DNA history of Egypt

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The genetic history of the demographics of Egypt reflects Egypt's geographical location at the crossroads of several major cultural areas: Northeast Africa, Northwest Africa, the Sahara, Sub-Saharan Africa, the Middle East, and the Mediterranean.

In general, various DNA studies have found that the gene frequencies of modern Egyptian populations are intermediate between those of the Middle East, the Horn of Africa, southern Europe and Sub-Saharan Africa,[1] though NRY frequency distributions of the modern Egyptian population appear to be substantially more similar to those of the Middle East than to any Sub-Saharan African or European population, suggesting a substantially larger Middle Eastern genetic component.[2][3][3][4][5][6][7]

Ancient DNA

Contamination from handling and intrusion from microbes create obstacles to the recovery of ancient DNA.[8] Consequently, most DNA studies have been carried out on modern Egyptian populations with the intent of learning about the influences of historical migrations on the population of Egypt.[9][10][11][12] One successful 1993 study was performed on ancient mummies of the 12th Dynasty, by Dr. Svante Pääbo and Dr. Anna Di Rienzo, which identified multiple lines of descent, some of which originated in Sub-Saharan Africa.[13]

Blood typing and ancient DNA sampling on Egyptian mummies is scant; however, blood typing of dynastic mummies found ABO frequencies to be most similar to modern Egyptians,[14] and some also to northern Haratin populations. ABO blood group distribution shows that the Egyptians form a sister group to North African populations, including Berbers, Nubians and Canary Islanders.[15]

In 2013, Nature announced the publication of the first genetic study utilizing next-generation sequencing to ascertain the ancestral lineage of an Ancient Egyptian individual. The research was led by Carsten Pusch of the University of Tübingen in Germany and Rabab Khairat, who released their findings in the Journal of Applied Genetics. DNA was extracted from the heads of five Egyptian mummies that were housed at the institution. All the specimens were dated between 806 BC and 124 AD, a timeframe corresponding with the late Dynastic and Greek Ptolemaic Kingdom periods. The researchers observed that one of the mummified individuals likely belonged to the mtDNA haplogroup I2[citation needed], a maternal clade that is believed to have originated in Western Asia.[16]

In 2015, genome sequencing of a 4,500-year-old skeleton from the Mota Cave in the highlands of southwest Ethiopia suggested that Middle Eastern farmers had migrated into Africa around three thousand years ago, bringing new crops to the continent such as wheat, barley and lentils. Mota was assigned to MtDNA haplogroup L3x2a and Y-DNA haplogroup E-P2. Although the scientists initially asserted that this ancient movement affected many different communities throughout the continent, subsequent DNA analysis indicated that this Neolithic agrarian population mainly settled in East Africa.[17]

DNA studies on modern Egyptians

In general, various DNA studies have found that the gene frequencies of modern North African populations are intermediate between those of the Horn of Africa and Eurasia,[18] though possessing a greater genetic affinity with the populations of Eurasia than they do with Africa.[3][3][4] The present population of the Sahara is more Caucasoid (though still mixed) in the extreme north, with a fairly gradual increase of Negroid component as one goes south.[6][19][20] The results of these genetic studies is consistent with the historical record, which records significant bidirectional contact between Egypt and Nubia, and the Levant/Middle East within the last few thousand years, but with general population continuity from the Early Dynastic Period of Egypt up to the modern day era.[21][22]

Genetic analysis of modern Egyptians reveals that they have paternal lineages common to indigenous North-East African populations primarily (Algeria, Tunisia, Morocco), and to Middle Eastern peoples to a lesser extent—these lineages would have spread during the Neolithic and were maintained by the predynastic period.[6][23]

A study by Krings et al. (1999) on mitochondrial DNA clines along the Nile Valley found that a Eurasian cline runs from Northern Egypt to Southern Sudan and a Sub-Saharan cline from Southern Sudan to Northern Egypt.[24]

