NCJ Number
248137
Journal
Forensic Science International Genetics Volume: 12 Dated: September 2014 Pages: 12-23
Date Published
September 2014
Length
12 pages
Annotation
Data are presented from the largest collection of Y-chromosomal STR haplotypes worldwide ever conducted.
Abstract
In a worldwide collaborative effort, 19,630 Y chromosomes were sampled from 129 populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat loci. The PowerPlex Y23 kit (PPY23) was used in the project, because it provided higher discriminatory power for forensic purposes than other marker sets. In approximately one-third of the populations studied, each sample could be identified unambiguously, because all haplotypes in the population were unique. Most of the non-unique haplotypes were detected in populations that either passed through a recent bottleneck (e.g., Finland) or that have a high reported degree of endogamy (e.g., Alaskan Natives and Kenya Maasai). The study found a considerable number of null and duplicated alleles that were caused either by non-allelic homologous recombination between paralogous DNA sequences or, in the case of nulls, by deletions or primer site mutations. For all five forensic marker sets studied, samples of African ancestry were clearly separated genetically from all other continental meta-populations. Europe was the most intensively sampled continent in the study, composing approximately 60 percent of the overall sample size. In some cases, relatively large genetic distances were found for pairs of migrant and potential source populations, such as African-Americans and autochthonous Africans. For forensic casework that involves these populations, separate reference databases must be established and used. On the other hand, populations with small genetic distances - such as Western or Eastern Europeans, Arabs from Iraq, and Lebanon or Mestizos from Peru and Bolivia - may be merged into meta-populations for the purpose of reference databases. 4 tables, 6 figures, and 40 references