Following Genetic Footprints out of Africa: First Modern Humans Settled in Arabia
ScienceDaily (Jan. 26, 2012) — A new study, using genetic analysis to look for clues about human migration over sixty thousand years ago, suggests that the first modern humans settled in Arabia on their way from the Horn of Africa to the rest of the world.
A new study, using genetic analysis to look for clues about human migration over sixty thousand years ago, suggests that the first modern humans settled in Arabia on their way from the Horn of Africa to the rest of the world. (Credit: © photoromano / Fotolia)
Led by the University of Leeds and the University of Porto in Portugal, the study is recently published in American Journal of Human Genetics and provides intriguing insight into the earliest stages of modern human migration, say the researchers.
"A major unanswered question regarding the dispersal of modern humans around the world concerns the geographical site of the first steps out of Africa," explains Dr Luísa Pereira from the Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP). "One popular model predicts that the early stages of the dispersal took place across the Red Sea to southern Arabia, but direct genetic evidence has been thin on the ground."
The international research team, which included colleagues from across Europe, Arabia and North Africa, analysed three of the earliest non-African maternal lineages. These early branches are associated with the time period when modern humans first successfully moved out of Africa.
Using mitochondrial DNA analysis, which traces the female line of descent and is useful for comparing relatedness between different populations, the researchers compared complete genomes from Arabia and the Near East with a database of hundreds more samples from Europe. They found evidence for an ancient ancestry within Arabia.
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Copyright © 2012 The American Society of Human Genetics All rights reserved.
The American Journal of Human Genetics, 26 January 2012
doi:10.1016/j.ajhg.2011.12.010
REPORT
The Arabian Cradle: Mitochondrial Relicts of the First Steps along the Southern Route out of Africa
Verónica Fernandes1, 2, Farida Alshamali3, Marco Alves1, Marta D. Costa1, 2, Joana B. Pereira1, 2, Nuno M. Silva1, Lotfi Cherni4, 5, Nourdin Harich6, Viktor Cerny7, 8, Pedro Soares1, Martin B. Richards2, 9, 11 and Luísa Pereira1, 10, 11, 
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1 Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto 4200-465, Portugal
2 Faculty of Biological Sciences, Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK
3 General Department of Forensic Sciences and Criminology, Dubai Police General Headquarters, Dubai 1493, United Arab Emirates
4 Laboratory of Genetics Immunology and Human Pathology, Faculty of Sciences of Tunis, Tunis 2092, Tunisia
5 Higher Institute of Biotechnology of Monastir, Monastir 5000, Tunisia
6 Laboratoire d'Anthropogénétique, Départment de Biologie, Université Chouaïb Doukkali, El Jadida 24000, Morocco
7 Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague 128 43, Czech Republic
8 Institute for Advanced Study, Paris 75648, France
9 School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK
10 Faculdade de Medicina da Universidade do Porto, Porto 4200-319, Portugal
Corresponding author
11 These authors contributed equally to this work
Abstract
A major unanswered question regarding the dispersal of modern humans around the world concerns the geographical site of the first human steps outside of Africa. The “southern coastal route” model predicts that the early stages of the dispersal took place when people crossed the Red Sea to southern Arabia, but genetic evidence has hitherto been tenuous. We have addressed this question by analyzing the three minor west-Eurasian haplogroups, N1, N2, and X. These lineages branch directly from the first non-African founder node, the root of haplogroup N, and coalesce to the time of the first successful movement of modern humans out of Africa, ∼60 thousand years (ka) ago. We sequenced complete mtDNA genomes from 85 Southwest Asian samples carrying these haplogroups and compared them with a database of 300 European examples. The results show that these minor haplogroups have a relict distribution that suggests an ancient ancestry within the Arabian Peninsula, and they most likely spread from the Gulf Oasis region toward the Near East and Europe during the pluvial period 55–24 ka ago. This pattern suggests that Arabia was indeed the first staging post in the spread of modern humans around the world.
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