Recent observations in human DNA-minisatellite mutations.

We report maternal and paternal mutation rates at loci D1S7 (MS1), D7S21 (MS31), D12S11 (MS43A), and D7S22 (G3). The respective mutation rates were as follows: [table: see text] At loci D7S21, D12S11, and D7S22 statistically significant differences in mutation rates exist between the sexes. No such difference was observed at locus D1S7. However inspection of the latter data reveals that by mutation at spermiogenesis approximately two-thirds of the fragments showed an addition of repetitive units, while a 50: 50 ratio was encountered in the series of maternal mutations. We also report the observation of naturally occurring 3-fragment patterns.