[Observation and analysis on mutation of routine STR locus].

OBJECTIVE: To observe and analyze the characteristic of mutation at STR locus. METHODS: 27 mutant genes observed in 1211 paternity testing cases were checked by PAGE-silver stained and PowerPlex 16 System Kit and validated by sequencing. RESULTS: Mutant genes locate on 15 loci. The pattern of mutation was accord with stepwise mutation model. The mutation ratio of male-to-female was 8:1 and correlated to the age of father. CONCLUSION: Mutation rate is correlated to the geometric mean of the number of homogeneous repeats of locus. The higher the mean, the higher the mutation rate. These loci are not so appropriate for use in paternity testing.