Portuguese Genetics: Abstracts and Summaries

Family Tree DNA: Genetic Testing Service Get genetically tested to discover your relationship to other families, other people from the Iberian Peninsula, and other ethnic groups. People of Portuguese descent are welcome to join Family Tree DNA's "Portugal DNA Project". They also have some Brazilians and Cape Verdeans. The Portuguese participants' Y-DNA haplogroups include E-L117, E-L17, E-M183, E-M35, G-M201, G-M406, G-P303, I-M223, I-M253, J-M172, J-M267, R-L21, R-M269, R-P312, R-U152, T-M70, and many others, with R-M269 being their most common one. Family Tree DNA also has an "Azores DNA Project" and a "Madeira DNA Project".

The Portuguese are natives of Portugal on the Iberian peninsula in southwestern Europe. They speak Portuguese, a Romance language similar to varieties of Spanish that's particularly close to the Galician language of northwestern Spain. The people, too, are closely related to Spaniards and Basques. Their traditional religion is Roman Catholicism.

Ancestors of Portuguese include Lusitanians (Indo-European speakers), Celtici (Celts), Calaicians, Coelerni, Cynetes, Narbasi, Tapoli, and many other tribes. In ancient times peoples like the Lusitanians started to speak Latin and became citizens of the Roman Empire.

Varieties of R1b, a common Y-DNA haplogroup in western Europe, are found in abundance among Portuguese men. About 60 percent of Southern Portuguese and about 83 percent of Northern Portuguese belong to the subclade of R1b known as the Atlantic Modal Haplotype (AMH). There are even some areas in Portugal where the AMH is found in about 90% of men.

The mtDNA haplogroups H, U, and L were found in substantial numbers in the population of Portugal in ancient times (including the Epipaleolithic, Neolithic, and Chalcolithic eras) just as they are today.

Millions of mixed-race (white/black/Amerindian) descendants of Portuguese live in Brazil today. Some Portuguese of Portugal themselves have a small portion of black ancestry as well. This is true of the mainland, in part since African slaves were brought to southwestern Portugal's Alcácer do Sal region in the 1400s-1800s, but even moreso for those from Madeira who often show Sub-Saharan African scores above 1 percent in 23andMe's ancestry composition reports, even as high as 4.8%. The vast majority of the African slaves imported into Madeira were from Senegal, and since 2018, 23andMe correctly identifies most of their Madeiran descendants' ancestry as belonging to the "Senegambian and Guinean" cluster. Also, some from Madeira are presented with estimates of 0.1% or 0.2% Amerindian admixture by 23andMe.

Portuguese people occasionally match European Jews in the autosomal DNA databases as a result of having shared Sephardic Jewish ancestors. All Jews who stayed in Portugal after 1497 were forced to convert to Catholicism.

Peter Ralph and Graham Coop. "The Geography of Recent Genetic Ancestry across Europe." PLOS Biology (May 7, 2013). Excerpts:

"[...] Patterns for the Iberian peninsula are similar, with both Spain and Portugal showing very few common ancestors with other populations over the last 2,500 years. However, the rate of IBD [identical-by-descent] sharing within the peninsula is much higher than within Italy--during the last 1,500 years the Iberian peninsula shares fewer than two genetic common ancestors with other populations, compared to roughly 30 per pair within the peninsula; Italians share on average only about eight with each other during this period. [...]"

Cristian Capelli, Valerio Onofri, Francesca Brisighelli, Ilaria Boschi, Francesca Scarnicci, Mara Masullo, Gianmarco Ferri, Sergio Tofanelli, Adriano Tagliabracci, Leonor Gusmão;, António Amorim, Francesco Gatto, Mirna Kirin, Davide Merlitti, Maria Brion, Alejandro Blanco Verea, Valentino Romano, Francesco Cali, and Vincenzo Pascali. "Moors and Saracens in Europe: Estimating the medieval North African male legacy in southern Europe." European Journal of Human Genetics 17:6 (June 2009): pages 848-852. First published online on January 21, 2009.
       This includes 659 Y-chromosome samples from Portuguese males. North African male lineages represent 7.1% of these Portuguese samples, about the same as in the Spanish and Sicilian samples, but far more than in the mainland Italian samples.

