黑麦属种间叶绿体DNA的变异性和种系发生的关系

CHLOROPLAST DNA VARIATION AND PHYLOGENETIC RELATIONSHIP AMONG SECALE SPECIES

为了获得有关黑麦属种间关系、黑麦属与小麦属和山羊草属种系发牛关系的新资料,应用Ban HI等8种限制性核酸内切酶酶解黑麦属5个种的叶绿体DNA,进行琼脂糖凝胶电泳,分析其酶解图谱。结果表明,黑麦属种叶绿体基因组的大小与小麦属和山羊草属的叶绿体基因组非常相似。根据黑麦属5个种遗传距离的估算,并与小麦属和山羊草属已知叶绿体基因组间所观察到的遗传距离相比,黑麦属叶绿体基因组的分化很少;这些资料进一步证实黑麦属的近代起源;并表明黑麦属、小麦属和山羊草属间的亲缘关系是非常密切的。

In order to get new informations on the interspecific relationship in the genus Secale and its phylogenetic relation to two related genera, Triticura and Aegilops, chloroplast(ct) DNAs were purified from five Secale species, and the restriction fragment patterns were analyzed by agarose gel electrophoresis of their BamHI, EcoRI, HindⅢ, KpnI, PstI, SalI, SmaI and XhoI digests The chloroplast genome sizes of all Secale species are very close to those of Triticura and Aegilops.The five Secale species did not show any great differences on the ctDNA restriction fragment patterns with each other. The ctDNAs of all four species, except S. silvestre, produced the identical patterns with the all enzymes, revealing no difference(?) among them (Fig. 1). The ctDNA of S. silvestre, when digested with BamHI, PstI and SinaI, showed one to three fragment differences from those of the other four species (Fig. 2, Fig. 3).The genetic distance between the chloroplast genomes of S. silvestre and the other four Secale species was compared with those observed chloroplast genomes known in Triticum and Aegilops (Fig. 4). From this figure, it is evident that the chloroplast genome diversification in Secale is much less. This fact suggests the recent origin of this genus, as previously indicated by the results of morphological, cytological, ecological and biochemical investigations.The genetic distances between the chloroplast genomes of S. cereale and selected Triticum and Aegilops species were calculated, based on which a dendrogram shown in Fig. 5 was drawn by cluster analysis. It clearly shows that the genus Secale is placed within the range of variation found in Triticum and Aegilops, so far as their chloroplast genomes are concerned.