禾谷类作物的比较基因组研究

 水稻是基因组最小的禾谷类作物,饱和遗传连锁图谱的构建,以及在此基础上开展的标记辅助选择和抗病基因克隆,表明水稻基因组研究已经领先于其他禾谷类作物。比较基因组研究表明：小麦、玉米、高粱、谷子和甘蔗的基因组均可由水稻染色体区段重新排列而成，这些区段上DNA标记的排列顺序在各个种之间保留。各种作物基因组大小的差异可能由于各个区段内基因间重复顺序扩增的程度不同所致。根据这些区段在各种作物染色体的排列顺序，有人提出根据水稻染色体区段排列单个原始禾谷类染色体的设想，为深入研究禾谷类作物的进化遗传提出了全新的思路。禾谷类作物基因组之间的共线性有利于在小基因组内克隆大基因组作物的同源基因，使生物技术在作物育种中发挥更大的作用。

Comparative Analysis of Cereal Genomes

Among cereal crops, rice has the smallest genome. Construction of saturated linkage maps in rice, establishment of marker assisted selection and map based cloning of disease resistance genes show the advancement of rice genome research. Comparative mapping in cereals indicates that genetic maps of wheat, maize, sorghum, foxtail millet and sugarcane can be reconstituted by rice linkage segments, but their gene content and order are conserved. The differences of genome size among cereals may be due to different degrees of repetitive sequence amplification in intergenic regions in different species. Based on the comparison of the organization of linkage segments in different cereal genomes, an ancestral cereal chromosome is proposed which provides a basis for the collation and exploitation of biological information collected separately for these cereals for the past 50 years. The collinearity among cereal crops favors the application of the results of genetic and physical mapping of the small genome cereal rice to map based cloning of interesting genes from large genome relatives. More significant roles can be expected for biotechnology in crop improvement.