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Ancestor

 

 
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Ancestor
 
 
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An ancestor is a parent
Parent

A parent is a mother or father; one who sexual reproduction or gives birth to and/or nurtures and raises an offspring. The different roles of parents vary throughout the tree of life, and are especially complex in human culture....
 or (recursively
Recursion

Recursion, in mathematics and computer science, is a method of defining Function in which the function being defined is applied within its own definition....
) the parent of an ancestor (i.e., a grandparent
Grandparent

Grandparents are the father or mother of a person's own father or mother, being respectively a grandfather and a grandmother . Everyone has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, etc....
, great-grandparent, great-great-grandparent
Family

Family denotes a group of people affiliated by a common ancestry, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," some cultural anthropology have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts r...
, and so forth).

Two individuals have a genetic
Genetics

Genetics , a discipline of biology, is the science of heredity and Genetic variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding....
 relationship if one is the ancestor of the other, or if they share a common ancestor. In evolution
Evolution

In biology, evolution is change in the heritability trait of a population of organisms from one generation to the next. These changes are caused by a combination of three main processes: variation, reproduction, and selection....
ary theory, species who share an evolutionary ancestor are said to be of common descent
Common descent

A group of organisms is said to have common descent if they have a common ancestor. In modern biology, it is generally accepted that all living organisms on Earth are descended from a common ancestor or ancestral gene pool....
. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer
Horizontal gene transfer

Horizontal gene transfer , also Lateral gene transfer , is any process in which an organism incorporates genetic material from another organism without being the Reproduction of that organism....
.

Assuming that all ancestors are unrelated, an individual has 2n ancestors in the nth generation before him and about 2g+1 total ancestors in the g generations before him.






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An ancestor is a parent
Parent

A parent is a mother or father; one who sexual reproduction or gives birth to and/or nurtures and raises an offspring. The different roles of parents vary throughout the tree of life, and are especially complex in human culture....
 or (recursively
Recursion

Recursion, in mathematics and computer science, is a method of defining Function in which the function being defined is applied within its own definition....
) the parent of an ancestor (i.e., a grandparent
Grandparent

Grandparents are the father or mother of a person's own father or mother, being respectively a grandfather and a grandmother . Everyone has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, etc....
, great-grandparent, great-great-grandparent
Family

Family denotes a group of people affiliated by a common ancestry, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," some cultural anthropology have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts r...
, and so forth).

Two individuals have a genetic
Genetics

Genetics , a discipline of biology, is the science of heredity and Genetic variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding....
 relationship if one is the ancestor of the other, or if they share a common ancestor. In evolution
Evolution

In biology, evolution is change in the heritability trait of a population of organisms from one generation to the next. These changes are caused by a combination of three main processes: variation, reproduction, and selection....
ary theory, species who share an evolutionary ancestor are said to be of common descent
Common descent

A group of organisms is said to have common descent if they have a common ancestor. In modern biology, it is generally accepted that all living organisms on Earth are descended from a common ancestor or ancestral gene pool....
. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer
Horizontal gene transfer

Horizontal gene transfer , also Lateral gene transfer , is any process in which an organism incorporates genetic material from another organism without being the Reproduction of that organism....
.

Assuming that all ancestors are unrelated, an individual has 2n ancestors in the nth generation before him and about 2g+1 total ancestors in the g generations before him. In practise, however, it's clear that the vast majority of ancestors of humans (and indeed any other species) are somehow related (see Pedigree collapse
Pedigree collapse

Pedigree collapse is a term created by Robert C. Gunderson to describe how Cousin marriage or other relatives, deliberately or unknowingly, make family trees smaller than they could be....
). Consider n = 40: the human species is surely more than 40 generations old, yet the number 240 dwarfs the number of humans that have ever lived
World population

The world population is the total number of living humans on Earth at a given time. As of March 2009, the world's population is estimated to be about 6.76 1,000,000,000 ....
.

As far as contribution to one's autosomal DNA is concerned (this does not include Y-chromosomal DNA or mitochondrial DNA) assuming that none of one's ancestors had children with relatives (even distant relatives), an individual has a total of 2046 ancestors up to the 10th generation, 1024 of which are 10th-generation ancestors. With the same assumption, any given person has over a million 20th-generation ancestors (generally equivalent to around 500 years) and this theoretical number increases past the total population of the world at around 1400 AD.

Some cultures place great reverence on ancestors, both living and dead; contrastingly, people in more youth-oriented cultural contexts may display a lesser degree of veneration for elders. In other cultural contexts, some people seek providence from their deceased ancestors; this practice is sometimes known as ancestor worship
Ancestor worship

Ancestor worship or ancestor veneration is a practice based on the belief that deceased family members have a continued existence, take an interest in the affairs of the world, and/or possess the ability to influence the fortune of the living....
 or, more accurately, ancestor veneration.

See also

  • Genealogy
    Genealogy

    Genealogy is the study of families and the tracing of their lineages and history. Genealogists use oral traditions, historical records, genetic analysis, and other records to obtain information about a family and to demonstrate kinship and pedigree of its members....
  • Ancestor worship
    Ancestor worship

    Ancestor worship or ancestor veneration is a practice based on the belief that deceased family members have a continued existence, take an interest in the affairs of the world, and/or possess the ability to influence the fortune of the living....
  • Cousin
  • Family
    Family

    Family denotes a group of people affiliated by a common ancestry, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," some cultural anthropology have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts r...
  • Family relationship
  • Most recent common ancestor
    Most recent common ancestor

    In genetics, the most recent common ancestor of any set of organisms is the most recent individual from which all organisms in the group are directly Common descent....
  • Kinship
    Kinship

    Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. In anthropology the kinship system includes people related both by descent and marriage, while usage in biology includes descent and mating....
  • Ethnicity