假基因的组成、分布及其分子进化

假基因（pseudogene）是指基因组中与正常基因序列相似,但是缺乏功能的DNA序列.通过序列同源性搜索,可以收集基因组中假基因的群体特性、染色体分布和同源家族等特性.假基因很好地保留了数百万年前基因组中祖先基因的分子记录,被视为＂基因化石＂,因此假基因在进化和比较基因组学中是重要的资源.应用假基因和基因比较体系,可以探究生物基因的进化史和基因组稳定性.如：用Ka/Ks比值确定假基因的自然选择压、物种亲缘关系和进化距离,分析假基因自身的进化趋势,探讨DNA突变的成因等.

Composition and Distribution of Pseudogenes and Their Molecular Evolution

Pseudogenes are sequences of genomic DNA with such similarity to functional genes that they are regarded as nonfunctional copies or close relatives of genes. Homology search of genomic DNA can reveal pseudogene sequences, and some properties of pseudogenes such as population, distribution, and homology family can be examined. Pseudogenes are important resources in evolu- tionary and comparative genomics and are considered gene fossils, because they provide molecular records of the ancient genes that existed in the genome millions of years ago. Comparison of genes and pseudogenes offers new insights into the evolutionary history of genes and the stability of the genome as a whole, for example, the determination of the natural selection pressure of pseudogenes with Ka/Ks, the relation and the evolutionary distance between species and tendency of pseudogenes and the origin of DNA mutation.