E_M81_I3A
03-15-2018, 07:48 PM
I am just reposting here some tables I posted in other threads as I think it is the first time we have a clear picture of mtDna L in the Iberian Peninsula based on rather large samples from all regions.
1) Spain
In July 2016, Ruth Barral-Arca et al, "Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula" (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159735) reported the below frequencies for Spain (S1/S2 Tables) :
https://image.ibb.co/gNDqCx/Spain_Mt_Dna.jpg (https://imgbb.com/)
And as we can see, if we exclude small samples, Galicia has the highest frequency of mtDna L at about 3% (16/548). If we consider that in that region, mtDna L comes from Berbers and is not linked to Slave Trade, it could mean, as Berbers have about 20% mtDna L, a NW African maternal contribution of about 15%. Note that if Berbers of the Middle Ages did not have such high frequency of L than modern Berbers it could mean an even more important contribution.
2) Portugal
For Continental Portugal, Ruth Barral-Arca et al reported an average of sub-Saharan mtDNA L lineages at 6.2% (88/1429).
But contrary to Spain, very likely some L are linked to Slave Trade.
Here is another table showing frequencies for mtDna L found (as well North African U6) in all Portuguese samples tested so far by different studies for different regions :
http://img15.hostingpics.net/pics/244543PortugalAfricanMtDna.jpg (http://www.hostingpics.net/viewer.php?id=244543PortugalAfricanMtDna.jpg)
Source:wikipedia
The mean frequency for mtDna L, typical for sub-Saharan populations (but also found on average at 20% in North Africans), reaches 6-7% in Portugal. Increasing frequencies are observed for northern Portugal (3.2%) through the center (7%) and to the south (12.5%, similar to Madeira). Azores frequency is similar to North Portugal.
Highest mtDna L frequency ever reported in Europe was found in South Portugal at 22% in Alcacer do Sal by Pereira et al 2010, Genetic Characterization of Uniparental Lineages in Populations from Southwest Iberia with Past Malaria Endemicity (http://www.ncbi.nlm.nih.gov/pubmed/20737604) in a sample of 50 non related individuals (11 different sequences : L1b1, L1c2, L2a, L2a1, L2a1a, L2b, L3d, L3d, L3e1a, L3e2, L3e2b). Here what the author writes about it :
"In Alcacer do Sal, the frequency of sub-Saharan mtDNA L lineages was the highest ever reported (22%) in Europe...The presence of Sub-Saharan maternal lineages in Alcacer do Sal is likely associated with the influx of African slaves between the 15th and 19th centuries"
"As for Alcacer do Sal, the exceptionally high frequency of L lineages (22%), two times greater than the frequency usually found in Portugal, is interesting... "
"Overall, the frequency of the sub-Saharan L types in Portugal is very high for the European context. Previous studies addressing this issue (Pereira et al., 2000) clearly demonstrated that this feature of the Portuguese maternal gene pool denotes the influx of African lineages that occurred during the Atlantic slave trade, a major modern human migration that lasted from the mid-15th century until the late-18th century. During this period, many enslaved Africans were brought to Portugal where, mainly in the south, they eventually composed more than 10% of the population (Lahon, 1999; Thomas, 1998)."
"In Alcacer do Sal, the remarkable sub-Saharan component denotes the demographic impact of African people whose presence in the region gained significance with the onset of the slave trade in the 15th century. By the 16th century, the whole Sado Basin, where Alcacer do Sal is located, had experienced an important African immigration as a way to compensate for the demographic deficit that accompanied the Portuguese Overseas Expansion. Later, in the 18th century, a new wave of slaves was recruited to Alcacer do Sal to work in salt production and rice cultivation, two important economic activities in the region (Cruz et al., 2001). Both activities are highly demanding in terms of need for labor and were carried out under an environment of endemic malaria that was eradicated only during middle 20th century. Hence, the immigration of African people into Alcacer do Sal might have intensified not only because of the demand for work but also because of their increased resistance to malarial infection; this intensification would explain why Alcacer do Sal has retained stronger signs of the forced African emigration than is observed elsewhere in Portugal. The African influence shapes the maternal and paternal pools of Alcacer do Sal differentially; this fact is widely documented in admixture events between Europeans and Africans. When such events involve the incorporation of African lineages in a prevailing European background, usually the maternal pool retains stronger signs of the assimilation of African lineages, as was indeed observed in Alcacer do Sal."
