Studies on the evolution of gene families such as those coding for CHS, trypsin inhibitor, etc. The studies have found that CHS genes in most plant families could be classified into two groups based on their base substitution rates. One group has fast rates and the other group has relatively low rates. It has also been found that the gymnosperm plants have few copies of CHS gene in a particular nuclear genome, but copy number varies greatly in the angiosperm plants. About 10 genes are found in the rice genome encoding Bowman Birk trypsin inhibitor. The phylogenetic analysis and sequence comparison of the 5’ and 3’ UTR showed that the genes with three-repeat structure evolved from the genes with two-repeat structure. Further analysis showed that the second repeat in the genes has been under the positive selection. The function of the 10 genes is under investigation now. Many factors can cause plant population to diverge. A recent study by this research team on the plant populations separated by the Great Wall of China has showed that the subpopulations along two sides of the Wall were significantly differentiated genetically. The research group has also collected about 30 natural populations of Arabidopsis thaliana from about 10 provinces of China, and the studies on the genetic diversity and phylogentic trees revealed that most of the Chinese populations formed a monophyletic group and their distribution in China may be resulted from one founder effect. The analysis on the transcription profiles of different populations under stress treatments showed significant differences among populations and it may be correlated with environmental factors to which they have been adapted. Further studies on the possible molecular mechanisms will be the main focus.