Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences and the Institute of Evolution, University of Haifa, Haifa 3498838, Israel.
School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 6997801, Israel.
Genes (Basel). 2021 Feb 25;12(3):338. doi: 10.3390/genes12030338.
and are two tetraploid wheat species sharing as a common ancestor, and domesticated accessions from both of these allopolyploids exhibit nonbrittle rachis (i.e., nonshattering spikes). We previously described the loss-of-function mutations in the genes and in the A and B subgenomes, respectively, that are responsible for this most visible domestication trait in . Resequencing of a large panel of wild and domesticated accessions subsequently led to the identification of the two progenitor haplotypes of the and domesticated alleles. Here, we extended the haplotype analysis to other subspecies and to the homologues in the related species. Our results showed that all the domesticated wheat subspecies within share common and haplotypes, confirming their common origin. In , however, we identified a novel loss-of-function allele underlying a partially brittle spike phenotype. This novel recessive allele appeared fixed within the pool of domesticated Timopheev's wheat but was also carried by one wild accession exhibiting partial brittleness. The promoter region for could not be amplified in any accessions with any primer combination, exemplifying the gene-level distance between the two species. Altogether, our results support the concept of independent domestication processes for the two polyploid, wheat-related species.
和 是两个共享 作为共同祖先的四倍体小麦物种，来自这两个异源多倍体的驯化品种都表现出非脆性穗轴（即不爆裂的穗）。我们之前描述了分别在 A 和 B 亚基因组中导致 最明显驯化特征的 基因 和 基因的功能丧失突变。随后对大量野生和驯化 的测序，导致了 和 驯化等位基因的两个祖源单倍型的鉴定。在这里，我们将单倍型分析扩展到其他 亚种和相关 的 同源物。我们的研究结果表明，在 内的所有驯化小麦亚种都共享共同的 和 单倍型，证实了它们的共同起源。然而，在 中，我们鉴定出一个新的功能丧失 等位基因，导致部分穗轴脆性表型。这个新的隐性等位基因似乎在驯化的提姆菲耶夫小麦群体中固定，但也存在于一个表现出部分脆性的野生 中。任何 引物组合都无法扩增 的 启动子区域，这充分体现了这两个物种之间的基因水平差异。总的来说，我们的研究结果支持了这两个多倍体、与小麦相关的物种独立驯化的概念。