So very likely many of these L lineages were introduced in Portugal by Slave Trade and some by the Moors.
1) Spain
In July 2016, Ruth Barral-Arca et al, "Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula" (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159735) reported the below frequencies for Spain (S1/S2 Tables) :
https://image.ibb.co/gNDqCx/Spain_Mt_Dna.jpg (https://imgbb.com/)
And as we can see, if we exclude small samples, Galicia has the highest frequency of mtDna L at about 3% (16/548). If we consider that in that region, mtDna L comes from Berbers and is not linked to Slave Trade, it could mean, as Berbers have about 20% mtDna L, a NW African maternal contribution of about 15%. Note that if Berbers of the Middle Ages did not have such high frequency of L than modern Berbers it could mean an even more important contribution.
2) Portugal
For Continental Portugal, Ruth Barral-Arca et al reported an average of sub-Saharan mtDNA L lineages at 6.2% (88/1429).
But contrary to Spain, very likely some L are linked to Slave Trade.
Here is another table showing frequencies for mtDna L found (as well North African U6) in all Portuguese samples tested so far by different studies for different regions :
http://img15.hostingpics.net/pics/244543PortugalAfricanMtDna.jpg (http://www.hostingpics.net/viewer.php?id=244543PortugalAfricanMtDna.jpg)
Source:wikipedia
The mean frequency for mtDna L, typical for sub-Saharan populations (but also found on average at 20% in North Africans), reaches 6-7% in Portugal. Increasing frequencies are observed for northern Portugal (3.2%) through the center (7%) and to the south (12.5%, similar to Madeira). Azores frequency is similar to North Portugal.
Highest mtDna L frequency ever reported in Europe was found in South Portugal at 22% in Alcacer do Sal by Pereira et al 2010, Genetic Characterization of Uniparental Lineages in Populations from Southwest Iberia with Past Malaria Endemicity (http://www.ncbi.nlm.nih.gov/pubmed/20737604) in a sample of 50 non related individuals (11 different sequences : L1b1, L1c2, L2a, L2a1, L2a1a, L2b, L3d, L3d, L3e1a, L3e2, L3e2b). Here what the author writes about it :
"In Alcacer do Sal, the frequency of sub-Saharan mtDNA L lineages was the highest ever reported (22%) in Europe...The presence of Sub-Saharan maternal lineages in Alcacer do Sal is likely associated with the influx of African slaves between the 15th and 19th centuries"
"As for Alcacer do Sal, the exceptionally high frequency of L lineages (22%), two times greater than the frequency usually found in Portugal, is interesting... "
"Overall, the frequency of the sub-Saharan L types in Portugal is very high for the European context. Previous studies addressing this issue (Pereira et al., 2000) clearly demonstrated that this feature of the Portuguese maternal gene pool denotes the influx of African lineages that occurred during the Atlantic slave trade, a major modern human migration that lasted from the mid-15th century until the late-18th century. During this period, many enslaved Africans were brought to Portugal where, mainly in the south, they eventually composed more than 10% of the population (Lahon, 1999; Thomas, 1998)."
"In Alcacer do Sal, the remarkable sub-Saharan component denotes the demographic impact of African people whose presence in the region gained significance with the onset of the slave trade in the 15th century. By the 16th century, the whole Sado Basin, where Alcacer do Sal is located, had experienced an important African immigration as a way to compensate for the demographic deficit that accompanied the Portuguese Overseas Expansion. Later, in the 18th century, a new wave of slaves was recruited to Alcacer do Sal to work in salt production and rice cultivation, two important economic activities in the region (Cruz et al., 2001). Both activities are highly demanding in terms of need for labor and were carried out under an environment of endemic malaria that was eradicated only during middle 20th century. Hence, the immigration of African people into Alcacer do Sal might have intensified not only because of the demand for work but also because of their increased resistance to malarial infection; this intensification would explain why Alcacer do Sal has retained stronger signs of the forced African emigration than is observed elsewhere in Portugal. The African influence shapes the maternal and paternal pools of Alcacer do Sal differentially; this fact is widely documented in admixture events between Europeans and Africans. When such events involve the incorporation of African lineages in a prevailing European background, usually the maternal pool retains stronger signs of the assimilation of African lineages, as was indeed observed in Alcacer do Sal."
So very likely many of these L lineages were introduced in Portugal by Slave Trade and some by the Moors.