THE BERBERS of NW Africa - STR Analysis

[djoser-xyyman]

Notice the distance between Aframs and Berbers are 16 and 33. The distance between ALL AFRICANS and EUROPEANS is 77. Quote: It should be noted that the most robust branch (77%) in the tree is that separating NW Africans from Europeans.

The diagram makes perfect sense. ….geographic sense. Distance BETWEEN EACH branch. Notice all Africans are on the same side of the tree
Of course the Mazabite are distinct. That is how it works. They are stating the obvious not something profound. The Mozabite will be different from the other Berber groups. Why? Geographic distance. They are thousands of miles away from Morocco. Siwas of Egypt will give the same pattern. Similarly for West Africans(Aframs). The length of the branch is a representation of isolation and genetic "variation" NOT genetic distance .
Yes, West Africans are genetically different to NW , they have a largest branch because they have more differentiation i.e. variance. The Mazabite are different because of isolation. BUT, the distance between them at the main trunk is extremely close. In other words they are the same stock i.e. indigenous Africans.
So always consider geographic location when you interpret these studies, forget your modern day political views. Demic diffusion is a fact but teleportation is not.
ALSO!! Notice Iberians are next closest to Africans then also Italians. Why? Geography. It is really not that difficult.

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[djoser-xyyman]

From the Study:
The two strongest genetic boundaries in the geographical area comprised by NW Africa and the Iberian Peninsula (see Figure 3) were found to encircle single populations.

STR diversityAMONG populations
Genetic differentiation among the populations of both the extended and basic sets was analysed by computing Fst genetic distances and representing them by means of neighbour- joining trees (Figures 1a and 1b). We also computed other genetic distances (data not shown):
the NW African populations cluster together, although with short and not very statistically robust branches among them. In the basic analysis, the Mozabites stand out from the rest of the NW Africans


It should be noted that the most robust branch (77%) in the tree is that separating NW Africans(AND AFRAMS) from Europeans. Among
the Iberians, Andalusians and Portuguese are closest to NW Africa.

Afrrican-Americans appear linked to NW Africa through a long branch.



Notice the distance between Aframs and Berbers are 16 and 33. The distance between ALL AFRICANS and EUROPEANS is 77. Quote: It should be noted that the most robust branch (77%) in the tree is that separating NW Africans from Europeans.

[djoser-xyyman]

Genetic structure of north-west Africa revealed by STR analysis

Elena Bosch1, Francesc Calafell1, Anna P´erez-Lezaun1, Jordi Clarim ´on1, David Comas1,

We have analysed a large set of autosomal short tandem repeat (STR) loci in several Arabic and
Berber-speaking groups from north-west Africa (ie Moroccan Arabs, northern-central and southern
Moroccan Berbers, Saharawis, and Mozabites). Two levels of analysis have been devised using two sets of
12 STR loci, (D3S1358, vWA, FGA, THO1, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317 and
D7S820) and 21 (the former set plus D9S926, D11S2010, D13S767, D14S306, D18S848, D2S1328, D4S243,
F13A1, and FES/FPS).


Berber is a branch of the Afro-Asiatic language family; this branch embraces more than 30 distinct languages with a distribution from Egypt to Senegal which were the only languages spoken in the area until the Arab invasion.

Saharawis, who live in the Western Sahara, speak
Hassani, a different Arabic dialect. Tachelhit, spoken mainly
in the Souss valley, is a Berber language confined to southern
Morocco and distinct from other Berber languages spoken in
the northern (Tarifit) and central (Tamazigh) areas of Morocco. The Mozabites are a very well defined Berber population in Algeria: they speak Mzab (a distinct Berber language) and originated from the Ibadite religious community who settled in this region in the 11th century.


The Mozabites, which are geographically distant from all other populations considered, may be an exception.

As expected, Basques appeared as the most differentiated population within the Iberian Peninsula.

We have found quite clear genetic differentiation between Iberians and NW Africans in several of the analysis presented. Both groups of populations seem to belong to two different
genetic pools.

This general genetic differentiation between NW Africa and the Iberian Peninsula does not apply equally to all populations. While some Iberians have genetic distances to
NW Africans that are as large as those between other Europeans and NW Africans, others, particularly the Andalusians, seem to be genetically closer and to have received
some gene flow from NW Africa.

[pristy]

Good post Djoser-xyyman

[Dawn2Earth]

Can someone explain the graph to me?

I'm sorry, I remember what the length of the twigs mean - the longer the twig, the more distinguishable that group is with respect to the rest of the groups, and so the less likely it is they were admixed by, or offshoots of the others; you could not recreate them out of the other groups - but what exactly do the distances between the trunks mean again?

[djoser-xyyman]

The graph is very simple. They are designed to visualize different things. In this case. Notice numbers are between branches of the main tree. Visualize a tree with "two sets" of branches along the main trunk. One set is European and the other Africans. The distance between the two set is 77. Which is the longest distance between the branches. The African branches have short distances between them.
Notice also the Basque, Aframs and MAzabites have extremely huge branches. But the base of the branches are still close to their respective sets. That means there are unusual genetic variability. The Basque and Mazabites ..due to isolation. The Aframs/West Africans extreme varibility. Notice also the Europeans close the African mainland is also closer to Africans on the tree cf to North Europeans.

STRs are very good indicators but not the only ones.

[djoser-xyyman]

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