Wheat domestication in light of haplotype analyses of the Brittle rachis 1 genes (BTR1-A and BTR1-B)

PubMedID: 31203884 Wheat domestication was a milestone in the rise of agrarian societies in the Fertile Crescent. As opposed to the freely dispersing seeds of its tetraploid progenitor wild emmer, the hallmark trait of domesticated wheat is intact, harvestable spikes. During domestication, wheat acquired recessive loss-of-function mutations in the Brittle Rachis 1 genes, both in the A genome (BTR1-A) and B genome (BTR1-B). In this study, we probe the geographical provenances of these mutations via haplotype analyses of a collection of wild and domesticated accessions. Our results show that the precursor of the domesticated haplotype of BTR1-A was detected in 32% of the wild accessions gathered throughout the Levant, from central Israel to central Turkey. In contrast, the precursor of the domesticated haplotype of BTR1-B, which carries a distinct 11 bp deletion in the promoter region, was found in only 10% of the tested wild accessions, all from the Southern Levant. Moreover, we identified of a single wild emmer accession in Southern Levant that carries the progenitor haplotypes for both BTR1-A and BTR1-B genes. These observations suggest that at least part of the emmer domestication process occurred in Southern Levant, contrary to the widely held view that the northern part of the Fertile Crescent was the center of wheat domestication. © 2019 Elsevier B.V. United States-Israel Binational Science Foundation United States - Israel Binational Agricultural Research and Development Fund: IS-4829-15 Israel Science Foundation Israel Science Foundation: 1137/17 United States - Israel Binational Agricultural Research and Development Fund United States-Israel Binational Science Foundation: 2015409 Çukurova Üniversitesi: FBA-2017-7930 This research was funded by the United States – Israel Binational Science Foundation (BSF grant 2015409 ), the US-Israel Binational Agricultural Research and Development Fund (BARD project No. IS-4829-15 ), and the Israel Science Foundation (ISF grant 1137/17 ). HO acknowledges support from Çukurova University (FBA-2017-7930). Appendix A