A cloned child has unilineal descent, not bilineal descent; he or she is genetically kin to only one progenitor. What is more, in unilineal descent, the genetic kinship is near-total. The cloned child is not genetically unique, but shares almost completely the genetic endowment of the original progenitor. Bilineal descent is system of family descent where blood links and rights of inheritance through both male and female ancestors are given equal importance. The most common form is bilateral descent.
Many societies construct kinship groupings exclusively through the patrilineal matrilineal line and are called unilineal descent groups. Descent concerns the tracing of relationships through succeeding generations, i.e., who has descended from whom. There are several ways of tracing descents.
Unilineal Descent or one-line descent is that form of descent in which a relationship is emphasised through one sex or line. It is of two types:
1. Patrilineal Descent or Agnatic Descent is a form of unilineal descent traced through males only. It is important to remember that the person calculating descent may be either female or male.
2. Matrilineal Descent or Uterine Descent is a form of descent traced through females only. Both females and males trace their descent in this way.
There is also the form of Double
or Duo Lineal Descent or Bilineal Descent. It is a form of unilineal descent which
combines both patrilines and matrilines.
Cognatic or Bilateral Descent is non unilineal descent. Here descent is traced through all progenitors, female and male, through both the mother and the father.
In India we generally find the Patrilineal Descent and matrilineal descent systems. Of the two, patrilineal descent system is more common. Patrilineal descent is more prevalent in North India.
Tribes such as the Khasis and Garos of North-East have the Matrilineal Descent system. The Nayars of Kerala are a good example of matrilineal descent.
Unilineal descent groups often take the form of lineages and clans. Lineage is a set of kin, whose members trace their descent from a common ancestor through known links.
Evans-Pritchard and Meyer Fortes
argued that the Tallensi and the Nuer were primarily organised around unilineal descent
groups. Such groups function are characterised by common purposes, such as administering
property or defending against attacks
Unlineal and Bilineal Descent: How Various Cultures Trace Their Heritage
By Joe Norton
There are two types of descent practiced:
Bilinineal Descent - which is descent traced back through both parents
Unilineal Descent - which is descent traced back through one parent.