Support/Ancestry/Maternal/Paternal Line

More about Haplogroups

23andMe
posted this on April 10, 2012 08:43 AM

Haplogroup is the term scientists use to describe individual branches, or closely related groups of branches, on the genetic family tree of all humans. All members of a haplogroup trace their ancestry back to a single individual. Our Maternal Line and Paternal Line features provide haplogroup assignments which allow you to trace your ancestry from your mother through her mother and beyond, and for men, from your father through his father and beyond.

Haplogroup maps

The haplogroup map shows you where most of the people with a given haplogroup lived prior to the age of European exploration, about 500 years ago. Before that time people moved a little less, and rarely moved between continents. Therefore the map reveals where people with a particular haplogroup lived for thousands of years.

In general, the map reflects human migration over the last 70 millennia. During that period humans migrated from eastern Africa to inhabit every continent on Earth except Antarctica. As they spread out geographically, they also diversified genetically at a relatively constant rate.

Every once in a while a mutation appeared in an inhabitant of a particular region and was passed down through the paternal or maternal line to descendants now living in that region, and wherever else people with the mutation might have migrated. So by looking at the pattern of mutations in present-day populations geneticists can trace backwards in both time and space, reconstructing the genetic and migration history of the male half of the species using Paternal Haplogroups and matrilineal lines using Maternal Haplogroups.

Most world maps locate the Americas on the left. For these features we use a map where the Americas are located on the right. The reason for this shift is that human prehistoric migrations began in Africa and moved north and east, eventually crossing the Bering Strait to reach the Americas. The map with the Americas on the right allows visualization of the entire route from Africa to the Americas without the need for "wrapping" back around to the other edge of the map.

Haplogroup locations may be widespread, such as in A and M, or more localized as in B and T:

 Locations of haplogroups A and M

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Locations of haplogroups B and T

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Haplogroup names and "star" lineages

The naming of haplogroups is somewhat arbitrary. There are, however, a few rules. Most haplogroup names start with a capital letter (or two). Additional numbers and lowercase letters indicate haplogroups that are subgroups of the major haplogroup.

All lineages of a subgroup share one or more mutations. Sometimes there are a few lineages that don't fit into any subgroup of a haplogroup. Since there isn't a mutation that links these lineages, they don't get their own subgroup. Instead, these lineages are given the main haplogroup label plus a star (*) to indicate that they are part of the main haplogroup but don't fit into any of the known subgroups. Example of these "star" lineages include I1* - the Mendels paternal haplogroup - as well as E1b1a8a* (Desmond Tutu) and E1b1b1c1* (Napoleon Bonaparte).

"Star" lineages sometimes arise when a population grows rapidly. If your paternal haplogroup assignment ends with a star, your paternal lineage may have participated in such a population expansion. The age of the haplogroup indicates, roughly, when that rapid population growth happened.

Sometimes research leads to the discovery of mutations that link several of the "star" lineages. When that happens the lineages get a new name and lose their "star" designation.

Haplogroup ages

Each haplogroup has an approximate age listed in the overview box on the right side of the Maternal or Paternal Line page:

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Researchers have used a variety of methods for estimating when a haplogroup arose. In choosing which estimates to present, we have considered both published estimates of dates and our own estimates. Maternal haplogroup estimates are derived from published complete sequences of mitochondrial DNA genomes. Paternal haplogroup estimates are derived from Y chromosome sequence data.

Using the Haplogroup Tree

When you first reach the Paternal or Maternal Line page, you will see a map and a brief history of your haplogroup. Click on the Haplogroup Tree tab to see yourself highlighted on the haplogroup tree:

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At the left edge of the tree is the common ancestor of all living people.  For Paternal Line, we use "PoP" (Papa of all Papas) and for Maternal Line, we use "MoM" (Mother of all Mothers). To the right are the descendants represented by green haplogroup labels, or "leaves." Blue people icons next to a haplogroup label indicate that you or your shares belong to that haplogroup or one of its subgroups.

If a haplogroup includes lower-level subhaplogroups, its green label will have a + sign on the right side of the label. Click the + sign to reveal lower level haplogroups. There may be additional expandable haplogroups-within-haplogroups, so keep an eye out for more + signs.

Clicking on the green "leaves" at the branch points of the tree shifts the associated Map and Story pages to that haplogroup. Clicking on the tree and dragging enables you to move the tree around to view different sections. You can also do this by clicking on the arrows. To zoom in or out click the large plus and minus signs.

 

 
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