摘要
mRNA 3′端的多聚腺苷酸化是真核细胞内mRNA转录后处理的三个最主要步骤之一.对DNA序列上发生多聚腺苷酸化的位置即PolyA位点的识别,对于理解mRNA的形成机制以及进行基因结构预测具有重要作用.本研究利用机器学习方法对PolyA位点进行预测,其实现过程分为以下三个步骤:特征的生成、特征的筛选、特征的综合分析聚类.首先,我们采取统计k阶核苷酸频率的方法来生成初始的特征;然后,通过信息学知识来对特征进行筛选;最后,使用SVM(Support Vector Machines,支持向量机)的方法进行特征的综合分析,确定参数,建立预测模型.在独立的测试数据集上进行测试,当敏感度(Sn)固定为60%时,在内含子水平和外显子水平上的特异性(Sp)分别为71.67%和80.77%,在内含子水平上的预测精度明显优于国际上的同类软件.
Polyadenylation (PolyA) occurs in mRNA 3'end is one of the three main steps of eukaryotic pre-mRNA processing. The prediction of polyadenylation sites in human DNA and mRNA sequences is very important for realizing the pre-mRNA processing and prediction of gene structure. This paper presents a machine learning method to predict polyadenylation signals (PASes) in human DNA and mRNA sequences. This method consists of three steps of feature manipulation: Generation, selection and integration of features. In the first step, new features are generated using k-gram nucleotide acid patterns. In the second step, a number of important features are selected by an entropy-based algorithm. In the third step, support vector machines are employed to recognize true PASes from a large number of candidates. At last, a mathematic model forms. When the sensitivity is 60%, the corresponding specificity is 71.67% on intron level, and 80.77% on exon level.
出处
《计算机学报》
EI
CSCD
北大核心
2008年第6期927-933,共7页
Chinese Journal of Computers
基金
国家自然科学基金重大研究计划(90608020)
高等学校博士点专项科研基金(20050487037)
"教育部新世纪优秀人才"和"科技部国家科技基础条件平台建设专项"资助~~
关键词
PolyA信号
机器学习
熵
支持向量机
Polyadenylation Signals
machine learning
entropy
support vector machines