Susan M. Adams, Elena Bosch, Patricia L. Balaresque, Stéphane J. Ballereau, Andrew C. Lee, Eduardo Arroyo, Ana M. López-Parra, Mercedes Aler, Marina S. Gisbert Grifo, Maria Brion, Angel Carracedo, João Lavinha, Begoña Martínez-Jarreta, Lluís Quintana-Murci, Antònia Picornell, Misericordia Ramon, Karl Skorecki, Doron M. Behar, Francesc Calafell, and Mark A. Jobling. "The Genetic Legacy of Religious Diversity and Intolerance: Paternal Lineages of Christians, Jews, and Muslims in the Iberian Peninsula." The American Journal of Human Genetics 83:6 (December 12, 2008): pages 725-736. First published online on December 5, 2008.
       Figure 1 includes, among other populations, Y-DNA haplogroups identified from 60 northern Portuguese samples (living north of the Mondego river) and 78 southern Portuguese samples (living south of the Mondego river). The approximate percentages are:
3% of northerners belong to E1
1% of southerners belong to E3a
2% of northerners and 3% of southerners belong to E3b*
5% of northerners and 4% of southerners belong to E3b1
3% of northerners and 8% of southerners belong to E3b2
2% of northerners and 1% of southerners belong to E3b3
12% of northerners and 9% of southerners belong to G
2% of northerners and 4% of southerners belong to I
2% of northerners and 3% of southerners belong to J(xJ2)
7% of northerners and 15% of southerners belong to J2
2% of northerners and 5% of southerners belong to K*(xP)
3% of northerners and 1% of southerners belong to R1a1
47% of northerners and 44% of southerners belong to R1b3*, by far the highest frequencies
2% of northerners belong to R1b3d
10% of northerners and 3% of southerners belong to R1b3f
These Portuguese were compared to other ethnic groups, including 174 Sephardic Jewish males who reside in Belmonte, Portugal and in Spain and the Sephardic diaspora. The scientists interpret their haplogroup frequency results as meaning that 36.3% of Southern Portuguese descend paternally from Sephardic Jews and that some Iberian peoples descend from North Africans, with on average 10.6% North African Y-DNA admixture. However, this estimate for their Sephardic ancestry is a huge exaggeration.

Sandra Beleza, Leonor Gusmão; Alexandra Lopes, Cíntia Alves, Iva Gomes, Maria Giouzeli, Francesc Calafell, Angel Carracedo, and António Amorim. "Micro-phylogeographic and demographic history of Portuguese male lineages." Annals of Human Genetics 70(Part 2) (March 2006): pages 181-194.
       663 males from all regions of Portugal had their Y-chromosomes analyzed for biallelic and microsatellite markers. The authors report in the Abstract that the paternal lineages show "a general genetic homogeneity of Portuguese sub-populations. The traditional division of the country in north, central and south, which is usually considered in studies addressing questions of the genetic variation distribution in Portugal, was not reflected in the Y-haplotype distribution. Instead, just one sub-region (Alentejo) stood out due to the presence of high diversity levels and a higher number of different lineages, at higher frequencies than in other regions."

Ruth Barral-Arca, Sara Pischedda, Alberto Gómez-Carballa, Ana Pastoriza, Ana Mosquera-Miguel, Manuel López-Soto, Federico Martinón-Torres, Vanesa Álvarez-Iglesias, and Antonio Salas. "Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula." PLoS ONE 11:7 (July 21, 2016): e0159735.
       Table 1 specifies that people who submitted their mtDNA samples included 190 from North Portugal, 253 from Central Portugal, 149 from South Portugal, and 1591 additional people from unspecified regions of Portugal. Excerpts from the Results section:

"[...] Within the Iberian Peninsula, Spain has overall higher values of haplotype diversity than Portugal. [...] Nucleotide diversity has its highest value in the Mediterranean area, but it is also high in Portugal. [...] The high frequency of haplogroup H in the North of Iberia spans all along the Portuguese territories, where frequencies range from 49% in the North to 45% in the South. Haplogroup U constitutes the second most frequent haplogroup in Iberia; its frequency is similar in the main Iberian regions; it reaches the highest frequency in North of Portugal (26%). [...]"

