甘蔗属及其近缘属种的rbcL基因序列变异和系统发育初步研究

甘蔗属及其近缘属种在分类关系上非常复杂,存在不少混乱,目前关于它们的分类学研究主要是基于形态学和同工酶水平,而基因水平上的报道很少,我们对甘蔗属及其近缘的属种的部分rbcL基因片段（1137bp)进行了测序比较,以期探讨rbcL基因能否用于研究甘蔗属及其近缘种之间的亲缘关系,序列比较显示rbcL基因在甘蔗属和近缘属种间的变异极低,一些来自不同属的个体序列完全一致,而某些同属内不同种个体却略有差异。这些结果表明rbcL基因在甘蔗属及其近缘属种之间的进化速率缓慢而不稳定,难以用于系统发育研究,不过,不同聚类方法都将斑茅与其它属种分开,放在玉米与甘蔗属和其他近缘属种分枝的外部,提示斑茅不应列入甘蔗属或蔗茅属,而应独立为一属。

Sequence Variation of rbcL Gene and Evolution of Saccharum and Related Species

Partial rbcL gene segments (1137bp) were sequenced in species from Saccharum and its related species,including one Arundinaceum and one Pennisetum purpureum sample Sequence variation of rbcL gene in Saccharum and related species were found to be highly conservative,and identical sequences were presented between Saccharum and Miscanthus ,and Narenga and Miscanthus ,while sequences of some individuals from same genus had some variation The results suggest that rbcL gene is not a good genetic marker for the phylogenetic study of Saccharum and related species Based on the facts that a relatively large sequence divergence exists between Arundinaceum and individuals from Saccharum or Erianthus ,and the similar phylogenetic position of Arundinaceum in the gene trees that fall out of the clade of "Saccharastrae"that considered,we tentatively suggested that Arundinaceum should be in an independent genus rather than being included in Saccharum or in Erianthus