Peopling of the green Sahara

[ycoamigofull]

genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1393-5


Results

In order to investigate the role of the last Green Sahara in the peopling of Africa, we deep-sequence the whole non-repetitive portion of the Y chromosome in 104 males selected as representative of haplogroups which are currently found to the north and to the south of the Sahara. We identify 5,966 mutations, from which we extract 142 informative markers then genotyped in about 8,000 subjects from 145 African, Eurasian and African American populations. We find that the coalescence age of the trans-Saharan haplogroups dates back to the last Green Sahara, while most northern African or sub-Saharan clades expanded locally in the subsequent arid phase.

Conclusions

Our findings suggest that the Green Sahara promoted human movements and demographic expansions, possibly linked to the adoption of pastoralism. Comparing our results with previously reported genome-wide data, we also find evidence for a sex-biased sub-Saharan contribution to northern Africans, suggesting that historical events such as the trans-Saharan slave trade mainly contributed to the mtDNA and autosomal gene pool, whereas the northern African paternal gene pool was mainly shaped by more ancient events

migration map

[djoser-xyyman]

already discussed on ES...

[zarahan]

We encourage folks to post any credible, relevant info, including cross-posting as you do with various items, which is a good thing. Keep on doing that- you are doing a good job. At one point it looked like movements were underfoot to take ES down hence some things mirrored at Reloaded, (and elsewhere) - and there is still that possibility, (certain legit, interesting pages seem to have disappeared for example) so saved info is still needed. They even had you banned for quite a bit, and I was wondering whether some of the valid info you had on there over time was being deleted. I post there once on a while- but time being critical these days am no longer able to be on there several hours per week as in years past. Maybe when schedule eases.

But anyway, one and all, cross-post to your heart's content, and add your own *credible* info that you have to share. It is ironic that all the Wikipedia moles that thought they could "bury" credible info on Egypt, that they kept removing, have utterly failed. The info they sought to keep out is now a virtual torrent online, well represented and easily accessible across multiple sites and search engines worldwide, even as they continue to "guard" laughably obsolete pages. Knock yourself out "guardians".. you are not doing anything significant.. LOL.

[zarahan]

Apr 27, 2018 22:58:13 GMT -5 ycoamigofull said:

genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1393-5


Results

In order to investigate the role of the last Green Sahara in the peopling of Africa, we deep-sequence the whole non-repetitive portion of the Y chromosome in 104 males selected as representative of haplogroups which are currently found to the north and to the south of the Sahara. We identify 5,966 mutations, from which we extract 142 informative markers then genotyped in about 8,000 subjects from 145 African, Eurasian and African American populations. We find that the coalescence age of the trans-Saharan haplogroups dates back to the last Green Sahara, while most northern African or sub-Saharan clades expanded locally in the subsequent arid phase.

Conclusions

Our findings suggest that the Green Sahara promoted human movements and demographic expansions, possibly linked to the adoption of pastoralism. Comparing our results with previously reported genome-wide data, we also find evidence for a sex-biased sub-Saharan contribution to northern Africans, suggesting that historical events such as the trans-Saharan slave trade mainly contributed to the mtDNA and autosomal gene pool, whereas the northern African paternal gene pool was mainly shaped by more ancient events

migration map

What they don't develop above is the maternal gene profile BEFORE the historic era...
Were they no women in North Africa prior to the trans-Saharan slave trade?

Other data yield a different picture:


"Our objective is to highlight the age of sub-Saharan gene flows in North Africa and particularly in Tunisia. Therefore we analyzed in a broad phylogeographic context sub-Saharan mtDNA haplogroups of Tunisian Berber populations considered representative of ancient settlement. More than 2,000 sequences were collected from the literature, and networks were constructed. The results show that the most ancient haplogroup is L3*, which would have been introduced to North Africa from eastern sub-Saharan populations around 20,000 years ago. Our results also point to a less ancient western sub-Saharan gene flow to Tunisia, including haplogroups L2a and L3b. This conclusion points to an ancient African gene flow to Tunisia before 20,000 years BP. These findings parallel the more recent findings of both archaeology and linguistics on the prehistory of Africa. The present work suggests that sub-Saharan contributions to North Africa have experienced several complex population processes after the occupation of the region by anatomically modern humans. Our results reveal that Berber speakers have a foundational biogeographic root in Africa and that deep African lineages have continued to evolve in supra-Saharan Africa."
- Frigi 2010. Ancient Local Evolution of African mtDNA Haplogroups in Tunisian Berber Populations. Human Biology (August 2010 (82:4)


