AFLP Analysis of a Collection of Tetraploid Wheats Indicates the Origin of Emmer and Hard Wheat Domestication in Southeast Turkey

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Abstract
Western agriculture and its most important crop plants are thought to have originated about 10,000 years ago in the Fertile Crescent, a geographical region extending from modern-day Israel, Jordan, Lebanon, and western Syria into southeastern Turkey and along the Tigris and Euphrates rivers into Iraq and Iran (Smith 1995 ; Bar-Yosef 1998 ; Diamond 1998 ; Moore, Hillman, and Legge 2000 ; Zohary and Hopf 2000 ; Gopher, Abbo, and Lev-Yadun 2002 ). Two traditional lines of evidence support that view. First, the geographical distributions of wild progenitors of modern cereal species, among them wild wheats (Triticum urartu, T. boeoticum, T. dicoccoides, Aegilops tauschii), wild barley (Hordeum spontaneum), and wild rye (S. vavilovii), intersect in this region (Nesbitt and Samuel 1996 ; Moore, Hillman, and Legge 2000 ; Zohary and Hopf 2000 ; Gopher, Abbo, and Lev-Yadun 2002 ). Second, seeds of the wild species occur in early archaeological sites of the region, followed in radiocarbon age and stratigraphic succession by the remains of domesticated forms (Moore, Hillman, and Legge 2000 ; Zohary and Hopf 2000 ; Gopher, Abbo, and Lev-Yadun 2002 ). Recently, molecular evolutionary studies have also begun to weigh heavily on this issue. Genetic identification of the natural stands from which wild crops were domesticated addresses the question of where specifically within the Fertile Crescent humans invented agriculture. The approach involves comparing wild and domesticated populations using molecular markers, which give genome-wide estimates of genetic similarity (Heun et al. 1997 ; Badr et al. 2000 ; Martin and Salamini 2000 ). One of the most promising of these techniques is amplified fragment length polymorphism (AFLP), a polymerase chain reaction (PCR)-based procedure that resolves radioactively labeled electrophoretic bands (polymorphic loci) on sequencing gels.