National Y-STR Haplotype Database

Y-STR loci, unlike traditional STR markers, are not independent of one another and are co-inherited as extended haplotypes of linked markers. Haplotype frequencies are required to provide a statistical estimate of the significance of a match. The estimation of the frequency of occurrence of a particular Y-STR haplotype necessitates the use of a counting method, which is entirely dependent upon the size of the database used. Therefore, the establishment of a comprehensive national Y-STR reference database is essential to facilitate the generation of reliable estimates of Y-STR haplotype frequencies. A US Y-STR Haplotype Reference Database was created by the International Forensic Y-User Group and is maintained by the Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany. However, this database is limited to a set of 9 core Y-STR which sometimes limits is operational usefulness, particularly in light of the development of Y-STR multiplexes consisting of additional Y-STR loci.

NCFS has designed and developed a comprehensive, and soon to be on-line, Y-STR database. The intention is to type all known forensically useful Y-STR markers for geographically and ethnically diverse populations. Initially the database records comprise data generated in the NCFS laboratories based upon a 49 Y-STR locus extended haplotype. Although some (unpublished) data exists for some of these loci in US populations it is not readily accessible to the crime laboratory community and usually does not contain 'extended' haplotype data due to the technological restraints of the systems employed by the investigators. A key component of the strategy is to allow for the continuous updating of haplotype data using the same samples. This ensures that as new markers are developed the same samples would be re-typed by NCFS and a new extended haplotype developed. Thus, any laboratory needing haplotype data for any combination of Y-STR markers would be served. NCFS is enlisting the aid of geographically diverse crime laboratories to obtain the necessary samples. In exchange for the samples the crime laboratory benefits by obtaining, at no cost, a custom built local Y-STR database.

For More Information

Jack Ballantyne
Department of Chemistry, CH 117
University of Central Florida
Orlando, FL 32816
Telephone: 407-823-0163
FAX: 407-823-2252
E-Mail: jballant@mail.ucf.edu