Sofia L. Marques, Ana Goios, Ana M. Rocha, Maria João Prata, António Amorim, Leonor Gusmão, Cíntia Alves, and Luis Alvarez. "Portuguese mitochondrial DNA genetic diversity–An update and a phylogenetic revision." FSI Genetics 15 (March 2015): pages 27-32. Excerpts from the Abstract:

"[...] In the case of Portugal, previous population genetics studies have already revealed the general portrait of HVS-I and HVS-II mitochondrial diversity, becoming now important to update and expand the mitochondrial region analysed. Accordingly, a total of 292 complete control region sequences from continental Portugal were obtained, under a stringent experimental design to ensure the quality of data through double sequencing of each target region.* Furthermore, H-specific coding region SNPs were examined to detail haplogroup classification and complete mitogenomes were obtained for all sequences belonging to haplogroups U4 and U5. In general, a typical Western European haplogroup composition was found in mainland Portugal, associated to high level of mitochondrial genetic diversity. Within the country, no signs of substructure were detected. The typing of extra coding region SNPs has provided the refinement or confirmation of the previous classification obtained with EMMA tool in 96% of the cases. Finally, it was also possible to enlarge haplogroup U phylogeny with 28 new U4 and U5 mitogenomes."

María Cerezo, Alessandro Achilli, Anna Olivieri, Ugo A. Perego, Alberto Gómez-Carballa, Francesca Brisighelli, Hovirag Lancioni, Scott R. Woodward, Manuel López-Soto, Ángel Carracedo, Cristian Capelli, Antonio Torroni, and Antonio Salas. "Reconstructing ancient mitochondrial DNA links between Africa and Europe." Genome Research 22 (2012): pages 821-826. First published electronically on March 27, 2012.
       The researchers analyzed the genomes of 69 European holders of L haplogroups, including people from Portugal, Spain, Italy, and Wales. The researchers found Portuguese holders of the mtDNA haplogroups L1b1a12 and L1b1a6a. Two of the Portuguese samples carried L1b1a6a, whose "immediate ancestor [...] seems to have evolved in West-central Africa (as represented by two entire genomes from Burkina Faso and Guinea Bissau)".

V. Pereira, V. Gomes, António Amorim, Leonor Gusmão, and Maria João Prata. "Genetic characterization of uniparental lineages in populations from Southwest Iberia with past malaria endemicity." American Journal of Human Biology 22:5 (September-October 2010): pages 588-595. Excerpts from the Abstract:

"[...] Two hundred and eighty-five individuals were sampled in Coruche, Pias, and Alcacer do Sal. All were analyzed for the control region of mitochondrial DNA (mtDNA); males were additionally examined for Y-chromosome markers. Results were then compared with data from other Portuguese and non-Portuguese populations. In Coruche, the genetic profile was similar to the profile usually found in Portugal. In Alcacer do Sal, the frequency of sub-Saharan mtDNA L lineages was the highest ever reported (22%) in Europe. In Pias, mtDNA diversity revealed higher frequencies of Mediterranean haplogroups I, J, and T than usually found in surrounding populations. 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, whereas in Pias, the Mediterranean influence might be traced to ancient contacts with Greeks, Phoenicians, and Carthaginians, who established important trading networks in southern Iberia."

