基于Waxy基因序列的西南地区玉米地方品种的演化

Evolution of Maize Landrace Varieties by Waxy Sequences in Southwest China

以40份西南地区玉米地方品种群体为材料,对Waxy基因第9外显子和第14外显子之间的DNA序列进行测序,将测序得到的40条序列与Gen Bank中来自普通玉米、小颖玉米、墨西哥玉米和二倍体多年生玉米的20条同源序列作比对分析。结果表明,来自西南地区四川、重庆、云南和贵州的玉米地方品种群体分别有180、152、163、164个多态性位点,供试种群遗传多态性指数依次为小颖玉米>四川地方品种>墨西哥玉米>重庆地方品种>二倍体多年生玉米>贵州地方品种>云南地方品种>普通玉米。Tajima’D、Fu and Li’D和Fu and Li’F检验表明,Waxy基因是中性进化基因。比较种群间Waxy基因序列的共有多态性和固有差异,玉米地方品种与墨西哥玉米和二倍体多年生玉米间存在较高的固有差异和较低的共有多态性。Waxy基因的系统演化分析结果表明,小颖玉米、普通玉米和玉米地方品种有相近的遗传关系,小颖玉米是普通玉米和玉米地方品种的共同祖先。

Using 40 maize landrace populations from southwest China as the materials, a portion of Waxy wassequenced. The homologous sequences from 20 samples representing common maize, Z. mays ssp. parviglumis, Z.mays ssp. mexicana, and Z diploperennis from Genbank were downloaded. There were 180, 152, 163 and 164 poly-morphism sites in maize landraces from Sichuan, Chongqing, Yunnan, and Guizhou, respectively. Based on estimates of π per base pair and θ per base pair, the highest level of sequence variation was found in Z. mays ssp.parviglumis, followed in turn by maize landraces from Sichuan, Z. mays ssp. Mexicana, Z diploperennis, landracesfrom Chongqing, landraces from Guizhou, landraces from Yunnan, and common maize. The test of Tajima＇s and Fuand Li＇s D statistic for Waxy gene was not significant in the taxa, suggesting that neutrality cannot be rejected. Incomparison, more fixed differences than shared polymorphisms between maize landraces and both Z. mays ssp. Mexicana and Z diploperennis were found. The genealogical analysis indicated that Z. mays ssp. parviglumis, togetherwith common maize and maize landraces, were genetically not distinct and common maize and maize landraces werederived from Z. mays ssp. parviglumis.