Luis et al. (2004) found that the male haplogroups in a sample of 147 Egyptians were E1b1b (36.1%, predominantly E-M78), J (32.0%), G (8.8%), T(8.2%), and R (7.5%). E1b1b and its subclades are characteristic of some Afro-Asiatic speakers and are believed to have originated in either the Middle East, North Africa, or the Horn of Africa. Cruciani et al. (2007) suggests that E-M78, E1b1b predominant subclade in Egypt, originated in "Northeastern Africa", which in the study refers specifically to Egypt and Libya [2][25]

Other studies have shown that modern Egyptians have genetic affinities primarily with populations of Asia, North and Northeast Africa,[26][27][28][29] and to a lesser extent Middle Eastern and European populations.[30]

Some genetic studies done on modern Egyptians suggest that they are not closely related to most Sub Saharan Africans.[31] Other studies suggest that they are instead mostly closely related to other North Africans.[28] In addition, some studies suggest lesser ties with populations in the Middle East, as well as some groups in southern Europe.[29] A 2004 mtDNA study of upper Egyptians from Gurna found a genetic ancestral heritage to modern Northeast Africans, characterized by a high M1 haplotype frequency and a comparatively low L1 and L2 macrohaplogroup frequency of 20.6%. Another study links Egyptians in general with people from modern Eritrea and Ethiopia.[27][32] Though there has been much debate of the origins of haplogroup M1 a recent 2007 study had concluded that M1 has West Asia origins not a Sub Saharan African origin[33] Origin A 2003 Y chromosome study was performed by Lucotte on modern Egyptians, with haplotypes V, XI, and IV being most common. Haplotype V is common in Berbers and has a low frequency outside North Africa. Haplotypes V, XI, and IV are all predominantly North African/Horn of African haplotypes, and they are far more dominant in Egyptians than in Middle Eastern or European groups.[34]

Y-DNA haplogroups

A study using the Y-chromosome of modern Egyptian males found similar results, namely that North East African haplogroups are predominant in the South but the predominant haplogroups in the North are characteristic of North African and West Eurasian populations.[35]

Population Nb A/B E1b1a E1b1b1 (M35) E1b1b1a (M78) E1b1b1b (M81) E1b1b1c (M123) F K G I J1 J2 R1a R1b Other Study
1 Egyptians 147 2.7% 2.7% 0 18.4% 8.2% 9.5% 0 7.5% 9.5% 0 19.7% 12.2% 3.4% 4.1% 2.1% Luis et al. (2004)[36]
2 Egyptians from El-Hayez Oasis (Western Desert) 35 0 5.70% 5.7% 28.6% 28.6% 0 0 0 0 0 31.4% 0 0 0 0 Kujanová et al. (2009)[37]
3 Egyptians from Siwa Oasis (Western Desert) 93 28.0% 6.5% 2.2% 6.5% 1.1% 2.2% 0 0 3.2% 0 7.5% 6.5% 0 28.0% 8.3% Dugoujon et al. (2009)[38]
4 Northern Egyptians 44 2.3% 0 4.5% 27.3% 11.4% 9.1% 6.8% 2.3% 0 0 9.1% 9.1% 2.3% 9.9% 6.8% Arredi et al. (2004)
5 Southern Egyptians 29 0.0% 0 0 17.2% 6.9% 6.9% 17.2% 10.3% 0 3.4% 20.7% 3.4% 0 13.8% 0 Arredi et al. (2004)
Distribution of E1b1b1a (E-M78) and its subclades
Population N E-M78 E-M78* E-V12* E-V13 E-V22 E-V32 E-V65 Study
Southern Egyptians 79 50.6% 44.3% 1.3% 3.8% 1.3% Cruciani et al. (2007)[39]
Egyptians from Bahari 41 41.4% 14.6% 2.4% 21.9% 2.4% Cruciani et al. (2007)
Northern Egyptians (Delta) 72 23.6% 5.6% 1.4% 13.9% 2.8% Cruciani et al. (2007)
Egyptians from Gurna Oasis 34 17.6% 5.9% 8.8% 2.9% Cruciani et al. (2007)
Egyptian from Siwa Oasis 93 6.4% 2.1% 4.3% Cruciani et al. (2007)

