Kilian Benjamin, Ozkan Hakan, Kohl Jochen, von Haeseler Arndt, Barale Francesca, Deusch Oliver, Brandolini Andrea, Yucel Cemal, Martin William, Salamini Francesco
Max-Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg, 10, 50829, Koeln, Germany.
Mol Genet Genomics. 2006 Sep;276(3):230-41. doi: 10.1007/s00438-006-0136-6. Epub 2006 Jun 7.
Archaeological remains indicate that the origin of western agriculture occurred in a brief period about 10,500 years ago in a region of the Middle East known as the Fertile Crescent, where the wild progenitors of several key agricultural cereal species are endemic. Domestication entailed the appearance of agronomic traits such as seed size and threshability. For a representative sample of 20 domesticated barley (Hordeum vulgare) lines, including 13 two-rowed and 7 six-rowed varieties, we determined the haplotypes at seven loci-Adh2, Adh3, Amy1, Dhn9, GAPDH, PEPC and WAXY encompassing 5,616 bases per line-and compared them to the haplotypes at the same loci for 25 wild forms (Hordeum spontaneum) collected within and outside the Fertile Crescent. In comparisons of wild versus domesticated barley, the number of haplotypes (70 vs. 17), average nucleotide diversity, pi, (0.0077 vs. 0.0028), and Watterson's theta at silent sites (0.0104 vs. 0.0028) was reduced in domesticated lines. Two loci, Amy1 and PEPC, were monomorphic in domesticated lines; Amy1 and GAPDH produced significant values of Tajima's D. At GAPDH, pi was slightly higher in domesticated than wild forms, due to divergent high-frequency haplotypes; for the remaining six loci, 87% of nucleotide diversity has been lost in the domesticated forms. Bottlenecks acting on neutrally evolving loci either during the domestication process, during subsequent breeding, or both, are sufficient to account for reduced diversity and the results of Tajima's test, without the need to evoke selection at these loci. Phylogenetic networks data uncover distinct wild and domesticated barley genotypes and suggest that barley may have been domesticated in the Jordan valley. Because, based on AFLP data, the domesticated Turkish cultivars had a genetic basis as large as that present in large germplasm collections, all comparisons provided in this paper are of general value more than being restricted to the Turkish barley germplasm.
考古遗迹表明，西方农业起源于约10500年前的一段短暂时期，位于中东一个被称为新月沃地的地区，这里是几种主要谷类作物野生祖先的发源地。驯化过程带来了诸如种子大小和脱粒性等农艺性状的出现。对于20个驯化大麦（Hordeum vulgare）品系的代表性样本，包括13个二棱和7个六棱品种，我们确定了7个位点（Adh2、Adh3、Amy1、Dhn9、GAPDH、PEPC和WAXY）的单倍型，每个品系包含5616个碱基，并将它们与在新月沃地内外收集的25个野生型（Hordeum spontaneum）相同位点的单倍型进行比较。在野生大麦与驯化大麦的比较中，驯化品系的单倍型数量（70对17）、平均核苷酸多样性π（0.0077对0.0028）以及沉默位点的Watterson's θ（0.0104对0.0028）均有所降低。两个位点Amy1和PEPC在驯化品系中是单态的；Amy1和GAPDH产生了显著的Tajima's D值。在GAPDH位点，由于高频单倍型的差异，驯化品系的π略高于野生型；对于其余6个位点，驯化型中87%的核苷酸多样性已经丧失。在驯化过程中、随后的育种过程中或两者兼有的作用于中性进化位点的瓶颈效应，足以解释多样性的降低和Tajima检验的结果，而无需在这些位点上进行选择。系统发育网络数据揭示了不同的野生和驯化大麦基因型，并表明大麦可能是在约旦河谷驯化的。因为基于AFLP数据，驯化的土耳其品种具有与大型种质库中一样大的遗传基础，所以本文提供的所有比较具有普遍价值，而不仅仅局限于土耳其大麦种质。
