Database and information hub for forensic X-chromosomal markers


Short tandem repeat (STR) markers located on the X chromosome (ChrX) are widely used to solve complex kinship cases, especially when autosomal STRs are not informative. The typical ChrX inheritance (one ChrX in males that is passed on completely to all female offspring and two ChrX copies in females with possible recombination that are passed to both sexes) makes these markers an important genetic tool for population studies and forensic kinship investigations.

The aim of this website is to provide a database of ChrX STRs and ChrX STR haplotypes containing published population data from several countries. However, we do not claim to present a complete literature review. This page only contains data published in peer reviewed scientific journals for which the respective authors are responsible.

In contrast to ChrY markers, which do not recombine during meiosis, the genetic localization is an important issue for autosomal and ChrX markers when used in kinship testing. Since all ChrX markers are located on the same chromosome within an area of 240cM, working with these markers requires exact knowledge about their genetic localization. On this website, genetic location of established forensic markers is displayed on the ChrX STR linkage table and on the ChrX ideogram.

In kinship testing, ChrX STR cluster typing is a powerful tool if the alleles of the linked markers can be assigned to haplotypes. Therefore, we present haplotype frequencies of several populations for selected STR clusters. Please note that markers that are very closely linked regularly show a linkage disequilibrium. Hence, frequencies of haplotypes cannot be calculated by multiplying the frequencies of the alleles involved in the haplotype, but must be determined by population studies.

About us

This website was founded by Reinhard Szibor, Jeanett Edelmann and Sandra Hering

Currently responsible for the scientific content:

Jeanett Edelmann, Institut für Rechtsmedizin, Universität Leipzig, Germany
Christa Augustin, Institut für Rechtsmedizin, Universität Hamburg, Germany

Technical management: qualitype GmbH

We try to operate this website with a high degree of care and scientific responsibility. However, we cannot rule out the possibility of errors. We therefore look forward to hints and comments.

This website only presents already published data of appropriate quality. The responsible persons of the website decide about a publication on this site. The legal process is excluded.


Based on the review of december 2018, it has been decided in cooperation with the X working group to remove the PI calculation from this website.