Genetic studies on Arabs refers to the analyses of the genetics of ethnic Arab people in the Middle East and North Africa. Arabs are genetically diverse as a result of their intermarriage and mixing with indigenous people of the pre-Islamic Middle East and North Africa following the Arab and Islamic expansion. Genetic ancestry components related to the Arabian Peninsula display an increasing frequency pattern from west to east over North Africa. A similar frequency pattern exist across northeastern Africa with decreasing genetic affinities to groups of the Arabian Peninsula along the Nile river valley across Sudan and the more they go south. This genetic cline of admixture is dated to the time of Arab migrations to the Maghreb and northeast Africa.
In the Levant, the introduction of Islam to the region and the conversion of the region's population to it caused major rearrangements in populations' relations and affinities through admixture with "culturally similar but geographically remote populations" with whom they enjoyed a shared Islamic culture, Arab culture and Arabic language, which led to "genetic similarities between remarkably distant populations like Jordanians, Moroccans, and Yemenis".
A 2018 study of Arabs found that Peninsular Arabs genetically showed two distinct clusters and that Arabs in general can be genetically stratified into four groups; the first consisting of Maghrebi Arabs (Algerians, Moroccans, Tunisians and Libyans) along with the first Arabian Peninsula cluster, which consists of Saudis, Kuwaitis and Yemenis, the second consisting of Levantine Arabs (Palestinians, Lebanese, Syrians and Jordanians) along with Egyptians and Iraqis, the third compromising Sudanese and Comorians, and the fourth compromising the second Arabian Peninsula cluster consisting of Omanis, Emiratis, and Bahrainis. The study confirmed the high genetic heterogeneity among Arabs, especially those of the Arabian Peninsula.
Uniparental markers
Y-chromosome The most dominant Paternal Y haplogroup in Arab countries is the Arabian haplogroup J1 (J-M267) and especially its main clade J1-P58 reaching up to 80% in some countries such as Yemen, Qatar and Sudan, according to latest samples studies. J1-M267 that is not P58 are found in Yemen and Oman. The mutation STR DYS388 equal or above 16 found in J1-p58 was used as genetic profiling in forensics since the 1980s to determine Middle Eastern ancestry.
Below is the general distribution of Y-DNA haplogroups among populations of the Arab world: Population Language FamilyIE = Indo-European nFirst column gives the amount of total Sample Size studied R1bSecond column gives the Percentage of the particular haplogroup among the Sample Size n R1a n I n E1b1b n E1b1a n J n G n N n T n L Arabs (Algeria) Afro-Asiatic (Semitic) 35 35 32 35 Arabs (Algeria – Oran) Afro-Asiatic (Semitic) 102 102 102 102 102 Arabs (Bedouin) Afro-Asiatic (Semitic) 32 32 32 32 32 32 Arabs (Iraq) Afro-Asiatic (Semitic) 218 218 156 Arabs (Israel & West Bank) Afro-Asiatic (Semitic) 143 143 143 143 143 143 Arabs (Morocco) Afro-Asiatic (Semitic) 44 Haplogroup frequency data in table 1 44 44 49 49 Arabs (Oman) Afro-Asiatic (Semitic) 121 (Errata ) 121 121 121 121 121 121 121 121 Arabs (Qatar) Afro-Asiatic (Semitic) 72 72 72 72 72 72 72 72 72 72 Arabs (Saudi Arabia) Afro-Asiatic (Semitic) 157 157 157 157 157 157 157 157 157 157 Arabs (UAE) Afro-Asiatic (Semitic) 164 164 164 164 164 164 164 164 164 Arabs (Yemen) Afro-Asiatic (Semitic) 62 62 62 62 62 62 62 62 62 62 Arabs (Syria) Afro-Asiatic (Semitic) 20 20 20 20 20 20 20 20 20 Arabs (Lebanon) Afro-Asiatic (Semitic) 31 31 31 31 31 31 31 31 31 Arabs (Sudan) Afro-Asiatic (Semitic) 102 102 102 102 Arabs (Tunisia) Afro-Asiatic (Semitic) 148 148 148 148 148 148 148 148 148 Arabs (Libya) Afro-Asiatic (Semitic) 63 63 63 63 63 63 63 63 63 Saharawi (SADR) Afro-Asiatic (Semitic) 29 29 29 Egyptians Afro-Asiatic (Semitic) 92–147 - 92–147 - 92–147 - 92–147 - 92–147 - 92–147 - 92–147 - 92–147 - 92–147 - 92 Egyptians (North) Afro-Asiatic (Semitic) 43 43 43 43 44 43 43 43 Egyptians (South) Afro-Asiatic (Semitic) 47 ; Supplementary Data 47 Lebanese Afro-Asiatic (Semitic) 914 914 914 914 914 914 914 914 914 914
mtDNA analysis The maternal ancestral lineages of Arabic countries are diverse. The original and still most prevalent maternal haplogroups of Lower Egypt, the Near East and Yemen are R0a1, M1, and HV1. In Syria, there is a Eurasian maternal gene flow where U5 peaks.
HLA antigens Many of the genetic disorders specific to Arabs are located on HLA segment on chromosome 6. These same segment mutations are also markers of Arabs in genealogical and forensic profiling tests and studies.
Autosomal DNA There are various West-Eurasian autosomal DNA components that characterize the populations of the Arab world, namely: the Arabian, Levantine, Coptic, and Maghrebi components. The Arabian component is the main autosomal element in the Persian Gulf region. It is most closely associated with local Arabic-speaking populations.
The Arabian component is also found at significant frequencies in parts of the Levant and Northeast Africa. The geographical distribution pattern of this component correlates with the pattern of the Islamic expansion, but its presence in Lebanese Christians, Sephardi and Ashkenazi Jews, Cypriots and Armenians might suggest that its spread to the Levant represents an earlier event. A separate study by Iosif Lazarides and colleagues published in the same year, correlated this component with Epipaleolithic Natufians from the Levant. This study produced genome-wide ancient DNA from 44 ancient Near Easterners between ~12,000 and 1,400 BCE, including Natufian hunter–gatherers, and suggested an earlier spread of Natufian ancestry to populations of the Levant and Eastern Mediterranean. Natufians were found to be of exclusive West-Eurasian origin, most closely related to modern Arabs like the Bedouins and Yemenis, followed by Egyptian and Berber peoples. A 2018 re-analysis of Natufian samples, including 279 modern populations as a reference, found that the Natufians were largely of local West-Eurasian origin, but harbored 6.8% Eastern African-related ancestry, specifically an Omotic component, which peaks among the Aari people. It is suggested that this Omotic component may have been introduced into the Levant along with the specific Y-haplogroup sublineage E-M215, also known as "E1b1b", to Western Eurasia. The Levantine component is the main autosomal element in the Near East and Caucasus. It peaks among Druze populations in the Levant. The Levantine component diverged from the Arabian component about 15,500-23,700 ypb. The Coptic component peaks among Copts in Sudan. The Maghrebi component is the main autosomal element in the Maghreb. It peaks among the non-Arabized Berber populations in the region. The modern Northern African (Berber) populations have been described as a mosaic of Northern African (Iberomaurusian), Middle Eastern, European (Early European Farmer), and Sub-Saharan African-related ancestries.
A genetic study published in the "European Journal of Human Genetics" in Nature (2019) showed that Middle Easterners (Arabs) are closely related to Europeans and Northern Africans as well as to Southwest Asians. The "Arab macropopulation" is generally closely related to other "West-Eurasian" populations, such as Iranian peoples.
Moorjani et al. (2011) estimated that some Arabs have inherited 4%–15% sub-Saharan ancestry (approximately 9.3% in Palestinians, 14.5% in Bedouins and 4.4% in Druzes), although the percentages were higher (ranging from 5.6% in Druzes to 15.6% in Bedouins) when reanalyzed with the 'STRUCTURE' statistical model.