Most of their "North African" sampling is along the coastal strip with the usual *distant* "sub-Saharan" samples juxtaposed against "the north" and does not seem to include many samples from within the broad belt of the Sahara itself. Where for example substantial samples from the Sudan, CHad, Mauritania, or Mali? Niger has a few but not much. These countries are plenty "Saharan" yet most of the sampling is outside them...

[Tukuler al~Takruri]

This article is great for the south originating
male uniparental. I still haven't read through
it yet. For me it's all about the data. How the
major Inner African nrY DNA developed and
expanded during the early and mid Holocene
driven by Monsoon and Grassland.




The Sahara is no pump. It absorbed water, vegetation,
animals, and people from the south. The Monsoon is the
pump. The Sahara is a passive non-agent dependant on
the Monsoon which cyclically gives it enough rainwater
to form massive lakes and many rivers. The Sahara is a
sponge.


The MSY coverage allows for prehistorical surmises on
the birth of "Niger-Congo" speaking groupage including
the Black Americans, origins or adaptation of Nilo-Saharan
west of Lake Tschad, and insights into Africa NW, NE, and
 the far NE extension (misnomered SW Asia).

Professionals will have to incorporate this stuff
into their Bantu discourse. It seriously challenges
the assumed date and number of dispersals and
even the supposed biological unity.




I'll right here suggest analyzing a study's data BEFORE
reading its text. Avoids absorbing the authors opinions
so as not to effect one's own independent minded interpretation.

I narrowed my focus to E-M2 which came up from
Inner Africa to enter and cross Saharan Africa and
from there on into North, i.e., Mediterranean Africa.


PS it's always good to keep in mind Inner African mtDNA
female uniparentals in North and Mediterranean Africa.
Being there before 18k establishes they were Dabban
mommies if not Maurusian. Anyway these L ladies were
North Africans before the Last Glacial Arid Maximum
made N <->S communication virtually impossible.

This L component goes ignored in favor of
boosting the Pleistocene U and Holocene H.

[zarahan]

Takuri said:
Inner Africa to enter and cross Saharan Africa and
from there on into North, i.e., Mediterranean Africa.


PS it's always good to keep in mind Inner African mtDNA
female uniparentals in North and Mediterranean Africa.
Being there before 18k establishes they were Dabban
mommies if not Maurusian. Anyway these L ladies were
North Africans before the Last Glacial Arid Maximum
made N <->S communication virtually impossible.

This L component goes ignored in favor of
boosting the Pleistocene U and Holocene H.

The Sahara is no pump. It absorbed water, vegetation,
animals, and people from the south. The Monsoon is the
pump. The Sahara is a passive non-agent dependant on
the Monsoon which cyclically gives it enough rainwater
to form massive lakes and many rivers. The Sahara is a
sponge.

Good points all- I have to read through the whole thing in detail myself- it needs a
careful reading. Haven't had time as in old days. Maybe in a week or so

So your model is to view the Sahara as a "sponge"- so to speak
and not a pump? Hmm, an interesting angle. Maybe the "pump" analogy only holds
in intense period of desiccation. The lush green era was indeed a sponge, and I
think this calls into questions approaches treating the desert as if it were some
sort of static entity as far as its peopling, and peoples go. Even today it shows
net movement of some miles every year towards the south, making people who were
once "sub-Saharan" become NON sub-Saharan, sometimes not even African at all
according to some claims and approached because the desert margins creeped down.
Based on this I see Kush/Nubia as a both a supra-Saharan AND "sub-Saharan" entity-
from Aswan in today's Egypt, down to the approaches of Eritrea and the Horn.

