A multicenter study has been carried out to characterize 13 polymorphic short tandem repeat (STR) systems located on the male specific part of the human Y chromosome (DYS19, DYS288, DYS385, DYS388, DYS389I/II, DYS390, DYS391, DYS392, DYS393, YCAI, YCAII, YCAIII, DXYS156Y). Amplification parameters and electrophoresis protocols including multiplex approaches were compiled. The typing of non-recombining Y loci with uniparental inheritance requires special attention to population substructuring due to prevalent male lineages. To assess the extent of these subheterogeneities up to 3825 unrelated males were typed in up to 48 population samples for the respective loci. A consistent repeat based nomenclature for most of the loci has been introduced. Moreover we have estimated the average mutation rate for DYS19 in 626 confirmed fatherson pairs as 3.2 x 10(-3) (95% confidence interval limits of 0.00041-0.00677), a value which can also be expected for other Y-STR loci with similar repeat structure. Recommendations are given for the forensic application of a basic set of 7 STRs (DYS19, DYS3891, DYS389II, DYS390, DYS391, DYS392, DYS393) for standard Y-haplotyping in forensic and paternity casework. We recommend further the inclusion of the highly polymorphic bilocal Y-STRs DYS385, YCAII, YCAIII for a nearly complete individualisation of almost any given unrelated male individual. Together, these results suggest that Y-STR loci are useful markers to identify males and male lineages in forensic practice.

Relevant for various areas of human genetics, Y-chromosomal short tandem repeats (Y-STRs) are commonly used for testing close paternal relationships among individuals and populations, and for male lineage identification. However, even the widely used 17-loci Yfiler set cannot resolve individuals and populations completely. Here, 52 centers generated quality-controlled data of 13 rapidly mutating (RM) Y-STRs in 14,644 related and unrelated males from 111 worldwide populations. Strikingly, >99% of the 12,272 unrelated males were completely individualized. Haplotype diversity was extremely high (global: 0.9999985, regional: 0.99836–0.9999988). Haplotype sharing between populations was almost absent except for six (0.05%) of the 12,156 haplotypes. Haplotype sharing within populations was generally rare (0.8% nonunique haplotypes), significantly lower in urban (0.9%) than rural (2.1%) and highest in endogamous groups (14.3%). Analysis of molecular variance revealed 99.98% of variation within populations, 0.018% among populations within groups, and 0.002% among groups. Of the 2,372 newly and 156 previously typed male relative pairs, 29% were differentiated including 27% of the 2,378 father–son pairs. Relative to Yfiler, haplotype diversity was increased in 86% of the populations tested and overall male relative differentiation was raised by 23.5%. Our study demonstrates the value of RM Y-STRs in identifying and separating unrelated and related males and provides a reference database.

The reference database of highly informative Y-chromosomal short tandem repeat (STR) haplotypes (YHRD), available online at http://ystr.charite.de, represents the largest collection of male-speci®c genetic pro®les currently available for European populations. By September 2000, YHRD contained 4688 9-locus (so-called``minimal'') haplotypes, 40% of which have been extended further to include two additional loci. Establishment of YHRD has been facilitated by the joint efforts of 31 forensic and anthropological institutions. All contributing laboratories have agreed to standardize their Y-STR haplotyping protocols and to participate in a quality assurance exercise prior to the inclusion of any data. In view of its collaborative character, and in order to put YHRD to its intended use, viz. the support of forensic caseworkers in their routine decisionmaking process, the database has been made publicly available via the Internet in February 2000. Online searches for complete or partial Y-STR haplotypes from evidentiary or non-probative material can be performed on a non-commercial basis, and yield observed haplotype counts as well as extrapolated population frequency estimates. In addition, the YHRD website provides information about the quality control test, genotyping protocols, haplotype formats and informativity, population genetic analysis, literature references, and a list of contact addresses of the contributing laboratories. #

No abstract

By means of a multicenter study, a large number of males have been characterized for Y-chromosome specific short tandem repeats (STRs) or microsatellites. A complete summary of the allele frequency distributions for these Y-STRs is presented in the Appendix. This manuscript describes in more detail some of the population genetic and evolutionary aspects for a restricted set of seven chromosome Y STRs in a selected number of population samples. For all the chromosome Y STRs markedly different region-specific allele frequency distributions were observed, also when closely related populations were compared. Haplotype analyses using AMOVA showed that when four different European male groups (Germans, Dutch, Swiss, Italians) were compared, less than 10% of the total genetic variability was due to differences between these populations. Nevertheless, these pairwise comparisons revealed significant differences between most population pairs. Assuming a step-wise mutation model and a mutation frequency of 0.21%, it was estimated that chromosome Y STR-based evolutionary lines of descent can be reliably inferred over a time-span of only 1950 generations (or about 49,000 years). This reduces the reliability of the inference of population affinities to a historical, rather than evolutionary time scale. This is best illustrated by the construction of a human evolutionary tree based on chromosome Y STRs in which most of the branches connect in a markedly different way compared with trees based on classical protein polymorphisms and/or mtDNA sequence variation. Thus, the chromosome Y STRs seem to be very useful in comparing closely related populations which cannot probably be separated by e.g. autosomal STRs. However, in order to be used in an evolutionary context they need to be combined with more stable Y-polymorphisms e.g. base-substitutions.