Facing to the fact above, this dissertation will use EM algorithm to estimate parameters, to construct a fine phylogenetic tree of the sequences which have the same length after deletions and insertions.

• 针对这种事实，本篇论文将使用EM算法对存在插入和缺失但序列长度假设不变的观测序列构建系统发育树进行参数估计，以为含缺损数据的序列构建良好的系统发育树。