I think your "sponge" model is also good in that it can explain certain physical changes
in the area peoples, due to a rich foraging base, as better nutrition can impact body mass,
rather than mystical settlers from elsewhere, though as we all know the Nile Valley
was never isolated and had interchange with several points.

So do you see M2 as providing the foundational peopling profile?

[Tukuler al~Takruri]

Apr 30, 2018 21:15:23 GMT -5 zarahan said:

So your model is to view the Sahara as a "sponge"- so to speak
and not a pump? Hmm, an interesting angle. Maybe the "pump"
analogy only holds in intense period of desiccation. The lush
green era was indeed a sponge, and I think this calls into questions approaches treating the desert as if it were some  sort of static entity ...

The Sahara is passive. A pump is active. Whether wet
or dry outside actors are deciding that region's being.
The Sahara is anything but static just like you say.

SAHARA TIMELINE
• 40m sea bed (once a part of Tethys)
• 3m tropical swamp dries as desert is born
• 90k monsoon greens the region

Due to the cosmos, at least from 90k on, every 20000
years the Monsoon extends north for 5000 years. Then
it swiftly retreats back south within 200 years leaving a
desert for the next 15000 years.

Vast desert between 85k-70k doesn't support a north
east OoA route from Inner Africa. The 70k Monsoon
driven greening ended 65k. It does. 50k offers another
such window.

Apr 30, 2018 21:15:23 GMT -5 zarahan said:

... I see Kush/Nubia as a both a supra-Saharan AND "sub-Saharan" entity-
from Aswan in today's Egypt, down to the approaches of Eritrea and the Horn.

SSA is a loaded term that pending the user can mean
a literal geography or a broad group of people that
may well even live in the Sahara.

Shifting sand isn't origin. It won't change any peoples'
regional origin if they get some sand all around them.

I acknowledge your Upper Nubia view. Me? The Nile Valley
is a separate region. The Lower and Middle Nile Valley
is adjacent to the Sahara from the Delta to Cataract 6.
It is neither above nor below the Sahara but beside it.

For either SSA, subSahara or supraSahara, I go by
the actual desert from satellite map. Roughly, south
of 17° is geographic subSahara. SupraSahara is very
narrow and sporadic. It's the Maghreb proper north of
the Atlas and a few tiny stretches in Libya.

Apr 30, 2018 21:15:23 GMT -5 zarahan said:

I think your "sponge" model is also good in that it can explain certain physical changes in the area peoples, due to a rich foraging base, as better nutrition can impact body mass, ...

Full of freshwater lakes and their connective rivers, people
employed serious fishing skills. Fish is lean protein and a
brain food. LSA mode 5 picks up bone and microliths.


Last Moonsoon Optimum settlement at Lake Gobero Niger
shows an initial occupation of robust somewhat 'archaic'
folk. After a local dry spell people built exactly like us came.
Both were fishers with all the lifestyle benefits fishing drives.
But they were two different major peoples. One with 10000+
years of Med coastal background, the other with inner
continental antecedents and cattle and grains economy.

So do you see M2 as providing the foundational peopling profile?

I was only interested in Inner Africa (south of 27° N).
The study is transSaharan, only considering haplogroups
from one side of the desert that show up on the other.

No E-M33 or 78, too local or young. Not even thinking
about A or B. More bang for my buck concentrating on
M2.

M2 people went north just keeping up with their
friendly neighborhood Grasslands being pushed by the
Monsoon Optimum.

GRASSLANDS TIMELINE
• 24k Guinea > L Tschad > G Lakes > SW & S
• 13k Senegal > Somalia : S Africa > L Mweru
• 10k Mauritania > Sudan : Somalia : Sn Afr
• 8k Mauritania/WnSahara > Eritrea/Egypt
• 5k Senegal > Port Sudan > Somalia : Sn Africa > L Tanganyika

For me it's really about the Monsoon and the Grassland
pushing E-M2 and their women ever north. Then when
Monsoon and Grassland retreat south M2 folk get
pulled right along with them. That's how I see it right now.