以谷子和玉米为研究对象，基于比较基因组学，利用改进的基因同源共线性方法对其基因组结构和基因同源信息进行比对分析，确定了物种基因组加倍的规模和加倍后的进化规律。结果表明：谷子中有3846对（10.9％）、玉米中有6016对（18.5％）由多倍化产生的重复基因，它们之间的直系同源基因对为13652对；通过同源共线基因间的同义核苷酸置换率分析证实，玉米与谷子不仅共同经历了一次古老的全基因组加倍，而且在约12个百万年前玉米独立发生了一次较近的全基因组加倍；加倍后产生的大量重复基因片段常分布在染色体末端；基因组进化分析发现，玉米基因组进化速率比谷子快1/14。%Based on the comparative genomics and the improved homologous gene collinearity method ,the genomic structure and gene homology information of C4 plant Setaria italica and Zea mays were comparatively analyzed in order to determine the doubled scale of genomes and the evolution law of polyploidy .The result showed that 3 846 pairs of paralogs (10.9% ) in Setaria italica genome and 6 016 pairs of paralogs (18.5% ) in Zea mays genome were generated by whole-genome duplication(WGD) ,and 13 652 pairs of orthologs were identified between them . The analysis of synonymous nucleotide substitution rate between homologous colinear genes indicated that Zea mays and Setaria italica shared an ancient WGD ,and a maize-specific WGD event occurred 12 million years ago .The duplicated genes often distributed near the ends of chromosomes .The analysis of genome evolution showed that the gene evolution rate was 1/14 faster in Zea mays than in Setaria italica .
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