Evolution of the high molecular weight glutenin loci of the A, B, D, and G genomes of wheat
Evolution of the high molecular weight glutenin loci of the A, B, D, and G genomes of wheat
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DOI：
10.1139/gen-42-2-296
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发表时间：
1999-04-01
期刊：
影响因子：
3.1
通讯作者：
Brown, TA
中科院分区：
文献类型：
--
作者：
Allaby, RC;Banerjee, M;Brown, TA
我们利用聚合酶链式反应从小麦的高分子量谷蛋白基因中获得了系统发育信息序列。通过对12个已发表的麦谷蛋白等位基因序列的部分比对构建相邻连接树，证实了部分序列比对作为研究谷蛋白系统发育的一种手段的有效性。然后利用聚合酶链式反应从小麦和山羊草属的不同物种中获得了20个新的麦谷蛋白等位基因序列，其中包括一个3000年前保存的小麦。从所有已知的麦谷蛋白等位基因序列衍生的邻接连接树有八个分支，代表从其获得等位基因序列的八个座位，并被分成两半，一个包括来自Glu-1-1座位的等位基因，另一个包括Glu-1-2等位基因。该拓扑结构与假设的A、B、D和G基因组之间的关系是一致的。Glu基因复制事件初步确定为720万-1000万年前(MYA)，四个基因组起源于5.0-6.9MYA，B和G基因组的分裂发生在2.5-3.5MYA。栽培小麦中的Glu-B1-1等位基因分为两个亚群，分别为1.4-2.0MYA，表明二聚体经过两次驯化。D等位基因序列差异较大，表明导致六倍体面包小麦的杂交事件可能发生了不止一次。
We used PCR to obtain phylogenetically informative sequences from the high molecular weight glutenin genes of wheat. The validity of partial sequence comparisons as a means of studying glutenin phylogenetics was established by constructing neighbour-joining trees from partial alignments of 12 published glutenin allele sequences. PCR was then used to obtain 20 novel glutenin allele sequences from various Triticum and Aegilops species, including a 3000 year old preserved wheat. A neighbour-joining tree derived from all known glutenin allele sequences had eight clades, representing the eight loci from which the allele sequences were derived, and was split into two halves, one comprising alleles from the Glu-1-1 loci and the other comprising Glu-1-2 alleles. The topology was compatible with the postulated relationships between the A, B, D, and G genomes. The Glu gene duplication event was tentatively dated at 7.2-10.0 million years ago (MYA), the origin of the four genomes at 5.0-6.9 MYA, and the split between the B and G genomes at 2.5-3.5 MYA. The Glu-B1-1 alleles in cultivated wheats fell into two subgroups that diverged 1.4-2.0 MYA, suggesting that emmer was domesticated twice. The D allele sequences were relatively diverse, indicating that the hybridization event that resulted in the hexaploid bread wheats might have occurred more than once.