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The trans-Saharan slave trade - clues from interpolation analyses and high-resolution characterization of mitochondrial DNA lineages.

Harich N, Costa MD, Fernandes V, Kandil M, Pereira JB, Silva NM, Pereira L - BMC Evol. Biol. (2010)

Bottom Line: Ages for the haplogroups observed in both sides of the Saharan desert testify the recent origin (holocenic) of these haplogroups in sub-Saharan Africa, claiming a recent introduction in North Africa, further strengthened by the no detection of local expansions.The interpolation analyses and complete sequencing of present mtDNA sub-Saharan lineages observed in North Africa support the genetic impact of recent trans-Saharan migrations, namely the slave trade initiated by the Arab conquest of North Africa in the seventh century.Sub-Saharan people did not leave traces in the North African maternal gene pool for the time of its settlement, some 40,000 years ago.

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Affiliation: Laboratoire d'Anthropogénétique, Départment de Biologie, Faculté des Sciences, Université Chouaïb Doukkali, El Jadida, Morocco.

ABSTRACT

Background: A proportion of 1/4 to 1/2 of North African female pool is made of typical sub-Saharan lineages, in higher frequencies as geographic proximity to sub-Saharan Africa increases. The Sahara was a strong geographical barrier against gene flow, at least since 5,000 years ago, when desertification affected a larger region, but the Arab trans-Saharan slave trade could have facilitate enormously this migration of lineages. Till now, the genetic consequences of these forced trans-Saharan movements of people have not been ascertained.

Results: The distribution of the main L haplogroups in North Africa clearly reflects the known trans-Saharan slave routes: West is dominated by L1b, L2b, L2c, L2d, L3b and L3d; the Center by L3e and some L3f and L3w; the East by L0a, L3h, L3i, L3x and, in common with the Center, L3f and L3w; while, L2a is almost everywhere. Ages for the haplogroups observed in both sides of the Saharan desert testify the recent origin (holocenic) of these haplogroups in sub-Saharan Africa, claiming a recent introduction in North Africa, further strengthened by the no detection of local expansions.

Conclusions: The interpolation analyses and complete sequencing of present mtDNA sub-Saharan lineages observed in North Africa support the genetic impact of recent trans-Saharan migrations, namely the slave trade initiated by the Arab conquest of North Africa in the seventh century. Sub-Saharan people did not leave traces in the North African maternal gene pool for the time of its settlement, some 40,000 years ago.

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Routes for trans-Saharan slave trade. Adapted from Segal (2002) and Lovejoy (1983).
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Figure 1: Routes for trans-Saharan slave trade. Adapted from Segal (2002) and Lovejoy (1983).

Mentions: But, if geographical and climatic conditions have not been favorable to sub-Saharan gene flow to North Africa in the last 5,000 years, the Arab trans-Saharan slave trade could have facilitate enormously this migration of lineages. Till now, the genetic consequences of these forced trans-Saharan movements of people have not been ascertained, being over-shadowed by the Atlantic slave trade towards the New World. In fact, the huge number of sub-Saharan people introduced in the New World from the 16th century onwards allowed to investigating in great detail the genetic consequences of this historical event [11-13], and the complete sequencing of L-lineages is indicating very precisely about the origin of lineages observed nowadays in America [14]. Nonetheless, some authors affirm [15] that the Arab slave trade of black slaves was much the same in total to the Atlantic slave trade, and interestingly far longer in the time scale. It began in the middle of the seventh century (650 A.D.) and survives still today in Mauritania and Sudan, summing up 14 centuries rather than four as for the Atlantic slave trade. Although estimates are very rough, figures are of 4,820,000 for the Saharan trade between 650 and 1600 A.D., and, for comparison purposes, of 2,400,000 for the Red Sea and the Indian Ocean trade between 800 and 1600 A.D. [16]. Notwithstanding the thousands of kilometers along the edge of the Sahara, the Red sea and the East African coast, from where slave exports came, there were relatively few export points, concentrating geographically the impact of the trade. Black slaves were brought by Berber and Arab merchants mainly to actual Morocco, Algeria, Libya and Egypt through six main routes that crossed the desert (Figure 1): one went north to Morocco from ancient Ghana (at present southeastern Mauritania and Western Mali); a second brought slaves to Tuwat (southern Algeria) from ancient Timbutku (Mali); a third passed from the Niger valley and the Hausa towns through the Air Massif to Ghat and Ghadames; a central route linked Lake Chad region to actual Libya (Murzuk), being one of the most important in slave commerce as it offered oases at regular intervals that could satisfy the caravan's needs; in East Africa, the slave caravan followed mainly the Nile River from actual Sudan (Dar Fur) to Egypt (Assiout); and a sixth passed north from the confluence of the Blue and the White Nile to Egypt. Some of these routes were interconnected: the routes north from Timbuktu went to Morocco, Algeria, and Libya; while the Dar Fur-Egypt route connected with the route north from the upper Nile valley.


