Reticulated origin of domesticated tetraploid wheat

The past 15 years have witnessed a notable scientific interest in the topic of crop domestication and the emergence of agriculture in the Near East. Multi-disciplinary approaches brought a significant amount of new data and a multitude of hypotheses and interpretations. However, some seemingly conflicting evidence, especially in the case of emmer wheat, caused certain controversy and a broad scientific consensus on the circumstances of the wheat domestication has not been reached, yet.The past phylogenetic research has translated the issue of wheat domestication into somewhat simplistic mono-/polyphyletic dilemma, where the monophyletic origin of a crop signalizes rapid and geographically localized domestication, while the polyphyletic evidence suggests independent, geographically separated domestication events. Interestingly, the genome-wide and haplotypic data analyzed in several studies did not yield consistent results and the proposed scenarios are usually in conflict with the archaeological evidence of lengthy domestication.Here I suggest that the main cause of the above mentioned inconsistencies might lie in the inadequacy of the divergent, tree-like evolutional model. The inconsistent phylogenetic results and implicit archaeological evidence indicate a reticulate (rather than divergent) origin of domesticated emmer. Reticulated genealogy cannot be properly represented on a phylogenetic tree; hence different sets of samples and genetic loci are prone to conclude different domestication scenarios. On a genome-wide super-tree, the conflicting phylogenetic signals are suppressed and the origin of domesticated crop may appear monophyletic, leading to misinterpretations of the circumstances of the Neolithic transition.The network analysis of multi-locus sequence data available for tetraploid wheat clearly supports the reticulated origin of domesticated emmer and durum wheat. The concept of reticulated genealogy of domesticated wheat sheds new light onto the emergence of Near-Eastern agriculture and is in agreement with current archaeological evidence of protracted and dispersed emmer domestication.