Luisa Pereira, Carla Cunha, Cintia Alves, and António Amorim. "African Female Heritage in Iberia: A Reassessment of mtDNA Lineage Distribution in Present Times." Human Biology 77:2 (April 2005): pages 213-229.
       The mtDNA haplogroup L is identified as being of Sub-Saharan African origin. Some descendants brought L to the Iberian peninsula, where European mtDNA lineages remain predominant. In this study of 1045 people from Portugal and Spain, 5.83% of the Portuguese participants carried L lineages, which is higher than their 2.9% frequency in Spain. Such high frequencies are not typical of other Europeans. Haplogroup L is more common in southern Portugal (10.8% frequency) and central Portugal (9.7%) than in northern Portugal. Carriers of L probably descend from Sub-Saharan African slaves who were brought to work in Portugal during the 15th-18th centuries. The mtDNA haplogroup U6, of North African origin, is found in 2.39% of Iberian people, and the authors express surprise that it has a higher frequency in northern regions of Portugal compared to southern regions of Portugal, because they presume U6 came to Iberia during the period of Islamic rule from the 8th-15th centuries and "the Islamic political and cultural influence [...] lasted longer and was more intense in the south."

Luisa Pereira, Maria João Prata, and António Amorim. "Diversity of mtDNA lineages in Portugal: Not a genetic edge of European variation." Annals of Human Genetics 64:6 (November 2000): pages 491-506.
       A study consisting of mitochondrial DNA samples from 100 Northern Portuguese, 82 Central Portuguese, and 59 Southern Portuguese. Portuguese people have more genetic diversity than some of their neighbors. They carry "all the most important European haplogroups, including those that expanded through Europe in the Palaeolithic, and those whose expansion has occurred during the Neolithic." They also carry the mtDNA haplogroups U6 and L, both of African origin. U6 is "restricted to North Portugal whereas L was widespread all over the country." They found U6 in 7% of their Northern Portuguese. L1 was found in 1% of Northern Portuguese, 1.3% of Central Portuguese, and 1.7% of Southern Portuguese. L2 was found in 3% of Northern Portuguese, 2.4% of Central Portuguese, and 1.7% of Southern Portuguese. L3 was found in 1% of Northern Portuguese, 2.4% of Central Portuguese, and 1.7% of Southern Portuguese. Haplogroup M1 was detected in 1.3% of Central Portuguese but not in the other two groups. Similarly, haplogroup N was found in 1.3% of Central Portuguese but absent in the other two groups. The most prevalent haplogroup by far in all three Portuguese groups is H, found in 41% of the northerners, 37.8% of the central populations, and 44.1% of the southerners. U* is also frequent, representing 16% of northern samples, 14.6% of central samples, and 11.9% of southern samples. The other Northern Portuguese frequencies are 11% for T, 8% for V, 6% for J, 3% for K, 2% for W, and 1% for I. The other Central Portuguese frequencies are 11% for T%, 7.3% for V, 6.1% for J, 7.3% for K, 1.3% for W, 3.6 for X, and 2.4% for other haplogroup(s). The other Southern Portuguese frequencies are 10.2% for T, 6.8% for V, 8.5% for J, 6.8% for K, 1.7% for I, 1.7% for X, and 3.4% for other haplogroup(s).

H. B. Côrte-Real, V. A. Macaulay, M. B. Richards, G. Hariti, M. S. Issad, A. Cambon-Thomsen, S. Papiha, J. Bertranpetit, and Bryan C. Sykes. "Genetic diversity in the Iberian Peninsula determined from mitochondrial sequence analysis." Annals of Human Genetics 60:4 (July 1996): pages 331-350.
       54 Portugese people, undifferentiated by region, have their mtDNA typed here. The results were: 1.8% belonged to the mtDNA haplogroup L2, 1.8% to L3, 11.1% to T, 5.6% to J, 9.3% to U*, 5.6% to U6, 7.4% to K, 3.7% to HV, 48.1% to H, 3.7% to V, and 1.8% to other haplogroup(s).

