DNA碱基组成和碱基关联的进化

据ＤＮＡ序列新资料，研究了ＤＮＡ碱基组成和关联与序列进化的关系，进一步证实了关于分子进化信息参数的发现：Ｄ２和Ｘ及其第一子序列的值在粗粒平均的意义下随进化增长，对ＭｙｏｓｉｎＨｅａｖｙＣｈａｉｎ（ＭＨＣ）序列进行了单独的研究，也证实了这个结论，同时研究了信息参数对度的依赖，发现由于碱基组成和关联的漂变造成长序列某些参数值的变小

The Evolution of Base Composition and Base Correlation in DNA Conding Sequences

The relation between base composition and base correlation with sequence evolution is investigated according to the GenBank new data. The result proves the findings in 1988and 1990 on the informational parameters of molecular evolution:the secondary information redundancy D2 in coding sequence and its corresponding quantity in first subsequence Da,the parameter X=D2/D1 D2) and its corresponding X(1) incerase with evolution in the meaning of coarse grain. The data used in this investigation are one-order more than in original analyses in 1988 and 1990. Then,we study thelength dependence of informational parameters and find slight decrease of D1 and D2 in long sequences which may be due to the drift of base composetion and base correlation. To limit the potential bias that may arise secondary to nonuniform evolutionary pressures and differences in nucleotide content between unrelated genes,we make further analysis on the genome of (Type 2) myosin heavy chain family. From the analyses of 37 MHC genes the same conclusion on the evolution of D2 and X is deduced,namely,D2 and X for Pri,Rod,Mam and Vrt are higher than for Inv and Fun. It valids associate evolution of coding and noncoding regions of these genes.