Spanish and Portuguese-speaking Working Group of the International Society for Forensic Genetics

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Study of mutations in a set of 12 X-STR

Collaborative Exercise GHEP-ISFG

“Study of mutations in a set of 12 X-STRs”

Accordingly with the presented and approved in the General Assembly in the last Meeting in Coimbra, we propose one collaborative exercise for the study of mutation rates in a set of 12 X-STRs.

Main Goals:

The working group has as main objective the study of the mutation rates of the set of X-STRs considered in the commercial kit Investigator Argus X-12 QS – Qiagen, aiming a broader approach than the one that is traditionally performed taking only into account the simple proportioning of the mendelian incompatibilities.

Through analyses of father-mother-daughter trios, and notwithstanding the traditional up-mentioned approach, the working group would try to find a correlation between the rates and type of mutations and the repetitive motif of the sequence, following up preliminary results already obtained for STRs of the Y chromosome.


  1. The data will concern markers from the kit Investigator Argus X-12 QS – Qiagen, analyzed in father-mother-daughter trios in cases where the biological relationship (at least the paternity) is ensured by the analysis of autosomal markers.

NOTE: Aiming to eliminate some of the silent alleles detected with previous versions of the kit, “extra” primers were added to Investigator Argus X-12 QS. For this reason, the laboratories should only send results obtained with the new version of the kit.

  1. The coordinators will send to each one of the laboratories interested in participating one form with the required information and one template to be filled with the obtained genotypic data.
  2. After receiving the data from all the participating laboratories, the coordinators of the exercise assure the statistical treatment and inferences, both per marker and sequence of the repetitive motif.

Requirements for participants

  1. The participants must be GHEP members and have the membership fees up to date.
  2. Participating laboratories should send the certificate of the quality control exercise of GHEP-ISFG, showing the obtaining of correct results for the markers of the kit Investigator Argus X-12 QS – Qiagen. In case laboratories do not have these results they should genotype the samples of the exercise of 2018 (Kinship module, basic level) and send to coordinators the obtained results until March 30, 2018.


Deadline for registration: October 31, 2017

Deadline for submission of the results for the samples of the GHEP-ISFG Exercise 2018 (Kinship module, Basic level) for the kit Investigator Argus X-12 QS – Qiagen: March 30, 2018

Deadline for submission of the genetic profiles: June 31, 2018


- Qiagen showed interest in collaborating on this exercise, providing discounts to participant laboratories in the purchase of the kits Investigator Argus X-12 QS. The amount of the discount will depend on the number of laboratories showing interest in participate.

- Electrophoregrams and/or .fsa files of all runs should be saved as they may be needed to clarify questions that may arise.

- To the publication of results a limit of one author per each 70 trios of genotyped individuals is established, for a maximum of 2 authors per laboratory.

- Authors will be ranked considering the number of analysed trios (by author) and, for laboratories with the same number, by alphabetical order.

Coordinators and contacts:

Nádia Pinto (preferential contact), IPATIMUP/i3S, Porto, Portugal:

Leonor Gusmão, UERJ, Rio de Janeiro, Brazil:

Gabriela Garcia, Manlab, Buenos Aires, Argentina: