Genetics

Single gene may cause curly hair

(PhysOrg.com) -- Scientists in Australia have identified a single gene that strongly influences whether you have curly or straight hair.

Genetics

World's most advanced genetic map created

A consortium led by scientists at the University of Oxford and Harvard Medical School has constructed the world's most detailed genetic map.

Genetics

Genetic study clarifies African and African-American ancestry

People who identify as African-American may be as little as 1 percent West African or as much as 99 percent, just one finding of a large-scale, genome-wide study of African and African-American ancestry released today.

Genetics

Friendship may have a genetic component

(PhysOrg.com) -- New research suggests groups of friends may have common genetic patterns. Social scientist Professor James Fowler of the University of California, San Diego, came to this conclusion after looking at data ...

Genetics

Population genetics reveals shared ancestries

More than just a tool for predicting health, modern genetics is upending long-held assumptions about who we are. A new study by Harvard researchers casts new light on the intermingling and migration of European, Middle Eastern ...

Genetics

Mexican genetics study reveals huge variation in ancestry

In the most comprehensive genetic study of the Mexican population to date, researchers from UC San Francisco and Stanford University, along with Mexico's National Institute of Genomic Medicine (INMEGEN), have identified tremendous ...

Psychology & Psychiatry

Determined DNA hunt reveals schizophrenia clue

An 18-year study using the DNA of thousands of people in India has identified a new clue in the quest for causes of schizophrenia, and for potential treatments.

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Ancestor

An ancestor is a parent or (recursively) the parent of an ancestor (i.e., a grandparent, great-grandparent, great-great-grandparent, and so forth).

Two individuals have a genetic relationship if one is the ancestor of the other, or if they share a common ancestor. In evolutionary theory, species which share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer.

Assuming that all of an individual's ancestors are otherwise unrelated to each other, that individual has 2n ancestors in the nth generation before him and a total of about 2g+1 ancestors in the g generations before him. In practice, however, it is clear that the vast majority of ancestors of humans (and indeed any other species) are multiply related (see Pedigree collapse). Consider n = 40: the human species is more than 40 generations old, yet the number 240, approximately 1012 or one trillion, dwarfs the number of humans that have ever lived.

Ignoring the possibility of other inter-relationships (even distant ones) among ancestors, 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 billion 30th generation ancestors (who lived roughly 1000 years ago) and this theoretical number increases past the estimated total population of the world in around AD 1000. (All of these ancestors will have contributed to one's autosomal DNA is concerned: this excludes Y-chromosomal DNA and mitochondrial DNA.)

Some cultures confer reverence to ancestors, both living and dead; in contrast, some more youth-oriented cultural contexts display less veneration of elders. In other cultural contexts, some people seek providence from their deceased ancestors; this practice is sometimes known as ancestor worship or, more accurately, ancestor veneration.

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