Autosomal DNA

On 13 January 2012, an exhaustive genetic study of North Africa's human populations was published.[40] The researchers analyzed around 800,000 genetic markers, distributed throughout the entire genome in 125 North African individuals belonging to seven representative populations in the whole region (Saharawi, South Moroccans, North Moroccans, Algerians, Tunisians Berbers, Libyans and Egyptians) and the information obtained was compared with the information from the neighbouring populations. The results of this study show that there is a native genetic component ("Maghrebi") which defines North Africans. The study identified mainly two distinct, opposite gradients of ancestry: an east-to-west increase of this native North African ancestry and an east-to-west decrease in likely Middle Eastern Arab ancestry.

The study also reveals that the genetic composition of North Africa's human populations is very complex and is the result of five distinct ancestries : a local component (Maghrebi) dating back thirteen thousand years and the varied genetic influence of neighbouring populations on North African groups during successive migrations (European, Middle Eastern, eastern and western Sub-Saharan Africa). According to the authors, the people inhabiting North Africa today are not descendants of either the earliest occupants of this region fifty thousand years ago, or descendants of the most recent Neolithic populations. The data shows that the ancestors of today's North Africans were a group of populations which already lived in the region around thirteen thousand years ago. Furthermore, this local North African genetic component is very different from the one found in the populations in the south of the Sahara, which shows that the ancestors of today's North Africans were members of a subgroup of humanity who left Africa to conquer the rest of the world and who subsequently returned to the north of the continent to settle in the region. As well as this local component, North African populations were also observed to share genetic markers with all the neighbouring regions, as a result of more recent migrations, although these appear in different proportions. There is an influence from the Middle East, which becomes less marked as the distance from the Arabian Peninsula increases, similar proportions of European influence in all North African populations, and, in some populations (South Moroccans, Saharawi...), there are even individuals who present a large proportion of recent influence from the South of the Sahara in their genome.

Admixture analysis

Recent genetic analysis of North African populations have found that, despite the complex admixture genetic background, there is an autochthonous genomic component which is likely derived from "back-to-Africa" gene flow older than 12,000 years ago (ya) (i.e., prior to the Neolithic migrations). This local population substratum seems to represent a genetic discontinuity with the earliest modern human settlers of North Africa (those with the Aterian industry) given the estimated ancestry is younger than 40,000 years ago. North Morocco, Libya and Egypt carry high proportions of European and Middle Eastern ancestral components, whereas Tunisian Berbers and Saharawi are those populations with highest autochthonous North African component.[41]

Copts

A 2008 study of a Copts group in Sudan found relatively high frequencies of the Sub-Saharan Haplogroup B. According to the study, the presence of Sub-Saharan haplogroups may also be consistent with the historical record in which southern Egypt was colonized by Nilotic populations during the early state formation.[42]

A 2015 study by Dobon et al. identified an ancestral autosomal component of West Eurasian origin that is common to many modern Afroasiatic-speaking populations in Northeast Africa. Known as the Coptic component, it peaks among Egyptian Copts who settled in Sudan over the past two centuries. Copts also formed a separated group in PCA, a close outlier to other Egyptians, Northeast and Middle East populations. The Coptic component evolved out of a main North African and Middle Eastern ancestral component that is shared by other Egyptians and also found at high frequencies among other Afro-Asiatic populations in Northeast Africa (~70%). The scientists suggest that this points to a common origin for the general population of Egypt. They also associate the Coptic component with Ancient Egyptian ancestry, without the later Arabian influence that is present among other Egyptians.[43]

See also

References

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