The GHEP-ISFG organized a collaborative study to estimate mutation rates for the markers included in the
Investigator Argus X-12 QS kit Qiagen. A total of 16 laboratories gathered data from 1,612 father/mother/
daughter trios, which were used to estimate both maternal and paternal mutation rates, when pooled together
with other already published data. Data on fathers and mothers’ age at the time of birth of the daughter were also
available for ∼93 % of the cases. Population analyses were computed considering the genetic information of a
subset of 1,327 unrelated daughters, corresponding to 2,654 haplotypes from residents in several regions of five
countries: Argentina, Brazil, Ecuador, Portugal and Spain. Genetic differentiation analyses between the population
samples from the same country did not reveal signs of significant stratification, although results from
Hardy-Weinberg and linkage disequilibrium tests indicated the need of larger studies for Ecuador and Brazilian
populations. The high genetic diversity of the markers resulted in a large number of haplotype combinations,
showing the need of huge databases for reliable estimates of their frequencies.
It should also be noted the high number of new alleles found, many of them not included in the allelic ladders
provided with the kit, as very diverse populations were analyzed. The overall estimates for locus specific average
mutation rates varied between 7.5E-04 (for DXS7423) and 1.1E-02 (for DXS10135), the latter being a troublesome
figure for kinship analyses. Most of the found mutations (∼92 %) are compatible with the gain or loss of a single
repeat. Paternal mutation rates showed to be 5.2 times higher than maternal ones. We also found that older fathers
were more prone to transmit mutated alleles, having this trend not been observed in the case of the mothers.