The 2013 Genetic study found that Kuwaiti natives can roughly be divided into three groups: the first one is largely of West Asian ancestry, representing Persians with European admixture; the second group is predominantly of city-dwelling Arabian tribe ancestry, and the third group includes most of the tent-dwelling Bedouin surnames and is characterized by the presence of 17% Sub-Saharan African ancestry. Population differentiation FST estimates place the first group near Asian populations, the second one near Negev Bedouin tribes, and the third one near the Mozabite population.
The Arab expansion marked one of the last expansions of West-Eurasian ancestry into Africa, with the earliest scientifically attested West-Eurasian geneflow into Africa being dated back to 23,000 BCE (or already earlier), and may be associated with the spread of the Proto-Afroasiatic from the Middle East.
Hodgson et al. (2014) found a distinct non-African ancestry component among Northeastern Africans (dubbed "Ethio-Somali"), which split from other West-Eurasian ancestries, most closely to the Arabian ancestry component, about 23,000 years ago, and migrated into Africa pre-agricultural (between 12,000 and 22,000 years ago).
This component is suggested to have been present in considerable amounts among the Proto-Afroasiatic-speaking peoples. The authors argue that the Ethio-Somali component and the Maghrebi component descended from a single ancestral lineage, which split from the Arabian lineage and migrated into Africa from the Middle East. In Africa, this West-Eurasian lineage diverged into the Maghrebi component, predominant in Northern Africa, and the Ethio-Somali component, found in significant varying degrees among populations of the Horn of Africa.
In 2021, a study showed no genetic traces of early expansions out-of-Africa in present-day populations in the Near-East, but found Arabians to have elevated Basal Eurasian ancestry that dilutes their Neanderthal ancestry.
Genetic disorders The Arab world has one of the highest rates of genetic disorders globally; some 906 pathologies are endemic in the Arab states, including thalassaemia, Tourette's syndrome, Wilson's disease, Charcot-Marie-Tooth disease, mitochondrial encephalomyopathies, and Niemann-Pick disease.
Databases Several organizations maintain genetic databases for each Arabic country, such as Saudi Human Genome Program (SHGP). Even though the KGP, SHGP, QGP, BGP and EGP are revisiting the genetics and genomics of Arab populations' ancestries, lack of complete coordination between the initiatives is a major limitation on revealing the real disease markers of the Arab population.
The Centre for Arab Genomic Studies (CAGS) is the main organization based in the United Arab Emirates. It initiated a pilot project to construct the Catalogue for Transmission Genetics in Arabs (CTGA) database for genetic disorders in Arab populations. At present, the CTGA database is centrally maintained in Dubai and hosts entries for nearly 1,540 Mendelian disorders and related genes. This number is increasing as researchers are joining the largest Arab scientific effort to define genetic disorders described in the region. The center promotes research studies on these emergent disorders.
Some of the genetic disorders with high frequencies in the Arab world are: hemoglobinopathy, sickle cell anemia, glucose-6-phosphate dehydrogenase deficiency, and fragile X syndrome (FXS). The centre provide information about specific countries, and maintain a list of genomic diseases.
Specific rare autosomal recessive diseases are high in Arabic countries like Bardet Biedl syndrome, Meckel syndrome, congenital chloride diarrhea, severe childhood autosomal recessive muscular dystrophy (SMARMD), lysosomal storage diseases and PKU are high in the Gulf states. Dr Teebi's book provides detailed information and by country. The Middle East respiratory syndrome coronavirus (MERS-CoV) that was first identified in Saudi Arabia in 2012 has infected over 3,000 people, mostly in the Middle East and Europe. Nearly 900 of them – over a quarter — have died. MERS is not yet a pandemic, but could become pervasive in genetic disease patients.