Molecular population genetics of wild ancestral species of wheat

利用4-切酶对5种二倍体大麦和2种野生四倍体小麦（T.dicoccoides和t . araratium）叶绿体DNA 5 ~ 6kb区域的限制性内切图谱变异进行了研究。在250多个限制性位点中，仅有7个位点具有多态性。其他二倍体和四倍体种均未发现限制性内切位点多态性。此外，还检测到6个插入/删除多态性，但它们是唯一的或物种特异性的。估计伊蚊的核苷酸多样性（pi: Nei和Li， 1979）为0.0006。所有其他被调查的物种为0.0000。在Ae。在speltoides中，Tajima’s D（1989）的结果均不显著，表明DNA多态性没有明显偏离中性。多态限制性位点之间的10对组合中有3对存在显著的非随机关联。各质体型（质体基因型）之间的系统发育关系表明，双孢霉和花生霉属双种起源。一种Ae的质体型。speltoides的加入与主要类型的t . araratium（包括T.timopheevi）相同。在Sitopsis物种中发现的三种质体型与T.dicoccoides、T.durum和T.aestivum非常相似，但并不完全相同。采用随机核DNA克隆技术，研究了5种海葵属植物Sitopsis切片的限制性内切片段长度多态性。Ae.的多态性水平。Speltoides的种间分化程度与其他四种相同。通过RFLP分析得到的系统发育关系与基于形态学和叶绿体DNA RFLP分析的经典分类结果一致。

Restriction map variation in two 5-6 kb chloroplast DNA regions of five diploid Aegilops species in the section Sitopsis and two wild tetraploid wheats, T.dicoccoides and T.araraticum was investigated with a battery of 4-cutter restriction enzymes. More than 250 restriction sites were scored, of which only seven sites were polymorphic in Ae.speltoides. No restriction site polymorphisms were detected in all the other diploid and tetraploid species. In addition, six insertion/deletion polymorphisms were detected, but they were unique or species-specific. Estimated nucleotide diversity (pi : Nei and Li, 1979) was 0.0006 for Ae.speltoides, and 0.0000 for all the other investigated species. In Ae.speltoides, none of Tajima's D (1989) were significant, indicating no clear deviation from the neutrality of DNA polymorphisms. Significant non-random association was detected for three combinations out of ten possible pairs between polymorphic restriction sites in Ae.speltoides. Phylogenetic relationship among all the plastotypes (Plastid genotype) suggested the diphyletic origin of T.dicoccoides and T.araraticum. A plastotype of one Ae.speltoides accession was identical to the major type of T.araraticum (T.timopheevi inclusively) . Three of the plastotypes found in the Sitopsis species are very similar, but not identical, to that of T.dicoccoides, T.durum and T.aestivum. Restriction fragment length polymorphisms in the five Aegilops species of Sitopsis section were investigated by using random nuclear DNA clones. Level of polymorphism in Ae.speltoides is as high as that of interspecific divergence between the other four species. Phylogenetic relationship obtained by this RFLP analysis agrees with with those of classical taxonomy based on morphology and RFLP analysis on chloroplast DNA.