分子进化研究中多重突变的校正方法  

Correction Methods of Multiple Mutations in Biological Molecular Evolution

作　　者：李可群[1] LI Kequn(School of Chemical Science and Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学化学科学与工程学院,上海200092

出　　处：《安庆师范大学学报（自然科学版）》2020年第4期52-55,共4页Journal of Anqing Normal University(Natural Science Edition)

摘　　要：利用泊松分布的可加性证明了对于进化路径上进化速率发生变化和存在位点突变速率差异的核苷酸和蛋白质序列分子,它们发生的突变均可用单一的泊松分布来准确描述。从理论上推导出了蛋白质和核苷酸序列分子经回复突变和平行突变校正后的物种分歧时间计算公式,同源蛋白质序列分子比较时需校正的回复突变率和平行突变率之和为其序列差异率的1/10,而对于转换突变率比颠换突变率大较多的同源核苷酸序列分子比较时,需校正的回复突变率和平行突变率之和为其序列差异率的1/2。蛋白质和核苷酸序列分子的最大遗传距离分别约为2.3和0.7。It was proved that mutations of nucleotide and protein sequences with variable mutation rates on their evolutionary path and with different site mutation rates can be described precisely by a single Poisson distribution by using additivity of Poisson distributions.In addition,calculation equations for taxa divergence times of protein and nucleotide sequences after back mutation and parallel mutation correction were deduced theoretically.Our work also revealed that total back mutation and parallel mutation ratio of homologous protein sequences,which needs to be corrected,is 1/10 of their sequence divergence ratio.The total back mutation and parallel mutation ratio of homologous nucleotide sequences which needs to be corrected is 1/2 of mutation ratio of their sequence divergence ratio when transition rate is much larger than transversion rate.At above situations,the maximum genetic distances of protein and nucleotide sequences are about 2.3 and 0.7,respectively.

关 键 词：分子进化 多重突变 回复突变 平行突变 校正方法 

分 类 号：Q343.1[生物学—遗传学] Q111