白菜类蔬菜Chs基因克隆及分析

Cloning and Analysis of Chs Gene in Cabbage(Brassica rapa) Vegetables

为探讨我国白菜蔬菜的起源及遗传多样性,克隆、测序白菜类蔬菜不同变种的Chs基因序列。结果表明,白菜类蔬菜Chs基因序列没有大于3 bp的插入/缺失,白菜类蔬菜Chs基因是一个非常保守的基因,揭示出白菜类蔬菜之间遗传差异较小,亲缘关系较近。系统发育树将白菜类蔬菜分成2个分支:第1分支包括山东白菜、塌棵菜、雅安白菜、紫菜苔、重庆白菜和伊犁野生油菜,相对较进化;第2分支包括广西菜心、青菜、雅安黄油菜、芜菁和涪陵野生油菜,相对较原始。网状支系分析没有显示明显的星状结构,说明所选材料中没有白菜类蔬菜进化的共同祖先。网状进化式样分析表明供试的白菜类蔬菜间不仅存在树状的进化关系,还存在大量的非树状进化史。研究结果支持白菜起源的"分化起源"假说,认为现代栽培的白菜类蔬菜是由更加原始的祖先进化而来,在白菜类蔬菜进化史上存在较多的网状进化事件。

To explore the DNA polymorphism and evolution of Chs genes in Chinese cabbage vegetables, the Chs DNA sequences from Brassica were cloned and sequenced. By aligning these sequences and analyzing DNA variations in Chs loci, no insertion/deletion more than 3 bp occured in the Chs sequences, indicating a low level of DNA polymorphism in Chinese B. rapa vegetables. A maximum likelihood analysis showed that the B. rapa sequences were separated into two well-supported groups. Clade one included Shandong Chinese cabbage,broadbeaked mustard, Yaan Chinese cabbage, purplepakchoi, Chongqing Chinese cabbage, and Yili wild rapeseed,which were more evolutionary. Clade two included Guangxi floweringcabbage, pakchoi, Yaan Yellow rapeseed,turnip, and Fuling wild rapeseed, which were ancestral types. Median-joining(MJ) network analysis showed that no obvious star like structure was found. It indicated that no common ancestor was found among the B. rapa. A Splits Tree analysis indicated that both tree and reticulate evolution existed among Chinese B. rapa and its related plants. This supported the evolution hypothesis of'Differentiation Origin'model in Chinese cabbage. The modern Chinese cabbage vegetables were evolved from more primitive ancestors. Many reticulate evolution events occured during the evolutionary of Chinese cabbage vegetables.