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  #41  
Old 15th December 2006, 07:59 PM
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casadecoqui casadecoqui is offline
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Humans Migrated Out of Africa, Then Some Went Back, Study Says

New study coming out tomorrow in Science by Torroni et al:

Humans Migrated Out of Africa, Then Some Went Back, Study Says


Humans first moved out of Africa about 70,000 years ago, but 30,000 years later some of them moved back.

That's according to a new study based on DNA evidence from ancient human remains found in Africa.

The study shows that a small group of early humans returned to Africa after migrating to the Middle East.

In addition, the research suggests that the humans' return occurred around the same time that another group of humans left the Middle East and moved into Europe.

"We were rather surprised by the age of the migration back to Africa," said Antonio Torroni, a geneticist at the University of Pavia in Italy.

"We did not really expect that it was 40,000 to 45,000 years old."

"But the age and the fact that the migration had originated in the Levant [a geographical term referring to a large part of the Middle East] led us to link the migration to Africa to that occurring at the same time toward Europe from the same region," added Torroni, who led the research team.

The findings are reported in tomorrow's issue of the journal Science.
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  #42  
Old 1st January 2007, 06:33 PM
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African American mitochondrial DNAs often match mtDNAs found in multiple African ethn

I thought this article might interest some of you:
http://www.biomedcentral.com/1741-7007/4/34

Catherine
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  #43  
Old 3rd January 2007, 06:54 PM
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casadecoqui casadecoqui is offline
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Hello, Catherine:

This article was mentioned in this POST

when it first came out. I happen to know Dr. Jackson and Dr. Ely has visited my brother in Puerto Rico.

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Originally Posted by Francois
I thought this article might interest some of you:
http://www.biomedcentral.com/1741-7007/4/34

Catherine
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  #44  
Old 7th January 2007, 03:43 PM
GregKiroKH2 GregKiroKH2 is offline
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Did he quote the abstract? I am reading more essays like this. When does a paraphrase really becomes better than a quote. Now, people are wonder why peacocks have tails, and men do not.

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Originally Posted by casadecoqui
Hello, Catherine:

This article was mentioned in this POST

when it first came out. I happen to know Dr. Jackson and Dr. Ely has visited my brother in Puerto Rico.
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  #45  
Old 15th January 2007, 07:28 PM
Francois Francois is offline
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Greg,

I am sory but I don't know what you mean. I found that article and posted it not realising that it had already been mentioned.

Catherine


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Originally Posted by GregKiroKH2
Did he quote the abstract? I am reading more essays like this. When does a paraphrase really becomes better than a quote. Now, people are wonder why peacocks have tails, and men do not.
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  #46  
Old 17th January 2007, 12:15 AM
GregKiroKH2 GregKiroKH2 is offline
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I thought the article was interesting, Catherine. I thought your post was interesting too because I did not read the paper when I read the Scientific American article. I was pointing out "how people quote one another" is a little confusing. The Scientific American article is not as confusing as some students' papers I read. The original article by Bert Ely, Jamie Lee Wilson, Fatimah Jackson, and Bruce A Jackson was titled African-American mitochondrial DNAs often match mtDNAs found in multiple African ethnic groups. I noticed in 2005 that I had mixed motifs of L1c and K in my HVR-I region. People said that it was impossible. I could only be one motif. I did not know about that. I just noticed that I could take the mutations from both groups. And I would almost get my mutations for my HVR-I region if I added two more mutations. Some of the earlier papers have recognized that American DNA did not always match African DNA. And idea of multiple African ethnic groups was interesting to me.

Quote:
Originally Posted by Francois
Greg,

I am sory but I don't know what you mean. I found that article and posted it not realising that it had already been mentioned.

Catherine

Quote:
Researchers report that mitochondrial DNA isolated from African-Americans matched up to distinct African ethnic groups in fewer than 10 percent of cases, based on a partial database of African DNA samples. October 13, 2006

http://www.sciam.com/article.cfm?cha...B083414B7F00A7
Quote:
Consequently, common mtDNA haplotypes are shared among multiple ethnic groups. . . .

When two independent African-American samples were analyzed, more than half of the sampled HVS-I mtDNA haplotypes exactly matched common haplotypes that were shared among multiple African ethnic groups. Another 40% did not match any sequence in the database, and fewer than 10% were an exact match to a sequence from a single African ethnic group.

Received 31 May 2006

http://www.biomedcentral.com/1741-7007/4/34
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  #47  
Old 28th April 2007, 01:36 AM
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Hidden African Ancestors

Hidden African Ancestors: Hidden secrets of your ancestors

Peter de Knijff1

1Department of Human Genetics, Center for Human and Clinical Genetics, Leiden University, Medical Center, P O Box 9600, 2300 RC Leiden, The Netherlands

Correspondence: Peter de Knijff, Tel: +31 71 526 9537; Fax: +31 71 526 8278; E-mail: p.de_knijff@lumc.nl