Antonio Arnaiz-Villena, J. Martínez-Laso, E. Gómez-Casado, N. Díaz-Campos, P. Santos, A. Martinho, and H. Breda-Coimbra. "Relatedness among Basques, Portuguese, Spaniards, and Algerians studied by HLA allelic frequencies and haplotypes." Immunogenetics 47:1 (1997): pages 37-43. Excerpts from the Abstract:

"HLA-A, -B, -DRB1, -DQA1, and DQB1 alleles were studied in Iberian and Algerian populations by serology and DNA sequence methodologies. The genetic and cultural relatedness among Basques, Spaniards, and paleo-North Africans (Berbers or Tamazights) was established. Portuguese people have also maintained a certain degree of cultural and ethnic-specific characteristics since ancient times. The results of the present HLA study in Portuguese populations show that they have features in common with Basques and Spaniards from Madrid: a high frequency of the HLA-haplotypes A29-B44-DR7 (ancient western Europeans), A2-B7-DR15 (ancient Europeans and paleo-North Africans), and A1-B8-DR3 (Europeans) are found as common characteristics. Portuguese and Basques do not show the Mediterranean A33-B14-DR1 haplotype, suggesting a lower admixture with Mediterraneans; Spaniards and Algerians do have this haplotype in a relatively high frequency, indicating a more extensive Mediterranean genetic influence. The paleo-North African haplotype A30-B18-DR3 present in Basques, Algerians, and Spaniards is not found in Portuguese either. The Portuguese have a characteristic unique among world populations: a high frequency of HLA-A25-B18-DR15 and A26-B38-DR13, which may reflect a still detectable founder effect coming from ancient Portuguese, i.e., oestrimnios and conios; [...]

Rui Martiniano, Lara M. Cassidy, Ros Ó Maoldúin, Russell McLaughlin, Nuno M. Silva, Licinio Manco, Daniel Fidalgo, Tania Pereira, Maria J. Coelho, Miguel Serra, Joachim Burger, Rui Parreira, Elena Moran, Antonio C. Valera, Eduardo Porfirio, Rui Boaventura, Ana M. Silva, and Daniel G. Bradley. "The population genomics of archaeological transition in west Iberia: Investigation of ancient substructure using imputation and haplotype-based methods." PLOS Genetics 13:7 (July 27, 2017): e1006852.
       This autosomal DNA study includes a section titled "Comparison of ancient samples from Portugal with ancient and modern individuals using directly observed haploid genotypes".

C. Santos, M. Lima, R. Montiel, N. Angles, L. Pires, A. Abade, and M. P. Aluja. "Genetic structure and origin of peopling in the Azores islands (Portugal): the view from mtDNA." Annals of Human Genetics 67(Part 5) (September 2003): pages 433-456.
       The Azores islands of Portugal, located in the Atlantic Ocean, were first settled by Portuguese people following their discovery by Portuguese navigators in the 15th century. The researchers gathered 146 mtDNA samples from unrelated Azorean people and subdivided the samples into eastern (n=50), central (n=60), and western (n=37) groups. The researchers found that "the majority of mtDNA lineages originated from the Iberian Peninsula, mainly from Portugal (mainland). However contributions from other European populations, especially from Northern Europe, cannot be disregarded." Western Azoreans have a different haplogroup distribution than eastern and central Azoreans. Excerpts from the Abstract:

"[...] African haplogroups were found in all the groups of islands. Therefore the presence of Moorish and African slaves on the islands, as reported in historical sources, is supported by the mtDNA genetic data, especially in the Eastern group. The presence of Jews in the Central group is also supported by the mtDNA data. [...]"

A. Brehm, Luisa Pereira, Toomas Kivisild, and Antonio Amorim. "Mitochondrial portraits of the Madeira and Açores archipelagos witness different genetic pools of its settlers." Human Genetics 114:1 (December 2003): pages 77-86.
       155 mtDNA samples from Madeira people and 179 mtDNA samples from Azorean people were analyzed. The archipelagos of Madeira and the Azores were settled by Portuguese people in the 15th century. Years of slave trade involving Madeira, including the transport of slaves directly from West Africa to Madeira, explain Madeira's "stronger sub-Saharan imprint" in the modern gene pool, reflected in the mtDNA "haplogroups L1-L3 constituting about 13% of the lineages." The researchers also found the North African mtDNA U6 cluster in Madeira, but at a lesser frequency than Spain's Canary Islands, however both have more of it than in the Azores.