The trans-Saharan slave trade - clues from interpolation analyses and high-resolution characterization of mitochondrial DNA lineages.

Harich N, Costa MD, Fernandes V, Kandil M, Pereira JB, Silva NM, Pereira L - BMC Evol. Biol. (2010)

Routes for trans-Saharan slave trade. Adapted from Segal (2002) and Lovejoy (1983).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2875235&req=5

Figure 1: Routes for trans-Saharan slave trade. Adapted from Segal (2002) and Lovejoy (1983).
Mentions: But, if geographical and climatic conditions have not been favorable to sub-Saharan gene flow to North Africa in the last 5,000 years, the Arab trans-Saharan slave trade could have facilitate enormously this migration of lineages. Till now, the genetic consequences of these forced trans-Saharan movements of people have not been ascertained, being over-shadowed by the Atlantic slave trade towards the New World. In fact, the huge number of sub-Saharan people introduced in the New World from the 16th century onwards allowed to investigating in great detail the genetic consequences of this historical event [11-13], and the complete sequencing of L-lineages is indicating very precisely about the origin of lineages observed nowadays in America [14]. Nonetheless, some authors affirm [15] that the Arab slave trade of black slaves was much the same in total to the Atlantic slave trade, and interestingly far longer in the time scale. It began in the middle of the seventh century (650 A.D.) and survives still today in Mauritania and Sudan, summing up 14 centuries rather than four as for the Atlantic slave trade. Although estimates are very rough, figures are of 4,820,000 for the Saharan trade between 650 and 1600 A.D., and, for comparison purposes, of 2,400,000 for the Red Sea and the Indian Ocean trade between 800 and 1600 A.D. [16]. Notwithstanding the thousands of kilometers along the edge of the Sahara, the Red sea and the East African coast, from where slave exports came, there were relatively few export points, concentrating geographically the impact of the trade. Black slaves were brought by Berber and Arab merchants mainly to actual Morocco, Algeria, Libya and Egypt through six main routes that crossed the desert (Figure 1): one went north to Morocco from ancient Ghana (at present southeastern Mauritania and Western Mali); a second brought slaves to Tuwat (southern Algeria) from ancient Timbutku (Mali); a third passed from the Niger valley and the Hausa towns through the Air Massif to Ghat and Ghadames; a central route linked Lake Chad region to actual Libya (Murzuk), being one of the most important in slave commerce as it offered oases at regular intervals that could satisfy the caravan's needs; in East Africa, the slave caravan followed mainly the Nile River from actual Sudan (Dar Fur) to Egypt (Assiout); and a sixth passed north from the confluence of the Blue and the White Nile to Egypt. Some of these routes were interconnected: the routes north from Timbuktu went to Morocco, Algeria, and Libya; while the Dar Fur-Egypt route connected with the route north from the upper Nile valley.

Bottom Line: Ages for the haplogroups observed in both sides of the Saharan desert testify the recent origin (holocenic) of these haplogroups in sub-Saharan Africa, claiming a recent introduction in North Africa, further strengthened by the no detection of local expansions.The interpolation analyses and complete sequencing of present mtDNA sub-Saharan lineages observed in North Africa support the genetic impact of recent trans-Saharan migrations, namely the slave trade initiated by the Arab conquest of North Africa in the seventh century.Sub-Saharan people did not leave traces in the North African maternal gene pool for the time of its settlement, some 40,000 years ago.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire d'Anthropogénétique, Départment de Biologie, Faculté des Sciences, Université Chouaïb Doukkali, El Jadida, Morocco.

ABSTRACT

Background: A proportion of 1/4 to 1/2 of North African female pool is made of typical sub-Saharan lineages, in higher frequencies as geographic proximity to sub-Saharan Africa increases. The Sahara was a strong geographical barrier against gene flow, at least since 5,000 years ago, when desertification affected a larger region, but the Arab trans-Saharan slave trade could have facilitate enormously this migration of lineages. Till now, the genetic consequences of these forced trans-Saharan movements of people have not been ascertained.

Results: The distribution of the main L haplogroups in North Africa clearly reflects the known trans-Saharan slave routes: West is dominated by L1b, L2b, L2c, L2d, L3b and L3d; the Center by L3e and some L3f and L3w; the East by L0a, L3h, L3i, L3x and, in common with the Center, L3f and L3w; while, L2a is almost everywhere. Ages for the haplogroups observed in both sides of the Saharan desert testify the recent origin (holocenic) of these haplogroups in sub-Saharan Africa, claiming a recent introduction in North Africa, further strengthened by the no detection of local expansions.

Conclusions: The interpolation analyses and complete sequencing of present mtDNA sub-Saharan lineages observed in North Africa support the genetic impact of recent trans-Saharan migrations, namely the slave trade initiated by the Arab conquest of North Africa in the seventh century. Sub-Saharan people did not leave traces in the North African maternal gene pool for the time of its settlement, some 40,000 years ago.

Show MeSH