中文摘要：

Z曲线是DNA序列信息的一种几何学表示形式。利用Z曲线坐标所对应的生物学含义，可以对DNA序列的生物信息进行系统分析。本文对40株自测序和从GenBank下载的新城疫病毒（NDV）全基因组序列，利用网络提供和自开发的Z曲线分析系统，对NDV生物信息进行了比较分析，构建了NDV全基因组的X、Y、Z分量沿序列的分布曲线和三维Z曲线，比较了不同基因型NDV基因组Z曲线的特征。结果显示，在NDV全基因组中A、G碱基或A、C碱基是占优势的，在基因组的前1／3序列中，G、C含量大于A、T的含量。不同基因型NDV全基因组的Z曲线（从ClassI到Classll的I-VIII型）有向Z轴靠拢的趋势。

英文摘要：

The Z curve is a geometrical tool available for visualizing and comparing genomes.Since the coordinates of the Z curve corresponding to special biological information,DNA sequences could be analyzed systematically.In the present investigation,40 complete genomes of Newcastle disease virus（NDV） were retrieved from GeneBank,including one isolate ZJ1 sequenced by our laboratory.With some free software available from the web and the Z curve analyze system developed ourselves,the 40 genomes of NDV were compared.We construct the distribution curve of independent component X,Y and Z axes,respectively,and the 3-dimensional Z curve of NDV genome.Different genotypes of NDV genome were also compared to study the characteristics of their Z curves.It was found that A and G/C made the predominant base composition of the NDV genome.In the first one third part of the genome,the content of G and C was more than the other two.Data also showed that the Z curves of different genotypes of NDV,from class I to class II（from I to VIII）,have a tendency to get more and more close to the Z axis.