the living members constitute of recognized social group it may be called lineage group, Sometimes the lineage consist of all descendants through male of a single ancestor which is called a patrilineage or an agnatic lineage; one consisting of descendants through female is known as matrilineage.
2. Lineage usually has exclusive common ritual observance, perhaps totemic in nature and is usually exogamous. The clan is often the combination of a few lineages and descent may be human and human like animal or plant or even inanimate. Radcliffe Brown takes up a slightly different position and defines lineage as sib. He introduced the term. A sib is a consanguineous group, but its members do not share a common residence.
3. A descent group is any social group in which membership depends on common descent from a real or mythical ancestor. Thus a lineage is a unilineal descent group in which membership may rest either on patrilineal descent (patrilineage) or on matrilineal descent (matrilineage) In some societies the child is regarded as a descendant equally of both the father and the mother, except that titles and surnames are usually passed down along the male line. ……………………….. Such a system is termed Bilateral or Cognatic. The individual belongs simultaneously to several descent groups-those of the two parents, the four grandparents, the eight greatgrandparents, and so on. This link is limited only by memory or by some conventionally determined cut-off point at, say, four or five degrees removal. In small intermarrying communities, membership will probably overlap, and in case of dispute or feud, the individual might find his or her loyalties divided. There are some cognatic systems where the individual has the right by descent to membership of several cognatically recruited groups, but this right is actualized only if the person is able to reside in a particular group’s territory. Modern nationality laws often make this type of requirement.

Types of Descent:

1. In other societies, by contrast and your own is most probably one of them descent is reckoned unilineally, that is, in one line only. The child is affiliated either with the group of the father, that is, patrilineal descent, or with the group of the mother, that is, matrilineal descent. Theories of the physiology of procreation and conception often correlate with these different modes of reckoning descent. In the former, the father is often given the primary role in procreation while the mother is regarded as merely the carrier of the child, in systems of the latter type, the father’s role may not be acknowledged at all.
2. Additionally, in some societies one finds that the child is affiliated to the group of either parent, depending on choice, or to one parent for some purposes (for instance, inheritance of property) and to the other parent for other purposes (for instance, the inheritance of ritual or ceremonial roles). This is called double unilineal descent.
3. The principle of unilineal descent provides the individual an unambiguous identification with a bounded social group that exists before he or she is born and that has continuity after he or she dies. Members of a descent group have a sense of shared identity, often referring to each other as ‘brother’ and ‘sister’ even when no genealogical relationship can be traced.
4. Descent groups are also very often, (though not inevitably), characterized by exogamy. That is, marriage must be with persons outside this group. For instance, traditional Chinese society was divided among approximately a hundred ‘surname’ groups-you could perhaps call them clans-within which marriage was disallowed, and these groups further divided into lineages, whose members claimed to be able to trace their descent, perhaps for several hundred years, from a founding ancestor, and then into further localized subline ages and so on down to the individual co-resident families. Sometimes a whole village might be settled by members of a single lineage. The gotras of Indian caste society are also exogamous descent groups, segmented in rather the same way.

Functions of Descent Groups:

1. Apart from the function of exogamy, unilineal descent groups tend to be ‘corporate’ in several other senses. Their members may often come together for ritual and ceremonial functions, for instance, for collective worship of lineage gods, totems or ancestors. The descent group will have a built-in authority structure, with power normally exercised by senior males, and it may well own corporate property. An individual’s economic rights and responsibilities will be defined by his or her position in the descent group.
   • In many societies, unilineal descent groups are also jural units, internally deciding their own disputes, and externally acting as a unified group in relation to other similar groups in the conduct of feud, etc. For this reason, lineage structure is often conterminous with the political structure in societies lacking a centralized state structure.
2. Lineages cannot expand indefinitely in a single locality and often segment into smaller, more manageable and economically viable lineage segments. You can see the lines of segmentation on the ground, as it were. Consider the pattern of land ownership in an Indian village, or at the pattern of village or urban settlement; a particular quarter of the village or town may be inhabited by the descendants of a single founding ancestor. Often, the large havelis divide among brothers or step-brothers, and these quarters are further divided among their descendants. In case a lien dies out, the property would be reconsolidated.
3. Given the range of social functions that descent groups may potentially perform, it is little wonder that concern with the principles of unilineal descent has dominated the work of many students of comparative kinship. However, even these scholars realize that unilineal descent is not the whole story. In ancient Rome, women after marriage several all contact with their natal group. In certain slave societies, the slave has no ‘family’ of his or her own. In patrilineal systems, the mother’s father, mother and sister, and especially the mother’s brother, are important examples of relationships which need further discussion. To take note of the importance of these relationships, the scholars have identified another principle. This has been termed the principle of complementary filiation which explains the significant ritual and social roles of the mother’s brothers in the lives of their sister’s children. It reminds us that, in most societies, an individual is a child of both parents, however descent is formally reckoned.