Variation in chloroplast microsatellite loci among wild and cultivated species of Emmer wheat

栽培二粒小麦(Triticum dicoccum Schubl.)起源于其野生祖先(T.dicoccoides Korn.)大约八千年前，在肥沃的新月会的某个地方被驯化。为探讨栽培二粒小麦的起源，以100份二粒小麦和72份二粒小麦为材料，对其叶绿体基因组8个微卫星座位的等位基因多样性进行了研究。参考文献分析了5份古卷曲霉属、2份硬粒卷蛾种质和1份普通卷叶卷蛾、卡氏卷叶卷蛾、伊斯帕哈尼姆卷蛾、波罗尼卷叶卷蛾和土耳其卷叶卷蛾各1份。用聚合酶链式反应和聚丙烯酰胺凝胶电泳法测定每个基因座的重复数，在8个基因座中有7个获得了多态性条带。多态微卫星每个座位的等位基因数在2~5个之间，平均2.92个。对每个物种内每个基因座的等位基因多样性进行了估算。二粒盾壳的平均等位基因多样性(0.349)约为其等位基因多样性(0.109)的3.2倍。二粒小麦和所有参考材料中有一种与中国春小麦相同，占品种总数的80%。而栽培小麦的这一主要体型仅在西北肥沃新月区的一个地区收集到的6份双胞胎小麦材料中得到鉴定。除了这个主要的母系谱系外，我们还鉴定了从野生二粒小麦到栽培二粒小麦的一个次要血统。这些结果表明，栽培的二粒小麦中至少存在两个母系，并且以质型为主的二粒小麦的驯化发生在西北可育新月区。

It is generally accepted that cultivated Emmer wheat (Triticum dicoccum Schubl.) originated from its wild ancestor (T.dicoccoides Korn.) by domestication about eight thousand years ago, somewhere in the Fertile Crescent. To study the origin of the cultivated Emmer wheat, allelic diversity in eight microsatellite loci of the chloroplast genome was investigated using 100 accessions of T.dicoccum and 72 accessions of T.dicoccoides. Five accessions of=T.paleocolchicum Men., two of T.durum L.and one each of T.aestivum L., T.carthlicum Nevski, T.ispahanicum Heslot, T.polonicum L.and T.turgidum L.were analyzed as references. The number of repeats in each locus was determined using PCR followed by PAGE.Polymorphic band patterns were obtained at seven out of the eight loci. As for the polymorphic microsatellites, the number of alleles per locus ranged from two to five with an average of 2.92. Nei's allelic diversity was estimated for each locus within each species. The average allelic diversity of T.dicoccoides (0.349) was about 3.2 times larger than that of T.dicoccum (0.109). One plastotype representing 80 % of the T.dicoccum accession and all accessions of references was identical to that of T.aestivum cv Chinese Spring. Whereas this major plastotype of the cultivated wheat was identified only in six T.dicoccoides accessions collected in one region in the north western Fertile Crescent. In addition to this major maternal lineage, we have identified a minor lineage from the wild Emmer to the cultivated Emmer wheat. These results suggest that there are at least two maternal lineages in cultivated Emmer wheat, and that the domestication of Emmer wheat with the major plastotype occurred in the north western Fertile Crescent.