Genealogy is no longer simply a matter of pen, paper, and patience. It seems that modern genealogical reconstruction is not complete without genetic confirmation by means of Y-chromosome genotyping. As usual, when there is a demand, commercial enterprises pop up like autumnal mushrooms. A simple Google search with genealogy+y+DNA results in approximately 468 000 hits. Many of these sites are surname-specific projects or internet companies offering commercial genotype services. What these companies offer is what I call a blindfold scenario: a male with surname X has his Y-profile typed and compared to all other types in the companies' database in the hope of finding a (near) match to someone else in the database irrespective of its surname. The error-prone nature of such a process is perfectly illustrated by the link by Oxford Ancestors of one of their clients to Genghis Khan.1 Only rarely genealogists adopt the much more reliable open-eyed hypothesis driven kind of request: a genealogist has reconstructed a certain pedigree and either wants to have this pedigree confirmed or needs a genetic 'link' between branches of the pedigree which cannot be linked otherwise. This pedigree-based design was also used to obtain the first mutation rates of Y-STRs2 and the reconstruction of the pedigree of Thomas Jefferson.3

In most Western societies surnames are co-transmitted with Y-chromosomes. As a consequence, surname and Y-chromosome reflect the same patrilineal ancestry. Generally speaking, the rarer a surname, the better its transmission over time reflects that of a particular Y-chromosome.4 It has even been shown that in the ideal case population substructure can be inferred only on the basis of detailed surname analyses.5 Although this might be true in general, in isolated cases false paternity or in vitro fertilization by means of anonymous sperm donors disrupts the link between a particular surname and its corresponding Y-chromosomal genotype. Of course, also a perfectly legal marriage can introduce 'exotic' Y-chromosomes into a pedigree. When this happened in the past, and is not adequately documented, one could learn something quite unexpected about one's ancestors. This is exactly what was described in the recent issue of this journal.6

King et al, much to their own surprise, discovered a single male carrying a classical African Y-chromosome type, called haplogroup A1, among a set of 421 males who were analyzed as part of an ongoing large British surname study. The surname of this male matched to another 121 individuals in the public record, predominantly in east Yorkshire. From these, 18 apparently unrelated males were relocated and genotyped. Of these, six more males also carried the same African A1 Y-chromosome. Genealogical research allowed them to be connectedto two pedigrees going back to 1788 AD and 1789 AD. These two pedigrees could not be connected, but a detailed Y-chromosome study strongly suggests that originally they must share a single common male ancestor. As such, the presence of African Y-chromosomes among Western European populations is not without precedent. At least for Britain, the presence of Africans has been reported since 200 AD (see King et al.6). However, what is surprising is the exact type of African Y-chromosome. In Africa itself three major Y-haplogroups are most frequently observed (A, B, and E) with frequencies of approximately 7.3, 11, and 69%, respectively. The frequency of haplogroup A1 is only about 1% in Africa. Its presence among a Yorkshire family dating back about 300 years was therefore quite unexpected.

Since nothing more definitive can be inferred on the basis of the present data, exactly how and when this very rare African Y-chromosome was introduced into the otherwise perfectly indigenous English family will most likely remain unknown. On the basis of Y-STR analysis a Western African origin of this Y-chromosome is likely, despite its rarity. A more detailed surname analysis and a coalescence analysis based on Y-STR differences failed to yield a more exact coalescence date between the two families, although it is probably within a few generations (ie 100?150 years) before 1788. Based on this, it cannot be decided whether the introduction is due to a direct or indirect route. The former could relate to reports of Nubians in the Roman army defending the North territories; the latter could be associated with the later slave trade, which brought the first West Africans to England in 1555.6

The study of King et al demonstrates that a Y-chromosome-only reconstruction of geographic origins can be seriously misleading. It also illustrates how a hitherto unknown secret pops up during a rather innocent pedigree reconstruction by means of Y-chromosome testing. As such it once again shows the importance of a general concept often ignored by participants of pedigree-based Y-testing: if you do not want to know, do not have yourself tested.
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  #48  
Old 7th May 2007, 10:36 PM
GregKiroKH2 GregKiroKH2 is offline
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We were talking about the distribution of polymorphisms between different haplogroups. And the topic a Lorentzian and Gaussian waveshapes came up. Why do you think there are distributions of polymorphisms?

Quote:
Control region rates follow a negative binomial distribution (gamma distribution).
Most sites -invariant
Few sites -fast

High α(low variation)
Low α(high variation)

The SHAPE of the curve (α) is inversely related to the amount of heterogeneity
Yang, 1996

Meyer and von Haeseler (2003) Mol. Biol Evol. Analyzed the 53 mtGenomes from Ingman et al. (2000).
http://www.cstl.nist.gov/biotech/str...dingregion.pdf
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  #49  
Old 22nd May 2007, 02:28 PM
GregKiroKH2 GregKiroKH2 is offline
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What is the Difference between 3594 L3 and 3592 L3?

What does it mean if a L has the 3594 mutation instead of the 3592 mutation?

Quote:
We build on the phylogenetic analyses of European (Richards et al. 1998; Macaulay et al. 1999) and African (Rando et al. 1998) mtDNA, which combine HVS-I and RFLP information. According to the nomenclature of those analyses, human mtDNAs are divided into three supergroups?L1 (13592 HpaI, 210806 HinfI), L2 (13592 HpaI, 216390 HinfI), and L3 (23592 HpaI). L1 and L3 are further subdivided into haplogroups, which can be recognized by specific restriction sites (table 1).
http://www.gene.com.br/ExamesGenetic...ilianmtDNA.pdf
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  #50  
Old 22nd May 2007, 03:31 PM
GregKiroKH2 GregKiroKH2 is offline
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L3 does not have the mutation 3592. The minus sign means that it was lost with the L3 people. This is why it is not seen much outside of Africa.

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What does it mean if a L has the 3594 mutation instead of the 3592 mutation?
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